Question for the electric boater with prior sailing experience

[wcralle1]

Question for the electric boater with prior sailing experience.

Do you have an electric boat? Or have actual experience with an electric boat?
Did you use to be into sailing?
Then maybe you can help me out with some advice.

The background:
I am in the process of building a 22 foot sailboat. The princess 22 cat ketch sharpie by B&B yacht designs to be exact. I am building this boat as a trailer sailor. I chose this design because it looks like an easy and fast boat to launch and recover, and I like the no hassle cat ketch rig for easy tacking. I have a lot of sailing experience in boats of this size.
I have decided on electric propulsion for this boat.

My most favorite things about sailing are:
 The laid back pace.
 The quiet.
 The excitement of speed and getting the rail down on a brisk day.
 The look and feel of the sails set and full.

My least favorite things about sailing are:
 Long and involved launch routine from trailer to water, and long recovery.
 Flat limp sails on a no wind day.

The Premise:
I have done quite a bit of research on electric propulsion of boats, and the more I read, the more I like the idea. For my type of boating, electric propulsion seams to fit the bill.
So now I am thinking about leaving off the “sailboat” stuff (centerboard trunk, masts, and sails), and making this into an electric launch.
I am thinking that I might spend the majority of my boating being pushed around by electricity rather than the wind.

The way I see it the advantages are:
 Quick launch, no raising of masts, and rigging sails and lines. Just slide off the trailer into the water.
 Speed comparable to sailing, 3 to 5 knots.
 Satisfactory Cruising time that is in line with the majority of my outings (6 hours at 4 knots.)
 Quiet and odor free.
 Faster build time by eliminating the rigging and the complicated and leak prone centerboard trunk.
 Less money spent on masts, sails, and tackle.


The question:
Do you miss sailing?
It looks to me like the electric launch has 2 out of the 4 things I like about sailing, and none of the things I don’t like. The electric launch doesn’t have the excitement of rail down sailing on a brisk day, or the beauty of full set sails. But it also has the hands down advantage of low setup time when launching, and ease of handling. Making short outings (1 to 3 hrs) on the water feasible for the person with limited spare time.
If you were in my shoes, and in the building process, would you carry on and invest the time and expense to complete the boat as a sailboat?
I have estimated the cost of motor, batteries, charger, and E-meter to be comparable to the cost of masts, sails, lines, and tackle.
Is it worth spending the extra money and building time to end up with a boat that possesses the attributes that are unique to a sailboat? Or is an electric launch fun enough?
If I build this as an electric launch, will I be sorry that I didn’t go ahead and make a sailboat?

Thanks William

[Frank Wentzel]

Down here in Florida we have several springs that use electric launches. They are about 35 feet long an carry 20 people. Actual run time is on the order of 4 hours per day at less than 5 knots. One of the boats recently had the battery replaced. It used 3 batteries that weighed 1,200 lb each. I was told they had an 8 hp motor. That points up the only problem with electrics - terrible energy density. I've always loved the idea of electric propulsion (on land and water). But the energy storage problem is always there.

/// Frank

[PugetSound]

And what happens to all of the toxic stuff in the used batteries when they are refurbished?? Electric power has it's attractions, there is no denying that, but no way is it pollution free. More like pollution deferred.
Frankly, I think you can do pretty well with one of those hybrid setups where you use a small genset to top-off the battery. But for your average Saturday outing in semi-protected waters, a simple electric setup will work fine provided you remember that the charge duration (energy density/mileage-per-charge)degrades at some point (about 2/4 to 3/4 of the battery life span of about 500 rechargings).
I think your original idea of a sailboat with an electric auxilary is the best bet.

[doorstop]

How much area of solar panels would be needed to help the batteries out? Silly Q???

[nedL]

Years ago, at a yard I worked at, I was in charge of building "reproduction" circa 1880's, 22 foot long fantail launches. They were offered in steam (Semple steam engine), gas (Easthope engines), or electric( used golf carts). Yes, I would go scout out used golf carts, have them delivered, & cannibalize the guts out of them. They were a cheap & effective solution. About $100 for the golf cart & then 4 - 6 deep cycle 12v. batteries. The launches did 4 - 5 knots nicely. ---Just an idea for you.

