Click for Abeking Click for Glendinning Click for Westport Click for Abeking Click for Burger

Detroit 12V71

Discussion in 'Engines' started by Sam Bellows, Apr 13, 2022.

You need to be registered and signed in to view this content.
Page 2 of 2
  1. Pascal, Apr 13, 2022
    #21
    Pascal

    Pascal Senior Member

    Joined:
    Feb 29, 2008
    Messages:
    8,546
    Location:
    Miami, FL
    Combined. See my last reply. I never include gen because i run the gen 24/7 so I keep track of that burn separately.

    the key is to not exceed hull speed. For a 67 footer hull speed is going to be 10kts. Not 10.5 kts… an extra 1/2 kts above HS will Cost you 30% more fuel. An extra knot? Close to double
  2. Capt Ralph, Apr 13, 2022
    #22
    Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    13,436
    Location:
    Satsuma, FL
    HP is fuel
    Crudely, if each engine is delivering 250 HP to the same props and same ratios, Yes.
  3. Capt Ralph, Apr 13, 2022
    #23
    Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    13,436
    Location:
    Satsuma, FL
    Hull speed can be calculated by the following formula:
    v h u l l ≈ 1.34 × L W L {\displaystyle v_{hull}\approx 1.34\times {\sqrt {L_{WL}}}}
    [​IMG]

    where
    L W L {\displaystyle L_{WL}} [​IMG] is the length of the waterline in feet, and
    v h u l l {\displaystyle v_{hull}} [​IMG] is the hull speed of the vessel in knots
  4. Sam Bellows, Apr 13, 2022
    #24
    Sam Bellows

    Sam Bellows New Member

    Joined:
    Apr 13, 2022
    Messages:
    7
    Location:
    Galveston
    I wholeheartedly appreciate your willingness help and give me some numbers to go on. Im a diver and the ability to use it as a live aboard not to mention a dive boat or occasionally as a chartered dive boat and run it kinda affordably, I’m not expecting a half gallon an hour, is rather important. I’m wanting the yacht equivalent of a Chevy suburban. The places I’d like to go in the Caribbean and gulf are far enough out I don’t want to do it in a 30’ bathtub.
  5. rusty882000, May 12, 2022
    #25
    rusty882000

    rusty882000 New Member

    Joined:
    May 11, 2022
    Messages:
    1
    Location:
    New Zealand
    Any idea what the Detroit 12V-92TA 8122-7400 rated shp 775@2300 rpm would burn at 1800rpm cruising?
    Cant find any performance data on this engine.
  6. Capt Ralph, May 12, 2022
    #26
    Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    13,436
    Location:
    Satsuma, FL
    Correctly loaded, 34 (US)GPH.
Page 2 of 2