Join Date: Sep 2011
Location: Dolphin Beach, B.C.
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Re: Beneteau 36CC does not reach hull speed
I have the same engine and a 2.21:1 ratio gearbox in a C&C 32. I believe my hull speed is around 6.5 knots.
At about 12,000 lbs. fully loaded and with a 16"x14" fixed 3 blade prop at 2800 rpm my boat will cruise at 7 gps knots in any reasonable conditions.
It sounds like your boat may be under propped or under geared. My boat is a bit over propped but it seems to do ok.
There are two gearboxes for this engine. One is 2.21:1 and the other is around 2.8:1 if I remember right. Find out which one you have before you make a prop decision.
If you have a feathering prop you can have them repitched for a better bite. If it is a folder then maybe it is a bit small for your application.
I never run my 3gm30f over 3 grand. I don't think I have ever had it at wide open throttle, ever.
We have three rules;
No bleeding on the sails.
No slobbering on the charts.