[Frank Wentzel]

The "toxic" material in a lead acid battery is the lead itself. Other than the plastic case and any connector bolts the battery is made of lead - active material, grids, intercell connectors - all lead. Because of this the lead acid battery is one of the easiest items to recycle. No metals separation or refinement is necessary. Almost 98 percent of all lead acid batteries are recycled. That claim can't be made for any other material. The bulk of the lead comes back as new batteries.

In the olden days, when I were a tyke, lead battery smelters were an environmental disaster. Since the EPA got on them lead smelters have become one of the cleanest industries imagineable. No need to feel "ungreen" for using lead acid batteries.

/// Frank ///

[wcralle1]

Frank Wentzel
I have been to one of those springs in Florida. Don’t remember exactly which one, but it was close to Tallahassee. The electric boat was a very nice quiet ride. It was also much heavier than my application.
I project my boat to weigh in around 1800 lbs.
One horsepower at the shaft will deliver 60 pounds of static thrust.
The sq rt of the length (21.17 feet) is 4.60.
The cubed root of the displacement/horse power ratio is 12.165
((10.665 / 12.165 ) * 4.6) = 4.06 knots.

One horsepower at the shaft requires 937.5 watts of energy.
(h.p. = 750 watts divided by an efficiency factor of .80 equals 937.5 watts).
A six hour cruise will require (937.5 wats * 6 hours = 5627 watt/hrs).
Battery bank size needs to be 30% greater than the energy needed, so you never discharge the batteries below 30%. In this case about 305 amp hours at 24 volts.

Eight 6-volt AGM deep cycle batteries weighing 65 lbs apiece will provide the ballast 520 lbs. for the boat.

So, I don’t know about you, but a 6 hour cruise, ghosting along at 4.06 knots sounds pretty nice. And most of my boating would probably be in the 2 to 4 hour range.

Custom Skiffs
Hi. As I understand it you have actually sailed the princess 22. What are your thoughts on electric propulsion of that boat? Would I miss sailing if I left off the masts? By the looks of it, the hull should slip thru the water just fine.

Pugetsound
Thanks for your thoughts. Actually I am not too concerned with the “green” aspect of electric boats. I just like the idea of moving thru the water silently. I need ballast anyway, why not use 520 pounds of batteries? As you can see, “energy density” in this case one pound equals 14.07 watts, is clearly sufficient for my intended use.

Dorestop
Haven’t done the math on solar panels yet, but they are on my mind. Just off the top of my head I would guess that a solar awning would extend the range by between a third and a half.

Nedl
4 to 5 knots sounds fine to me. Thanks.

The question:
Will I miss sailing if I build this as an electric launch? Did you?

[Andrew]

If you have to ask, I think you will.

[Ian McColgin]

'Course you'll miss it.

Why not concentrate on easy ways to get the rig up quickly and maybe put in some sweeps for those windless days. Also, that extra quarter ton of batteries will require its own support and I think you'll end up adding extra weight for support, not to mention the motor and such. Better figure on an extra 700# at least. I'd push on some sweeps quite a lot before I tried to reengineer a light boat to take that load bumping around behind a trailor.

Electric motors, like steam, have their attraction for the right kind of monkey wrench or solder tip sailor. To each their own but I think you want to be talked out of this one .

G'luck

[Seppo]

Hi

you might look at the electric boat association's web pages at www.electricboat.com. Here in Europe, in Britain, is one electric (boat and other) engine maker at www.lynchmotors.com (if I remember it right). Lots of info; association has got a discussion list.

Seppo

[wcralle1]

Ian,
Thanks for your thoughts.
You are probably right about missing sailing. The truth is that I don't really know if I will or not. Currently I am pretty enamored with the idea of electric propulsion, and a solar awning, and hassle free silent boating. The concepts sound very attractive to me. What I am looking for is some actual experience with these. Is it all its cracked up to be? Maybe the silent hassle free aspects will turn out to be rather booring. Who knows??
Anyway, The designer wants over 400 pounds of ballast in this boat anyway, and in conversations with him, he has said he wouldn't mind seeing a little more ballast. So the 520 pounds of batteries are not really overloading the boat. Electric motors are very light weight for their h.p. so no real allowance for the weight of the motor needs to be made.
Im not familiar with "sweeps". Oh wait...... is that the same thing as oar locks? If so, then yes. not a bad idea.

