What prop would you recommend?

[johnnymac3687]

I am a new boat owner so I don't have any experience with props and I want to put a SS prop on to replace aluminum. Boat is a 2001 Larson 230 LXI with a 2000 Volvo 5.0 Gi SX drive. Boat weighs approx. 3100 lbs . Existing prop is a 3 blade aluminum solas 14.25 X 19. WOT is recommended 4800-5000 which aluminum operates in that range. Top speed was gps at 51. I would like a little more top speed without sacrificing ride or hole shot too much. I am thinking about going with a Volvo Penta 3 blade SS prop 14.75 x 19. With SS being stronger and blades being cupped I am wondering if it will help with performance? Also not sure what the larger diameter would do to performance? Any help would be appreciated thanks!

 

[steelespike]

Re: What prop would you recommend?

What is the actual wot rpm lightly loaded. If we use 1.6 ratio @ 4800 we get a very respectable 5% slip.If we use 5000 rpm we get an also respectable 9% slip. normal slip runs about 8 to 12%.
Usually a cupped prop is said to operate like it is an inch higher pitch. So if you replace the al with a 19" ss prop assuming it makes 4800 rpm at 5% slip speed would be about 54. BUT actual results could be a overall performance increase but net speed could range from a few tenths to a few mph.
Non of that is carved in stone as going to ss can be unpredictable,depending how the boat reacts to the prop and how well
previous prop worked. If we assume the ss works like it is an inch higher pitch we would think it would lower rpm a little but:: it is more refined than the al and if it gets the boat up on the water better the rpm change may be a wash.
If I was going to a ss prop I would go with the same pitch as the al prop.
The diameter difference may lower rpm 50-100 . But a 19" should run like a 19" Usually diameter is a secondary consideration.
Of course we have already considered the results of a cupped prop.
Some of the prop gurus may be along though on the holiday it may be awhile.