A question you may have never heard

Hi guys/gals, I have a question that will hopefully invoke a bit of laughter, and serious response.

My 6 year old and I are in the Boy Scouts this year. He is a Tiger Cub, and I, his fledgling den leader. We are doing a 'Raingutter Regatta' in which we take a piece of wood (http://www.buckskin.org/Resources/Cubs/raingutter_regatta.htm)and other materials, and make a little bitty sailboat, then blow it down a raingutter with a straw.

My questions are: Should I round the hull as much as possible, attach the keel and then apply some sort of filler around it (the keel) in order to shape it? No right angles would be good, No? It would seem beneficial to a degree to reduce the amount of hull that is in the water. Is there a way to determine the optimum amount of keel hang-down? Design? Would the mast leaning backwards slightly give it a small degree of lift? Is there an optimum mast placement on such a small boat powered by straw? Apply a substance like wax or rainx to the hull in order to decrease the drag? Optimal sail design/shape/material? Am I a total geek for trying to research a balsa boat? hehe

Sad, I know. But I will actually be competing against other grown up kids too, and we all know that a loss is not an option. Thanks for letting me make you laugh.

Mike

 

This boat only operates downwind so design for that.

Put your sail way fwd, make the lines full fwd so the bow isn't driven under.
Get enough beam to get stability, put the keel aft of midships, chined edges will be ok on the hull and will be simpler to carve. Keel can just be screwed on no fairing is really reqd on such a small model.

Good luck

 

raceboat

I agree with what Mike said but with the chined hull you probably don't need a keel as such-just hang a thin(6% thickness /chord) rudder off the transom. If you could, experiment with getting the thing to track well as narrow as you can possibly make it. Using a straw to supply wind you may have some steering and you shouldn't have much rolling moment. Shoot for 9/1 beam to length ratio or more.
The sail should probably be rectangular with the long dimension athwhartship and as low down as you can get it. If you had to catch real wind you wouldn't want it low but in this case it will help as long as the lower yard doesn't get in the water. Good Luck!