Open electric displacement boat 16-18'

[Kaa]

I would like to have some ideas thrown in my general direction :-)

The brief is: an open boat, 16-18' long, electrically powered. This means it won't plane so it will move around at displacement speed only. The boat should carry 4 people comfortably (and let's not forget a couple of lead-acid batteries). It will not be rowed other than in emergencies. Style is generally Scandinavian/Oughtred/lapstrake kind (and NOT the common steam launch look). Expected waters are protected only (lakes, rivers, maybe sheltered bays on quiet days) and the boat won't be asked to do heroics in bad weather. On the other hand, powerboat wakes shouldn't be a cause for concern, either. The boat should be stable enough so that landlubbers can stand and move around in it without problems.

So far the possibilities include the Oughtred's Shearwater/Gannet/Fulmar series and a Selway-Fisher coble.

What other hulls do you think would be suitable?

Kaa

[htom]

Four plus batteries? Oughtred Caledonia Yawl. Atkins Valgerda

[P-man]

there's some nice traditional Swedish designs at this site:

http://batritningar.se/boatplans

like this:

[St.J]

Inboard or outboard?
A fraction smaller than you specify but still with plenty of space:

Paul Fisher's Port Pegasus keeps drawing me back to his website. This is high on my list of future boats:

St.John

[Thorne]

Have you studied the electric boat systems -your mention of "a couple of batteries" makes me wonder. What sort of range / distance / time on the water are you looking for? Will it live mostly in the water, or do you plan on trailering it every time you use it? I've moved too many marine batteries in and out of boats to ever want to do it on a regular basis!

If you plan to trailer it with batteries in place, you may need a design and trailer supports that can handle that. Can't imagine anything of the size and capacity you describe with fewer than 4 batteries, quite possibly more. And if you'll be going out daily, you'll need to be able to either recharge the banks at the dock, or swap charged batteries in & out of the boat.

[mcdenny]

First you need to set your range and speed expectations. That defines the battery energy you must carry, then decide if lead acid or lithium batteries are in your budget. That sets the battery weight the boat must carry.

Then decide outboard or inboard. Outboards are simple and everything comes in one box. Inboards are pretty much still science experiments, fun if you like that sort of thing.

A CY with a Torqeedo 2.0 in a well would be a sweet E boat. It could easily carry 300# of batteries which would take you 30 or 40 miles at 5ish mph. Put the well on the centerline, forget the rudder and steer with the motor. Side stick steering like Harry Bryan wrote about in the last WB would work great.



Denny Wolfe
Www.wolfeboats.com

[Kaa]

I have in mind a lesser project than many of you are thinking of. This boat is not meant for cruising or exciting voyages -- it is meant for puttering around not-too-big lakes, basically.

The range -- say, 10 miles or so. Speed -- 4-5 knots, maybe, while sprinting :-) less when just ambling by. Lithium-ion batteries are still too expensive and weight isn't such a big issue in a boat -- so definitely lead-acid batteries. The boat will be trailerable and live out of water. Putting batteries in and taking them out is not a big deal -- that's just exercise that you can do without going to the gym :-)

I certainly don't expect to need more than two batteries. Again, this is not a boat for going fast or far. As a reference point, I can do most of the things that I want that boat to do right now using an inflatable I have. You put in one battery, mount a trolling motor, and it works sufficiently well. However, the inflatable is a pig (in looks as well as in water resistance :-D), a bit too small, and generally not too satisfying if functional. So if one battery in a piggy inflatable is enough or almost enough, two batteries in a proper hull would be perfectly fine.

I like simplicity, so an outboard is preferable. Unfortunately, I also like double-enders :-) The issue is still to be decided, but outboards have a great deal of advantage here.

CY and Valgerda I know well, but they are designed as sailboats. I don't think I need any keel, not to mention centerboards and such. The force would be applied to a different part of the hull. I am sure they can be made to work, but it looks like overkill to me. If I were to go that way, I'd probably try to adapt an Elfyn rather than a CY.

http://batritningar.se/boatplans -- yes, thank you, I forgot about that site. And yes, things like the motorsnipas there are the kinds of boats that I'm looking for.

