The quest for the inexpensive small inboard with reverse [Archive]

mike hanyi

07-02-2006, 01:24 PM

I hope this shows some interest.
some years ago I purchased a small double ended traditional finnish boat type called a fiskari (fishermans boat) it is about 15 ft and maybe 5 ft wide, it is more or less a double ended rowboat with an inboard rudder and engine. engine being a B&G 5hp, directly hooked to the propshaft. now soon I will start its rebuild. over the time I started to appreciate the simple and inexpencive nature of this honest boat, its light enough for 2 people to pick it up and move it.the motor is more used for doing longer distances and is maneuvered under oar as there is no way to go slow with the motor.

which brings me to the idea of a cheap transmission for small aircooled engines.

Engine canadates are Honda, B&G, also are small aircooled diesels that seem to be now affordable.
there is no watercooled 5hps out there as there is no demand for them.

The Idea
cheap reversing transmission for small motors.

I will try to work on the concept of the motor mounted on a hinge,
there may be some kind of spring to lift the hinge slightly
the motor is equipped with standard pulley, and a wide collar,
directly under the pulley is another pulley which is on the propshaft, on one of the shafts is also a hard rubber tyre, the other shaft should have a smooth metal wheel to make contact with the tyre when the hinged motor is lowered.

how does it work?
some kind of hand lever lifts the motor and puts tension on the belt=forward
release the lever and the motor sits on the short springs=neutral
no tension on the belt
pressure is applied to the lever and the springs are compressed, the hard rubber tyre is now pressed against the metel wheel=reverse.

this whole idea should be able to be made easily, except for the pulleys,
there will need to be a thrust bearing in a bearing housing, the type that is self aligning, so that alignment between the motor and the prop shaft is no so critical.

also I have seen model airplane propellers used sucessfully on low powered electric motors, it would be easy to use this idea, cheap propellers that come is lots of pitches and sizes.

I am really interested in making several kits for a production run of these cheap simple boats. feedback on this concept would be great.
remember this is to be a cheap plan and not over engineered.

mike

Canoeyawl

07-02-2006, 02:28 PM

http://www.robbwhite.com/rescue.minor.machinery.html

Thorne

07-02-2006, 02:40 PM

Wasn't there a recent thread here about some small German diesel marine engine - probably worth a search.

RonW

07-02-2006, 03:20 PM

I understand simply, cheap, readily available. BUT....

But on the other hand a 5 hp air cooled briggs and straton is the noisiest thing available to the public. Are you going to wear ear plugs.
Then also there is the vibration, and fumes.
Personally I wouldn't care if it got 199 miles to the gallon and only cost a total out lay of $150. to set up.

Sorry to be negative, but some things are not worth it.
A little quiet time on your boat is worth a few xtra dollars.

Tom Robb

07-02-2006, 05:12 PM

How about the transmission from one of Europe's very small cars?
I'd think that the less "Mickey Mouse" the better, and why reinvent the wheel as it were?
But, the boat had no transmission originally. Should you ask yourself why you need one?

Thorne

07-02-2006, 09:26 PM

From what I've heard, forget the aircooled option unless you are (or wish to become) deaf.

For a different motor, and/or possibly a transmission to fit, try this site, click on the Engines link on the left -

http://boatdiesel.com

Vetus and several others have old models listed that are 5hp, Thornycroft has an 11, Volvo has a current 10hp model in production. This was just with a quick look at various manufacturers on this site.

Also, somewhere on the web I've seen pics of a metal shield / housing that can be rotated around the prop to block the propulsion -- not a true reverse but does generate some backward thrust, and allows you to stop forward thrust without killing the motor.

Stu Fyfe

07-02-2006, 09:52 PM

http://www.farymann.de/frames_englisch.htm

One of the few small diesel makers left. I've had two of them 5 1/2 HP and 9 HP. Reliable and easy to work on.

Cuyahoga Chuck

07-02-2006, 10:17 PM

Most small motors have a powerband that is too high in the RPM range to drive a propeller efficiently. They need a gear reduction. That's why your boat was always trying to go so fast. Unfortunately, a suitable gear reduction box can be quite expensive (worth more than your motor) and a little hard to find and a little hard to install.
The motor/transmission setup is ideal because it can be compact and most of the rotating components are safely away from the passengers.
So whatever you create will have to compete with the traditional motor/ transmission. If it requires too much space and endangers the boaters no one will want it.
Airplane propellers are designed to operate in air which has different dynamics that water. While they may push the boat I doubt they will be as efficient as a boat propeller.

mike hanyi

07-02-2006, 10:57 PM

thank you canoeyawl- you were the only good answer out there,
on the comment of "just buy a ferryman" we are talking the difference of 500 dollars verses 3500 dollars,
remember I wanted to come up with a cheap setup

Its the transmission I am interested in, people can choose whatever engine they like, about the reduction its pretty streight forward to use the pulleys as the reduction.
If only I could get a picture of the robb white transmission??

mike

Bradley Stemen

07-03-2006, 07:38 AM

A small, lightweight transmission can be found at

www.olympicgear.com

These 3 speed w/reverse transmissions have been around for over 50 years, used in riding tractors, Crosley autos, factory/airport material handling vehicles, they are bulletproof and are still being made. Find a used one out of a riding mower or Crosley auto and the rebuild parts (if needed) can be had through Olympic Gear.

Brad

openboater

07-03-2006, 09:42 AM

Aircooled engines can be made very very quiet.

Just look and listen to the Honda EU series of generator, These are so quiet....... Look at the technology used in the EU series for quietness.

Rick Starr

07-03-2006, 09:52 AM

The Snapper concept is incredibly simple and works pretty well, and I have always wondered if there was a marine application for it.

http://www.snapper.com/images/discDriveTransmission.jpg

It might need a vertical shaft motor, but that might carry hidden blessings in terms of mounting and removal. More about Snapper mowers on the web, principally here:

http://www.snapper.com/rear_engine_riders.html

mike hanyi

07-03-2006, 04:09 PM

thanks people- I started doing some hunting for the troybilt setup- If someone knows an exact location many thanks, the snapper idea is worth looking at also, as the world is just full of used lawnmower motors, if people only changed the oil every year B&G,s would last forever.

mike

P.I. Stazzer-Newt

07-03-2006, 04:28 PM

The infinte improbability drive.
http://www.classic-daf.nl/images/vario2.jpg

Paul Pless

07-03-2006, 04:50 PM

Have you visited this sight?

http://www.oldmarineengine.com/index.html

Philip Maynard

07-03-2006, 06:54 PM

I have a direct drive 5HP in a 15'-8" sailboat. It is not quiet but I would not call it real loud either but I would like to find a better muffler for it, I am using a small tractor muffler but that really was not much better than a small B&S muffler I originally purchased for it. Once I adjusted the governor it has a little wider speed range, I naturally would like reverse but would not think the increase in complexity is worth it. The EU generators are not very helpfull in terms of adapting what they are doing for general aircooled engines - I see they are "totally enclosed" which must help make them quiet because I think a surprising amount of the noise is mechanical - does anyone know of a quiet in-line muffler with say 1/2 to 3/4" fittings for 5HP?

openboater

07-03-2006, 09:05 PM

a nice little write up of various propulsion systems. Maybe something here will help the creative juices flow

http://www.dieselduck.ca/machinery_page/propulsion_layout/propulsion_layout.htm

I thing one of the easiest is a small gas motor running a large alternator that then converts to DC that runs an electric motor to tun the prop. easy to make go forward and backward and run at different speeds, something a mechanical setup has problems with.

Or possibly a combination system, the 5hp gas for forward, and a cheap trolling motor for maneuvering around the dock. But your oars are cheaper.

Cuyahoga Chuck

07-04-2006, 12:27 PM

"a small gas motor running a large alternator that then converts to DC that runs an electric motor to turn the prop"

Easy? In the confines of a 15' sailboat? It would certainly do away with any need for ballast.

PeterSibley

07-04-2006, 07:11 PM

openboater

07-04-2006, 08:44 PM

Chuck, I think you might find it smaller than you think. The motor alternator can be put anywhere in the boat,just run cables from alternator to motor. and since he already has a 5hp in the boat, that part of the package is the same with the addidtion of a 100 amp truck / car alternator. when I said large I meant in output not size. Simple rectifier to go from ac to dc.

The electric motor of 2 hp is about the size of a 1 gallon jug. that mates up to the prop shaft with a small and easy to build reduction belt drive. forward nuetral and reverse consists of a switch. gas motor is measured in peaking hp and electric is measured in continous, that's why a smaller electric is the same as a larger gas.

it's just that sometimes you can make things simpler by making things seem more complex, but really they are simpler.

making all these mechanical gizmo's plus a clutch, and forward neutral and reverse with belts, somebody's gonna start loosing fingers and toes if they aren't careful.

Cuyahoga Chuck

07-06-2006, 10:17 PM

geeman

07-06-2006, 10:49 PM

How about possibly a 12 hp B&S lawn tractor motor.More power,your transmission is there(reduced) maybe drop the exhuast in the water ?I've heard its being done.Change the gearing in the tranny to get the prop speed closer to what you want?Just thinking out loud here.The biggest problem I see here would be closing in the air cooled motor too much to suppress noise and smothering the engine to where it cant get enough cool air.With this set up you also get a charging system for running electronics.

mcdenny

07-06-2006, 11:04 PM

I've done a lot of web searching for a small marine motor and have not been able to find anything "marine" other than expensive yanmar diesel engines.

There is no more economical marine drive than an outboard motor for lower horsepower needs. The trick is packaging it so it doesn't spoil the looks of a traditional boat. Maybe you could mount a short shaft engine is a well and perhaps still steer with the rudder. A lot of extra space is needed to accomodate the tilting function but if you were happy with the inboard maybe you could forgo the tilt feature.

A brand new 8hp Yamaha 4 stroke OB is only $1500. 5 hp Tohatsu is $1100. What, maybe 10 minutes of labor to install? Works good and easy to resell if you change your mind. Hard to beat that.

George Ray

07-07-2006, 06:15 AM

Look at the scooter market.
Several SMALL fluid cooled engines with transmissions.

Honda =>Rukus:
Aprilia => ?models?:

The aprilia engine is apparently very sopisticated but I can't speak to any details.
***************

Paul G.

07-08-2006, 06:20 AM

Jay Greer

07-08-2006, 03:21 PM

There are two tiny two cylinder two cycle marine engines on the market. The "Vire" built in Finland and the Dolphin, made in England.
Both engines weigh about 120 lbs, including the reverse gear and put out 12hp. I have installed the Vire in one Danish double ender and it is more than adequite to power the little 23 footer. How ever, the engine has an aluminum manifold that requires a heat exchanger in order to prevent electrolosys. My prefrence would be for the English Dolfin as it is built of cast iron.
http://www.fairwaysmarine.com/vire/index.asp
http://www.dolphinengines.co.uk/
JG

merlinron

07-08-2006, 06:17 PM

what about the hydrostatic drives that are used in riding lawn mowers. has anyone ever tried one?
they all have infinite speed, neutral and reverse. most have a fan built onto them for cooling and i would think they would work with electric or int. combustion power sources.
possibly, they might be a bit slow at the axle, but some of that can be sped up with a different size pulley on the input shaft and on the motor. the guys that race riding mowers speed up the living daylights out of them and they don't have any problems with them. i do know that they replace the standard oil with synthetic because of heat break down from the mineral based oils normally used. that, and small horizontal honda from a push mower might make an easily built, quiet drive for a small sailboat or launch.
i have been thinking of looking into that for my boat, i already have the hydro unit. i just don't know if i want all the drag from the prop being in the water all the time, vrs using a trolling motor. if a guy could get a small folding prop, that didn't cost an arm and a leg, i think it would be ideal, at least for my purpose of just getting to and away from the dock.
if you wanted to get really fancy, you could remove the unused side of the drive axle at the differential, cut/machine the corresponding axle housing off and cap it. with that removed, you could mount the motor lower in front of the hydro unit and jack-shaft the belt drive back up to the top of the hydro unit, where the input shaft usually is.
there are also horizontal input shaft types, from club cadet shaft drive riders, these actually have the axles housing bolted to the differential, which would make removing the unused axle and capping the dififferential a snap. you could then use a horizontal output power source and make i neat compact drive unit.
this could actually be done with any of the gear drive differentials from older riding mowers as well..... there's tons of both types laying around in junk yards.

merlinron

07-08-2006, 06:39 PM

i just thought of another way....
there are snowmobiles that have tiny reversing gear boxes, with a neutral station as well. snowmobile drive systems are pretty highly stressed,pretty much, constant drag, expotential to speed. i would think one of these might be rugged enough able to survive a marine application. could be used direct drive, in-line with the motor and the prop shaft.

