Propulsion system for a high speed trimaran

Discussion in 'Multihulls' started by boat88, Aug 30, 2009.

  1. boat88
    Joined: Aug 2009
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    Location: TE

    boat88 Junior Member

    Hello,
    I try to find the best propulsion system for a high speed planning boat,its a trimaran with these characteristics

    Length=10m
    Beam=5m
    Maximum speed=60 knots
    Cruise speed=50 Knots
    Weight=4.5 ton

    but i have problem to decide between stern drive and outboard propulsion systems.
    Also i want to know how many propulsion systems is more proper for this situation(i.e. 2 or 3)?
    Thank you.
     
  2. Jameswright4
    Joined: Sep 2009
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    Location: London UK

    Jameswright4 Junior Member

    Answer to your question

    A sterndrive is much preferable.

    We have two outdrives on the outer hulls of our yacht and the problems are as follows:

    1. 40% Power is lost by the distance frm the shafts to the legs to the engine in the aft cockpit (Yanmar 55 which drives the two legs which hydraulically are raised and lowered)

    2. Noise is increased via vibration as transmitted through the drive shafts. ..Makes more noise than the engine!

    3. In a heavy sea the legs often come out of the water yet the props still spin
    and thuis makes for more inefficiency.

    A sterndrive with moveable twin props takes care of all these woes.

    To see my boat enter LARINKA into Google and up she comes or check out
    www.planesail.com and see the utube video.

    Hope this helps James Wright
     
  3. boat88
    Joined: Aug 2009
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    boat88 Junior Member

    Dear james,
    Thank you for your reply, you helped me so much, would you tell me which outboard motor do you use?
     
  4. Jameswright4
    Joined: Sep 2009
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    Location: London UK

    Jameswright4 Junior Member

    Do not even think about it......Volvo and Vetus combination
    and all non standard as not meant to lift and lock in positions designed.

    Focus only on Stern drive and if possible depending on size also fit a bow thruster.

    A fixe wing evne when feathering doe have a little bit of movement in tight manouvering such as coming in to dock. ..takes experience from inside control cockpit to judge width for our boat is 9 metres wide.
     

  5. Speng
    Joined: Jun 2007
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    Location: USA

    Speng Junior Member

    for 60 knots you probably want to go with a surface piercing drive like Arneson or something like that. Like the offshore powerboats use.
     
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