Thanks for the ideas, keep them coming :-)

Kaa

[JimD]

I have a 24 volt minnkota, so it takes 2 batteries and puts out 65# thrust. That's not much power to move a boat full of crew and batteries and I get about 3 hours max running time. I don't use it much these days. Got tired of having to watch the clock and the 1.5 hour turn around time. Always seemed I had to end the outing earlier than I wanted. Ideally, I would want something a little more sophisticated to go electric. Maybe 4 batteries and solar panels. And as mentioned that's a lot of weight to be trailering in a small boat that wasn't designed to be trailered that heavy. I would be seriously looking at narrow bottom wide flared dory hulls since they seem to behave better the more weight to put in the bottom of them. Anyone know anything about Atkin's Calypso 17?

The plans of Calypso show a shipshape little hull 17 feet 2 inches in over all length; 14 feet on the water line; 5 feet 5 inches in breadth; and 5 3/4 inches in draft. The freeboard at the bow is 2 feet 1/4 inch, the least freeboard, 1 foot 2 5/8 inches, and the freeboard at the stem, 1 foot 6 1/2 inches. It will thus be seen that by any stretch of the imagination this is not a small boat. ...The dory is primarily a rowing boat; but despite its beginning in oars the model is as much at home under the urge of a modest gasoline engine, or for that matter a center board and sails, as it is beneath the strong arms of an oarsman. For those that dislike muscular activities I would suggest the application of an outboard motor for this or some other dory.

That reminds me. Time to start a new solar panel thread

[Full Tilt]

Hi Kaa,
My St. Lawrence Skiff and Torqeedo outboard fit your criteria pretty well (except for the 'four standing landlubbers' part). The SLS is a very easily driven hull that takes full advantage of the Torqeedos slow turning torque for maximum range. Electric craft come with a phenomenon known as 'range anxiety', so I very much appreciate being able to sail or row home if I have to. It rarely happens since I have two batteries, one for the journey out and one for the journey back.
A sailing/electric hybrid is an extremely effective combination of two different modes of propulsion, and very compatible with each other. Running an electric motor while sailing in light winds has the effect of increasing the sailing speed due to the increase in apparent wind, and does not detract from the sensation of sailing itself.
Stop by Toronto this summer and try out my 'Anna J' and you will see what I mean.
Mike

[Gib Etheridge]

Like Jim, I would be looking at a dory. You prefer a double ender so I suggest a gunning dory or surf dory, either of which can hold a lot of weight and would be really easy to install a well in. An alternative to a well would be to mount a Minn Kota Riptide engine mount unit with remote throttle on a rudder post.

Surf Dory



Gunning dory

[Ian McColgin]

Pease is restoring an interesting huskey launch and incidentally converting her from infernal compustion to electric. Unfortunatly the pix on their site don't give an overall view of the whole boat.

[Full Tilt]

[QUOTE=mcdenny;3500934]First you need to set your range and speed expectations. That defines the battery energy you must carry, then decide if lead acid or lithium batteries are in your budget. That sets the battery weight the boat must carry.

Then decide outboard or inboard. Outboards are simple and everything comes in one box. Inboards are pretty much still science experiments, fun if you like that sort of thing.

A CY with a Torqeedo 2.0 in a well would be a sweet E boat. It could easily carry 300# of batteries which would take you 30 or 40 miles at 5ish mph. Put the well on the centerline, forget the rudder and steer with the motor. Side stick steering like Harry Bryan wrote about in the last WB would work great.



Denny Wolfe

If you're steering with the outboard in a well, what would the 'side stick steering' be attached to? I wouldn't eliminate the rudder if I was you, or you may find yourself ramming a lot of docks.
Mike

[Thorne]

If budget is such a limiting factor, and if you can do without the 4 crew all moving around at once, consider picking up an old wood or fg centerboard / daggerboard daysailor and converting it into a small electric runabout. I've seen photos of several and they are CUTE! The easily-driven hull will help maximize the limited range you'll get from only two batteries, and still be reasonably stable if batteries and seating is placed correctly.

