Which motor for max hull speed. Hunter 25

[KennyH]

My original 1979 evinrude 9.9 long shaft died and parts to fix could not be found. I replaced it temp with a 6hp short shaft. I would like to find a new motor that would run 6 knots in most conditions. Do I need a 9.9,8 or less. My hull is need of a bottom job and the 6hp will only do 5 knots which is fine for now. Just wonder what people are using and what max speed they get out of it. Thanks.

 

[Bill Roosa]

max hull speed is:
1.25 * square root of water line length
for you case that would be 6.25ish
the 1.25 constant is a hull shape number. "finer" hulls have larger (1.3) and "fatter" hulls have lower (1.1) numbers.
All bets are off if you surf down big waves BTW

 

[Jackdaw]

I would care too much about maxing your hull speed. I'd worry more about having enough beans to keep you off a lee shore in a crappy seastate and a blow.

 

[FourPoints]

basic rule of thumb for engine size is 2hp per 1000lbs of displacement. that should normally be enough power for hull speed even in 1-2 foot seas, the more wetted surface (full keel) or heavier seas you expect to be in, the more power you'll need.

 

[Db421]

Depends, do you like to waterski?

 

[KennyH]

Thanks to all and mostly fourPoints I have settled on a Sailmaster 9.9. It has a 25 inch shaft to keep the shaft in the water and should have the power for hull speed of 6.25 knots. I will let you know how it goes after it is installed. It is electric start so I am looking forward to push button starts. The current 6hp only gives me 5 knots at full power.

 

[KennyH]

A follow up on 9.9 sailmaster

Love the electric start. Love the charging it does to my batteries. Has plenty of power. I am seeing close to 6 knots and I need a bottom job bad as it has been 5 years on my current bottom job. I think it is the perfect power and shaft length for the boat.:dance:

 

[ChiTownSail]

I got a lot of push-back from people not liking what I did....but I recently put a 15HP Tohatsu long-shaft on my 78' hunter 25. I love it, great power, plenty of torque, and a great charging system. I used the garelick 15" travel mount and it works great, I have not had one issue.

 

[Erieau]

Electric start = awesome.

I don't regret the 15 horses on my O' 25 either.

 

[DianaOfBurlington]

Fix the old motor.

Parts for your 1979 motor can be found. Try this guy, in my estimation THE source for Evinrude/Johnson 9.9-HP and 15-HP outboards. You can just about build a new motor from what he has available.

(BTW I have a 1987-88 Evinrude long-shaft/electric start 9.9; and this is the guy I am using for parts.)

:dance:

 

[SkipperMike]

Re: Fix the old motor.

Is there a website or contact number for this guy? Did I miss it? Thanks,

Mike