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
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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
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    Doug Lord Flight Ready

    IMOCA 60 with trim tab:

    Trim tab Imoca 60.jpg
     
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  10. mihkel
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    mihkel Junior Member

    Wondering if anybody has tried adding something like that to cruisers? Many extend their aft to get some extra LWL length + access to water. Why not add foldable trim tabs to a sailboat? Some extra feet but no extra mooring cost?
     
  11. JamesG123
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    JamesG123 Senior Member

    Cruisers, except I guess for the very high end of the market, are very slow to adopt innovation (unless it reduced production costs) . For one thing, the market is swamped with older boats, so new production is relatively low. Few owners have the resources, motivation, or knowledge to retrofit modern hydrodynamics.
     
  12. CT249
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    CT249 Senior Member

    Are they slow to accept innovations? Perhaps it's just that they aren't logically worth it? How does one say how fast other people should spend their own money on innovations that affect their own fun?

    The article on interceptors mentions that they were used on the Open 60 Ecover, among several other boats. So why are they not used any more in racing yachts? Because every single designer (including the one who tried them on Ecover) is an idiot, or because they didn't work well? I'd wager the latter.

    So even assuming interceptors do work on sailboats - how well do they work and how much do they cost? If they increase downwind speed in a breeze by say 0.5 knots at a cost of $15,000 plus maintenance plus antifouling issues, it's perfectly reasonable for owners to say it's not worth it.

    Why assume that people are slow to accept innovation? In racing boats, many innovations are picked up extremely quickly, but others aren't actually worth it. Maybe it's the same in cruisers?
     
  13. Dolfiman
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    Dolfiman Senior Member

    That was Paprec-Virbac, a Farr Yacht Design Imoca launched in 2007 for Jean-Piere Dick, in view the 2008 Vendée Globe, and the trim tab was an option (100 kg, 60000€) that Jean-Pierre accepted to take. But that does not give significant improvements and was abandoned.
    Ref : De Rucanor à Paprec-Virbac, une histoire de flaps ! http://www.seasailsurf.com/4277-De-Rucanor-a-Paprec-Virbac-une-histoire-de-flaps
     
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  14. JamesG123
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    JamesG123 Senior Member

    Because that's not the case. Mihkel's post about cruising adopting whatever was trendy in racing is what I was referring to. Some people race cruisers, but you don't sell racers to cruisers. Racing and cruising are two separate markets even in a production setting. Some technology crosses over, but you get as much crossover from the RV world.
     

  15. Doug Lord
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    Doug Lord Flight Ready

    ==================
    The article (googletrans) didn't say anything about it not working-do you have a link to anything about how it actually worked? The article was apparently written before the system was tested? 60,000 euros seems like reason enough to abandon it unless it worked exceptionally well!
     
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