Cuyahoga Chuck

07-08-2006, 09:17 PM

Most of the tractors that feature hydrostatic drive are the upscale moderls which feature fairly large motors. Even if it would work it would not be cheap.
I have an old 11HP lawn tractor with 5 forward and one reverse speed. They can probably be had quite cheaply but, I wouldn't call it very compact. It has an axle coming out of each end of the transmission. And there is a question of proper lubrication if the unit had tobe oriented differently than it was in the tractor.

geeman

07-09-2006, 06:01 AM

No need to change the engine orientation,move the tranny closer to the motor pully using a smaller belt I think the tranny wouldnt be a problem.I've got a 12 hp tractor motor in my shop I've been experimenting with along the lines you are talking about.I believe the tractor motor concept is very doable.It sounds weird because we tend to think in conventional terms.We need to start thinking outside the box now days .Remember ,no alternator needed with that set up too.

merlinron

07-09-2006, 09:12 AM

upscale models, i don't know about that, my hydro unit came out of 15 year old craftsman( crapsman) 11 hp. rider.just about the lowest scale rider you can buy.most all of even the lower power riders could be had in hydro or ger drive, so it's just a choice, there.becuse of the inclination of the drive, i would think a hydro unit would eliminate the possibilities of lubrication problems. the hydro differential is about the same size as a football, with the axle housings hanging off each side. elimination of one axle housing makes it about 18 inches long total, 12 of that being the axle housing that woud be in line with the prop shaft. that's not too big, i would think. i don't think orientation would be a problem, most marine drives aren't much more that 15 degrees inclined, i have almost a half acre of my yard on slightly more slope than that and i never had a problem with the hydrounit starving out.
most riders do have bigger moters, granted, but it's not for moving the mower, that doesn't take a bunch of power, the bigger motor is for swinging the blades.the hydro unit doesn't know how big a motor it's attatched to, it just changes the direction of whatever torque is applied to it at whatever reduction ratio is designed into the hydraulic transfer.
setting it up for a sail drive would simply mean changing the axle orientation from being at right angle to the drive belt line (as it is in a riding mower) to being in line (or parallel) to the belt drive line.
eliminating one axle side would allow the drive unit to be moved closer, by the length of eliminated axle, to the power source, using shorter belts. with the axle eliminated, the power source (a verticle shaft lawnmower motor of any hp. rating chosen) could be lowered in front of the drive unit and a jack shaft could be inserted between the hydro unit and the power source to transfer the belt drive back up to the top of the unit..... the pto on the motor is on the bottom.... belt to bottom pully on jack shaft,positioned verticaly, between motor and hydro unit... belt from top pully of jack shaft to input shaft/pully on hydro unit. the entire drive unit could be fastened to a fabricated frame of angle and plate that positions the motor, jack shaft and hydrounit in the proper location to each other, then mounted to bed rails in the boat. i would think entire unit wouldn't be any bulkier than any other drive beng concocted here. the length of the axle housing can't be included in the overall size of the drive unit, because it is in line with the prop shaft and only would take up some of the space of a normal prop shaft, the shaft being shorter by the length of the axle housing.

geeman

07-09-2006, 11:06 AM

We're so caught up on what is "boaty" we dont take a close look at what can be done.A motor set up like that could be run all day long high rpm, tractor motors like high rpm's btw.on a couple of gal's of gas.Not just sail boats,but about any reasonable size boat.Parts are easy to get,and not expensive,,,,,,

Cuyahoga Chuck

07-09-2006, 01:18 PM

"The quest for the inexpensive small inboard with reverse "
This is where we started and I think we are hung up on what "inexpensive" means.
A small 1960's era outboard with enough refurbishing to keep it reliable could easily fit into my "inexpensive" catagory. But, I doubt that many of the suggestions made here could come within $500 of said outboard even if you left out the reversing requirement. If the inboard setup required any amount of professional welding and machining the price could soar.
American ingenuity could , probably, produce everything that was mentioned here. It's when you put a pricetag on it that things start going to hell.
I wish Mike luck but, I think he is going to have his hands full for a while and I think the idea of doing it on the cheap will take some readjusting.

Charlie

merlinron

07-09-2006, 06:01 PM

"on the cheap" in relation to what a small commercial inboard drive costs would be pretty easy to do, i think that's the criteria, here. i don't think i'll have anywhere near 500 bucks in a drive like i described. everything but the prop, shaft and stuffing box is readily available at any big box store, mild steel angle and plate is dirt cheap from a salvage yard, hydros can be had from bone yards for 20 bucks and i see small push mowers for sale all over for 25-50 bucks. i guarantee you i could put this together with no machine work beyond a shaft cut to fit the prop to. it could be done without even welding anything if you wanted to. the sahft ,prop and stuffing box might put me in that 500 dollar range, i'll admit... i don't know what that stuff goes for, but it wiil still look better than a 500 dollar outboard hanging off my classic boat.

paladin

07-09-2006, 06:34 PM

re the above comment on the size of electric motors.....I just tossed a motor 5 1/2 inches in diameter and 11 inches long rated at 10 hp at 24 volts........it was a starter motor modified for use with a gatling gun.......so they can be small.....
Transmissions.....think chevy cogged belt drive....will give reduction when the proper pulleys are chosen, also the timing belts for the small 4 banger chevies.....they are strong enough to use with a 225 hp six cylinder buick V6 modified for aircraft use...
mufflers...ain't difficult to make your own, think silencer for 50 cal machine gun....as designed and invented by Hiram Percy Maxim....can be made from stock stainless pipe, and bronze wool packing...put a water jacket on the outside for additional cooling...rig it to a bilge pump for water when the air cooled engine is running...youse guys gott move to china or thailand to see some real innovations..:D

merlinron

07-09-2006, 08:35 PM

yup, if a guy's wprried about slippage with a v-belt, the cog belt's the way to go. only problem with them is that the pullies don't come cheap. they sure can handle the horsepower though. subaru aircraft conversions use cog belts also.... reliable, less friction and heat. essentially, chain could also be used, but would require some guard fabbing to keep lubrication from contaminating everything. chain might be a little less maintenance criticle(?)... maybe chain on the bottom drive (harder to get at, less likely to be inspected) and belt on top for ease of tweeking final hydro drive speed.
i jiust looked at my hydro unit, it's 19.5" outside axle housing to ouside axle housing, with about 4.5" of 3/4" dia. axle stub extending from the ends.one could easily eliminat about 4-5 " of axle housing on one side. the othe side is longer( 10") and about 1.75" in diameter, which would be pointed at the stuffing box, in place of the prop shaft. the end of the axle is just a shoulder with a 3/8" threaded hole for the bolt that holds the wheel hub on. this would easily accept a commonly available flange-type rubber flex coupler that any bearing house would be able to get, they probably would show up in a granger catalog, also.
if, by chance you can't get the hydro unit's final rpm. up to good prop speeds, you could overdrive the prop shaft with another belt drive at the axle. this might allow you to keep the hydro unit inside it's normal operating rpm range,wear and tear wise. there is quite a reduction there... (between input shaft rpm. and axle rpm)..., it probably would still have enough power after overdrive to be efficient enough at the prop.
so far this is all just ideas, but i'm getting more interested....i have to look into these hydrostatic drives by manufacturer's specs and find what rpm range they are supposed to be run at.
paladin,
you wouldn't need to rig an electric pump for cooling water. any small gas engine can be tapped for a tillotson type pulse fuel pump. the go-karts racers do it all the time when they run their 5hp briggs class engines on alchohol with a tillotson carb, they use secondary compression from the crankcase to run the pump.
as for muffling, most of the small engines are actually pretty quiet as soon as you put any length of exhaust pipe on them and get the exhaust pulses organized, as you would routing the exhaust out of a boat's motor well.
china and thialand... yup... the macgivers of the world.

Excalibur

03-30-2007, 02:54 PM

Open,
No engineer here but, I think you are creating energy out of thin air.
A 5 HP gas motor puts out only as much torque as a 1¼ HP electric motor. You couldn't run your generator with a 1¼ HP electric motor and expect it to simultaneously make enough juice to run a 2HP electric motor.
I would think with the expected energy losses from the various conversions involved you would have to start out with a gas motor of 10 HP to generate enough juice to run the 2HP electric motor.
The math to proove this point is beyond me but, I know from past experience that an electrically driven air compressor needs a gas motor that is rated at 4 times more HP to provide the same torque as the original electric.

Charlie

Chuck, I'm not certain where your math is going, but race car battery chargers run by lawnmower engines are a pretty common sight around racetracks. An article on building one can be found here:

http://theepicenter.com/tow02077.html

I'm certain there are others. Also, modern auto alternators usually have rectification and regulation built in, so they are really putting out full wave DC, not AC. You just need a battery (a motorcycle battery will do), to smooth out the waveform. According to Honda, their 2500 watt genset (that is what we are bulding here, of course), uses a 5.5 hp engine. 2500 watts of power ( 208 amps at 12 volts) will drive any most high thrust trolling motor on the market and get that little 15 footer moving.

alkorn

03-30-2007, 03:32 PM

Hoffco-Comet http://www.hoffcocomet.com/comet/index.asp makes a small reversing gearbox for use on gocarts. I don't know what it costs, but I assume it must be fairly cheap. They don't show it on their website, but I heard about it and inquired. They sent me a PDF file which I've posted to http://www.filebox.vt.edu/users/alkorn/FNR.pdf .

I've thought about using this with a small air-cooled engine as an inboard drive. I think it would work. I don't know how long-lived it would be. Go-carts don't run many hours compared to boats, but then again there is a lot more shock loading in driving a wheeled vehicle than in turning a prop.

brian.cunningham

03-30-2007, 06:47 PM

Well, feathering props are great on sailboats.

Why not find one that can be 'reverse feathered' if you catch my drift.
Then you can skip the gearbox.
http://www.varipropusa.com/images/front_03.jpg

Cuyahoga Chuck

03-30-2007, 08:15 PM

Ex,
Charging a battery is done at a low amperage so not much HP is required. And it's much different than running a gas motor to drive a generator that supposed to power the electric motor that drives the screw. That's where this thread was going when I made that comment way back when.
In general, present day electric drives are hostage to heavy batteries. The longer the cruising range desired the bigger the array of batteries that have to be installed. And if you discharge a battery array too severely it takes a lot of time to bring it back. There are some new electric drives on the horizon that have improved motors and improved batteries but they are wildly expensive.
So, electric drives are available for those who can afford them and those that are not in a hurry. Most electric drives have to be kept at 50% power or so if you expect to cover any distance and have enough juice to get home.

leaotis

03-30-2007, 09:06 PM

I found a very small 4.5hp water-cooled ATV engine on a Chinese website. My excitement was short lived when I saw that it idled at 4,000 rpm.

Air cooled engines can be made quiet but only ones with overhead valves.

stef

03-30-2007, 11:24 PM

Cuyahoga Chuck

03-31-2007, 12:42 PM

Air cooled engines can be made quiet but only ones with overhead valves.

This is a distinction that doesn't seem rational to me. Without a water jacket there is nothing to soak up the noise and all aircooled motors need a fan which also produces noise. And, if you try to operate a fan cooled motor at low RPM's to keep the noise down the motor could overheat because the fan isn't processing enough air.
Whether the valve stems point up or down doesn't seem to be much of a distinction in terms of DB output.

Ron Carter

03-31-2007, 04:55 PM

[quote=merlinron;1337254]" the sahft ,prop and stuffing box might put me in that 500 dollar range,quote]

My experience is if you can't find the above used you will have well over $500 in the three before you even buy a shaft coupling much less the other components. Propellors for low hp applications that don't turn at outboard speeds are almost impossible to find unless ordered new. Seroiusly spendy in that case.

zenda

04-01-2007, 02:15 AM

leaotis

04-01-2007, 07:19 AM

This is a distinction that doesn't seem rational to me.

I know that a flat head like a Briggs & Stratton produces as much noise from the head as the exhaust port. The head is thin and perfect to radiate sound as well as heat.

I don’t know exactly why but an overhead valve engine is much quieter probably a lot has to do with being a much more modern design. I build an insulated box for an OHV generator but made sure air flow was not restricted.

openboater

04-01-2007, 08:58 AM

The forward / reverse with inboard rudder was fixed by Admiral Kitchen. I remember reading about it in an obscure magazine named 'Woodenboat Magazine'.

Tylerdurden

04-01-2007, 06:42 PM

The forward / reverse with inboard rudder was fixed by Admiral Kitchen. I remember reading about it in an obscure magazine named 'Woodenboat Magazine'.

