paddle wheel jon boat

Hi guys Im planing on making a paddle wheel boat out of a jon boat I have a lawn tractor engine and the transmission from that i need help with the design part of it. I want it to be a stern wheeler if you go to the link i attached That is what i want to make i just need help figuring out how to make it im not very good with designing stuff the boat will be an aluminum jon boat http://www.citlink.net/~tpickles/SternWheelPaddleBoat.htm

 

Here's some information about one I built, which is pretty much what you want to do. Feel free to ask questions...

http://www.boatdesign.net/forums/propulsion/do-they-exist-articulating-paddle-wheel-19475.html

 

How did you attach the arms that are on the wheel to the boat and how did you make the wheel that seams like it will be the hardest part

 

The whole thing was made pretty much with what we had laying around. The engine was a 5 HP B&S engine. It doesn't take much power, so you don't have to build stuff like a tank. The arms were something like 3x4" and I just bolted them to the side of the hull. The two sides of the wheels were 1x1" steel tubing. The wheel diameter was 4' and pretty close to 4' long. I drew the layout on a piece of plywood, cut the tubing and clamped it to the ply. Tack weld one side, flop it over and weld the other side and then flop it back and finish welding the first side. I welded the ends to a piece of pipe that had a 1" inner diameter. I drilled some holes in the pipe and then put a 1" steel shaft through the pipe, and that was supported by the bearings. I welded the pipe to the shaft through the holes I had drilled in the pipe. That kept the shaft all straight and true without warping it by too much welding. The paddle blades were 1x6" treated decking. We had a dock that we kept it at and a problem that develops with wood paddles is a few sit in the water all the time and get heavy with water and then the wheel gets out of balance. Paddlewheelers are always coping with too much weight in the stern, so keep that in mind.

 

oh i never thought about the paddles sitting in the water and being unbalanced and one more thing i forgot to ask is how did you setup the steering i will be putting the rudders behind the wheel on the outside

 

I had two rudders in front of the wheel. They looked like the ones in the full sized sternwheeler I showed in post # 22 in the thread I referred to earlier. In post #17 of that thread you can see the two rudder posts, how they are connected together and the pully and cable system for actuating them.

 

You didn't mention the type of transmission, but I'm assuming it is hydrostatic. If it was an inexpensive lawn tractor (under $2500 new), it probably has a low-end hydrostatic tranny. Those transmissions are not designed for heavy work (for example, my $1800 26hp lawn tractor is not designed for mowing on hillsides or towing heavy loads). I suggest you determine the make/model of the transmission (the Tufftorq K46 is the most common one in lawn tractors of the last decade) and determine the operating specs it was designed for, and try not to exceed those. Additional cooling may be necessary.

 

the transmissoin is a five speed and is cappable of pulling a wagon filled with 300 pounds of cement bags

 

He's right, pulling a wheeled trailer is a relatively light "rolling" load, which is a whole lot less demanding then pushing water. This is why a small sub compact can pull a 1,000 pound trailer. If you remove the wheels, you'll quickly find out how much it can actually pull.

 

That's what I had, was a 5 speed manual transmission plus reverse. A small boat like you're planning only needs 5 hp or so. Build the boat and use it, if something breaks, try something else.

It's kind of odd having 26 hp and you can't pull a load. Grass can't be that tough to cut, so what 's the point of all the hp?

 

The point of 26hp is sales and marketing. I 'inherited' the tractor, and the user manual points out not to use it on slopes exceeding some laughably small angle of inclination. Part of it is safety liability, and part of it is the strength of the tranny. Here is the infamous K46 (found in majority of sub-$2500 lawn tractors) and its specs: http://www.tufftorq.com/?page_id=137

I got around this 'limitation' by installing smaller-diameter rear tires with ag tread (for traction on hills). I also filled each tire with 5 gallons of windshield washer fluid to lower CoG - the extra weight isn't too hard on the tranny since it is a rolling weight. I keep the transaxle clean and don't work it hard on hot days - so far, so good.

Also, those HP figures are likely exaggerated by the manufacturer. I could probably find some vintage 50's/60's tractors with 14hp that would outpull this thing, even if it had a manual tranny.

 

Yes, insurance and warranties seem to be the limiting factors, but if you try, it's surprising how much abuse some things can take. And then some can't take any abuse also. I really don't think 5 hp will be too much for the transmission, but if it breaks, old broken down lawn tractors are cheap if not free and sometimes it's the engine or rust that wrecked them and not the tranny.

 

ya i have an 8 hp on the tractor i will be using for the boat and the factorey engine was a 17 hp so i think the tranny will do just fine. is there any other things that i should know or any problems that came up in your build samsam (and anyone else that built one) That you think might come up in mine

 

Well, if you use a regular aluminum jon-boat hull, the bottom will be flat all the way to the transom. A stern wheeler needs a bottom that rises before the transom. That helps feed water to the wheel when going forward. The wheels generally aren't lower than the main part of the hull and if you don't have the upturn, when in reverse the water will just hit the transom and go nowhere.

Keep as much weight forward as you can as they are stern heavy.

Somehow muffle the engine noise.