Future Trends In List/heel Control

Discussion in 'Stability' started by ahldjk, Apr 10, 2014.

  1. ahldjk
    Joined: Apr 2014
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    ahldjk New Member

    can anyone elaborate about modern systems to prevent Listing/Heeling of ships. one such Interesting concept is SATRAP system on board French Aircraft carrier Charles De Gaulle.
    You can also discuss the systems in use currently.
     
  2. BMcF
    Joined: Mar 2007
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    BMcF Senior Member

    There have been active stabilization systems that control the running list and trim (in addition to damping pitch and/or roll motions) in service for decades. Various effectors are employed, often in combination; interceptors, transom trim tabs, moveable fins , and fixed fins with trailing edge flaps.

    A very recent, but typical, example that our company provided the stabilization package for is a 63-m fast attack craft that achieves nearly flat ("flat" being zero heel angle) turns at full speed and hard-over rudders with the system active, but exceeds 10 degrees of heel in turns executed at much lower speeds and degree of helm when the stabilization system is secured.

    SWATH vessels are another type where active control of list and trim have been used for a long time to impart a high degree of stability underway.
     
  3. ahldjk
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    ahldjk New Member

    what kind of stabilization package was used for the 63m FAC. I want to know the system working. please if you can share. This is for my Project work.
     
  4. BMcF
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    BMcF Senior Member

    The "standard", if there is such a thing, solution for stabilizing high-speed mono hulls uses transom trim tabs or interceptors, actively controlled by a digital motion stabilization package. Interceptors are sometimes used instead of trim tabs, and while lower in weight and cost, and requiring less power to operate, are not usually as effective, especially at more moderate speeds of operation.

    To either of the above, can be added controllable fins, or foils (root mounted or in a T-foil configuration) mounted as near the bow as possible.

    The 63-m FAC uses a pair of 3-square-meter transom trim tabs and a pair of 2-square-meter controllable foils mounted forward.
     
  5. keysdisease
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    keysdisease Senior Member

    I am seeing more and more gyro stabilized vessels in yacht sizes down to 80 ft or so. Mitsubishi seems to be a player in larger vessels and Seakeeper in smaller vessels.

    Nice thing about these systems is that there are no protrusions on the hull like fins or foils and they seem to work at zero speed.

    :cool:
     

  6. BMcF
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    BMcF Senior Member

    Gyro stabilization systems can do nothing to control the average list angle. They are motion damping solutions, reducing transient/resonant motions.

    As for zero-speed/low speed control of mean or quasi-mean list angle, that requires the ability to transfer ballast, either in the form of water in tanks (a typical SWATH solution) or some other moveable weight(s), as the French have included in their SATRAP system.

    Koop experimented with moving-transverse-weight systems (both linear as well as pendulum) quite some years ago and installed at least a couple prototypes.
     
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