Going to be trying a kitchen rudder for my Rescue Minor. For lower HP its a cinch, I have had to beef it up for my design

DLC

04-03-2007, 11:32 AM

Is this kinda what you were thinking of

http://i148.photobucket.com/albums/s8/a2by4/reotrollabout.jpg

DLC

Excalibur

04-03-2007, 12:46 PM

Ex,
Charging a battery is done at a low amperage so not much HP is required. And it's much different than running a gas motor to drive a generator that supposed to power the electric motor that drives the screw. That's where this thread was going when I made that comment way back when

Chuck, I understood you. As I mentioned, the Honda generator puts out 2500 watts, and uses a 5 hp engine to do it. This is about 3.26 hp of electricity (one hp = 756 watts). I am trying to show that a generator using a 5 hp engine does produce enough continous power to move a small boat. The link to the battery charger was only to show how such a generator could be built at home, and used to produce DC instead of AC. A 5 hp gas engine will easily turn a 100 amp alternator and produce enough continuous power to run an 80 pound thrust trolling motor, or a 2.5 hp starter motor mounted inboard. Add a DC controller and reverse polarity switch, and you have the whole package.

phiil

04-03-2007, 02:23 PM

Mike:
I have just read a lot of replies, most of them offering suggestions on every available option except the one you proposed in your original post. I like the idea of a v-belt drive for forward, and a roller drive for reverse. The motor shaft would have both a small pulley, say 2" or so, and a similarly sized roller of hard rubber or other composite. The prop shaft would be equipped with a large pulley, 8-10 inches or so, and also a disc of similar diameter. With the motor in the up position, the prop shaft is driven by the v-belt, in the motor direction, at a reasonable reduction. Dropping the motor drives the prop shaft in reverse through your friction roller. You have a rudimentary neutral with the motor halfway down. The whole rig is sort of a poor-man's planetary transmission.

A properly set up v-belt can be quite efficient. It will not be engaged/disengaged nearly as often as a car, lawn tractor, or motorbike, so should last about forever. Same is true of the friction wheel reverse gear. This whole setup has the added advantage of being able to slip should the prop run across something stronger than it is, (think rock) preventing additional damage to running gear.

Excalibur

04-03-2007, 02:38 PM

Point taken. Didn't Vespa scooters use a roller drive system? I think it was a metal roller that drove the rubber tire directly with a spring to hold tension. Pulling in the clutch pulled against the spring, and raised the metal roller off the tire. Maybe you could use Vespa parts? I would use a solid rubber tire tho. Here is a good pulley calculator:

http://www.owwm.com/Math/ArborRPM.asp

mike hanyi

04-03-2007, 03:38 PM

Wow, I have been watching this thread for a looooong time now and finally people are looking at the ORIGINAL question- DLC, you hit the nail on the head, just love to ask where you found the picture,what is it? can we have the picture from another view? like to see where the device lifts.

Phiil, right on.
No- vespa never had a drive like that, I have had over 7 vespas and now Im down to 3.5 of them-I like boats over them. I do remember a go-ped had a drive like that.

Mike

openboater

04-03-2007, 04:16 PM

Yes, DLC, your second post is a gem.

any more info you can pass along ?

DLC

04-03-2007, 05:08 PM

This is a Reo trollabout it came as a kit to convert a row boat to inboard

http://i148.photobucket.com/albums/s8/a2by4/reotrollaboutkit.jpg

this is it all together

http://i148.photobucket.com/albums/s8/a2by4/reotrollabout2.jpg

the bottom pulley moves an the shaft has a flex coupling in it just inboard of the stuffing box

http://i148.photobucket.com/albums/s8/a2by4/reotrollabout3.jpg

by the way it is 1 and 3/4 hp

DLC

Rick-Mi

04-03-2007, 07:38 PM

Very interesting thread Mike. Get this rig fine tuned and I might just get a chance to see one in person. In the summer of 08 I'm planning a trip back to Finland to visit my "roots." My Grandfather was a highly decorated officer during the Winter War who immigrated with a wife and three snotty nosed kids through Ellis Island into the United States right after WWII. One of them was my mother......

SISU

Cuyahoga Chuck

04-03-2007, 09:06 PM

Chuck, I understood you. As I mentioned, the Honda generator puts out 2500 watts, and uses a 5 hp engine to do it. This is about 3.26 hp of electricity (one hp = 756 watts). I am trying to show that a generator using a 5 hp engine does produce enough continous power to move a small boat. The link to the battery charger was only to show how such a generator could be built at home, and used to produce DC instead of AC. A 5 hp gas engine will easily turn a 100 amp alternator and produce enough continuous power to run an 80 pound thrust trolling motor, or a 2.5 hp starter motor mounted inboard. Add a DC controller and reverse polarity switch, and you have the whole package.

I admit I'm getting a little over my head but , I am a little knowledgeable about old fashioned auto electrics.
Auto alternators only put out partial amperage for most of their lives. Is it possible to keep an alternator at or near max amperage for long periods without burning it up?
And "starter motors" have been mentioned several times. All the starter motors I am familiar with were series wound. They put out a lot of torque and a lot of heat. Can they survive if run for long periods? And being series wound there is no way to control RPM's. If you run them without a load they will run away and damage themselves.

Craic

04-04-2007, 03:02 AM

Mike and all,
I wish to remind you of the Watermota 'Shrimp' system from the seventies.:

The driveshaft is coupled directly to the aircooled engine (camshaft 1:2 PTO) and the two-blade propellor can be feathered into any position between Forward/Neutral/Reverse/Sail (no drag).

Great system, very lightweight, works fine in my Drascombe Driver since 1976, there today coupled to a 9.5 HP Kubota OHV ex-generator engine, very quiet. (Photo of boat: http://www.pbase.com/kathymansfield/image/65018299)

I have an original brochure but cannot upload here.

Alas, the system is no longer being sold, but well worth to be remembered and reproduced today. Lightweight, inexpensive, mechanically proven, can be coupled to any off-the-shelf commodity engines (Gasoline or Diesel) up to 15 BHP.

C.

johnw

04-04-2007, 03:59 PM

StevenBauer

04-04-2007, 04:26 PM

Holy crap Craic! Your link leads to Kathy Mansfields public photo albums! Thanks. :)

Great stuff there:

http://k53.pbase.com/v3/53/578453/1/51008610.Mariquita9268.JPG

Cuyahoga Chuck

04-04-2007, 04:27 PM

What if you built a tunnel to push the water through? Prop pushes the water the same direction all the time, but you have two ports you can open or close, one pushing water forward and one aft. For neutral you close the water intake.

Congradulations. You have just infringed on the patents of the guy who invented the jet-ski drive.
On a practical note, any time you enclose a propeller there are sizeable losses incurred that may require a bigger motor to get the same amount of propulsion a bare prop would give. And the longer the enclosure, the more the loss.
Not even the jet-ski folks have figured out a sophisticated way to duct water effectively. They just use a deflector housing that incurres tremendous losses of thrust.

mike hanyi

04-04-2007, 04:29 PM

craic- do you still keep your red wine in the fuel canister of steamy?
I got a great picture of that.
Its been some time since we met!
Mike

brian.cunningham

04-04-2007, 05:46 PM

A jetskeet engine would be the cheapest way to go.
Since they're getting banned on some many lakes lately, you can pick up an old one real cheap. Those things have so much power, the losses are nothing to worry about.

Holy crap Craic! Your link leads to Kathy Mansfields public photo albums! Thanks. :)

I think I'd let the sheet out just a tad ;)

johnw

04-04-2007, 06:22 PM

Congradulations. You have just infringed on the patents of the guy who invented the jet-ski drive.
On a practical note, any time you enclose a propeller there are sizeable losses incurred that may require a bigger motor to get the same amount of propulsion a bare prop would give. And the longer the enclosure, the more the loss.
Not even the jet-ski folks have figured out a sophisticated way to duct water effectively. They just use a deflector housing that incurres tremendous losses of thrust.

I think that depends on how you do it. I've looked at the pump jet for personal watercraft, and it doesn't look like what I've described.

http://en.wikipedia.org/wiki/Pumpjet

As for efficiency, I'm sure it wouldn't be that great when you have to change the direction of flow. Ducted fans in general can be efficient because of the endplate effect. You would get lots of skin friction inside the ducting it it was long.

Stiletto

04-04-2007, 07:19 PM

Am I correct in thinking that no patent infrigement occurs if you build an item for your own use?

04-04-2007, 07:45 PM

The Cox ride on mower made in Oz has a simple and clever forward/reverse/neutral setup. I'll try to describe it. Basically the rear axle has 2 cone shaped plates facing each other a few inches apart near the centre. Below them is a cone shaped wheel, which is moved from side to side by the foot control pedal. Move one side it enages with one of the cones on the drive shaft and turns the axle to drive forward, move to the other side it turns the axle to drive backward. Really really simple and robust.

Craic

04-05-2007, 04:22 AM

craic- do you still keep your red wine in the fuel canister of steamy? ....

No. I finally grew wary of the odd taste. Am using water canisters now, minus the water of course.:o

Hello Mike, nice to CU. Really been a while, Scotland 2004.

Would you -or anyone- know how I can upload my Watermota 'Shrimp' brochure here?

I was actually tempted to buy that business in 2005 to redesign it for cheaper manufacturing in the East. I was very much convinced there could be a renaissance for a cheap and lightweight inboarder system for small boats, because of the betterl weight distribution in the boat and especially Watermota's no-gearbox and no-drag propellor feathering system.

But today, there is alternative solution for outboarders with most of the advantages of the inboarder systems, plus some. The -small & short shaft- outboarder (around 12 kgs) is mounted in a well which itself has only a small slit at the bottom. When the engine is tilted up, that slit is closed by a rigid fairing flap. The engine sits well and protected inside the hull, well forward, the weight of it is low, and no drag while sailing.

Swallowboats are building that into their SeaRaiders and BayRaiders, and it works superbly, the boats row and sail as if they had no engine at all. (www.swallowboats.com (http://www.swallowboats.com)) It is a clear advantage when you can remove the engine. Inboarders must stay put all through the year, rain, shine and swamping.

BTW, the small commodity generator engines mentioned above work well enough on boats, but there is a fair amount of corrosion especially at the exhaust/silencer because that is made from non-marine mild steel. In connection with heat and saltwater spray, that rusts away like ice in the sun.

C.

Tylerdurden

04-05-2007, 07:31 AM

I have photo's somewhere of Robb Whites setup, If I can find them I will scan them. Where he used an air bag to force the motor down into reverse I was considering using a lever operated hydraulic ram to drive two cylinders and accomplish the same. No auxiliary air, electric or hydraulics needed.

Stiletto

04-05-2007, 06:54 PM

Craic, if you scan your brochure, upload it to imagestation or the like, you can then link to the forum using the postcard icon on the reply panel to insert the link into.

I have a photocopied watermota shrimp manual that shows the B&S motor and the two variable pitch options they made, one a feathering prop and the other a reversing and feathering prop.

Caleb Chia

04-06-2007, 08:36 PM

paladin

04-06-2007, 09:05 PM

The vespa had a conventional drive...the French Velo-Solex used the steel roller on the front tire to engage the wheel.....that's what I used as airport transport around the hangars in the philippines.

Paul Fitzgerald

04-07-2007, 01:40 AM

Wasnt the roller on the back tyre?

Wes White

04-07-2007, 09:13 PM

My father used the air spring to tension the v-belt, and a foot pedal to get reverse. He wound up replacing the air spring with a kind of telescoping device using a semi-truck valve spring and abandoned the reverse. The original system worked fine, he just found that the Rescue Minor didn't need reverse, and decided to simplify it.

kenjamin

04-08-2007, 01:41 PM

My new Yamaha 4HP four stroke cost $1200 American but is portable, quiet, efficient, looks nice and has forward and reverse gears and a remote tank. Motor weighs 47 lbs.

Caleb Chia

04-10-2007, 02:57 AM

How about this?

Engaged, forward gear
http://www.imagestation.com/picture/sraid225/p661dfccf9c0123860b15a287f5fd822f/e9fb10f3.jpg (javascript:viewExifData())

The gray/white shafts and discs are the drive-shaft.(sorry about the weird shadows, I just sketched it up really fast on Rhino and the render came out funny)

One shaft (and disc) slides forwards for neutral...
http://www.imagestation.com/picture/sraid225/p488eb639c8af33d9c7d48f48b594e399/e9fb0f46.jpg (javascript:viewExifData())

The red rollers are free to turn on the yellow rod. The rod comes up with some mechanical device, and the shaft slides back against the rollers for Reverse Gear.

http://www.imagestation.com/picture/sraid225/pb91e70e7e8db906b978136b0666754dc/e9fb101b.jpg (javascript:viewExifData())

Simple and efficient eh? The discs could have a layer of rubber fastened on and the rollers could be small ball bearings. Making some device to bring the rollers up between the discs should be easy, a pivot on one side of the rod maybe. I think the main difficulties(or costs) with this design would be aligning the two discs, and how to make the shaft move back and forth neatly. (I guess you could move the whole motor, but would the bearings in the motor handle the slight pressure?)
Do you guys think this would work?
It dosnt have any reduction gearing, so you would have to get a motor with built in reduction.(they come in 1:2 and 1:6 ratios I think)

Bob (oh, THAT Bob)

04-10-2007, 04:04 AM

Some walk-behind lawnmowers that were self-propelled used this type of friction drive, and they varied the contact radius to vary the speed. But they worked poorly, the slightest mosture or contamination would make them slip. This is because of the small contact area. Compare this with a belt friction drive where the belt wraps 180 degrees around a pulley so has order of magnitudes greater contact area. You need that much area for a friction drive to be successful. (Unless perhaps what you describe would be used for reverse only, thus very low hours; I designed a simple transmission in college like that, chain drive forward and point contact friction drive like yours (but both wheels met circumferencially) for reverse, but it was never built.) Belt drives which vary the tension of the belt as a pseudo clutch have worked, my dad's rototiller drive worked like that. A better setup would be two parallel shafts, with both spur gears and a chain drive both engaged at all times ("constant mesh"), but one gear and one chain cog spin freely on rotating (ball or tapered roller) bearings on the same shaft. There is a double-sided dog clutch on that shaft between the gear set and chain drive which slides axially on the shaft but is keyed or splined to the shaft, with a shift lever connected to the dog clutch, and you shift between the gearset and the chain drive for forward and reverse. This is how most automotive manual transmissions work.

