Hi, My name is David and new to this forum.

I was referred here for help by a fellow drag racer.

A few months ago I converted a jetski from pump to propeller driven and have it running good numbers on top end with best 106mph at 7100 rpms 2005 GP1300R 175 hp efi 600lbs

The 3 problems I need help with are..
1 rudder isnt very effective
2 when I lift the throttle (even when lifting very easily) it wants to dart out from under me. I was tossed off at 96 mph a few weeks ago
3 the clever style propellers I run ventilate badly out of hole

My output shaft is currently 1 in 15spline mercury, but I can get another shaft made to allow use of the 2blade drag props.

I was suggested to go with a 2 blade because it would allow greater acceleration with less stern lift and handling issues when lifting the throttle..  also it was suggested to install a algon in my shaft to reduce drag when lifting throttle.


Any suggestions are appreciated, and if you need any additional information about my setup or pictures, I will promptly respond. I know this is an unusual project , but best guesses are appreciated


I have its first race in June and  will go for a record attempt at same time

thank you
David Bunn
252-341-5126

you can read about project here (kinda long 540 post 32000 views)
http://greenhulk.net/forums/showthr...hp?t=47449

or see a utube video
http://youtube.com/watch?v=zHdrg3mYSgk

pics here
http://i19.photobucket.com/albums/b176/ldyav8r73/greenprop2.jpg
http://i19.photobucket.com/albums/b176/ldyav8r73/greenprop1.jpg

Maybe a longer rudder or position ?Jet skies were not designed to go that fast it will probably never be a smooth shut down.You may want to try and move the prop in or out a little at a time and see how it reacts.Sounds fun.Good luck let us know how it goes.