Anyway, thanks to all for the advice. By my tally, It appears that the concensus is 100% unanimous in favor of me using electric propulsion for this boat.

William

[This message has been edited by wcralle1 (edited 11-15-2001).]

[carlg]

I've built three electric boats: 12', 16' and 20' sharpies and thoroughly enjoy cruising quietly and sneaking up on wildlife. The 20-footer is a double ender and is approximately the size you're building, but with much lower freeboard and no cabin - just a decked open boat. It moves along very smartly (probably about 5 kts...I've never checked it accurately) even against a strong wind and is powered with a slightly modified 24V 74 lb. thrust Minnkota trolling motor. One charge is good for a day's operation at moderate speeds.

You're probably considering an "inboard" electric motor rather than a trolling motor so you'd likely have more horsepower to move the additional windage. I'd go for it.

And I miss sailing. Used to race twice a week when I lived back on Lake Michigan. Will take it up again when I move back.

[Bruce Hooke]

To me a key part of what makes sailing different from motoring is that with sailing you are much more engaged in the process. Where in motoring you basically just adjust the throttle and head for where you are going, on a sailboat you are always paying attention to the wind, adjusting the sails, steering to meet the gusts, etc. For an evening cruise in a scenic spot with nice company an outing on a nice launch is a fine thing but for the most part I would rather be sailing. However, it all comes down to what you like to do. What you probably need to do is try to imagine repeated outings on a this boat as a motorboat and as a sailboat and sense how you would feel about each one. I wouldn't focus so much on the logic of this (I like this and this so therefore I should like that), because this isn't about logic. Focus instead on your internal (gut level) response to each possible experience...

[wcralle1]

carlg and bruce,
thanks for your enlightened and informed response. This is just the type of insight I was looking for. And as often happens when encountering great wisdom, the lightbulb goes on and you get one of those "of coarse" moments.

Following your sugested excersize in emagination, I realize that my boat must have sailing capabilities. otherwise as you so insightefully pointed out, I would be boat driving rather than sailing.

I am thinking about building a largish rudder with a trolling motor built-on in some way. possibly even 2 motors. I am looking at those trolling motors that are ment to be attached to the anticavitation plate of a gas outboard motor. these look like they would mount rather easily to a specially designed rudder. I want to have 2 h.p. available, but plan to motor about using 60 lbs thrust or less.

Thanks again for the insight.
William

[TomRobb]

Someone, WB I think, had a article about a rudder mounted trolling motor fairly recently.
MinnKota has 3 or 4 horse trolling motors. Of course HP is current and lots of current means either short run time or lots of very heavy batteries. Then there's the fairly short halflife of the batteries themselves which will cost as much as the motor.
Still quiet is nice.
One of the happiest motorboaters I ever saw was a guy w/ a trolling motor in a kayak.

[John M]

Check out Devlin's sailboat Nancy's China DC. It has the electric motor on the rudder.

http://www.devlinboat.com/dcnancyschinadc.htm

John M

[Ian McColgin]

The bit in the rudder is cool looking, but check also Phil Bolger's remarks about busting up components and concomitant warrantee problems. I don't think he's so much agin (after all, he's the guy that made a planing sternwheeler with a canard!) it as he likes boaters to have their eyes wide open.

Have a sweep anyway -
Electricity + Salt Water = Green Guinge

[Seppo]

Hi again...

just partially connected with the matter, in the German Yacht magazine was a story (some time ago) about a couple that went around the world with a sailing boat with electric motor in it; it seems that main problem was somewhere in Atlantic when they noticed that batteries were flat - the cockpit floor had leaked some water on the motor and it did not work any more... (it was the charging kind)

Well, they had a spare motor and switched the motors, fixed the floor and continued happy e'er after or so.