Craic

04-10-2007, 05:39 AM

Again, there IS (i.e. there until recently WAS) a very good inexpensive small inboard system with reverse AND with no propellor drag, the Watermota Shrimp system. Many are still around and are working fine, systems and spares keep popping up on the WWW from time to time.

Here are the brochures I have:

http://www.imagestation.com/8563606/3925510142
http://www.imagestation.com/8563606/3925509847
http://www.imagestation.com/8563606/3925509816
http://www.imagestation.com/8563606/3925509780
http://www.imagestation.com/8563606/3925509751
http://www.imagestation.com/8563606/3925509645

Again, the Watermota Shrimp system requires NO reversing gearbox, it can be connected to any engine with a revs reduction of at least 2:1 or more, for instance the camshaft PTO of fourstrokes works fine for me, in connection with a smaller than usual propellor.

C.

Caleb Chia

04-10-2007, 06:29 AM

Bob,
This design isnt a friction drive. Its more like a clutch, or disc brake thing. For forward drive(which you would use most of the time) you have the entire front surface area of the discs as contact area, MORE contact surface area than a belt drive pulley of equivalent diameter.
A belt drive uses only 180 degrees of the radius, while this design uses 360 degrees of the area.(for forward gear)
Only the reverse gear has less contact area, limited by the rollers. But that can be solved by adding more rollers around the circumference. Anyway, as you said, the reverse gear is used a lot less than drive.

Caleb Chia

04-10-2007, 06:43 AM

Craic, they look pretty good, but are you sure they are (or were) inexpensive?
They look quite expensive to me. Even normal propellers cost quite a bit, especially going by Mike's budget!!:D :D

http://www.imagestation.com/picture/sraid225/p1efb1598c7bac11dc988f47879fefaac/e9fa87fe.jpg (http://www.imagestation.com/mypictures/inbox/view.html?id=3925510142&url=http://www.imagestation.com/picture/sraid225/p1efb1598c7bac11dc988f47879fefaac/e9fa87fe.jpg)

leaotis

04-10-2007, 07:37 AM

Thanks Craic, I'd almost build a skiff just to go with a small variable pitch unit like that. I can’t read the brochures can you tell me how much hp can it handle?

Excalibur

04-10-2007, 09:08 AM

I admit I'm getting a little over my head but , I am a little knowledgeable about old fashioned auto electrics.
Auto alternators only put out partial amperage for most of their lives. Is it possible to keep an alternator at or near max amperage for long periods without burning it up?
And "starter motors" have been mentioned several times. All the starter motors I am familiar with were series wound. They put out a lot of torque and a lot of heat. Can they survive if run for long periods? And being series wound there is no way to control RPM's. If you run them without a load they will run away and damage themselves.

Chuck, you might be surprised at how large that partial load can be if you are driving a power hungry vehicle like a police car or a transit bus, or if you are using them on a boat. You certainly need an alternator that is at least 30% larger capacity than the expected continuous output. I know they get as large as 200 amps, but I don't know if they get bigger. In any case, cooling is the key. As you know, the diodes are pressed into the case, and the case is the heat sink. You would need to make certain that there is plenty of cooling air around the alternator.

Starter motors have progressed quite a bit since the old days, and modern ones from Honda and other Japanese makers are very robust. If I were making a sail aux engine just for docking, I think one of these motors would be OK. Some people are using aircraft starters which in the plane double as generators, and they are even more robust. If you would like to have a continuing discussion about hybrid drives, you might want to start another thread, since they are not a part of the original author's question. I'll be happy to participate. :)

pcford

04-10-2007, 12:37 PM

Cuyahoga Chuck

04-10-2007, 08:51 PM

Ex,
I only got into this thread because I thought some of the proposals were much beyond what even the most inventive mechanic could install in a 15' doubleender fishing boat. Which is the parameter Mike introduced this thread with.
I know a guy with a Dispro, which is exactly what we are talking about, but, I've never seen it in action.

Stiletto

04-11-2007, 02:42 AM

My tri had an approx 16hp Sachs Wankel rotary motor at a 2: 1 reduction by toothed belt about 60mm wide.

sds

05-25-2007, 12:05 AM

How about a version of Glen-L's electric drive found here http://www.glen-l.com/designs/special/electricdrive.html

With some mods I think you could still have forward, neutral, and reverse in the lower unit. Instead of electric motor build a mount for a vertical shaft Briggs

Tylerdurden

05-25-2007, 06:28 AM

I would think more along the lines of a barge drive. Run a small diesel
with a 1:1 right angle gearbox and you would have full 360 rotation.

fatehunter

06-20-2007, 10:03 PM

There is a boat called "Rescue Minor" that has a 20 hp diesel drive with a reverse by tilting the motor.

http://www.robbwhite.com/rescue.minor.machinery.html

Neat boat and featured in 'Woodenboat"

a few quotes:

My engine is a three cylinder Kubota basic engine of 722cc (including alternator, starter, water pump and fuel system... no bell housing or clutch.... just a naked flywheel on the stern). A legitimately "marinized" engine like it costs something like $5,000. I paid $1,300 on a "special" Kubota was having and I think the going rate for the same engine is up around $2,500 directly from Kubota now but they come up in surplus style situations every now and then. A friend of mine bought two of them for around $1,400 each. It pays to look around. Ebay is a good place to start.
My transmission set up is the most peculiar part. I have done that belt drive business before on sailboat installations. On those I used regular 'V' belts with one of those adjustable pitch sheaves so I could get the ratio exactly right for the propeller. Those were low horsepower rigs (usually with the Kubota 4hp Diesel engine they use to power the generator on those flashing arrow signs you see along the interstate) and we just rigged it so the flexible motor mounts could tension the belt. To get neutral, we pulled down on the engine to slack the belt and reverse was a "Troy Bilt" tiller rubber tired reverse disc which engaged another groove on the shaft sheave when the engine was depressed all the way. The whole thing was a copy of the Troy Bilt system which works real well on a tiller and did on a boat, too. The setup was silent and the engine could be suspended in gimpy enough motor mounts to eliminate vibration completely. The shaft ran in two pillow blocks (or flange blocks) so it always stayed aligned and the seal we used was a standard ceramic/graphite industrial pump seal which never leaked.

Andrew

06-21-2007, 02:43 PM

The forward / reverse with inboard rudder was fixed by Admiral Kitchen. I remember reading about it in an obscure magazine named 'Woodenboat Magazine'.

http://upload.wikimedia.org/wikipedia/en/thumb/a/a5/Kitchen-rudder-us-patent-489509.gif/240px-Kitchen-rudder-us-patent-489509.gif

http://en.wikipedia.org/wiki/Kitchen_rudder

Cuyahoga Chuck

06-22-2007, 11:29 AM

With apologies to the admiral, that's ,essentially the same set-up seen on jet-skies and other pump drives. I've never messed with any kind of pump drive, but, I hear the deflector set-up doesn't give much feel when trying manuever in tight quarters.

MTRiverDrifter

06-22-2007, 10:08 PM

donald branscom

06-24-2007, 08:44 PM

Go to :http://www.novaracing.co.uk/reversing-gearbox-for-inprop-shaft-installation-and-engine-coupling-kit.htm

Cuyahoga Chuck

06-25-2007, 03:23 PM

Admiral Kitchen's patent goes back to 1914. His idea was probably not inspired by jet ski set ups.

I was apologizing for the Japanese engineers, and any others, who built pump drives and had to infringe on the Admiral's ancient patent to get the necessary reversing force.
Long ago, when pump drives were first tried on cabin cruiser sized hulls, there were immediate complaints from those that found the pump/rotating nozzle/deflector set-up difficult to use when mauevering in close quarters.
I get the feeling from all the prop/deflector installations we don't see that the Admiral's brain-storm has recieved a tepid reception.

kengrome

06-25-2007, 07:55 PM

I was apologizing for the Japanese engineers, and any others, who built pump drives and had to infringe on the Admiral's ancient patent to get the necessary reversing force.I don't think they ever infringed on the Admiral's patents since they expired decades ago ... :)

I get the feeling from all the prop/deflector installations we don't see that the Admiral's brain-storm has received a tepid reception.The Kitchen rudder is still a great solution for moderate speed boats, but it creates too much drag for high speed boats, and most people demand to go as fast as possible these days, so it's no wonder it hasn't become more popular. Back in the Admiral's day marine gearboxes were probably much cheaper (relatively speaking) and more plentiful too, so his innovation had some "competition" that is basically non-existent today. I think we can thank the success of the outboard engine for killing the marine gearbox industry in the USA.

Maybe with the skyrocketing prices of fuel in America we will see more of these innovations come into use in current times. In Europe they commonly use controllable pitch propellers for infinitely variable prop pitch including neutral and reverse. I think they have been paying so much more for fuel there for so long that they had good reason to focus on the use of a more efficient drive system, whereas in the USA with cheap (until recently) fuel we just "throw a bigger engine on it" if the boat doesn't go fast enough for us.

A controllable pitch propeller is more efficient than a Kitchen rudder, I only wish there were a manufacturer of small ones for boats using 10-30 HP inboard engines. Too bad I cannot find any ... does this mean I have to develop one myself?

Craic

06-26-2007, 09:55 AM

...
A controllable pitch propeller is more efficient than a Kitchen rudder, I only wish there were a manufacturer of small ones for boats using 10-30 HP inboard engines. Too bad I cannot find any ... does this mean I have to develop one myself?

Well, yes, probably. But then you would not have to develop from scratch, you could in principal copy the above 'Watermota' system using cheaper modern off-the-shelf stainless steel materials instead of many cast and machined bronze parts Watermota was using.
If done neatly, simple and cheap, I think there would be a good market worldwide.
C.

kengrome

06-26-2007, 11:29 PM

Hi Craic,

The Watermota is exactly the kind of drive system I need. Can you email me the full-sized original scanned images from your Watermota brochure?

I looked at the files you uploaded to Sony ImageStation account, but they limit the image size I can view because I'm not one of their "premium users" -- and therefore I cannot read any of the text or see close-up drawings like I hope to.

If you want, I will post them on my own web site without this image size restriction, then everyone can see them at full size ... for free.

Thanks.

Craic

06-27-2007, 02:37 AM

Hi Craic,
The Watermota is exactly the kind of drive system I need. Can you email me the full-sized original scanned images from your Watermota brochure?
Thanks.

I will do that, gimme two days and your e-mail address through a PM. I have loads of stuff, brochures and parts, and will copy the most informative of it for you.

C.

kengrome

06-27-2007, 06:17 AM

Hi Craic,

I sent you my email address via PM, thanks for the effort to send me scanned images of your Watermota information!

Philip Maynard

06-27-2007, 05:05 PM

How about:

The quest for the inexpensive small reversing/feathering propeller

Canoeyawl

06-27-2007, 09:03 PM

I have had the Watermota gear apart and inspected it, and decided it would be prohibitively expensive to make less than a thousand of them…
There are precision fit spur gears made onto the blades and a sliding rack to engage them. It is actually a pretty delicate mechanism consisting primarily of machined castings. These pieces because of their shape would require special fixtures to machine them.
The control mechanism is another lovely bit of British engineering, but again expensive to manufacture.
All in all it is a lot of bronze parts that are precision fit and adjusted. The components are numbered like an old rifle or pistol, to keep the pieces together as one assembly, and indicating a certain amount of hand fitting to get it perfect.

Kiwidreamer

11-25-2007, 10:02 PM

I just bought a Hartley 18 with a Watermota run off a 3 1/2 HP Kubota Diesel. I think it was "old stock" from someone garage..but it is essentially new. It is the sail type with feathering prop. I paid $1400NZ for the boat..thats about $1000US. I wouldn't even install it for that..! (Forget about the sails..trailer etc. )
It's an ingenious system..from another age..I had never heard of them before..thats why I looked up this thread.

donald branscom

11-26-2007, 09:52 AM

It looks like a pretty basic transmission. Any cost guesses?

