T&T: Cruise RPM for Cummins 220.

[Jim Ague]

Hi John,

I went to the messages area of the Monk36OwnersAssociation group on Yahoo, 
Messages, and searched on RPM. This is an example from many that might fit 
your question:

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..., Hull 210 purchased new in 2001 with 220 Cummins & love
the boat. Drove it 2700 mile from Pt Pleasant to home port in Panama
City on the Florida panhandle.

On calm flat water with clean bottom, I ran topped tanks & fully loaded
for cruising at 100 RPM increments for 30 minutes from 1400 to 2300 to
determine speed and overall boat feel.
1800RPM is the optimum and I don't care what Al Smith says about 2000 or
2100 cruising speed! All you're doing is flailing the water to get
another one knot+/- of speed. The noise alone is not worth it,
disregarding the expense.

At 1800, I burn 2.7 gallons & another .75g/hour if Northern Lights 8kw
is running, this pushes me a steady 8.5kts. In four years I've put a
1000 hours on the Cummins with nothing but six month oil, filters & zinc
changes. Still runs like a Singer sewing machine straight across the
Gulf to Dry Tortugas, Key West or Tampa.
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You should be a member of this group and be able to look at other entries. 
With a Perkins 135 and 3 blades we get 7.5 kts at 2050 RPM.

(If the above Messages link doesn't work, try 
http://groups.yahoo.com/group/Monk36OwnersAssociation/messages.)

-- Jim
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Jim & Rita Ague
M/V Derreen, Monk 36
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