One interesting part was that you can apparently use the motor at four times the usual current (as long as you have the batteries for it...), for a short time - they had some miscalculations with tides and had to use do so to get thru some reef openings somewhere in Australia.

One small problem they had was when they were going thru the Kiel canal - they had sails up and the local police boat boarded them because you must have the engine running all the times there and the police saw no exhaust fumes or cooling water coming out...


Regards
Seppo

[Paul B]

Have you looked into the Electric Wheel, marinized by Solomon Technologies (http://www.solomontechnologies.com/wheel.htm)? I'm looking for some opinion on these.

[blisspacket]

I recently sold a Pearson Packet, 18', that I converted to electric power. 36 v MinKota 101 lb thrust, six WalMart deepcycle batteries. Total disp. about 1600 lbs. Last event we participated in was Round Wye Island, about 23 miles; came in with LOW batteries, but we finished. Enjoyed the company of 2 other elec.boat enthusiasts. Next day sailed the same boat in the MidAtlantic Small Boat Festival race. Worked and sweated and toiled to get the gunter rig up and tuned, reefed in the 15-18 knot winds. When I sold the Packet we did sea trials on just the electric. As such, it is eminently useable. Rigging and sailing she's a delight also, but USING and enjoying: electric is the way. Eboating is NOT for getting there:the journey is the destination.
I also rigged the MK motor onto the rudder shaft, and that makes it eminently maneuverable, including reverse. If you look at power provided by solar cells, you'll be amazed (I was anyway) by how costly and inefficient it is.
Decidedly for me MK (not Motorguide) is the way to go. My present boat is a Maxwell cutter. When I find a used 101thrust MK, I'll chuck the Tohatsu (I should say too that I have a Westerbeke genset that will pump up batteries when I'm away from the dock).
Yes, an Emeter is the intelligent instrument to have also.

[KarlSchmid]

I am a sailor and electric boat owner. My formerly electric-powered (three seasons) 19' skiff is currently being re-powered to diesel. Some of the reasons for this I posted on the current thread "Electric for Main Power" on the Resources/Product Search portion of this forum.

I've seen a cat-boat of approximately the size you are building with a 36 - volt 4hp system as the auxilary power. I think this is definitely the proper use for this technology at present. I was planning to save the motor and box intact for a future project of this kind, but am having second thoughts due to space limitations in my garage. (professionally-built box is awl-gripped with oak-trimmed lid) Contact me off-forum to discuss.

[Dan Hobson]

Wooden boats are cool, Sailboats are cool, Electric boats are cool. And the coolest thing is that there isn't any reason that you have to choose one over the other, because you can have all three!

If you simply select a design where the mast comes off of the boat without a crane, there is not a single reason to trouble your self about what you will be missing. Select a lightweight rig. It's just that easy. Sailboats don't have to run under sail. But to minimize the peanut gallery questions about when are you going to get the mast put back on, you might consider skipping the cabin and configuring an open boat with plenty of sun seating.

Everyone here has generously provided a lot of great information about variouse systems that will power your boat. A couple of thoughts that have come up in my reading I want to share with you. More power is good. Hull speed is not a brick wall. And power ratings for electric engines don't compare to gas engines.

Hull speed is where the curve of power to speed turns upward and becomes steeper. Your hull is not limited to it's hull speed. That's just where the power to speed ratio is most eficient. An electric motor will place the most drain on the batteries at it's highest output. If it reaches hull speed significantly sooner than highest output, the endurance of the batteries can be increased by a huge factor when you are cruising at hull speed. while it's true that more power may only result in a knot or two of extra top speed, that may be enough to make a difference in some circumstances. So don't just figure the hull speed of the boat to be the maximum power requirement for safe operation.

Good Luck

[brian.cunningham]

Originally posted by Frank Wentzel:
I was told they had an 8 hp motor.

You have to remember that that's a continuous rating, not the peak hp rating that we're used to with gas/diesel engines. My guess is that the peak rating is around 20hp. With whole lot of torque! which BTW happens when the motor it NOT spinning.

[Buddy Sharpton]

I have about five years field experience with a "half size" approximation of what you're considering in many ways.

Here are my "data points":

Mine is a 15' Joel White Marsh cat - a big boat for its length.