(you wouldn't need a windshield of course)

[TR]

"The boat should be stable enough so that landlubbers can stand and move around in it without problems."

That is not a dory........

[JimD]

There's no room for landlubbers in a small boat. If you're not part of the crew you're in the way.

[JimD]

So nobody seems interested in my solar panel thread. Kaa, permission to ask my questions here?

[Kaa]

The St.Lawrence skiff looks nice but is too small :-( I definitely need something bigger and beamier. Dories are interesting and they seem to behave better with significant weight down on the floorboards so batteries would be good for them -- but don't they have not that much initial stability? There is that landlubber issue again, perception of stability is important :-)

As to an old fg daysailor, I already have a cheap-and-nasty solution which is the inflatable :-) And it has the huge advantage of just fitting into the trunk without needing a trailer. In fact, if I just wanted to get onto the water for cheap, I could just buy a used bass boat or something like that, attach a trolling motor, and be good to go. However in this case I want something... nicer :-)

An interesting idea popped up in this thread -- a sail/electric hybrid. For my purposes a pure sailboat is no good, but an auxiliary sail that I can put up to, say, cross a lake, and then take it down might be an excellent idea. Since the boat doesn't need to plane, there are no usual hybrid hull form issues. The mast will have to be short to completely fit inside the boat, so that calls for some sort of a lug sail, I think. And in that case I'll need at least a bit of a keel -- but if the sail is just auxiliary and I will never tack into the wind, maybe just the rudder will suffice?

Hmm....

Kaa

[Kaa]

There's no room for landlubbers in a small boat. If you're not part of the crew you're in the way.

:-) Remember, "puttering around on not-too-big lakes". This is a relaxing-on-the-water boat, not wheeee! oh ****! wheeee! boat :-)

Kaa

[Kaa]

So nobody seems interested in my solar panel thread. Kaa, permission to ask my questions here?

Sure, go ahead. I don't think solar panels can provide a meaningful amount of power if propulsion is involved, but don't let me stop you :-)

Kaa

[TR]

There's no room for landlubbers in a small boat. If you're not part of the crew you're in the way.

Oh rubbish Jim.............All I'm saying is that some hull forms are better for certain uses......That is they have enough initial stability that nubes are un-concerned. Below is horrible example but it does illustrate the point, try this with any dory.......

[JimD]

Well then heck, build a catboat. Your guests will love it

[JimD]

Sure, go ahead. I don't think solar panels can provide a meaningful amount of power if propulsion is involved, but don't let me stop you :-)

Kaa

The panels would be for recharge and trickle charging while underway. I really don't know much about this stuff. But suppose I have three hours run time on my two batteries and long summer days with 14 hours of sunny daylight. How much topping up will the batteries get from something like 16 square feet of panel?

[mcdenny]

[QUOTE=Full Tilt;3501095]

First you need to set your range and speed expectations. That defines the battery energy you must carry, then decide if lead acid or lithium batteries are in your budget. That sets the battery weight the boat must carry.

Then decide outboard or inboard. Outboards are simple and everything comes in one box. Inboards are pretty much still science experiments, fun if you like that sort of thing.

A CY with a Torqeedo 2.0 in a well would be a sweet E boat. It could easily carry 300# of batteries which would take you 30 or 40 miles at 5ish mph. Put the well on the centerline, forget the rudder and steer with the motor. Side stick steering like Harry Bryan wrote about in the last WB would work great.



Denny Wolfe

If you're steering with the outboard in a well, what would the 'side stick steering' be attached to? I wouldn't eliminate the rudder if I was you, or you may find yourself ramming a lot of docks.
Mike

The stick works cable steering attached to the tiller arm of the motor. Eliminating the rudder and tiller, especially on a double ender, saves a lot of work.

