BoatBanter.com - View Single Post - Sea Ray 340. On topic, but be warned.......

On 12 Apr 2004 23:02:19 GMT, (Gould 0738) wrote:

You feel the engine needs to be backed off to about 60% of WOT for normal
cruise speed?

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Not necessarily, it depends on how the boat is propped, but 3,400
should be regarded as a maximum cruise RPM for any normal gas engine.
Ideally the boat should be propped so that 70% of WOT brings you to
about 3,200 to 3,400 RPM. That way the engine is developing about
half of its rated horsepower at cruising speed. Diesels are usually
spec'd out to run at 85% of WOT which works out to about 70% of full
horsepower.