I substituted two Group 27 12v deep cycle batteries for the recommended 180 pounds of ballast bags.

I built a 47 pound thrust trolling motor thru a tube into the skeg with the propellor right at the stern of the boat in a 2 1/2" gap between the skeg and barn door rudder. It can still swivel, but cannot be retracted in a well or kicked up like the transom mount it used to be.

I have on board in the cuddy a 29 pound 2 horse 4 stroke long shaft. Honda and a mahogany bracket for same which puts the motor head below the height of the transom out of the way of snagging the mainsheet, and being low ,blocks much of the sound from getting into cockpit. The motor can still kick the prop up clear of the water.

Recommended outboard power on this boat is a 4-5 horse outboard clamped to the top of the transom

The Marsh Cat sails up to 4 1/2 mph.
At 80% throttle, the "electric inboard" yields 2 1/2 mph.Each battery last about 2 hours and 15 minutes before I switch due to it slowing down.
It is never fully discharged.

The air cooled Honda has a sweet spot in speed/ noise ratio at 60% throttle yielding about 3 mph and burns its liter of fuel in about 45 minutes. WOT is about 4 1/4 mph.

No surprises in any of this performance data.

We also have a 15' Boston Whaler with a 50 horse 2 stroke engine.

My wife goes out with me 2/3 rds of the time. This is a BIG DEAL to me in enjoying boating. She likes sailing in that not too little, not too much but "just right" wind bracket. She likes fishing more.

We sail and fish on lakes and salt water coastal areas.

Hence both boats live on trailers ready to go. Do the long distances at 60 mph, then launch. Even around Savannah- closest ramp is 1 mile, use about four others up to an hour away mostly.

I can rig,launch and retrieve either boat single handedly and do so 20% of the time.

Mostly either boat gets used as a couple and about 20% of the time another couple of people are also aboard. So 2/3 rds of the time, it's just my wife and I.

Why I am really am chiming in on your thread -how we really have used the boats. Some results surprised me.

We usually sail just about only on the "perfect" days. The all weather utility convenience of the Whaler gets it used much more often. Old sailor man in me hates the truth, but with weekend company especially kids and ladies, I can't give a sailing adventure way, but they "might" like a boat ride. Launch the boat and keep it at our dock for two or three days at a time and make 1 1/2 to 4 hour outings.

Surely 85% of the time on the Whaler we are only putting around at 5 mph or at anchor. The sailboat can do that for goodness sake! But we can and do cross bays and run "out" or "back" the river at 28 mph planing speed. But most of the time we quietly putt along the creeks in the marsh. Seldom use the Whaler on lakes any more and kids have grown- not much skiing or knee boarding these days ( had the boat since 1988)

With either boat you can overnight- two board the cat boat or up to four with either boat camping on the shore. Don't do that more than twice a year, but we have all the gear prepared for bugs and rain and sun showers et al.

With the sail boat, on a lake we seldom use the Honda- The electric gets us out of slip or away from the ramp and out to the wind. Then we sail.
If the wind gets light we'll continue with silent running and four hours of running time is plenty. Our outings revolve around how many hours, not how many miles.

The Honda stays out of sight in the cuddy as trip insurance. Our sneaky electric inboard is a marvel to guests and on lookers. We "could" cover 30 miles and get home in 12 hours with 3 gallons of gas aboard, but 5 miles is our usual operating radius. Interestingly, at planing speeds the Whaler moves 25 mph at about 9 miles per gallon. The catboat goes about the same 9-10 miles per gallon at one eigth the speed. Both boats weigh 1200 pounds.

The electric motor is great for jockeying the cat boat onto trailer.

In the salt water ,the electric propulsion is great for motoring straight into the wind on short stretches of the winding creeks instead of short tacking against a tidal current, but when I'm alone I enjoy the tacking game against nature.

But because of the 3-4 mph current, I most often rig the Honda outboard from the get go. I put up with the "ugly" on the transom because of the practicality of the extra push and being able to transverse 4 mile stretches of wind creeks between rivers faster than on electric.

