Add-on foils or trim tabs

Discussion in 'Sailboats' started by mihkel, May 7, 2018.

  1. mihkel
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    mihkel Junior Member

    Motorboats have different foils that can be added to outboard motor or trim tabs. Do sailboats have any similar options?

    Adjustable trim tabs would probably enhance downwind performance probably - no?
     
  2. Doug Lord
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    Doug Lord Flight Ready

    Some monohull or multihull sailboats can benefit from rudder T-foils or DSS foils but ,generally, need to be designed from scratch for foils to use them most effectively.
     
  3. mihkel
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    mihkel Junior Member

  4. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    I have a picture that I can't find of trim tabs on a large racing sailboat-on some hulls they could be helpful. Also interceptors have been used on at least one big multihull(see illustration below).
    Most foiling boats do not need an interceptor or an aft trimtab because they use a rudder T-foil in combination with a main foil.
    The two main types of foil systems used on sailboats are : 1) foil assist-(like DSS) where the foil is used to partially lift the boat and, in some cases, to add righting moment(DSS). 2) Full foiling where at least two foils are used to lift the whole boat out of the water.
    There are threads in the "Sailboats" forum and in the "Multihulls" forum that show some of the many new foilers that are being introduced all the time.
    Full foiling systems can now be used on everything from windsurfers ,kiteboards and monohull keelboats to 100+' trimarans . Foil assist systems are being used on many different types of boats with DSS* systems the best example.
    *Dynamic Stability Systems
    The use of foils can increase top speed but can also increase stability and comfort while at sea. The last 18 years or so has seen the development of many high performance foilers but the Revolution is beginning to expand to foilers designed for light air take-off and comfort rather than an emphasis on top end speed.
    It's a very exciting time!

    interceptor-on powerboat hull.gif


    DSS on 30 footer:
    DSS on T 30 Drakes Trolley 2.jpg

    Foiler Moth:
    070702_Moth_06.jpg

    Quant 23-foiling keelboat #1:
    Quant 23 new foil 4-27-16.jpg

    Qunat 23 foiling keelboat #2:
    Quant 23 flying - Copy.jpg
     
    Last edited: May 7, 2018
  5. OzFred
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    OzFred Senior Member

    Why would they? What problem are you trying to solve?
     
  6. mihkel
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    mihkel Junior Member

    Just an idea of using trim tabs for auto balancing when sailboat is moving and creating better planing characteristics downwind.
     
  7. CT249
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    CT249 Senior Member

    It was tried on the early "supermaxi" Bols, I think, and on Rucanor Tristar, a Whitbread racer. In the latter case it was banned as being against the IOR rules. Bols apparently had other issues so I don't think it ever really got the system going.

    Yes, it may make a sailboat faster but there are probably other ways of making boats faster that have greater effect for similar hassle.
     
    Last edited: May 8, 2018
  8. rwatson
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    rwatson Senior Member


  9. Doug Lord
    Joined: May 2009
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    Doug Lord Flight Ready

    IMOCA 60 with trim tab:

    Trim tab Imoca 60.jpg
     
    rwatson likes this.
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