Prop choices - what is best

[SeaMonkey]

I have a 1991 Penn Yan 23.5 Avenger.
The boat weights about 4,300 dry.
Has a Mercruiser 5.0 Lt. V8 (305) Alpha One Stern Drive
It came from the salt water and does get a good bit of salt
water use today.

When I got the boat, it had a 21 pitch prop on it, however,
the prop spun on me a short time after.

A friend recommended a 16 x 16 and it seems to work pretty
well out of the hole. I top out at 3800 RPMS (WOT) and 28 MPH
using the 16 x 16 on there now (with 3 people on board).
The dealer recommends a 19.

I would like to get a little more top end.
Out of the hole is not that big a deal to me.


What are the pros and cons.

Hope I gave you guys enought info..

 

[QC]

Re: Prop choices - what is best

Well something isn't right and I am guessing the tach. Your WOT RPM target should be in the 4200 - 4600 range . . . So you are waaaaay off, but yet you claim that it has decent hole shot. Good hole shot and low WOT RPM just don't go together (opposite), so I am making a guess that your tach is wrong . . . Also, if it had a 21 and you like it with a 16 something else is weird too. Do you have the brand and part # of your existing prop?

 

[SeaMonkey]

Re: Prop choices - what is best

Thanks for your response.
I am sure that the tach is questionable.
I don't have a part number with me, but the
current prop is a Mercury 16x16 from West Marine.

I would not say that I liked the 21 pitch, that is just what
came on the boat. I never really got a chance to run it
too much before it spun on me. It , like everything else on the
boat is old and probably has not been run in a while.

Out of the hole is acceptable, but I don't usually open it up
right away. I am more of a slow cruiser.

 

[Bry21317]

Re: Prop choices - what is best

I have a Mercruiser 5.0 with 2bbl carb and thru hull exhaust. I also have the Alpha 1 drive with 1.65 gears. My boat ways about 3000lbs and I can spin my RPMS up to 5000 with a 21 pitch prop. I have just purchased a 23, hoping to drop the RPMS some, but I have not yet tried it. I might have to go higher.

You should be spinning alot more RPMS than you are, I would think. As stated, if the RPMS are correct, you might try a tune up on the engine.