I can tell I am dragging a three blade prop on the electic setup. Left as is, when sailing or outboarding the prop turns the electric motor and produces an annoying tick'tick'tick - a sort of speedometer. I made a "clutch" so the prop can freewheel and eliminate the noise, but you have to put your hand in the water about halfway to the elbow to disengage and reengage. I later read that a freewheeling prop is more drag than a locked one so I made a prop lock as well and you don't have to get your arm wet using it. Drag is still there.

On a white capping,windy( 12 mph) day the cat boat is only going to go so fast so I feel I have plenty of sail area to overcome the prop drag. But on lighter days when my wife would go out, I know the drag is often slowing me down.

So in salt, tidal water I more often pull the "inboard" prop at the ramp and mount the Honda.
Batteries stay aboard as ballast and to run the lights , bilgepumps ( keep rainwater out of open boat) and radio. And I don't worry about the drag.
Once you have started the Honda for the weekend, it will restart on one pull. The Honda is so light because it has no shifting gears. On my 22 foot sloop, I can pop the 8 horse Honda in and out of neutral to finesse a trailer or dock landing. On the catboat I used to use the electric drive the same way. But I have found its just as easy to kill the Honda and coast in, even with the current. If I am falling short, one pull gets me a boost. I have became very trusting of this technique- no real downside to a "spoiled" glide approach anyway.

I like that with the transon bracket mounting the long shaft powerhead lower, as with the electric inboard, the Honda will not hobby horse the prop out of the water in a chop. In practice, if it is blowing that hard the boat is more comfortable to sail in and only when I have reached the protected area of the dock or ramp to then start the motor and lower sails.

Point is, as nifty as the electric set up was to "engineer"and experiment with- if a had to choose one or the other...on the basis on weight ( and the catboat being a burdensome boat that will never plane, this is not a problem)... or the basis of money of bang for the buck ( but my money is already spent)... the envelope please...

I'd buy the Honda and go sailing.

Put the effort into a great bracket or motor well set up to ease the ugly or noise best you can and by all means be able to easily get the prop out of the water when you're sailing. Even with a light 29 pounds,off, up and away back into the cuddy or into a cockpit locker once you hoist sails and back onto the transom again when you drop the sails just isn't real life practicality. Doesn't happen that way except for the photo shoot. You don't have a "trophy" picture of a small sailboat with the outboard on the transom.

Put your design effort in a rig thats fast and easy to set up and take down.

Put as much effort into trailer bunks, rollers,tongue length, side guides and such that the boat floats off easily and returns to rest properly on the first time without repeated trys to "center" or lots of on shore manhandling.

If you dread the rig, launch and retrieve hassle but.. if the boat was already in the water... or you if could leave the boat in the water for a few days it would be "worth all that trouble" to put in..

Well you either have the wrong daysailer mindset, need amooring/ docking situation or go to work on improving your rig set up and trailer design.

And having said all of this, I have always had both a paddle and an sculling oar at the handy on either side of the centerboard trunk. Most of the time I sail all the way out and in and drop sail only before leaving the dock to get back on to the trailer, and the paddle works quite well. The barn door rudder itself sculls brilliantly to "power"straight line or crab against the current to put the boat right on the bunks.

So the O' Henry surprise ending to this long short story about my clever adaption of all today's technologies to the cat boat, really an 1850's fishing boat design...

If you in practice pleasure day sail a small boat on the "good" days- an oar or paddle is the power all you need.

If you are serious about finding and catching fish,a planing outboard boat is the way to go.

If you do both activities, have both knid of boats in a size small enough you can afford and use with a minimum of set up and maintenance hassle.

Bet the results of my experimenting didn't surprise anybody much but me.

[openboater]

I’m in the process of doing just what you want to do, I’m rebuilding an old sailboat into an electric launch.

I’ve spent my life as an avid canoe racer (33 yrs of racing). Mostly whitewater downriver, marathon flatwater, and some slalom. All canoe, I dislike sitting in kayaks. As I approach retirement, I want to cruise the shoreline of the lakes of NY and New England. I love cruising within 100yds of shore and looking around, Just like I love cruising the 2 lane roads. I’ve never found a garage-sale (tag-sale) on an interstate highway.