Combine in with a honda 4-stoke with a reduction gear 6:1 (I think this is a standard ratio off the shelf that is). Swinging a real sized prop on a displacement hull should be expected.

Best regards,

Stefan.

Mechanical engineers have already studied the problem and tested 18 foot boats with small air cooled engines, The 2:1 reduction engine worked best. NOT 6:1. Briggs and Stratton actually sold a complete set up for small boats. It had a 2:1 reduction gearbox.
Almost ALL regular outboard motors are 2:1 reduction.

Reverse/forward gear boxes are available thru NOVA racing. Google it.

donald branscom

11-26-2007, 10:19 AM

My solution. Honda 5.5 HP 2:1 gear reduction. Wet clutch.
http://i13.tinypic.com/72fohfd.jpg

donald branscom

11-26-2007, 11:36 AM

Rick-Mi

11-27-2007, 07:39 AM

donald branscom

11-30-2007, 05:01 PM

Chuck, I understood you. As I mentioned, the Honda generator puts out 2500 watts, and uses a 5 hp engine to do it. This is about 3.26 hp of electricity (one hp = 756 watts). I am trying to show that a generator using a 5 hp engine does produce enough continous power to move a small boat. The link to the battery charger was only to show how such a generator could be built at home, and used to produce DC instead of AC. A 5 hp gas engine will easily turn a 100 amp alternator and produce enough continuous power to run an 80 pound thrust trolling motor, or a 2.5 hp starter motor mounted inboard. Add a DC controller and reverse polarity switch, and you have the whole package.

Small 5.5 hp Honda EX160 engines have been used for years in small boats in indonesia. Direct drive. No need to do any math. Engineers have also studied the issue.Just google fishing boats indonesia. Like i said forget doing all that math unless you just like the mental exercise. But remember to calculate the type of prop. Drag coefffients etc..etc,etc.
NIAS ISLAND
http://i3.tinypic.com/6jcif0g.jpg

ssor

12-02-2007, 09:41 PM

Motor cycles don't have a reverse gear. You can paddle a boat back until you can turn and go forward.

Jay Greer

12-02-2007, 09:51 PM

kengrome

12-03-2007, 11:06 AM

The two cylinder Dolfin engine that weighs in at 120lbs. and produces 12HP. is probably the most compact lightweight marine engine and transmission on the market today.Jay, is this engine EPA-certified for use in the USA?

Jay Greer

12-03-2007, 03:38 PM

Jay, is this engine EPA-certified for use in the USA?
That is a question you should ask the dealer. However, I have seen several of the engines in US Boats.
Jay

kengrome

12-04-2007, 02:26 AM

I did a google search but I couldn't find any dealers or distributors in the USA so I emailed the manufacturer. However, I don't think they are going to tell me it's an engine that's available in the USA ... :(

So far I have yet to see an old two-stroke engine that will pass EPA. The only two-strokes passing these days seem to be newly engineered and incorporating high-tech ways of dealing with the exhaust emissions.

Craic

12-05-2007, 02:54 AM

The two cylinder Dolfin engine that weighs in at 120lbs. and produces 12HP. is probably the most compact lightweight marine engine and transmission on the market today.
http://www.dolphinengines.co.uk/specification.htm
Jay

With all due respect, this thing looks like a memento of the not too near past. Two-strokes are becoming extinct, by law. Good riddance.

12 HP engine and transmission gearbox weighing 120 lbs.?

: My complete Watermota / Kubota four-stroke 9.5 HP system weighs under 80 lbs., and that also includes electric starter, battery, tank, transmission, driveshaft and folding propeller.

kengrome

12-05-2007, 04:30 AM

Two-strokes are becoming extinct, by law.There is no law that bans two-strokes simply because they are two-strokes. Any manufacturer capable of producing two-stroke engines that pass EPA regulations is welcome to manufacture / import / sell them in the USA.

My complete Watermota / Kubota four-stroke 9.5 HP system weighs under 80 lbs., and that also includes electric starter, battery, tank, transmission, driveshaft and folding propeller.That's great, except for the fact that the Watermota you have is not being manufactured any more, the company that used to make them no longer exists, and there are no remaining replacement parts suppliers in the world. Don't get me wrong, I think it's a great system and I wish it were still available.

Craic

12-05-2007, 05:52 AM

...the fact that the Watermota you have is not being manufactured any more, the company that used to make them no longer exists, and there are no remaining replacement parts suppliers in the world...

... does not mean to me that 'The quest for the inexpensive small inboard with reverse' must end with what's on the market today. It should aim for something that is even better than what has been there already, not stay short of that.

kengrome

12-05-2007, 06:48 AM

... does not mean to me that 'The quest for the inexpensive small inboard with reverse' must end with what's on the market today. It should aim for something that is even better than what has been there already, not stay short of that.

Agreed, if the meaning of the quest is to design and develop such an animal rather than buying one new.

andrewe

12-06-2007, 03:06 AM

Seems like a a V-P set up is going to end up too expensive in producion.Just look at the price of feathering units.
A little reversing box is whats needed. One of the small engine people (Honda?) must make something suitable. The one mentioned above is for cars with big engines, and pricey. I´ve sketched up a couple using belts and chains to use cheap off the shelf bits. Not sure if I would want to mass produce them tho.
Andrew

John Turpin

12-06-2007, 08:39 AM

Garden tillers have reversing transmissions and regularly bolt up to Honda engines. Has anyone taken one apart to look inside?

Jay Greer

12-06-2007, 03:59 PM

Another engine is the Vire which is made in Finland.
It has a long history of supplying reliable power to small boats.
In fact I installed one in a customer's 23' Spitzgater ten years ago.
The owner is still very happy with the engine.
http://www.fairwaysmarine.com/vire/vire7.html
Jay

StevenBauer

12-06-2007, 04:43 PM

I had a great season with my Vire 12. A little noisy, perhaps. :) If it ever dies I'll probably go electric.

Steven

Stiletto

12-07-2007, 02:36 AM

To drift back to gearboxes with reverse, the relative simplicity of an outboard motor reverse gear system appeals to me.

I have often wondered if it would be possible to economically build something similar without the right angle. Is the reverse arrangement of a high powered outboard much different from that of the lower powered versions?

andrewe

12-07-2007, 03:23 AM

The problem with garden tractors,tillers et. al. is the hefty reductions,multiple forard gears and right angles drives, all of which are of no use on a boat. Outboards all use similar f-n-r systems. Outdrives and saildrives have the the rev. bits at the top of the leg.
I have built my system using an outboard leg belt driven by a vertical shaft air cooled 4-stroke Tecumse. I was a bit surprised by the weight of the leg. But it will have a proper alternator so no shortage of electrics.
Signed up for picturetrail yesterday. Will wrap a wet towel round my head and try to get a pic up here.
Andrew

kengrome

12-13-2007, 08:20 PM

The two cylinder Dolfin engine that weighs in at 120lbs. and produces 12HP. is probably the most compact lightweight marine engine and transmission on the market today.In response to my email inquiry with the Dolphin Engine company about the status of their engines, I just received an email from GT Jones & Co. They told me:

1- GT Jones & Co. has recently purchased the Dolphin Engine company.

2- New Dolphin engines are currently not in production. Instead they are only able to supply fully reconditioned examples (at this time) for those who wish to maintain existing installations.

3- Their engines are not EPA compliant, but they have a plan to begin a development program to satisfy emissions regulations in the future.

My understanding is that an old-style engine like this will not become EPA compliant unless it is (1) completely re-engineered, or (2) retrofitted with a catalytic converter. Since re-engineering is cost prohibitive I sent them a follow-up email asking if they will use a catalytic converter. Stay tuned for another update if/when they respond ... :)

Pierce Nichols

12-13-2007, 09:19 PM

Chuck, I think you might find it smaller than you think. The motor alternator can be put anywhere in the boat,just run cables from alternator to motor. and since he already has a 5hp in the boat, that part of the package is the same with the addidtion of a 100 amp truck / car alternator. when I said large I meant in output not size. Simple rectifier to go from ac to dc.

You need rather more than a 100A/12V alternator to drive a 2 Hp motor. That alternator only puts out 1200 W... and 2 Hp is around 1500 W, ignoring efficiency losses and startup surge. For a 2 Hp motor, you probably want around a 2-3 kW alternator, plus a battery in parallel (possibly with diodes to prevent overcharging, and a seperate charging circuit) to provide the starting current.

Zane Lewis

12-14-2007, 05:53 AM

ON the lines of using an old O/B leg and an electric motor,
Take the Leg which gives you forward neutral and reverse. Bolt on top a little hydraulic motor, bolt a small hydraulic pump to your engine, 3 hoses(Suction, Pressure, Return), a return filter and a small oil tank.
In NZD $1000 for pump and motor, $300 for hose and fittings, $80 for filter, .........
Zane
ed to add
not as cheap as a chain drive but placement of engine is open and no rotating bits to get wrapped up in.
No electricity, no large battery banks.
While not as efficient as a direct drive through a gear box it's probably better than an electric drive. Say 80% based on using cheap alloy pumps and motors rather than expensive cast pistion pumps.

ssor

12-15-2007, 04:14 PM

I went to the calculator on Boatdiesel and for a 6:1 reduction gear they recommend a 20 inch prop with a 27 inch pitch. They further recommend 1400 rpm shaft speed for this size boat with a 9x8 three blade prop for a 6 knot speed

john welsford

12-16-2007, 03:30 AM

Hi Mike, just a thought. In some parts of the world the English "Watermota" engine and drive combination was very popular. They used various proprietary engines mated to their own variable pitch props and shafts, they were very simple, and worked fine. I'd think that there are quite a few lying about with the motors unserviceable, and a trawl through your local equivalent of EBay might scare one up. A bit of tidying, and a motor , perhaps a Chinese built "Robin" or suchlike. I have a Chinese 3 1/2 hp overhead valve 4 stroke lawnmower, cost less than half the price of most others, and its unbelievably good engine wise. I see the same engines on cement mixers, generators, pumps and such. Should be fine. No gearbox required.
John Welsford

I hope this shows some interest.
some years ago I purchased a small double ended traditional finnish boat type called a fiskari (fishermans boat) it is about 15 ft and maybe 5 ft wide, it is more or less a double ended rowboat with an inboard rudder and engine. engine being a B&G 5hp, directly hooked to the propshaft. now soon I will start its rebuild. over the time I started to appreciate the simple and inexpencive nature of this honest boat, its light enough for 2 people to pick it up and move it.the motor is more used for doing longer distances and is maneuvered under oar as there is no way to go slow with the motor.

which brings me to the idea of a cheap transmission for small aircooled engines.

Engine canadates are Honda, B&G, also are small aircooled diesels that seem to be now affordable.
there is no watercooled 5hps out there as there is no demand for them.

The Idea
cheap reversing transmission for small motors.

I will try to work on the concept of the motor mounted on a hinge,
there may be some kind of spring to lift the hinge slightly
the motor is equipped with standard pulley, and a wide collar,
directly under the pulley is another pulley which is on the propshaft, on one of the shafts is also a hard rubber tyre, the other shaft should have a smooth metal wheel to make contact with the tyre when the hinged motor is lowered.

how does it work?
some kind of hand lever lifts the motor and puts tension on the belt=forward
release the lever and the motor sits on the short springs=neutral
no tension on the belt
pressure is applied to the lever and the springs are compressed, the hard rubber tyre is now pressed against the metel wheel=reverse.

this whole idea should be able to be made easily, except for the pulleys,
there will need to be a thrust bearing in a bearing housing, the type that is self aligning, so that alignment between the motor and the prop shaft is no so critical.

also I have seen model airplane propellers used sucessfully on low powered electric motors, it would be easy to use this idea, cheap propellers that come is lots of pitches and sizes.

I am really interested in making several kits for a production run of these cheap simple boats. feedback on this concept would be great.
remember this is to be a cheap plan and not over engineered.

mike

Tylerdurden

12-16-2007, 10:10 AM

Pierce Nichols

12-16-2007, 12:16 PM

ON the lines of using an old O/B leg and an electric motor,
Take the Leg which gives you forward neutral and reverse. Bolt on top a little hydraulic motor, bolt a small hydraulic pump to your engine, 3 hoses(Suction, Pressure, Return), a return filter and a small oil tank.
In NZD $1000 for pump and motor, $300 for hose and fittings, $80 for filter, .........

If you have the hydraulic setup, you don't need the F-N-R gear box; you just need a four-way valve to swap the fluid flows around to drive the hydraulic motor in the opposite direction. The same valve can also cut the motor out of the circuit for neutral. A relief valve is also required to avoid stalling the drive engine while switching.

