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Fuel burn question

Discussion in 'General Yachting Discussion' started by Keysbearfl, Feb 21, 2012.

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  1. Capt Ralph

    Capt Ralph Senior Member

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    WOW, that was moving nice (on calm water). I do like the design and da wife thinks she is real cool looking.
    Thx for the peek.

    I'll get into the rum later and pull out the calculator but my south Georgia senses concludes that the consumption (burn rate) in impressive.

    Thx again.
  2. Capt Ralph

    Capt Ralph Senior Member

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    original topic

    Hello Keysbearfl

    We have all had some fun here and I have learned a few things. How does our figures and comments compare to your real life consumption and plans?
    Did we ever answer your question?
  3. Keysbearfl

    Keysbearfl New Member

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    Thanks to all who responded. it appears that my numbers are fairly accurate. I calculated that the 8V92's would burn 30GPH @ 16 knots, 50GPH @ 20 knots, and 65-70gph @ WOT. As no one actually had a boat with this power option, I used the formula's several of the posters gave me. I really appreciate all the help.

    Thanks

    Keysbear
  4. K1W1

    K1W1 Senior Member

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    Hi,

    You say you calculated this? How does the calculation compare to the actual consumption on the boat underway?
  5. Keysbearfl

    Keysbearfl New Member

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    Hi K1W1,

    I cannot answer your question, as I am considering the purchase of a Betram 46, with the 8V92's. I cannot give the actual consumption of the boat underway as I do not know. That was the question I originally asked.

    Thanks,

    Keysbear
  6. Capt J

    Capt J Senior Member

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    It depends what HP rating they are of 8v92's. I cannot remember exactly, but 50-60 gph sounds right. Closer to 60 if they're the higher HP J+Ts or DDEC's.....
  7. AlfredZ

    AlfredZ Senior Member

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    Here is a quote about the same subject from ********** web page:

    "Re: 8V92 Fuel consumption at ~1200 RPM
    I have a fuel curve for the for the 8V92TA rated at 760 BHP at 2300 RPM (735 SHP @ 2300 RPM).

    Here are the specs as close as I can make them out looking at the graph. Could be +/- 1 gph.

    1200 - 8 gph
    1400 - 11 gph
    1600 - 16 gph
    1800 - 21 gph
    2000 - 27.5 gph
    2200 - 36.5 gph
    2300 - 42 gph

    Blaine "

    Cheers.
  8. K1W1

    K1W1 Senior Member

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    Hi,

    Thanks, As boats age they get heavier etc and it would be interesting to see how close the rel life consumption is to the calculated figures.

    If and when you get it please post with the actual numbers if you have time.

    It will not only satisfy my curiosity but further add to the knowledge base here at YF
  9. Loren Schweizer

    Loren Schweizer YF Associate Writer

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    Re-read post # 13. These are real-life numbers taken from a real boat. Really.
  10. Capt J

    Capt J Senior Member

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    It the propellors have been re-pitched or the engines still achieve their WOT 2300rpm's fuel consumption shouldn't change much at all with additional boat weight, only speed over ground at each RPM.