SS to aluminum prop

CJY

Lieutenant Junior Grade
Joined
Jun 19, 2005
Messages
1,242
Hello all,



Thanks for any and all help
 
Last edited:

Barnacle_Bill

Admiral
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Feb 8, 2004
Messages
6,469
Re: SS to aluminum prop

Have it repaired! You will have a much better prop for about the same money.
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: SS to aluminum prop

An aluminum prop has thicker blades, so it has more drag in the water. There is always a little bit better performance with a SS prop. At 70 HP, it probably would be hard to feel. I suspect, however, with that setup you need all you can get.

Also, the same mishaps that nicked the SS prop would probably put significant folds in an aluminum prop.

If it isn't messed up to the point of being out of balance, or bent, you would probably have better performance if you just hand filed the nicks to level and smooth them out than you would have with a new aluminum prop.

Cost to repair the SS prop would probably be a wash with a new aluminum prop, but SS would be a better prop.

hope it helps
John


Hello all,

Let me begin by apologizing if this question has been asked and answered many times prior to my asking it.

Right now, I have a SS 13-3/8 x 17 on my 70hp johnson. At wot, it runs at 5800 rpm's which is great. There are a few nicks in it and I have been debating as to have it repaired or by new.

My question is, if I switch to the same exact size prop, except go with aluminum(it's cheaper), what kind of performance change, if any, should/could I anticipate? How will it affect top end, hole shots, rpm's?

In the event this info is needed, this particular motor and prop set up is on a 17' Cajun fish and ski boat.

Thanks for any and all help
 

CJY

Lieutenant Junior Grade
Joined
Jun 19, 2005
Messages
1,242
Re: SS to aluminum prop

Any recommendations on a repair facility? I don't believe I have one locally.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: SS to aluminum prop

Hello all,

Let me begin by apologizing if this question has been asked and answered many times prior to my asking it.

Right now, I have a SS 13-3/8 x 17 on my 70hp johnson. At wot, it runs at 5800 rpm's which is great. There are a few nicks in it and I have been debating as to have it repaired or buy new.

My question is, if I switch to the same exact size prop, except go with aluminum(it's cheaper), what kind of performance change, if any, should/could I anticipate? How will it affect top end, hole shots, rpm's?

In the event this info is needed, this particular motor and prop set up is on a 17' Cajun fish and ski boat.

Thanks for any and all help

It would be interesting to see your GPS speed was at 5,800 rpm.
 

CJY

Lieutenant Junior Grade
Joined
Jun 19, 2005
Messages
1,242
Re: SS to aluminum prop

My overall top speed(is that what you want)? Between 38 and 42 mph.
 
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