Fuel consumption opinions

Discussion in 'Boat Design' started by janesci, Apr 30, 2013.

  1. janesci
    Joined: Dec 2012
    Posts: 30
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: KOREA

    janesci Junior Member

    Hi

    I was wondering about your thoughts or opinions of fuel fuel consumption for the below designs.

    LOA: 56ft/ B 25ft/ D 2.5ft
    Dsplcmnt: abt 90tons at light ship
    M/E 500HP @ 1,800 RPM with 66inch pitched prop.
    Gensets: 77kva
    Fuel tank abt 9,000ltrs.

    Hull type: round bilge with bulbous bow.

    I am planning to sail above boat for abt 6000nm at 11knot crusing speed.

    Can any one advise me for the approx fuel consumption to get fuel budgets?

    Thanks guys in advance.
     
  2. FAST FRED
    Joined: Oct 2002
    Posts: 4,519
    Likes: 111, Points: 63, Legacy Rep: 1009
    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    "11knot crusing speed. "


    The problem is your speed demand is far higher than an efficient speed.

    With a 56 ft boat the water line is not long enough , bulb bow or not.

    The Square root of the LWL say 49 ft is 7.

    Some where near 7 K is your long range cruise speed.

    Actually .9 to 1.15 times the sq rt is the number.

    Roughly it takes 2HP per ton to 3 HP per ton to move at Long Range Cruise speed.

    IF your boat displaces 100 tons (2240lbs per ton) between 200HP and 300HP will be required.

    A very modern diesel can produce 20 HP from a single gallon of fuel.

    200HP could be 10GPH at SLOW CRUISE! 300, 15GPH.

    I doubt 500 hp at full throttle would give much over 9K .

    To cruise at 11K will require a thousand more HP.
     
    1 person likes this.
  3. janesci
    Joined: Dec 2012
    Posts: 30
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: KOREA

    janesci Junior Member



    Thank you very much for your comment and advise. Helped to sort out a lot.
     
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