19" or 21" prop for Alpha I 305 Mercruiser

[skoboten]

Got a 20 foot '95 Bayliner with a 305 Mercruiser and Alpha I sterndrive. Had a 19" aluminum prop on it until my partner dog-eared that one then dog-eared the 21" aluminum spare. Don't ever co-own a boat with a jackass. Anyways, I'm looking at a 21" stainless steel prop on e-bay. My rationale is that I like to slalom waterski, so I want the holeshot of stainless steel, plus I like the top end properties of a 21" over 19":confused. I guess I have 3 questions, stainless or aluminum, 19 or 21, and buy used or new? Is there anything else to consider when buying off e-bay like diameter, etc to make sure I'm getting the right prop for an Alpha 1?

Thanks,

Chris

 

[QC]

Re: 19" or 21" prop for Alpha I 305 Mercruiser

Yes to all three . . . but you are missing a couple of very important things:

1) You should post this in the prop forum . . .

2) Aluminum of the same pitch usually has better hole shot but poorer top speed than SS and,

3) We need to know what your correct RPM is at WOT and trimmed out properly to help with this question.

BTW, welcome to iboats!! We can definitely help you here, but trust me, we need the RPM info . . .

 

[Don S]

Re: 19" or 21" prop for Alpha I 305 Mercruiser

Moving to Prop Forum

 

[rndn]

Re: 19" or 21" prop for Alpha I 305 Mercruiser

Are you sure you want to go to SS with a partner that is known to hit things with the prop? Aluminum is cheaper to buy, cheaper to repair, and self destructs before tranferring the energy to your drive system.

 

[Pierutrus]

Re: 19" or 21" prop for Alpha I 305 Mercruiser

Are you sure you want to go to SS with a partner that is known to hit things with the prop? Aluminum is cheaper to buy, cheaper to repair, and self destructs before tranferring the energy to your drive system.

I second that!!!!