27HP in 9000 lb hull?

[massnspace]

I am seriously looking at a sailboat for offshore trips.

Has a brand new Yanmar 3gm30 (27 hp) with a stated displacement of 8900 lbs.

I think the original engine was a 20 hp.

Engine seems too big. My concern is that it will be running at a low rpm, thus fouling it. I would plan to run it at high rpm’s for the last half hour of so to burn out the carbon or whatever, but, still, is that the right motor for the boat?

Any opinions welcome.

Thanks,

David
Seattle

[JimsCAL]

I have a Yanmar 3GM30F in my 11,000 lb Cal 33-2. Plenty of power for me so agree that a 2GM would have been enough for you. But I wouldn't worry about fouling. Low operating RPM is more likely with a prop with too much pitch than just a somewhat larger engine.

[deltaten]

Ok....lessee...usual published data on engine HP is at max revs. What would that be a normal max cruise? Waaaay better to have more available than less.
My 27 footer is nominally 7500#. Best guess at actual is over 8k. Engine is a new(ish) old stock Beta 20 with a bit under 300 hrs on it. Rated at 20hp at max 2600 (?) revs/ not recommender for more than a few moments, and max cruise use at 2400r.
I am a bit over prop'd at 9x13 and max R underway is 1950 or so. Hull speed calculated is 6.3kn. I can get 5.5-5.7kn at 1650 +/-, after that it's trying to bury the bow and scarfing down dinosaur squeezings. I'd sooner have the headroom to go scat when I want/need to.
Running ANY diesel a bit "hot" before shutting down is a pretty good idea in my book.
A lot depends on loaded weight and how she's propped. Your choice....just some comparative data. HTH. ��