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Your Fuel Mileage

Discussion in 'General Yachting Discussion' started by Capt. Mike, Nov 20, 2012.

  1. Capt. Mike

    Capt. Mike New Member

    Joined:
    Feb 28, 2008
    Messages:
    123
    Location:
    Nashville TN,
    I took a 300 mile on the 103 Lost Pearl this past week and I felt this would be a good time to check my fuel mileage. After running my speed 9.5- 10.5 and 300 miles and one night of anchoring out running a generator the entire trip I came up with 1.19 MPG. I have two generators." My main is a 30kw and my smaller one is 7.6kw. I only run the 30kw when anchoring, cooking or running all the airs. The 30kw drink 1.75 at full and the 7.6 drinks .53 at full so witch would you run.

    I would love to know do boats vary much in fuel mileage. Most seem to get around a mile per gallon whether larger or small. I live inland and this holds true up here but then again I'm kinda the one of few over 65 feet around here.
  2. Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    13,938
    Location:
    Fort Lauderdale
    displacement hulled motoryachts don't vary fuel milage much on size.

    Planing hulls vary greatly depending on size.....A 55' MY usually burns 2.5 GPM, a 75' Motoryacht as much as 7GPM..... etc etc....
  3. Pascal

    Pascal Senior Member

    Joined:
    Feb 29, 2008
    Messages:
    6,587
    Location:
    Miami, FL
    The key at slow speed is to realize that even a single knots will make a huge difference

    When you say 9.5 to 10.5mph, that can be a 60 to 75% difference l. As soon as you hit hull speed and go just beyond it your fuel burn goes up drastically. It is extremely obvious if you have flow meter On the 70 footer I run, from 10kts to 11kts flow goes from 18gph to over 30 . Push to 11.5 to 12kts and you re better off on plane doing 22kts on 85gph

    So whatever you do, try to keep it just below hull speed (1/4 to 1/2 kts below)