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Subject: Re: [worldcruising] olympic carter33
From: Bryan Genez (capella@XXX.XXX)
Date: Tue Jun 18 2002 - 18:38:20 EDT
Douglas Powers wrote:
> i am thinking of either a westerbeke,yanmar,or
> universal diesel.any thoughts on these as power? ihave
> been told 3 to 4hp per ton for power, a little more
> for awider beam. any ideas? as 35hp sounds like alot.
Horsepower is probably the most misleading and misused stat in boating. The
more important characteristic is torque, for that's what really defines the
power to the prop. Yanmar and Westerbeke engines typically generate their
HP numbers at very high RPM. High RPM = high noise and high wear; as a
result, most cruisers keep the RPM way down from their maximum, and they
realize much less than their rated HP.
As you're comparing engines, look at the power/RPM curves and compare the
torque output of the engines at the speeds you'll cruise at.
To your above, I recommend you consider Beta, which are marinized Kubota
engines. Kubotas are typically used on tractors; parts can be found at NAPA
or farm stores, which means they'll cost half what Yanmar will charge. RPM
is lower, weight higher, torque higher, and they're much more rugged than
many other more common marine engines.
As far as what size engine you need, most boats today are powered at about
4HP/ton, mainly because of the auxiliary demands (reefer compressors,
high-output alternators, etc) placed on the engine. If you aren't going to
need the auxiliary devices, you can get by with a smaller engine. If you
need power often because of adverse weather or currents, I'd recommend you
go larger. HTH
-- Best,Bryan (KB3HMZ) "Capella" Valiant 40 #158 Annapolis, MD
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