Prop recommendations

[speedmerchant]

Hi fella's,

Brand new to this forum, and think it is by far the most informative boat site on the internet. Great job.
Ok so here's the scoop. Bought a 21' Chris Craft last fall and had it out for the first time on the water last weekend. While it hauls the groceries ok I would like some more top end. The details are below

Boat: 2000 21.5' Chris Craft 215 sport cuddy
Weight: 3540lbs (empty) guessing around 4400lb for an average load
Engine: Volvo Penta 5.7GS (250hp)
Sterndrive: Volvo Penta SX-M with a 1.51 ratio
Current Prop: 14 1/2 x 19 aluminum
Hull: very good to new condition

The boat currently does about 48-49mph @ 4650-4700rpm with the banged up aluminum prop. Recommended operating rpm is 4200-4600 for this motor. I will definately buy a stainless prop but am wondering what prop pitch/dia might get me to the 55+mph area. Volvo lists a 14 x 21 which is what I am thinking might do the trick. 1/2" smaller diameter will increase the rpm but the more agressive pitch should bring it back down to keep it within the operating rpm range? Any help is greatly appreciated!

Cheers,

James

 

[junior1113]

Re: Prop recommendations

you on the right track 21 ss will do the trick 19 ss 4 blade would also. 4's are more effiecient can ride on a plane at slower speeds, better whole shot, better fuel ecomony at all ranges except wide open. either one will put u in a good position