Last year I bought an O’day Daysailer and strapped on a 4hp Tohatsu 4cycle. I ditched all the sailing stuff (mast, boom ,etc) in the weeds next to the garage and went on a few cruises.

Great Stuff ! But now I’m making it better. What I don’t like about a sailboat is the bench sideways seating , cuddy is too small to be useful and a leaky centerboard. I borrowed my neighbors Makita saws-all and attacked the Daysailer. Old fiberglass is hell on blades, dulls them in a matter of seconds. I ditched the Makita and got out the trusty Stihl. In about an hour I had the 280 lbs of fiberglass liner and cuddy cut out of the boat and weighed at the landfill. 20lb rudder and 20lb centerboard are over in the weeds with the mast. Next was Sanding the bottom and filled the centerboard trunk with mahogany 5/4 and epoxy.

The boat is now in my workshop for the winter, totally gutted and looking like a fat square-stern canoe. I’ve installed the rear bench seat athwartship facing forward (3 ft ahead of stern) and will install the forward bench facing rearward. Seating for 4. I will foam the bow and stern corners for flotation then add fore and aft decks and combing. Followed by an 8’ by 5’ canopy with the cute scalloped fringe.

I’m replacing the 4hp with MinnKota, probably 24 volt maybe 36, haven’t decided yet. The Tohatsu could easily drive the Daysailer past hull speed and make this big hole in the water behind the stern. I’ve had a 36 volt EZGO for the last 2 years and have fallen in love with the ease, quiet and simplicity and friendliness of direct current. We drive the EZGO for weeks between charges and it’s so much simpler than a gas engine. Test light and voltmeter are all the diagnostic tools I need.

I’ll try and get some pictures posted. While the hull maybe plastic, the work I’m doing is all wood, so it should be acceptable to the website.

[Thorne]

This is facinating stuff!

One primary issue seems to be the weight of the batteries -- which for any sort of primary power for any sort of distance, might very well turn a planing hull in to a displacement hull.

;- )

In other words, not all sailboat hull designs might correctly handle (say) 1200 lbs of batteries as ballast in addition to the weight of crew and other gear. These would need a reenforced frame/flooring to keep the batteries from stressing/breaking the bottom of the boat in heavy weather as well as holding them in place near the centerline of the hull.

Some of the electric launch designs have a wide keel-like space where the batteries are stored well below the waterline, putting the weight where it will do the most good. (WB August issue?)

Don't get me wrong, I like electric power! But the limiting factor seems to be the weight of the batteries.

For boats that stay in the water and have displacement hulls, no problem. But for boats that are trailered and may have very flat bottoms, the weight of the batteries may seriously limit their use as electric boats. And having to load and unload that amount of acidic ballast might do nasty things to one's back, arms, and enthusiasm.

[ 11-21-2005, 07:48 PM: Message edited by: Thorne ]

[Dan Hobson]

A couple of thoughts for these last two posters. Electric motors by MinnKota top out at about four to five knots. Pushing a feather through the water they could go no faster because their propeller pitch is just that way. So it doesn't matter how full the boat is or if the hull is a deep keeled displacement or a flat planing skiff, they just won't move any faster. So you should accept the limitations of the electric trolling motor right up front.

Kipawa propellers has produced a prop for the minnkota and motorguide motors that is of slightly higher pitch. The theory is that if the boat can be coaxed to hull speed at less than full throttle the battery life can be greatly extended for more time on the water.

One last thought about the battery configuration. I once left my boat at a public dock and two deep cycle batteries disappeared overnight. The opportunists are out there. So in my most recent configuration the batteries are secured inside the boat so that they are not plainly visible and they can't be removed without tools.

My little engineering project was set up inside a 12 foot instant cat boat because I didn't like being at the mercy of the wind on a working river. Barges can't stop for you to get out of the way. I use two type 27 marine deep cycles in closed plastic tool boxes mounted amidships and a 3hp Minnkota mounted in the rudder. I feel the boat is somewhat stabilized by seventy pounds of lead battery out on each side of the boat.

[ 11-21-2005, 11:08 PM: Message edited by: Dan Hobson ]