Hydrostatic paddle wheel boat

[neonguy07]

I'm in process of building a small 17' stern paddle wheeler.right now I'm to the point were I'm figuring out the powertrain design now because I don't want a mess of gears and chains everywhere I thought my riding mower with its hydrostatic trans...how feasibly does it sound using the engine transmission of hydrostatic mower for putting power to the paddle? It's the easiest forward reverse and speed modulation I can think of. My only other thought is cutting cutting apart the lower unit of sterndrive I have take the gears and shaft make a box for it to turn it into a stand alone gearbox(forward/neutral/reverse) ugh so many gears turning in my head

 

[BlueBell]

Hydrostatic drives are brilliant.
However, not very efficient typically.
Are you sure it's not a constant velocity clutch on your mower?

 

[neonguy07]

Yea its hydrogear brand hydro trans they mostly come standard on craftsmen

 

[neonguy07]

Anybody have a more efficient way I'm trying to use the smallest engine possible

 

[BlueBell]

Anybody have a more efficient way I'm trying to use the smallest engine possible

Why?

 

[KeithO]

You dont mention what engine you plan to run ? The Zero turn style transmissions are cheap to buy and easy to set up and you can pick whether to use a left hand or right hand side unit. But take note of rpm and torque limitations and final rpm since the wheel diameter on a mower is likely to be a lot smaller than your paddle wheel. You may need to add another speed reduction / torque multiplier stage to the mix.

 

[neonguy07]

Yea I did figure the I need another reduction I cant find anything on those units about rated torque and a 15-20hp I'd like to keep small don't need to much power on a boat that might do 7mph haha and I didnt think about the left and right units on zero turns could do a dual paddle both havi g their own fwd/reverse but that ps a bit more complicating

 

[KeithO]

The usual places (surplus center, small engine warehouse, bailey hydraulics) seem to be out of the hydrostatic transaxles. You can build your own hydrostatic transmission by buying a pump and motor and connecting a control lever to the swash plate control mechanism and by doing that you can "gear" it however you need by choosing the pump displacement and motor displacement which gives you the "final drive ratio" at highest speed.

It is likely to be a bit more expensive, but would almost certainly be stronger than the transmission off a mower, and also capable of higher power or torque. Should also need virtually no modification, whereas the mower transmissions almost always have a belt drive from the motor.

 

[BlueBell]

Anybody have a more efficient way I'm trying to use the smallest engine possible

Why? Weight? Budget?

You're going to need a reduction gear in there somewhere...
It would be nice if you could run it internally.

 

[neonguy07]

Sorry for late reply I've been trying to do some stupid person enginnering..so far I have 2 ideas keep engine trans inside of at the stern and just run a series of chains up and over to the wheel...2nd idea will be make 2 paddle wheel put the trans inside the middle of both to run right off the drive shafts and then locate engine on inside on stern and just find a really long belt to run to it..also at the moment I'm testing with 12hp briggs but will prolly go up to a 20hp

 

[gonzo]

A chain in water is not the best, but will last as long as you keep it lubricated. Since this is a budget build, I assume you don't want to spend a huge load of money on a stainless chain. A toothed belt would be a better solution, since they don't rust.

 

[neonguy07]

Hm true I'd I did go chain it would be covered and protected but the tooth belt would be a good idea