Join Date: Mar 2003
Location: South Freeport, Maine
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Re: Yanmar 3GM30F HP one-hour rating (??)
I believe PorFin is correct re: HP/rpm.
We too have a 3GM30F that runs "all day" with low fuel consumption. I have great confidence in this Yanmar. If you have the service manual you will see a chart showing the power curves. The owner's manual specifications specifically states the one hour vs. prolonged rpm max and related HP.
Previous owner recommended we cruise at 2400 rpm- We tend to run at 2500 - 2600 rpm. Comments by aa3jy and chef2sail cause me to wonder if I am running too low. I have had no apparent problems.
Nigel Calder recently (in Sail Mag?) wrote an article about rpm vs. fuel consumption noting that there is limited cost/benefit from pushing the boat beyond a certain point, with reduced benefit for additional fuel consumption.
In any event, perhaps your sea trial will tell you if the vessel seems to have enough power for your needs. Ideally you will have the opportunity to run it against a stiff wind or through a tidal current to see how she performs. GOOD LUCK!
"Grace" - Nauticat 33
Home Port - South Freeport, ME