Experience with zero speed stabilisers from different manufacturers on large yachts??

Discussion in 'Stability' started by BIGBOATBUILDER, Apr 9, 2008.

    Joined: Sep 2007
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    BIGBOATBUILDER Junior Member

    Hi, even though this might start a battle, I'd be interested to hear what your experiences with zero-speed stabilizer systems of the various manufacturers are.

    I'd be especially interested to hear about quality, service and reliability from manufacturers like:

    -TRAC / American bowthrusters
    -Wesmar (I think they are just about to bring a zero speed system on the
    -Najad / Vosper Thornycraft

    Thanks for your help,

  2. CTMD
    Joined: Dec 2007
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    CTMD Naval Architect

    I always specify TRAC and have never heard a complaint. Depending on the speed of your boat, they do some nice interceptors now too as an alternative to trim tabs.
  3. BMcF
    Joined: Mar 2007
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    Location: Maryland

    BMcF Senior Member

    Being 'somewhat familiar' with the development of the first 'zero-speed' fin systems, I would offer this; When the algorithms were proven and control effectivenes of the first 'at anchor' systems was borne out in practice, there was a rush to retrofit the controls to quite a few existing systems, keeping the existing fins and hydraulics in place. Two things became evident rather soon after that flurry of upgrade activity:

    1. The existing fin hardware was not up to the task of supporting the rapid and non-linear 'zero speed' fin activity without suffering from inadequte hydraulic capacity and/or rapid wear-out of fin hardware.

    2. Fins (and top plate design and actuation capacity) that were specifically taylored in planform, stock location, etc. to provide more effective zero-speed control were developed and perform far better than the typical/standard roll fins for that application.

    So I guess my short answer would be "beware of those offering the same fin hardware as they always have but now claiming that they can include zero-speed control option with it". It may be so - I'm not familiar with all of those you mentioned and would rather not go in to the details of those that I am quite familiar with. Just a little background that might be useful as you ask each potential supplier to address the 'hard questions' relating to proven performance and proven reliability.

    Edit: Note that interceptors cannot perfrom zero-speed control. Trim tabs can, in some cases, but nobody yet offeres, to my knowledge, an off-the-shelf solution for zero=speed control based on the use of active trim tabs. We've done it only on a custom and test/trials/R&D basis.

    Note also that Quantum offers both fin and Magnus-effect rotor zero-speed control systems..or combinations of the two technologies.
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