Zane Lewis

12-17-2007, 03:32 AM

Hi Pierce, You are quite right,
I was looking to avoid $500 for a valve and an extra hose. And I figured that if you are working with an old OB leg you have it all anyway. Still the valve would be complete with relief.

Must admit that unless you have a good reason Hydraulic drive is probably not the cheapest compaired to a belt or chain, or direct.

My interest is in our next boat which I hope to use a torque controled variable displacement pump to allow prop speed to vary based on load when motor sailing.

Sorry about the thread drift
Zane

Ron Williamson

12-17-2007, 05:51 AM

A used Honda powered log splitter has all of those parts except the hydraulic motor.
Less than $1k and a guy could still do firewood in the off season.
R

Zane Lewis

12-19-2007, 03:49 AM

Hi Ron,
Thats one I had not thought of. Too simple I guess.
Or maybe it's because I don't make any money from second hand stuff. Or at least not untill it's 20 years old and the pump / motor are worn out and the oil is dirty and then the owner dosn't want to spend any on on it cause he got it so cheap and wonder's why it's not doing what he was told it would do.
Sorry minor Rant over.

Ron is right, thats a good option, most log splitters don't do a lot of hours and as long as the Oil is OK and a suitable and functioning relief is fitted hydraulic components will last for a very long time. Much longer that the internal combustion engine driving them.
Zane

Nordicthug

12-19-2007, 05:07 AM

Can anyone say, "reinventing the wheel?"

Direct drive air-cooled engines were common in the NW in the 30s to 60s. A local boat type, the Poulsbo boat, was produced in the hundreds for fishing camps. a cast iron Wisconsin 5hp was usual power. Rugged power. Maintenance consisted of adding oil whenever the engine ran out and seized up.

I had a Poulsbo boat for a while. It had a 5HP Wisconsin equipped with an updraft carburetor and spark arrestor and a tiny planetary gearbox with forward, neutral, and reverse. There were half a dozen shops manufacturing these gearboxes before and just after WW II.

Another method is the simple brass cone clutch, it allows neutral and fwd, but no reverse. The good part is its cheap, easy to make and has one moving part.

Another possibility is a B&S engine with a factory installed reduction gear, usually aboaut 6:1. Check equipment suppliers like Northen Tool.

Back in the 80's I rigged a 17' flatiron skiff with a 4 HP B&S with a red. gear by putting a thrust bearing and a pulley on the shaft, then mounting the engine on a swing plate to tension or release the drive pulley belt, making it a clutch. That one worked like a dream. About 600 rpm max, throttling down to 150 or a bit less at the output shaft. The skiff would do about 7 kts in flat water, and would throttle down to 1/2 kt for trolling. Dirt cheap, too. Engine was about $125 new, shaft, stuffing box and Cutless bearing, $75 and propellor $25. Some new, some salvaged. The stuffing box was brazed into the end of a bronze tube, the cutless pressed into the other end. the entire perfectly aligned assy, was glued into the shaft log with a 1/10 gallon tube of sika flex.

There used to be a guy selling a little booklet, "Cheap Power" in the ads section of "Fishermen's News" back in the 80's. May still be doing it. I think he called himself Capt. Woody something or other. Buncha good ideas in there.

Silencing air cooled engines is difficult, quieting them isn't. Put an implement muffler on the exhaust, plumb it with galv. steel pipe and point it straight up. Then build a plywood box around the engine with some vent holes in it for cooling air. Line the inside of the box with one or two layers of beaver board. Silent? NO Quiet? You Bet'cha. When not in use put a tin can over the exhaust pipe to keep rain out.

I don't mean to kvetch, but too many of you guys seem intent on complicating the crap out of a fairly simple problem. I sense engineering degrees in play here, making "perfect" the enemy of "good enough".

As a practical matter a boat 20' or less really doesn't need reverse, a paddle will handle that duty. Neutral's pretty handy, though.

Gerry

john l

12-19-2007, 09:46 AM

Been though this whole thread several times.
Still think stripping a golf cart is the cheapest and easiest. Never mind clean.

Years from now if it burns fossil fuel it will be a micro turbine generator hybrid. We are not that far off.

i think you're right about the micro turbines. they are extremely fuel efficient. i was doing some research several years ago with the intent
on using them for lawn mowers. apparently micro turbines are used
alot in factory and industrial applications, for modeling etc. i've seen some interesting experimentation by an australian engineering co.
the golf cart motors do sound like a good alternative.

Tylerdurden

12-19-2007, 09:57 AM

i think you're right about the micro turbines. they are extremely fuel efficient. i was doing some research several years ago with the intent
on using them for lawn mowers. apparently micro turbines are used
alot in factory and industrial applications, for modeling etc. i've seen some interesting experimentation by an australian engineering co.
the golf cart motors do sound like a good alternative.

I was banging this issue around for a long time and understood almost at once that we need to go in a different direction than fossil fuels except as maybe a back up and the Micro turbine is the trick item for that.
I posted in resources about the thin film solar panels finally being shipped out the door, so if the technology holds true to .99 a watt a big part of electric drive is open for new business.
I am outfitting my boat with a stack of trojan t-105 batteries and converting an out board to run the e-tek motor. I intend to use wind on the mooring and some solar in combination with a small honda portable for those times wind and solar are no available.
I would like to pursue the micro turbine idea but so far no one is interested at such a fickle market as the small boat business.
It is my understanding though that we are only a few years away from surplus micro turbines hitting the market. Will be a fun time to play with them.

DLC

05-31-2010, 08:13 PM

http://www.jwboatdesigns.co.nz/projects/kane/RK-Houdini-6.jpg

It all depends on how far you want to go.
This bloke converted an outboard into a saildrive by shortening the leg and making a mounting plate. The boat is 13 feet long. I have seen it in the flesh and if I could've I would've!

do you have any pictures of this before it was instaled?
i want to do the same thing and any info would be great
thanks
dlc

gepetto143

05-31-2010, 08:55 PM

The Idea
cheap reversing transmission for small motors.

I will try to work on the concept of the motor mounted on a hinge,
there may be some kind of spring to lift the hinge slightly
the motor is equipped with standard pulley, and a wide collar,
directly under the pulley is another pulley which is on the propshaft, on one of the shafts is also a hard rubber tyre, the other shaft should have a smooth metal wheel to make contact with the tyre when the hinged motor is lowered.

how does it work?
some kind of hand lever lifts the motor and puts tension on the belt=forward
release the lever and the motor sits on the short springs=neutral
no tension on the belt
pressure is applied to the lever and the springs are compressed, the hard rubber tyre is now pressed against the metel wheel=reverse.

this whole idea should be able to be made easily, except for the pulleys,
there will need to be a thrust bearing in a bearing housing, the type that is self aligning, so that alignment between the motor and the prop shaft is no so critical.

mike

It's funny but when I read this, it made me think of the transmission on my old John Deer snowblower (5 speeds forward and 1 reverse). It would probably be possible to adapt the principles of the snowblower transmission to a small inboard motor. A "rubber" wheel transfer the power of the engine to a metal disk connected to the wheel (the rubber wheel and the metal disk are perpendicular) - if you place the rubber wheel on the left side of the metal disk, you go forward - if you place the rubber wheel on the right side, you go backward. You get the different speed by placing the rubber wheel closer to the center or the edge of the metal disk. You should take a look at how these work.

The snowblower is powered by a 10HP aircooled engine (I don't remember the brand) and the "transmission" can take quite a beating...

You can see the metal disk in the middle of the picture and the rubber wheel on the right side. It seems they are called friction wheel...
http://www.your-lawn-care-basics-coach.com/images/snowblowerfrictionwhellandtractionpulleyexposed.jp g

uptonsmillwork

02-14-2011, 10:38 AM

check this gear box http://www.mfgsupply.com/m/c/218390A.html not cheap though.

robert666

02-14-2011, 01:49 PM

pete culler wrote about cheap and dirty inboard instalations in Pete Culler on Wooden Boats, mcgraw hill books.
it includes propeller making, hardwood bearings and stuffing box and a simple clutch.

Huntsmanvb

04-18-2011, 03:02 PM

Small 5.5 hp Honda EX160 engines have been used for years in small boats in indonesia. Direct drive. No need to do any math. Engineers have also studied the issue.Just google fishing boats indonesia. Like i said forget doing all that math unless you just like the mental exercise. But remember to calculate the type of prop. Drag coefffients etc..etc,etc.
NIAS ISLAND
http://i3.tinypic.com/6jcif0g.jpg

Very interesting. I have a couple questions:

1. About what size prop is used with the 5.5 hp at no reduction?

2. I see that the prop shaft runs through a pipe to avoid the expense of a shaft log and such. What type of seal/stuffing box is used at the top of the pipe? I notice that the top of the pipe may be above the waterline.

3. Do they use stainless prop shaft, or is there a cheaper alternative.

I will be building an inboard skiff this year, and these Indonesian boats look to be the best template for a truly inexpensive installation. Thank you.

Craic

04-18-2011, 05:02 PM

Small 5.5 hp Honda EX160 engines have been used for years in small boats in indonesia. Direct drive. No need to do any math. Engineers have also studied the issue.Just google fishing boats indonesia. Like i said forget doing all that math unless you just like the mental exercise. But remember to calculate the type of prop. Drag coefffients etc..etc,etc.
NIAS ISLAND
http://i3.tinypic.com/6jcif0g.jpg

I doubt they are using the standard Honda 160 @ 3,600 RPM. It doesn't have the torque without reduction. The 160 is also made with two different flanged RPM reductions, 1/2 and 1/6. I had a 1/2 reduction, and that was pushing it, even in connection with a very modest pitch propeller. From that experience I would today go for the 160 with 1/6 reduction. Direct drive after that of course. C.

Huntsmanvb

04-19-2011, 12:39 PM

I doubt they are using the standard Honda 160 @ 3,600 RPM. It doesn't have the torque without reduction. The 160 is also made with two different flanged RPM reductions, 1/2 and 1/6. I had a 1/2 reduction, and that was pushing it, even in connection with a very modest pitch propeller. From that experience I would today go for the 160 with 1/6 reduction. Direct drive after that of course. C.

I would think that the 2:1 would be ideal up to a certain displacement; after that you are going to need 6:1 to push a heavy boat with a 5 horse.

I assume that the trick for using no reduction is a very small prop. I have been looking at some old plans for low horse power direct drive, and it appears that they went with 9" or less, essentially trolling motor props.

http://www.dngoodchild.com/5108pic.jpg
"Setting a new high in economy of operation, this 15-foot boat is designed for fishing and any general use that requires a seaworthy, low-cost, practical inboard motor boat. The remarkable economy in fuel—60 miles to a gallon of gasoline or even more—is made possible through a special design that assures maximum efficiency from the air-cooled marine motors on the market. Such inherently important factors as seaworthiness and shallow draft have in no way been sacrificed in obtaining this efficiency from the air-cooled marine the fact that an air-cooled motor is not subject to the corrosive action of salt water combine to make the boat ideal for salt-water use. Any desired trolling speed may be had. The hull is of a simplified V-bottom type, as easy to build as a flat-bottom boat. There is no difficult bending, and most of the planks can be put on in straight pieces with little or no fitting. The small, light motor offers no installation problems. Marine plywood may be used instead of planking, if desired, eliminating the need of battens and substantially reducing the total weight. The speed obtained with the 3/4-h.p. motor shown in the boat in the photograph was between 6 and 7 rn.p.h. This may be increased to as much as 10 m.p.h. by the use of a 4- or 5-h.p. motor."
http://www.dngoodchild.com/5108.htm

Huntsmanvb

04-19-2011, 01:32 PM

"The A-C series is primarily for smaller air-cooled inboard engines. Diameters range from 6" to 10" with straight bores."
http://www.miwheel.com/images/sized/uploads/products/weedless-ac-140x140.gif
http://www.miwheel.com/propellers/inboard/michigan-propellers/

I might call them up and see if they would recommend something from the A-C series for use with a 6.5 honda clone at 1:1.

john welsford

04-19-2011, 05:07 PM

"Kitchen" rudder and reversing gear http://en.wikipedia.org/wiki/Kitchen_rudder

JohnW

From what I've heard, forget the aircooled option unless you are (or wish to become) deaf.

For a different motor, and/or possibly a transmission to fit, try this site, click on the Engines link on the left -

http://boatdiesel.com

Vetus and several others have old models listed that are 5hp, Thornycroft has an 11, Volvo has a current 10hp model in production. This was just with a quick look at various manufacturers on this site.

