Bicycle Mechanics - Bike as winch

I love my bikes however I would like to use an old frame as a winch to pull my 18 foot catamaran up an incline to where I park it. Has anyone tried this? Any suggestions?

I was thinking that removing the rear spokes and rim and using the hub as a spool would work.

I remember years ago seeing a picture of a guy who used a bike frame and rear wheel (as a tow spool) to tow a radio controlled glider up into the air. Worked quite well. The guy was from South Africa I believe.

What's the boat weigh? How far do you ave to pull it, up what sort of slope, over what sort of surface?

The boat is around 350 to 400 pounds (350 if I remove the sail and daggerboards) Hobie Tiger.
Surface is smooth rock.
Boat sits on a 4 wheeled dolly.
Distance 15 to 20 feet.
Slope is OK for two guys to struggle up with.
Right now I have a hand winch that is OK, but the bike seems like it would be easier, 2 legs instead of one arm.

You have alot more than 2-1 reduction in your hand winch.Unless you plan on some gearing changes.

Good point but my two legs are stronger than one arm. Also I figure that I could use the gearing to improve things.

The bike winches I've seen have consisted of a bike frame, rigidly fixed to a fixture. the rear wheel gets replaced with an axle with two gears on it. A big one driven by a small chain ring, and a small one driving a chain that's connected to the actual drum of the winch, driven by as big a gear as available. The mechanical advatage isn't that good, only about 10 to one (2 to one in the chainring to axle, about 5:1 in the axle to winch.). They're handy for pulling small loads long distances, not big loads large distance. You'd also need some sort of brake or ratchet, to keep the load from sliding backwards.

Real gliders use power winches for launching at a field I've seen in North Holland.
Quite spectacular to watch. The planes climb at what looks close to 45 degrees, then sail for ages. Never looked at the winch closely. But would bet it's a long drum.

The bike plan sounds more effort than it's worth. I'd grab a couple of blocks, 43/63/83' of prestretched rope, and hand haul it.
Oh, and kudos on the Tiger.

The bike plan sounds more effort than it's worth. I'd grab a couple of blocks, 43/63/83' of prestretched rope, and hand haul it.
Oh, and kudos on the Tiger.
I agree, bike seems a lot of work to put together something to do such a simple short duratiion chore, plus the bike and it's parts will not like the marine environment very much. All the components and frame will start corroding badly pretty quickly with all the wetness and humidity, plus the salt, if you sail on salt water. Simple and cheap block and tackle will get you going quicker and longer IMO.

Chombi

Bike winch would be good for low load at high speed. You just need a block and tackle pulley system, for high force at low speed.

But if you put all these practical considerations aside, I think your plan would work. Using the rear hub as a drum gives you a great reduction since it's diameter is tiny compared to a wheel. You don't need the secondary chain and drum suggested above. You might need something to raise the flanges to keep your line on it and some ratchet or hook device would be good to hold your load when you get off the pedal pressure.