Oh great fountain of knowledge of STW can you help?
I have a bit of a scrap heap challenge, the application is for a Human powered Yacht. It's for the Three Peaks Yacht Race which I've done a few times before, I'm a runner/Cyclist not a sailor. As it's racing, no engines are allowed. So if there's no wind for periods of time, as there has been in previous years, we've used oars to at least try and keep moving. But as you might imagine a 7 ish tonne 30-40ft yacht isn't exactly designed for rowing not exactly efficient or comfortable means of power. So after rowing the length of the Lock from nie on the Corran Narrows to the Corpah through the night to land for dawn and have to run up and down Ben Nevis I'm looking for a more efficient mode of human power
I've got the following frame all set up which fits the rear of our charter with 2 old rear hubs ready to go, suitable propellers are on order, 16x16 model aircraft props (apparently good off the shelf option for a HPB)
IMAG0101
Prop pole only lying down and mocked up in the photo + won't be using u-clamps but BB shells to minimise drag/bearing load and all painted up in white now so it doesn't look so out of place in the boat.
Now my last task is to get and mount suitable pulleys and belts, which I'm really struggling to find. Basically I need to get the larger pulley mounted to the hub (Disc mount or bodged onto spoke flange) and the smaller mounted onto a Squarr taper BB axle (prop on other end)
The prop' pole will pivot around the hub, so they come out of the water, so as not to drag when we're sailing.
The belts being twisted through 90Degrees to turn the prop.
I'm trying to find suitable belts and pulleys which will fit the following criteria:
-That will take a 1 Human power (geared 1:5 ish) and not slip
-Pulley sizes 2:5
with the smallest being not much more that a few inches in diameter to minimise drag in the water
aiming for 400-500rpm, chain sections @ 1:2 already so cadence of 90ish I need the pulleys at about 2:5 to get a total of 1:5
-OK to Run partially through salt water
-Allow a twist of 90degrees
-and be about 2ft in length (centre to centre of pulleys)
and if possible be cheap too (moon on a stick??)
I think Car ones will be to inflexible and heavy duty to allow the twist
washing machine ones to flimsy (pulleys seem wrong sizes generally too, too big and small)
any one got any constructive thoughts/ideas which work with what I've got?
a complete redesign is out of the question (Next year maybe), only a few weeks left and not much free time to do it in
we still have the oars as a back up if all else fails.
Thanks
All
