How do I make a propeller for a toy boat without using rubber bands?

I don't know what type of mousetrap you have, but if your mousetrap have some stretching(something like sprin) part you can use that stretching power to push your boat forward. Instead of rubber band of this boat (a href="http://howtomakeatoyboat.blogspot.com/2010/12/how-to-make-rubber-band-powered-rowing.html)" rel="nofollow"http://howtomakeatoyboat.blogspot.com/20…/a fix your mousetrap sprin here and try.