Also, somewhere on the web I've seen pics of a metal shield / housing that can be rotated around the prop to block the propulsion -- not a true reverse but does generate some backward thrust, and allows you to stop forward thrust without killing the motor.

john welsford

04-19-2011, 05:12 PM

A lot of small utility engines are available with built in reduction gears, usually 2/1

JohnW

Most small motors have a powerband that is too high in the RPM range to drive a propeller efficiently. They need a gear reduction. That's why your boat was always trying to go so fast. Unfortunately, a suitable gear reduction box can be quite expensive (worth more than your motor) and a little hard to find and a little hard to install.
The motor/transmission setup is ideal because it can be compact and most of the rotating components are safely away from the passengers.
So whatever you create will have to compete with the traditional motor/ transmission. If it requires too much space and endangers the boaters no one will want it.
Airplane propellers are designed to operate in air which has different dynamics that water. While they may push the boat I doubt they will be as efficient as a boat propeller.

wayne nicol

04-19-2011, 09:22 PM

sorry to hijack here- but where can a 25 to 30hp inboard, water cooled 4 stroke gas engine be found- would going the ride on mower route be viable.
thanks
wayne

andrewe

04-20-2011, 02:01 AM

If you check out Honda's website, they have watercooled V-Twin engines of around 20 plus HP.

keyhavenpotterer

04-20-2011, 07:42 AM

Farryman do small marine diesels. They do a single cylinder 7hp water cooled marine diesel. Can be simple direct water cooled or fitted with a heat exchanger.

http://www.farymann.com/engines.php?page=18wMarine

mcdenny

04-20-2011, 09:26 AM

Kawasaki also sells water cooled V twins in the 20ish HP range. Not marine rated, though. Kohler used one in a marine gen-set and I inquired if I could purchase just the engine from Kawasaki. They said Kohler 'marinized' it, not them.

Craic

04-21-2011, 03:09 AM

From what I've heard, forget the aircooled option unless you are (or wish to become) deaf. ...

Not true. They sound very agreeable when big enough for not having to be run at full throttle all the time. And unlike the ones on lawnmowers on a boat you can always build some soundproofing around them. I really like the aircooling, no impellers, seawater inlets and such. And these engines are truly lightweights. C.

Huntsmanvb

04-21-2011, 08:13 AM

A lot of small utility engines are available with built in reduction gears, usually 2/1

JohnW

What annoys me is that horsepower is cheaper than gears, you can get a 11 hp engine for $229 on sale at harbor freight (I have used this brand engine in pumps, it's a good motor). In contrast, a 5.5 horse honda with gear reduction is around $500. I wonder if it would be smarter to just run the 11 horse at low rpms with an smallish prop.

http://www.harborfreight.com/media/catalog/product/cache/1/small_image/175x/9df78eab33525d08d6e5fb8d27136e95/i/m/image_1828.jpg

wayne nicol

04-21-2011, 09:24 AM

looking at all these options for small engines- what exactly would a layman need to "marinize" a stock engine- that was say used for a mower, or an off the shelf engine.
and what is the ideal rpm of the engine, and ideal rpm of the prop(i know this is a huge variable) lets say a 25hp gas engine pushing a 22 ft semi displacement hull.
i plan on building the atkins"big surprise".
thanks all.

mike hanyi

04-21-2011, 11:00 AM

amazing, 5 years and this thread is still alive! too bad the poor boat that started this thread did not last as long :(

Huntsmanvb

04-21-2011, 12:22 PM

Look at this one, forward and reverse gear box for $259.
Lister

http://www.mfgsupply.com/GoMiniAxlesGearbox.html/mv_session_id=5kUHnIVJ

Thanks! That may be the solution. Couple that with a 6.5 honda clone, and you have a inboard with reverse and neutral for under $400.

Craic

04-21-2011, 01:20 PM

Look at this one, forward and reverse gear box for $259.
Lister

http://www.mfgsupply.com/GoMiniAxlesGearbox.html/mv_session_id=5kUHnIVJ

I like that. Very much. All this Go Kart stuff is brilliant. Interestingly, this little gearbox incorporates a 2.7 : 1 reduction gear (for the reverse). Now, one could imagine to make that the forward direction on the boat, and leave the 1 : 1 direct for the reverse direction. Bingo!
And one other thing: Do not forget you need an axial bearing to get the thrust -or pull- from the propshaft into the hull. Fairly simple to do with a belt or chain drive link between PTO and propshaft.

Thanks for finding this gearbox!

Bruce46

04-21-2011, 04:06 PM

Canoeyawl

04-21-2011, 04:21 PM

- what exactly would a layman need to "marinize" a stock engine- that was say used for a mower, or an off the shelf engine.
That is a problem - Any electrical components that may cause a spark will have to be dealt with and if it is a potential it will have to be sealed. Next a fuel system that drips once in a while on your lawnmower is a non-issue but in a boat it is a huge issue. That will have to be addressed. Marine carburetors have venting and fuel bowl overfuels that are routed either back to the tank or into the intake.
And the intake will have to have a spark arrestor fitted.
And gravity fuel is a no-no.
And a fresh air blower system.
If the engine is not in a locker (or engine compartment) then some of this is not neccesary, you will just have to deal with a gasoline fire in the boat, not an explosion at first.
(The coast guard will have a long list.)
http://www.uscg.mil/d13/cfvs/docs/acsa/ACSA_References/46cfr58.05-10.pdf

Jay Greer

04-21-2011, 05:03 PM

I often find the rverese is not all that necessary in some small boats. Oars can be used for that purpose. Not having a reverese gear is lighter, simpler and cheaper.
Jay

andrewe

04-22-2011, 02:49 AM

In an earlier post on this thread someone suggested mating a vertical shaft engine to a cut down outboard leg. F.N.R. plus gear reduction solved cheap. a back yard version of pod drive. If you want a bigger prop use the leg off a bigger ob. Heck you could even use the stock water pump to cool the exhaust.
Yes, that was me. The catch was that the engine runs at half the RPM that the 2T outboard did. So I rigged a step up 2:1 with a toothed belt. The engine is alongside the leg, not on top of it. So the step up is from the bottom exit shaft of the motor, then a layshaft up with a 1:1 toothed belt to the top of the leg. A bigger leg would have solved the reduction with a bigger prop, but much heavier and not what I had lying around. The 10hp Suzuki leg is heavy enough as it is. According to other builders, engine weight is an issue with water tending to get in the self draining c/pit when heeled.

I haven't used it yet, as the boat is not finished and after putting together the basic unit, I dismantled it and the bits are in storage. And yes,the exhaust will be stainless and cooled by the water pump in the leg. That bit will wait until the boat is ready for it.
A

Huntsmanvb

04-22-2011, 12:31 PM

Check out post 7 in this thread: http://forum.woodenboat.com/showthread.php?14287-Prop-shaft-tube-cutlas-bearing-and-stuffing-box&

He used a 1:1 direct drive 5 horse with a 7" prop, to good results.

donald branscom

04-22-2011, 03:47 PM

w88k

10-28-2011, 03:40 PM

This thread is amazing in it's longevity... OK, I'll add to it. I am a retired Destroyer Sailor living on a fixed income (that means older than dirt and poor) so some three years ago I drew-up and built a glued-Luan-lap version of the little Gartside 10' Pims motor launch... additionally "Modified" in that I extended the freeboard with an additional plank and tumble home aft to keep the wife a little dryer.

She (Lil'bit) is powered with a 1.5hp 4-stroker and centrifugal clutch I got off an old "mini-bike" I had in the shed. We ran her direct-coupled to the clutch-face for the first season (the clutch engages at around 1800rpm, top-end is about 3200rpm) which drives Lil'bit, me and She-who-must-be-obeyed to almost 5 knots (7-5 brass two-blade wheel).

Last spring I look into the go-kart gearbox thing, the one referred to earlier in this thread. Even a $200 used one was a little too much for me... so my Grandson and I decided to built one. The reversing-gear design is loosely based on an old garden-tiller transmission I once saw... a 1:1 belt-driven friction-wheel planetary arrangement where the "Sun" and "Ring" are the in-put and out-put, and the planet-carrier is locked in place only when reversing is desired.

Our homemade FR-box is an all-gear-affair comprised of two spiral-bevel 1-11/16" ring-gears (Sun and Ring) which face one another, input and output shafts in-line, and a set of two 13/16" Planets attached to a carrier. The Planets, matching spiral-bevel pinions, are sandwiched perpendicular between the rings at 180 degrees one to the other. The planet gears are attached by SS Machine Screws axils to the carrier assembly which is a pipe section "just" slightly larger in diameter that the ring gears. The whole planet assembly "rides" on the ring gear's teeth and is more or less self-centering if shimmed correctly.

A simple steel brake-band setup holds the carrier cylinder stationary when in the occasional "Reverse" configuration. The clutch provides "Neutral" while idling. When in "Forward" the brake-band is released and the planets and cylinder are allowed to free-wheel. Due to the friction of the planets on the ring gears, the whole thing turns on the main axils, functioning as a 1:1 friction coupling.

I found the gear-sets in an on-line tool repair catalog, intended for a 11,000rpm 1hp right-angle grinder. I bought three sets from China for less than $25 (one set just to have a spare pair). With a scrounged-up 1" section of 2-1/2" steel pipe for the carrier, some 1/2" rod stock for axils, DOM steel tubing for bushings, various SS Machine Screws and washers and a little 4" steel con-box to stuff it all in, the whole shebang wound-up costing less that $50... welding, turning, drilling and taping done by my youngest Grandson at his High School Metal Shop.

So far, she's working like a champ, and contrary to some of the naysayer's, there seems to be little vibration if everything is tight. A really neat thing is: if you happen to pick-up a crab-pot line while out mess'n-round, the planet cylinder just spins-up decoupling the wheel, so you don't smoke the clutch or eat a pin. My guess is that the same arrangement with six pinions, instead of two, would easily handle 5hp.

wrenchguy

01-16-2012, 02:00 PM

Well here goes, I collect old aircooled inboard boat engines. I accidentally came across one 5 years back and bought it just for the transmission. With 5 years of research and with contact of some major Briggs Stratton engine collectors we've come to the conclusion that is the only one known to exist. (in collector world) We agree there must be more out there, probably still being used. This engine is a 1941 Briggs Stratton model BMG. What makes this thing unusual is the reverse gear, built by B&S 1941 only. There were 3 B&S models built using their own reverse gear; 1-3/4hp "AMG", 3hp "BMG" and the 4-1/2hp ZMG. We do know of a AMG and my BMG makes 2.

Now I'm trying to reach out and find more of these engines just to acknowledge their existence. I'd like to be able to increase my literature concerning all manufacturers of aircooled inboard engines. If you have anything you'd like to share about OLD aircooled inboard boat engines please contact me.

Pictured is the "BMG" carcass I saved from scrap 5 year back, and a video of its 1st startup at the worlds largest antique engine show Portland Indiana August 2011.
Thanks for any help.
http://i113.photobucket.com/albums/n210/wrenchguy49/iPhotoLibrary.jpg

http://youtu.be/ojTK7bsXzJM

Craic

01-16-2012, 02:29 PM

...
Pictured is the "BMG" carcass I saved from scrap 5 year back, and a video of its 1st startup at the worlds largest antique engine show Portland Indiana August 2011. ...

http://i113.photobucket.com/albums/n210/wrenchguy49/iPhotoLibrary.jpg

http://youtu.be/ojTK7bsXzJM

Wrenchguy, what a transformation!
Superb job, applause from me.
Aircooled marine inboard engines, about time someone started a list of all that are and have been out there.

Philip Maynard

01-17-2012, 09:45 PM

Craic

01-18-2012, 03:31 AM

... I'd like to be able to increase my literature concerning all manufacturers of aircooled inboard engines. If you have anything you'd like to share about OLD aircooled inboard boat engines please contact me.

How OLD? -I still have an unused marinised Briggs & Stratton from the seventies or eighties, complete with Watermota Shrimp drive, with literature, you or 1786anyone?

wrenchguy

01-20-2012, 09:57 AM

Wrenchguy, your the man. So how come they only made the transmissions 1 year? was it the war? bad design? how does it operate? I have to figure if it was a B & S it must have been relatively inexpensive and easy to fabricate. Is it practical to copy it? Any chance of getting your engine in a boat?

We think it was the war and competition from other reverse gear builders ( the biggest being "joes gears"). Briggs came on the inboard market late with others already marketing in the mid 30's. Largest being Wisconsin and Lauson. Its of planetary design, I wouldn't think it would practical to reproduce. I got a old 12' Thompson cedar strip hull that would neat to put in. I show 4-6 aircooled inboards at engine shows in the midwest because their easy to haul. I plan making a couple boat shows this summer.

thanks for complements.
mike

wrenchguy

01-20-2012, 10:00 AM

How OLD? -I still have an unused marinised Briggs & Stratton from the seventies or eighties, complete with Watermota Shrimp drive, with literature, you or 1786anyone?