[JimD]

17'3" KON BOT PUCKNot much has been written in the West about the traditional working craft of the East European countries but they had some fine craft and this is just one example of them. The KON was one of the smaller types of boat working on the Baltic around the Bay of Gdansk mainly in net fishing for flounder.Puck is our update on one of these craft. We have developed all the plank shapes for simple stitch and epoxy construction using 9mm plywood. 13 sheets are required for both the planking and decks and frames. We have changed the traditional dagger or leeboards for a steel plate centreboard and we have retained the sprit rig used on many of these boats. PUCK may be fitted out in a variety of ways and she is big enough to take a small cabin. She is a heavy working boat and would normally carry around 300 lbs. of scrap ballast. Details of an outboard well are shown and we can supply drawings covering various changes to suit your own requirements.

17'3" Kon Bot Puck Particulars
LOA	17'3"	5.26m
Beam	5'8"	1.73m
Hull Mid Depth	1' 11 3/4"	0.6m
Draft	10"/3'3"	0.25/0.99m
Sail Area	97 sq.ft	9 sq.m
Approx. Dry Weight	550 lbs	249 kg
Hull Shape	Narrow flat bottom plank plus 5 planks per side - round bilge
Construction Methods	Stitch and tape
Major plywood requirements for hull	12 sheets of 9mm and 1 sheet of 12mm plywood
Guidance Use	4-6 adults
Drawing/Design Package	3 x A1 drawings + 9 x A4 instruction sheets
Additions and alterations included with the plans

[P.I. Stazzer-Newt]

Selway Fisher has a range of potentially suitable hulls
http://www.selway-fisher.com/Mcanoe.htm << canoe types.
http://www.selway-fisher.com/Steamup20.htm < take yer pick.
http://www.selway-fisher.com/Steam2030.htm < there's a very elegant 20' model

[James McMullen]

I was at a steamboat gathering this weekend. Lots of nice little boats there in the size range we are talking about. . . .and I have to admit that it struck me how Rowan's general size and hull shape could likely work out just as well as most of them as a low-hp steam launch with just a few tweaks like adding a skeg to support the shaft and protect the prop. Indeed, Rowan seemed to have more beam and initial stability than several of the smaller launches. And I know of multiple people who have converted steam launch hulls to electric. I think the CY/ST/AT family of boats might serve well here, not to mention being stunningly pretty lapstrake double-enders to start with.

Something to putter with in my old age, perhaps?

[sailoar]

Something to putter with in my old age, perhaps?

Oars are for sissies! Just shut up and motor!

[htom]

The panels would be for recharge and trickle charging while underway. I really don't know much about this stuff. But suppose I have three hours run time on my two batteries and long summer days with 14 hours of sunny daylight. How much topping up will the batteries get from something like 16 square feet of panel?

Guessing, 10W per square foot peak. Average half that, or less, so 100W/hr from 16 square feet. I doubt you'd get 200W/hr even with the most modern cells. There's enough there to maybe run a bilge pump with a tiny leak, and an anchor light. Propulsion ... not yet.

[Dan Lyke]

How much topping up will the batteries get from something like 16 square feet of panel?

So a quick Googling about suggests that a solar panel will give you around 10 watts per square foot. Some give more, some less, mounting has a big deal to do with this (angled towards the sun), as does weather, but we'll use that as a ballpark.

Poking around a bunch of battery specs gives all sorts of numbers, for for the sake of illustration let's say 100Ah. Ignoring all of the Peukert effect (battery capacity changes depending on how fast you discharge it, etc) issues, this is mostly an illustration which you can apply to numbers you trust.

Watts is, for the sake of argument and DC and all sorts of other stuff, Volts times Amps. Lead acid batteries usually come in 12 volt assemblies, you said two of 'em, so 2400 watt hours (or 2.4 kilowatt hours, if you're trying to figure out how much it'd cost you to charge these things at home, I think I pay roughly $.13 per kWh).

16 square feet of panel is, then, 160 watts, which means you should be able to charge those batteries in 2400 watt-hours/160 watts, watts cancel, 2400/160 is 15, thus 15 hours of sunlight.

