I'm just getting into making Greenland paddles after a friend loaned, and subsequently gave me, his spare GP, which my wife promptly tried and claimed as her own. My first attempt turned out reasonably well - used it for a 15 km. run, and was reasonably pleased with it. The latest one, tho, isn't nearly as good - it 'wobbles' a lot, and you can see a lot of cavitation around the blade tip as it moves underwater. It also, strangely enough, actually squeaks as it moves thru the stroke! I've since thinned down the blade tip a lot, and taken some bulk out of the blades themselves - if anyone has any other suggestions for improvement, they'd be much appreciated!