Engine recomendations

We sail an old C&C and tend to motor in the mid 7's. This is at a Speed to
Length Ratio of 1.0 with an assumed prop efficiency of .25. Calculations
estimate we are pulling 29.6 Hp to attain this speed. The tranny is a
Borg Warner and costs us about 7% loss in Hp. We turn a 3 blade Max prop
and keep a fairly clean bottom.

In addition to propulsion we turn two high output alternators that pull
about 24 Hp when pumping out 280 amps. Our total motoring and charging cost
is (29.6/.93)+ 24=55.8Hp. Obviously we don't max out the alternators all
the time so the 55.8Hp tapers off as charge comes up.

The cast is: Westerbeke W108, Century 120N6, or Yanmar 4JH3 HTE.

The Yanmar turns at 2900 RPM, gives 48 Hp uses 10 l/hr fuel with a turbo and
intercooler.
The Westerbeke turns at 2600 RPM, gives 48 Hp uses 22.7 l/hr fuel with 6
cylinders, no turbo or intercooler.
The Century turns at 1700 RPM gives 48 Hp uses 12 l/hr with 6 cylinders, no
turboor intercooler.

Tranny efficiency is unknown for all engines.

Small and light is a turn on. Heavy, high RPM, Turbo, Intercoolers are
turn-off's. This is only my pereception.

The W108 is a direct drop in for the W100 which makes it real easy.

So does any one have time with these engines or like engines and can give me
some feedback.

Thanks,

Bryan


"Larry" <larry2.TakeThisOut@REMOVEisomedia.com> wrote in message
news:vn5v8rfmje2792@corp.supernews.com...
 > Please tell us what boat you have, and what speeds you usually cruise.
 >
 >
 > (¯`·._.· £ãrrÿ ·._.·´¯)
 >
 >
 >
 > "Bryan B" <bryanj.TakeThisOut@infinet.com> wrote in message
 > news:vn5bk5b0rs93d3@corp.supernews.com...
  > > We are getting ready to install a new engine in the boat this fall. Our
  > > considerations are a new Westerbeke, Century, or Yanmar. The boat
 > currently
  > > houses a Westerbeke so the conversion to a new Westerbeke is the
easiest.
  > > No messing with motor mounts, spares carry over, and this has been a
good
  > > engine 5400 hours. On the down side the Westerbeke is a big engine and
 > runs
  > > at 3600 RPM. The Century is rated at a lower RPM (2500) but is larger
yet
  > > than the Westerbeke. Both have only 1 year warranties. The Yanmar has
a
 > 5
  > > year waranty, is much smaller and lighter but again runs at a higer RPM
 > and
  > > gets Hp from the turbo and intercooler.
  > >
  > > So, any comments, good or bad with any of the above mentioned engines?
  > >
  > >
  > >
  > >
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Engine recomendations 

 >Subject: Re: Engine recomendations
 >From: "Bryan B" bryanj RemoveThis @infinet.com
 >Date: 9/25/03 2:24 PM Central Daylight Time
 >Message-id: <vn6g79bssr9jc0 RemoveThis @corp.supernews.com>
 >
 >We sail an old C&C and tend to motor in the mid 7's. This is at a Speed to
 >Length Ratio of 1.0 with an assumed prop efficiency of .25. Calculations
 >estimate we are pulling 29.6 Hp to attain this speed. The tranny is a
 >Borg Warner and costs us about 7% loss in Hp. We turn a 3 blade Max prop
 >and keep a fairly clean bottom.
 >
 >In addition to propulsion we turn two high output alternators that pull
 >about 24 Hp when pumping out 280 amps. Our total motoring and charging cost
 >is (29.6/.93)+ 24=55.8Hp. Obviously we don't max out the alternators all
 >the time so the 55.8Hp tapers off as charge comes up.
 >
 >The cast is: Westerbeke W108, Century 120N6, or Yanmar 4JH3 HTE.
 >
 >The Yanmar turns at 2900 RPM, gives 48 Hp uses 10 l/hr fuel with a turbo and
 >intercooler.
 >The Westerbeke turns at 2600 RPM, gives 48 Hp uses 22.7 l/hr fuel with 6
 >cylinders, no turbo or intercooler.
 >The Century turns at 1700 RPM gives 48 Hp uses 12 l/hr with 6 cylinders, no
 >turboor intercooler.

The figure for the Westerbeke seems way out of line. Could it be a typo??? As
given, it looks like about 0.9 lb/hp/hr, i.e., about double what one would
expect for a diesel.

Earl (no boat, sigh) Gasner



 >Tranny efficiency is unknown for all engines.
 >
 >Small and light is a turn on. Heavy, high RPM, Turbo, Intercoolers are
 >turn-off's. This is only my pereception.
 >
 >The W108 is a direct drop in for the W100 which makes it real easy.
 >
 >So does any one have time with these engines or like engines and can give me
 >some feedback.
 >
 >Thanks,
 >
 >Bryan
 >
 >
 > "Larry" <larry2 RemoveThis @REMOVEisomedia.com> wrote in message
 >news:vn5v8rfmje2792@corp.supernews.com...
  >> Please tell us what boat you have, and what speeds you usually cruise.
  >>
  >>
  >> (¯`·._.· £ãrrÿ ·._.·´¯)
  >>
  >>
  >>
  >> "Bryan B" <bryanj RemoveThis @infinet.com> wrote in message
  >> news:vn5bk5b0rs93d3@corp.supernews.com...
   >> > We are getting ready to install a new engine in the boat this fall. Our
   >> > considerations are a new Westerbeke, Century, or Yanmar. The boat
  >> currently
   >> > houses a Westerbeke so the conversion to a new Westerbeke is the
 >easiest.
   >> > No messing with motor mounts, spares carry over, and this has been a
 >good
   >> > engine 5400 hours. On the down side the Westerbeke is a big engine and
  >> runs
   >> > at 3600 RPM. The Century is rated at a lower RPM (2500) but is larger
 >yet
   >> > than the Westerbeke. Both have only 1 year warranties. The Yanmar has
 >a
  >> 5
   >> > year waranty, is much smaller and lighter but again runs at a higer RPM
  >> and
   >> > gets Hp from the turbo and intercooler.
   >> >
   >> > So, any comments, good or bad with any of the above mentioned engines?
   >> >
   >> >
   >> >
   >> >
  >>
  >>
 >
 >
 >
 >
 >
 >
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Engine recomendations