I'd like to stay no newer than the mid to late 50's at this time.
Neat stuff though.
thanks,
mike

kenjamin

01-20-2012, 10:25 AM

My 4HP Yamaha has forward reverse and neutral. It weighs 47 lbs. (21.3 kg). It cost $1400 new. It's very quiet at 5/8 ths throttle which is all it needs to push my Caledonia Yawl at maximum hull speed. It has an estimated range of fifty miles with the three gallon remote tank. Clamps easily to the boat so can take it with me or leave it at home (and just sail and row). Probably the best thing about it is the resale value if I ever get completely tired of listening to it. Don't really like to use it but sometimes it's a necessary evil when adverse wind and tides are predicted as I am three miles down river from open water.

Craic

01-20-2012, 12:48 PM

tprice

01-20-2012, 02:28 PM

An elegantly simple thing would be to have a B&S aircooled motor and couple it to a variable pitch prop. A sleeve over the shaft connected to a lever handle controls it. The pitch can change all the way to reverse. There was a British system that used that - Watermota? Prop was the expensive part but the whole system was relatively inexpensive and simple as heck. Sorry if someone has already mentioned this.
TP
There was a nice saildrive unit that OMC made with a small outboard unit coupled to a right angle saildrive. Tartans used them. Corrosion was their downfall - usually through the saildrive leg.

Craic

01-20-2012, 04:57 PM

[QUOTE=tprice;3276794 Sorry if someone has already mentioned this.
[/QUOTE]
Well yes, someone actually has, several times.

Philip Maynard

01-20-2012, 08:03 PM

An elegantly simple thing would be to have a B&S aircooled motor and couple it to a variable pitch prop. A sleeve over the shaft connected to a lever handle controls it. The pitch can change all the way to reverse. There was a British system that used that - Watermota? Prop was the expensive part but the whole system was relatively inexpensive and simple as heck. Sorry if someone has already mentioned this..
Yes way back in the beginning of this thread or others about that time, one of the forumites at that time looked at that unit and he offered to make a batch of them but it would have been expensive to reproduce it, as I recall that unit had some final hand fitting of the gearing. But either of these 2 approaches would work IF its low cost, small, light.

kenjamin

01-21-2012, 08:47 AM

And the relevance of this posting for this thread about "The quest for the inexpensive small inboard with reverse" is what exactly ?

Sorry, I misread the thread title. I could have said that I think of my little outboard as an inboard because I've mounted it midship on my Caledonia Yawl. It does feel like an inboard when you do this because the noise of the motor is well removed from the guy in the stern at the tiller. This set up could be referred to as an alternative to a "inexpensive small inboard with reverse" but the truth of the matter is I had a senior moment and just misread the thread title.

http://www.bodaciousboats.com/Birdrack.jpg

tpelle

01-21-2012, 09:52 AM

Has anyone mentioned the Kitchen Rudder? It would work perfectly with a direct coupled drive with no clutch or gearbox - that's what it was designed to do - as it provides forward/neutral/reverse/and steering!

There's a decent description on Wikipedia, if anyone wishes to persue it.

John A. Campbell

01-21-2012, 11:41 AM

I should have reported on this several months ago but failed to do so so now I'll tell my story..... I had attempted to install a Honda GX200 6 hp gasoline engine on an old Montgomery Wards garden tiller belt drive transmission to be installed in my 16-foot "Victor Slocum" ......I thought this idea was a good one but it damned sure didn't turn out that way. The main problem was the fact that the cast iron housing extending to the tiller tine gearhead had to be sliced off at a machine shop and a bearing installed to support a small jackshaft. The machinist was unable to bore the housing accurately enough to line up precisely with the front plate of the transmission. This resulted in some vibration, especially one particular time when I overchoked and flooded the engine. This resulted in the bearing being destroyed........I consigned the transmission to my junk pile and set the little Honda aside for another day. I'm thinking about installing it in my 10-foot skiff "Annabelle", a very nice Atkin design, along with the Comet torque converter and gearbox mentioned above......and many thanks to you, Lister, for finding that gearbox and torque converter. As for the "Victor Slocum", I have now taken delivery of an electric drive system from EVAmerica.....will run her on 36 or 48VDC with the A00-4009 traction motor........Denny Wolfe has been of great assistance in this continuing saga of the "Victor Slocum".

Philip Maynard

01-21-2012, 11:57 AM

I have been using my direct drive for over 10 years. It sure would be nice to have a small,cheap, light transmission but even without one I'll take it over an outboard any day.

Craic

01-21-2012, 04:59 PM

... the truth of the matter is I had a senior moment and just misread the thread title.
Kenjamin,
I respect you for that statement.
And I think you were not really so very far away from the thread after all.: Outboards are inexpensive, and maybe finding a way to adapt or convert them or parts of them to let them work as semi-inboards like you do is not so bad an idea.

Mad Scientist

01-21-2012, 05:55 PM

Kitchen Rudder: WoodenBoat 185, page 86. Article by Barry Millar.

Tom

wrenchguy

01-21-2012, 10:25 PM

And the relevance of this posting for this thread about "The quest for the inexpensive small inboard with reverse" is what exactly ?

as a noob i dint want to start a new tread..... this one was going 5 year and i found it thru google. remove it if its not acceptable.

Philip Maynard

01-22-2012, 07:15 AM

Wrenchguy, I think Craic was talking about kenjamins outboard post # 167, not your post - which fits perfectly with this thread..

Craic

01-22-2012, 07:38 AM

Indeed.

Craic

01-22-2012, 07:49 AM

Mike Hanyi started this thread 5 years ago, and the boat that he wanted a cheap small inboard with reverse for is past history. But why not carry on a bit?

First question is, and should have been 5 years ago: Generally speaking, what kind of boats today (design and intended use, examples) would really benefit from a small lightweight inboard today? -I myself had one small open longkeeler for fishing etc. and for that the inboarder was perfect. I have other flat bottom centreboard boats, and for those an inboarder would be nonsensical.

So again, what kind of boats are out there -and how many of them- which would benefit more from a small inboarder than from a small outboard?

Philip Maynard

01-22-2012, 04:10 PM

Well, I've posted this before, this is Edwin Monk's Cerlew, a 16' daysailor.
What makes it work as a type is it has a skeg to hide the prop and in my case the engine fits under the rear seat.
I have a 7" prop that's protected in the skeg in a boat that draws 10" with the CB up.
I open the fuel vent, open the fuel valve, turn on the ignition, set the choke and throttle and pull the starter, it usually starts on 1 or 2 pulls. The engine is never in the way, yet its readily available. The biggest drawbacks is the thru-hull fitting for the stuffing box and no reverse or neutral with direct drive. And of course I'm always dragging a prop, if I was in the back of the pack it would bother me but I'm not and the boat sails well so it doesn't bother me. Of course a folding prop or full feathering prop would help.

http://www.pmaynard.lunarpages.com/index_files/image028.gif

Jon Agne

01-23-2012, 09:47 AM

Has anyone ever used one of these?

http://www.dolphinengines.co.uk/

Craic

01-29-2012, 04:33 PM

tpelle

01-30-2012, 12:59 PM

I suspect small inboarders are a minority interest these days, inexpensive or otherwise. Outboards are so cheap and hull forms are going mostly flat bottomed, so why bother much about cheap inboard system.

However, even if it is just a mindgame, maybe it is time to find a new concept for inboard installations. So far, inboarder installations are still pretty conventional, engine, gearbox, driveshaft, propellor. There were suggestions in this thread to abandon the old mechanical ways and go for electric hybrid drives or for hydraulic drives, the parts for which may be found today in commodity garden machinery so being fairly cheap.

The intriguing bit is of course to be able to avoid a mechanical reversing gearbox, and a long driveshaft. Are there cheap parts out there suitable for an inboard electric hybrid drive, or for a cheap hydraulic drive? -Never mind the ultimate efficiency issue here.

Actually, if you really HAD to have some sort of power, say, to move the boat in and out of harbor (not really depending on cruising any great distance), the perhaps hydraulic might be a way to go. A small engine driving a hydraulic pump, a small hydraulic tank, then connect the hydraulic hoses down through the keel to a hydraulic motor driving the prop.......has some possibilities. Remember, the engine, pump, and hydraulic supply tank can be located anywhere in the boat. The motor could even be on the bottom of the rudder, with the hydraulic lines run down the rudder blade.

But then is this any better than a Torqueedo, or those do-it-yourself trolling motors stuck on the end of the rudder, as on, say, the electric version of Devlin's Nancy's China? For extended range you could run a small generator for recharging the propulsion batteries using a small engine. This is probably cheaper and easier than the hydraulic version, and probably more versatile, as you could go short distances silently!

Philip Maynard

01-30-2012, 06:32 PM

Your getting into complexity that will cost. Aircooled gasoline engines are common, cheap, well understood. As the original post stated, if we could just get neutral and reverse, we would be all set. Not to take away from hydraulic, electric, kitchen rudders, etc, what ever anyone wants to try by all means, but give me a simple mechanical F-N-R.

Ron Williamson

01-30-2012, 08:01 PM

Robb White described that in a WB article some time ago.
A small Kubota diesel was belted to a drive shaft below it.
Lift a lever to raise the engine and the belt tightened for forward.Lower the lever and it engaged solid rubber friction wheels for reverse.
I thought it was brilliant.
It may be mentioned earlier in this thread.

R

Philip Maynard

01-30-2012, 11:01 PM

Keep in mind the Kubota is much heavier and larger then the typical aircooled gas engine and anything with belts is going to be much larger than something geared. So far in this whole thread, nothing comes close to what wrenchguy posted as a match for small aircooled engines in the range of 4 - 6hp. A small enclosed box that is lubricated and at least somewhat protected as far as marine environment.

Craic

01-31-2012, 03:38 AM

Your getting into complexity that will cost. Aircooled gasoline engines are common, cheap, well understood. As the original post stated, if we could just get neutral and reverse, we would be all set. ...

Philip you make it sound simple, but it isn't really that simple. I had an aircooled gas engine with reverse.
First, aircooled gas engines rust in a marine sit like ice melts in the sun. You must replace them fairly often, I got five years use out of mine, but then couldn't replace it since Kubota had stopped making the model. That was not so simple.
Then, even if the engine comes with a mechanical starter, in a boat you really need an electric starter, because one cannot leave the helm for long to pull a starter cord a few times. But then, aircooled gas engines with electric starter are not really cheap anymore. And, one must have a battery installation with it as well, and that means weight and fusebox and cabling and electric corrosion and before long .. faults. Not so simple.
Then, one needs an exhaust piping, dry or wet, it is still quite some installation. If its just a dry exhaust, it must be insulated so it does not burn hull or fingers. For a wet exhaust, you will need a separate water pump connected to the engine.
And the tank temperature is an issue. No problem if the engine is in the open, but as soon as there is any housing around it, the thing heats up beyond safe levels. Not so simple to put the tank somewhere else because the cheap gas engines are gravity fed and have no fuel pump.

Then, the coupling of the engine to the shaft is a bit of a problem. Then, the small gas engines have no proper axial shaft bearings to take the propulsion force. Same problem with a belt connection btw, the propeller shaft must have both radial and axial bearings, proper ones.

Each in its own not a big problem, but it all adds up, so even if you are starting up with a small cheap gas engine, you will end up with quite an installation overall, and nothing to last for many years.

By contrast, to have an electric pod motor in the rudderblade, a removable lithium battery from an electric bicycle, an electric switch F-N-R, and a socket to plug in a small portable generator on occasion you want to go far, wouldn't that be much simpler, smaller, cheaper and lighter weight?

P.S. Oh I almost forgot the noise from the aircooled gas engine, it is considerable and after a while becomes problematic. And it is worse from an aircooled diesel. C.

Philip Maynard

01-31-2012, 07:22 AM

I do not need electric starter, I do not need thrust bearing, my first engine lasted 10 years. My experience with direct drive is its fairly simple, I'm mot saying the gearbox is simple, just everything else up to that point. You are free to go electric, hydraulic, whatever but I know what works for me. We all know aircooled is not quiet going into it (mine is about as loud in cruise as the honda 2.5 aircooled). The best sailing days are the days I do not use the motor.

Geoff Pike

01-31-2012, 12:00 PM

First off, thanks to everyone who has contributed to this thread. I have learned a lot, and discarded some previous ideas I held.
My motivation behind reading these posts is the planned construction of a St. Pierre dory for sea-duck hunts here in Maine. I could used an outboard in a well, but the extreme cold frequently causes the water pumps to freeze. This led me to either air cooled, or a closed loop coolant system.
The use of a small (10 h.p. approx) aircooled appeals to me on a couple of levels, one being cost!

I like Robb White's method of tilting the motor, belt drive, and the tire for reverse. I think the sheer simplicity speaks to the genius of it.

That said, with mention above about the lack of weight of these motors, I am trying to wrap my mind around a way to tension the belt without going to spring assist or pnuematics. Given a couple of months, and some warmer weather, I will start experimenting.
Any suggestions for a neutral using this method?
I am also thinking about a Brockaway skiff , because I have a temporary obsession with them, an using that as a test bed.
Thoughts?