First time boat builder, looking for comments and suggestion with project...

OKay, so I'm stationed in Germany originally from southern california and I'm interested in building a boat. Apparently here in Germany they don't allow gas powered engines, so I guess it has to be electric. But I want something faster than just a trolling motor. I'd like to build a two seater boat that has about the same power a 10 hp motor on an 11 ft john boat. The design was going to be about 11 or 12 ft by about 5 ft wide. with a an H shape in the from ..like two pontoons or skiffs coming out the front for a little added buoncy and maybe a little cutting power on the turns to help prevent rolling. I was thinking for the design.. I was going to make a mold using chicken wire which I could bend to the basic shape and size and then use plaster or paper machet' posible coated and then I suppose enamel or water whatever and then some kind of foam and then fiberglassed or whatever..Mind you I don't have any boat building expereince..so I need some refinement here for clarification to build a light and sturdy hull. Now what about this electric motor..I was thinking 2 electric engine side by side in a plexiglass box or having them in an engine compartment..here's my question though..what kind of engines could I use..could I rip a couple of engine out of some industrial front loading washing machines and use those..and then I was think Lithium ion batteries connected side by side...but would engine's out of a washing machine work if the rpm's were around say 3400 RPM's?I mean they seem to spin fast enough and they have torque to trun the wet clothes..I would think 48v from deep cycle marine batteries or maybe lithium ion batteries would..suggestions ..comments..I know I have more research to doi..this is part of my research..asking some folks who know more than I do to tell me if I'm on the right track and if my ideas will work...

 

Welcome to the list Slippery,

That is not a good way to build a hull at all, you might get something that will float, but it is not going to give the results you want I suspect. I would either build two hulls out of lightweight wood stringers and frames with a fabric covering, than seal with 4 or 5 layers of paint, the way they make skin-on-frame kayaks. It is minimal use of materials, and they are low cost materials. (do a google search on skin-on-frame kayaks to find excellent pictures and instructions).

The other way to build a decent hull for your usage would be to use plywood and build up your two hulls, like stitch and glue canoes, and than fiberglass over the outside. It will make more durable hulls, but more cost than the skin-on-frame method.

I can not help you with electric drives, seems to me you have to find motors that can run off battery power. Commercial washing machine motors use 3 phase alternating current, not really compatible with 12 or 24 volt DC current from a battery pack. You might just rig multiple trolling motors if you want a bit more speed, also gives you some redundancy.

Good luck.

 

Are you saying that there are no petrol outboards allowed anywhere in Germany - or just the lake where you can go ?

 

You might consider a car alternator as a motor conversion. With a little work they can be converted into motors.

You're almost certainly going to be looking at deep cell marine batteries I suspect, unless you are ready to spend a fortune on lithium batteries (they'd be really nice, just horrifically expensive). Car companies that use lithium for their electric/hybrid cars (like tesla for example) often use small laptop-size cells in huge numbers to build their lithium packs. This requires a ton of charging and control hardware ($$$$$) to keep everything from blowing up.

Bottom line, go deep cycle marine, way cheaper, better suited to getting wet, etc. The only real reason to go lithium is that they have higher energy density (lighter), but you can probably afford a little extra weight in your funboat if it saves you thousands.

Also, I wonder if they would allow a generator to be run onboard, seems like cheating the rules, but perhaps? Lawn mower engine + alternator == generator.

Also as to building techniques, I agree with petros, skin-on-frame or boxy plywood are probably your best options.

Take a look at:
http://www.simplicityboats.com/summerbreezeduckworks.html
I built this last year (my first boat). Nice build, and great boat until it was tragically crushed by a tree in a windstorm. The designer also has a great build log on his site, very helpful for the first-timer. Even if you build a different boat, still helpful.

http://www.pdracer.com/
This is a little 8 ft plywood sailboat. You could modify the dimensions to suit (I'm building a 12-footer right now using basically the same hull shape), but the building techniques can be the same. Good place to learn about building simple boxy plywood boats. It'll take a motor just as well as sail.

http://gaboats.com/
This guy has plans for skin-on frame boats (aka fuselage boats), I think he goes a little overboard on some things (kevlar roving to stiffen the hull, probably unnecessary, he glues all the ribs to the frames, lashing or nailing is easier, probably just as good in many cases, he uses a lightweight aircraft fabric, a heavy nylon or polyester (or canvas) is probably just as easy, cheaper, and more durable). Nonetheless, it's a good place to start if you're interested in using a skin-on-frame technique for any non-kayak form factor

http://wolfgangbrinck.com/boats/
More good info on skin-on-frame. More kayak-focused, but still very helpful in general.

Also, petros posted some good pics of a skin-on-frame sailboat he built on one of my threads, might be nice to take a look at. There's some good discussion too.
http://www.boatdesign.net/forums/boat-design/skin-frame-scow-41933.html