Range its all about efficiency

Discussion in 'Props' started by Mikthestik, May 28, 2016.

Page 2 of 2
  1. Barry
    Joined: Mar 2002
    Posts: 1,857
    Likes: 509, Points: 113, Legacy Rep: 158

    Barry Senior Member

    If you are referring to my calculations, I never mentioned prop diameter.
     
    Barry, Jun 12, 2016
    #16
  2. whitepointer23

    whitepointer23 Previous Member

    gph is a bit silly. mpg is much more useful to most people .
     
    whitepointer23, Jun 13, 2016
    #17
  3. 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

    "A 2 speed boat. Fast locally, slow to cross oceans. "

    You have answered your own question, a 2 speed transmission.

    By speeding up the prop at low engine speeds you can get back in the "bulseye" on a BMEP graph.

    ZF makes the tranny , but obtaining a BMEP graph from an engine source is almost impossible for small engines.

    Perhaps claiming your company is a pump builder or genset Mfg might spring one loose.
     
    FAST FRED, Jun 14, 2016
    #18

  5. mydauphin
    Joined: Apr 2007
    Posts: 2,161
    Likes: 53, Points: 48, Legacy Rep: 575
    Location: Florida

    mydauphin Senior Member

    "Range its all about efficiency" has a lot to do with the boat too.

    A variable pitch can also make a difference, acts like a variable speed transmission.

    gph, mpg are all not real... most boats gpm. Most boat never get below 1
     
    mydauphin, Jun 28, 2016
    #19
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