anyone got this boat?

[billder62]

Ive got a 240 sundancer 5.7, alpha one , wondering what prop your running .
Ive done several prop selector sites and come up with 15.25x 19 , 14.5x17,14.25x21 right now I have a 4 blade 15 x16 that came with boat , wot 5000, rpm. 30 mph no speed difference from 3500 rpm to 5000 rpm ?

 

[nlain]

Re: anyone got this boat?

I cannot help with what prop you should have but something is not right if you are going from 3500 to 5000 without a speed change, a 1500 rpm change should increase your speed. Are you checking this speed with the boat speedo or gps? If boat speedo it may not work properly, they are known for that, if gps then there is some other problem. You may want to post this problem up in the Propeller section, there is a lot of knowledge on this board. If you want more SeaRay specific info I will recommend www.clubsearay.com a mainly SeaRay site with a wealth of knowledge that is SeaRay specific.

 

[magster65]

Re: anyone got this boat?

It's difficult to guess what prop you need. Borrow one in the middle of the range there and try it. You need 4600 to 5000 rpm at full throttle. It sounds like your prop you have now might be cavitating because of the "no change in speed from 3500 to 5000 rpm".
Generally speaking it's 3 blade for top speed, 4 blade to combat "squatting" and 5 blade for a "holeshot" unit for watersports.