[Fr. Richard]

The limitations of current battery technology on moderate to long range cruising will require the intermediate step of hybrids such as the diesel-electric unit offered in early 2013, or other similar developments.

http://www.steyr-motors.com/marine-d...diesel-engine/

The automotive industry has rather successfully tapped into the interest in electric propulsion by offering hybrids while they continue to develop viable (affordable) all-electric vehicles.

[mcdenny]

Hybrid cars work because they can recapture energy lost to braking and engines are sized for acceleration, not cruising load. Neither applies at all to boats.

Hybrid boats have an ICE to go fast and/or far and an electric motor to cruise slowly and quietly.

A 16 or 18 foot boat can easily carry enough lead acid batteries to run at displacement speeds longer than most people would want to ride in an open boat with no shade or head. My Arctic Tern would go 4 mph for 2.5 hours with one 50# battery and a $150 trolling motor.

Lithium battery costs are coming down fast and you could put together a pack that might be only 3x the cost of an equivalent lead acid bank. This was 10x 5 years ago. Lithium batteries enable planing performance. I've seen videos of an old 17 ft Bayliner converted to electric that would go almost 30mph and could go 20 mph for 30 minutes. Lithium batteries don't make much difference in a displacement hull though as the weight savings doesn't help speed or range significantly

Denny Wolfe

[gilberj]

We have a small ferry powered by electric in our area. It is not really in service carrying people, but could be perhaps next year. It is a 26 foot lifeboat, with a bunch of batteries along the centre-line and a motor and a few controls etc. In service it would operate approximately 20 minutes of the hour. Load would very as the number of passengers. They found they could not quite operate a whole working day, (18 or so crossings and returns), charging in between and obviously overnight.
The lifeboat is not easily driven, and has a lot more drag than desirable.
I'd look first at rowing hulls, intended for your intended speed. Sailing hulls are better than powered hulls generally, but are designed to operate at various speeds. Powered hulls usually have sufficient extra power that a little increase in drag is inconsequential.

[nedL]

Atkins "Happy Clam" is 17' and moves easilly. Her origins are Scandinavian (though NJ).

[Fr. Richard]

Atkins "Happy Clam" is 17' and moves easilly. Her origins are Scandinavian (though NJ).

For those desiring something a bit larger in this vein, there are Atkin's Sallie Hyde and Fish Hawk.

[Kaa]

I think the CY/ST/AT family of boats might serve well here, not to mention being stunningly pretty lapstrake double-enders to start with.

So if you were to put an electric motor into such a hull, would you make it an inboard, then? 'cause an outboard bracket on the side with a trolling motor hanging off it does tend to spoil the "stunningly pretty" thing quite badly...

Kaa

[Kaa]

Atkins "Happy Clam" is 17' and moves easilly. Her origins are Scandinavian (though NJ).

Is that a small guy or the boat is cavernous? :-)

Also, do you think the Happy Clam has advantages over its Scandinavian ancestors of the snipa/sjekte/smakkejolle kind?

Kaa

[keyhavenpotterer]

Paul Gartside's Loopen small motor launch is a double ended design with Scandinavian overtones.



http://store.gartsideboats.com/colle...nch-loopen-178

There's a picture of one built if you click on link, under design outline, last of the four boxes with a colour picture. That one built has a rudder over the rear of the stem, as a Scandinavian would have it.

The design was free in a Watercraft magazine a year or so ago. Swap the heavy diesel for a light electric motor and bank of leisure batteries.

She's big enough for your brief and a very manageable size to bring out of the water, to take home and recharge at 500kg all up, as well as build, store and outfit.

Ed

[bogdog]

How about a snipa with a rudder mounted integrated motor? http://forum.woodenboat.com/showthre...electric-motor

[JimD]

So a quick Googling about suggests that a solar panel will give you around 10 watts per square foot. Some give more, some less, mounting has a big deal to do with this (angled towards the sun), as does weather, but we'll use that as a ballpark.

Poking around a bunch of battery specs gives all sorts of numbers, for for the sake of illustration let's say 100Ah. Ignoring all of the Peukert effect (battery capacity changes depending on how fast you discharge it, etc) issues, this is mostly an illustration which you can apply to numbers you trust.

