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SLOboat · Joined: 10 Aug 2008 Posts: 7 Location: Port San Luis, CA

I have an Endeavour 37, listed at 10 ton, with a Perkins 4.108. I've been told by a marine mechanic that a safe cruising rpm for long distances is 2200, but recently another mechanic told me not to take her over 1800 for sustained travel. Unfortunately, travel on the Left Coast invariably involves motorsailing, so I need to know the right top speed.

amkoppelman · Joined: 17 Aug 2007 Posts: 3 Location: Alexandria, Va.

Just got a rebuilt 4-108 replacement for my E37 - mechanic (who does a bunch of these for the Navy) says 2400 RPM is fine, and should be able to run up to 3000 RPM without too much bother. My own experience is 2400 RPM produces optimum cruising speed - 6.5 knots) and the engine maintains a reasonable temperature - about 190f.

All best,

Mitch Koppelman
Captain, S/V Coracle2
Gibson Island, MD
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Mitch Koppelman
S/V Coracle II
1979-E37B
Gibson Island, Md

munrobr · Joined: 30 Jul 2007 Posts: 6 Location: Duxbury Ma.

I have an 81 37' with a 4-108and run it between 1800 and 2200 with no problem. Ran it last summer at 2800 for 7 hours without a problem trying to out run a storm.

FastFred · Posted: Tue Apr 14, 2009 1:26 pm Post subject: Perkins-4108 cruising speed

Much depends upon the pitch and diameter of your prop, the condition of your bottom (is it clean?), and your displacement. If the engine is not under too much load (and the temperature guage is a good indicator of that), 3,000 + rpm is not going to damage the engine. Trying to push the envelope beyond your boat's hull speed is going to cost you fuel and more maintenance without much in return.
ymmv,
Fred V. E-40 Liberty