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Old 16-06-2009, 02:09   #1
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Question Max Engine for 25' Sailboat?

what is the largest engine you can put on a 25 ft sail boat and what is the horse power / mph conversion rate? thanks.
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Old 16-06-2009, 02:20   #2
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Planing hull or displacement? Inboard or outboard? There are a lot of variables Florida. Look at like boats and see what they have. I had a 25 footer with an 18 hp diesel and that went really well - displacement hull fixed keel though.
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Old 16-06-2009, 04:24   #3
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In a sailboat: 4HP each 1000 Kg of displacement
That is the minimun. I'll would add a 10% over that figure
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Old 16-06-2009, 21:27   #4
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if the waterline length is 25 feet...the fastest that you are going to go is 6.7 knots
doesn't matter how big an engine you put in it
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Old 17-06-2009, 06:37   #5
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One oft-quoted (Yanmar, Westerbeke, etc) rule of thumb for Horsepower Required (Displacement Hull):
One horsepower per 500 pounds ( 50lb) of displacement (4 HP/Ton) for coastal cruising
and
1.25 hp per 500 lb ( 50lb) of displacement (5HP/Ton) for offshore work .

Remember, most HP/Displ. calculations utilize “Propeller Horsepower”, which might be as low as Brake (Engine) HP.
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Old 17-06-2009, 13:29   #6
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Aloha Florida,
My Catalina 22 had a 6hp Johnson. That was more than I needed. I just sailed interisland on a Columbia 28 with a Honda 7.5. The 2 cycle engines are lighter and easier to handle and will not weigh down your stern as much as the 4 cycles. The 4 cycle engines are more economical and last longer. You don't need more than 10hp on your 25 and I'd go for a 7 to 8 hp.
Good luck in your choice.
Kind regards,
JohnL
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Old 17-06-2009, 16:52   #7
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Thanks all, your great!
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Old 24-06-2009, 21:00   #8
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I have a similar question...

Quote:
Originally Posted by florida newbie View Post
what is the largest engine you can put on a 25 ft sail boat and what is the horse power / mph conversion rate? thanks.
I have a 1981 Catalina 38 ( #109 ) and have to repower as the transmission has seized and I feel it is not fiscally wise to add a new transmission to an old, corroding engine.
I am considering a Beta engine to replace my Universal 2524 ( 24 HP).
Would a 35HP Beta ( rather than the 28) be overkill on the old Catalina?
And I would appreciate any comments on the Beta engine!

Thanks ...

Paul of "Waltzing Matilda"
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Old 24-06-2009, 23:23   #9
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what is the largest engine you can put on a 25 ft sail boat and what is the horse power / mph conversion rate? thanks.
Just one foot longer and you could put a 60 hp engine on it.

POWERING AND SKIING



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Old 25-06-2009, 21:25   #10
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A friend of mine has a Cape Dory 30 with a 22 hp engine. It pushes it around just fine.
One day he was going out through a pass in the barrier reef in Belize. Took him 10 minutes to go a couple of hundred feet. He forgot to dog down his forward hatch. He watched the water filling his boat for 10 long minutes as he could not turn or leave the tiller.
In short heavy seas you need a lot more power and a matching prop. It all depends on where you want to go.
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