Watts is, for the sake of argument and DC and all sorts of other stuff, Volts times Amps. Lead acid batteries usually come in 12 volt assemblies, you said two of 'em, so 2400 watt hours (or 2.4 kilowatt hours, if you're trying to figure out how much it'd cost you to charge these things at home, I think I pay roughly $.13 per kWh).

16 square feet of panel is, then, 160 watts, which means you should be able to charge those batteries in 2400 watt-hours/160 watts, watts cancel, 2400/160 is 15, thus 15 hours of sunlight.

Thanks for doing the math, Dan

[Kaa]

Paul Gartside's Loopen small motor launch is a double ended design with Scandinavian overtones.

13' -- that seems a tad small to me, especially given that it's not fully open. Also the page says "It is a complex and absorbing building project that will provide hundreds of hours of enjoyment for the experienced woodworker seeking a showpiece" which is not very encouraging :-)

A snipa with a rudder-mounted electric motor, now that's sounds like an excellent idea. Thanks for reminding me about that rudder-mounting, this might be the solution to not spoiling the looks of pretty double-enders :-)

Kaa

[P-man]

Is that a small guy or the boat is cavernous? :-)

Also, do you think the Happy Clam has advantages over its Scandinavian ancestors of the snipa/sjekte/smakkejolle kind?

Kaa

Happy Clam is one of Atkin's "Seabright Skiff" designs, which are shallow draft, 11 1/2 inches in this case.

[Kaa]

Thanks for doing the math, Dan

The starting number of 10W per sq.f. seems too optimistic to me.

Go here -- http://pv.nrcan.gc.ca/ -- and figure out your insolation. Note that it's very different depending on how your solar panels are mounted. If your boat in on a mooring you can't guarantee even the south orientation, for example, so the numbers will have be reduced appropriately. Multiply the insolation number by the efficiency of a solar panel in your price range and you'll get a reasonable estimate of power output on a long-term basis.

Kaa

[P.I. Stazzer-Newt]

The 10 watt per square foot is not wildly out.
Now remembering that the original brief was for "will move around at displacement speed only." - and the the fittest people on the planet can barely make 400 watts (Bradley Wiggins et al) perhaps a PV cell coated Bimini could make a useful contribution to propulsion.

[Kaa]

The 10 watt per square foot is not wildly out.
Now remembering that the original brief was for "will move around at displacement speed only." - and the the fittest people on the planet can barely make 400 watts (Bradley Wiggins et al) perhaps a PV cell coated Bimini could make a useful contribution to propulsion.

For peak power -- when the new clean panel is looking directly at the sun at midday on June 22 -- 10 watts/sq.f. is reasonable. But if you want daily power output on a fixed mount, I don't think it's a good starting point.

As a reference a "standard" smallish trolling motor here outputs 55 lbs of thrust and takes 50A @ 12V = 600 watts.

Kaa

[SJKaplan]

I too keep coming back to port Pegasus. But I am thinking about putting an outboard in a well in the stern (covered for appearances). Lovely lines. Suitable for a somewhat experienced amateur.

[landlocked sailor]

Nobody has mentioned Phil Bolger's Lily. Not a Nordic lapstrake hull but he did work out the power requirements and specs using OTC components.[IMG][/IMG]

[landlocked sailor]

Another view.[IMG][/IMG]Rick

[nedL]

Adding a bit about "Happy Clam", yes, she does have a lot of 'volume' for 17'. She is of sawn frame design which simplifies construction a bit, and she does have a rolled garboard keel (yes, a bit complicated in construction), which allows for upright beaching and an almost flat shaft angle. It does also allow for very easy hull speed movement through the water as much of her underbody is really double ended.

[Kaa]

Turns out this problem has already been solved by the internet X-D








Kaa

[keyhavenpotterer]

Just got this months Watercraft.

Free plans from Paul Gartside for a 20ft double ended steam launch.

Lovely in all respects.