Metanet Forums

I'm not sure if this is in the right forum.
It's kinda like a discussion...

Okay, here i go.

I gotta make a model boat before Friday the 13th (Unlucky number). It's going to be a balsa wood catamaran that is going to be no larger than 50cm x 50 cm x 50 cm when finished. I'm planning on using two paddlewheels at the side, but i dont know what to spin them with. If you can help me or find another better method of propulsion please tell me!
Note that-
I CANNOT USE BATTERIES
It must be SELF SUSTAINING Is that the right word? I mean that i cant push it or hold a fan and blow it along or anything like that.
And no, I'm not allowed to use a mouse and treadmill or anything like that.

I have an idea, but i doubt it will work.
So i have an axle, with the two paddlewheels on the two ends and a turbine in the middle, i have a container of water over the turbine that pours water onto the turbine-spinning it. The turbine then spins the paddlewheel, the problem is i dont know if the weight of the water container will make the boat sink.

And...yeah.

Use a mousetrap with the string attached to the trap and the other end wound around the axle for the paddles. When the trap is sprung, it will pull the axle, spinning the paddle.

I dont think that will be enough to take my boat 12.5m (The length of our school pool)
I need something slow and steady.

try using a wound up rubber band...

try buying a cheap solar radio, then taking out the solar charger. configure the ports so it will power your motor on the boat, put on waterproof casing, and walla!

Rubber band wont give enough energy
Solar power? Well my mum cant be bothered driving me to the place that can solder the wires onto the motor...

Man, why are you asking for our help if you are just going to all of our advice? Someone gives a tip, you either wave it off as not good enough seemingly without trying it or even trying to prove upon it. Now you're just being lazy. We can't give you a miracle pill that will do your project for you. You need to try things out first.

I'm not sure if this would work or how to do it, but maybe if you had like a string of rubber band or some way to switch the rubber band the paddles are connected to, so when ones dead the other starts to turn it.
My other idea is settin up the 2 paddles seperately with rubber bands, so that while one is turning and pushing the boat along, it's winding the other rubber band, which start spinning and charging the 1st one when its empty.

capt_weasle wrote:Man, why are you asking for our help if you are just going to all of our advice? Someone gives a tip, you either wave it off as not good enough seemingly without trying it or even trying to prove upon it. Now you're just being lazy. We can't give you a miracle pill that will do your project for you. You need to try things out first.

I apologize, but i HAVE tried most of these, I'll try to find something by myself. I'm going to give solar power a shot.
I think i could use a powerful extension spring in some way, but i dont know how (Cant push off from the wall of the pool). I'll figure out something, but I'm still taking advice.

Alex, that sounds cool, but would'nt it cause the boat to go forward in a squiggly zigzagging motion which would reduce efficiency? I'll think about it, it sounds like the thing I need.
What I need is a miracle pill...

I think your best option is a put-put boat type steam engine.
http://www.instructables.com/id/Pop-pop ... r-childre/

Basically, it pulls water into a small metal pipe and heats it into steam which then exits the boat to give thrust. When the steam exits, more water is pulled in and the cycle continues. You could either point the steam exhaust straight into the water behind the boat or point it at your paddle wheels. Just be sure to keep the wick of the fire from getting too wet as it runs.

Another option to maybe consider would be fire and foil sails.
http://www.instructables.com/id/Make-a- ... ed-by-Fire./

It's probably not as strong as the put-put motor, but that would require you to make more fire and bigger sails to propel it, which would look entirely more badass.

Make some bottle rockets (the watery kind, that is, not fireworks) and turn it into a jet boat! Or use it to power your turbine - it should give you more power than just tipping water on it. Actually, with an appropriate gear arrangement, you might be able to use it as a jet *and* have it powering your wheels as well - aim the bottle backwards, so the jet is striking your turbine and pushing it around; then rig it so the turbine and wheels turn opposite directions, thus pushing the boat through the water. I'm not sure this would actually work better than just having the jet, though.

Alternately, get the heaviest fishing line you can buy, attach one end to your paddle wheels, then twist it until it's at 400 lb of tension. Using a crank and/or pliers for leverage, if necessary. That should be more than enough to get it 12 metres.

You could also try hooking a windmill up to your paddlewheels. It's like a sail, but easier to steer! And probably much slower.

Fishing line!
You bloody legend, I'm going to try that right away.