Prop size for Yamaha CV25

[leachy]

Hi All

Just wanting a bit of advice on prop sizes. I have a Yamaha CV25 on a 3.95 Ally Craft Shadow. I have worked out that under normal load (two people, 60L water and gear) its hitting max revs at about 80% throtle. It has the standard prop which is 9 7/8 x 12 aluminium. I was thinking of going to a 13" pitch, most of them are 10 x 13 or slightly larger. Is this an issue if the diameter is larger, ie closer to the cav plate. Has any one done this before ie suggested sizes and is there a benefit of a stainless over aluminium, apart from the stainless never losing paint on this size motor.

Thanks in advance for any info.

Leachy

[BloodWorm]

Increasing your pitch is going to drop your revs further. Make your boat slower to plane and reduce your top speed.

Why do you want to do that?

NFI about your diameter Q suggest you speak to a Yamaha dealer or solas.

[leachy]

At the moment it gets up on the plan fast and it hits 24 Knots at only about 80% throtle and hits top rpm. So I am thinking that at WOT I will not over rev the engine which is what is happening now, with a bigger pitch prop, and the boat will now go faster.

Leachy

[BloodWorm]

hitting max revs at about 80% throtle

Miss interpreted what you wrote sounds like the greater pich will be the go.

Could be worth a call to http://www.solas.com.au/ they should be able to answer the diameter Q for you as well.

[leachy]

Thanks Bloodworm

I spoke with a very helpful sales lady, sorry I can remember her name, she gave me the kind of advice I would expect from a well informed sales person who know their products. She made an interesting comment that if I kept the same pitch but changed to a Solas would be like stepping up a pitch in the Yamaha prop.

So to that way of thinking the Yamaha props are not that well designed, I was just wondering if anyone else has experieneced something similar. I am not doubting the advice in anyway what so ever but I thought they would be OK seeing they would want the best performance out of their engines.

Regards
Leachy