Asymmetric engine trim on power cats

Discussion in 'Hydrodynamics and Aerodynamics' started by Mr Efficiency, Oct 24, 2013.

  1. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    On another forum, a discussion about outboard trim settings on planing power cats has some sharply divided opinions, some saying it is necessary to "get the best out of them", whilst others are less keen on the idea, on safety grounds. In an extreme example, e.g., the port engine could be trimmed right in, the starboard right out, when there are sharply rising waves approaching the starboard beam. The risk seems to me to come from unexpected wave encounters, from systems unrelated to the one that was being adjusted for by uneven trim. I'd like to hear what the experts here think.
  2. Alik
    Joined: Jul 2003
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    Alik Senior Member

    Sometimes I drive with uneven engine trim in beam wind or wave, or asymmetric loading. But in most of conditions driving with even trim is more comfortable and predictable.
  3. Stumble
    Joined: Oct 2008
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    Stumble Senior Member

    I can't see ever having my engines so far out of trim I could see it as a danger. Except if I was limping home on one engine. I can just barely plane on one if the second is out of the water.

    Generally I keep the trims pretty close.

  4. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    if your twins have the same prop rotation then you end up with unequal trim, thats the big issue
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