More Foils in Your Future?

Discussion in 'Sailboats' started by Chris Ostlind, Jun 18, 2008.

  1. Chris Ostlind

    Chris Ostlind Previous Member

    This morning, over on Sailing Anarchy, a new development in the use of lifting foils on monohulls was announced. The new company is DSS and they have come up with a leeward side lifting foil system along with the regular marketing claims for same.

    You can check out the home page for DSS here:

    You can decide for yourselves as to the real benefit vs the possible hassle of having a system like this on your boat.

    Let the opinions roll, gentlemen.

    Attached Files:

  2. Euler
    Joined: Jun 2008
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    Euler New Member

    What happens when a wave stops the lift force?

  3. Chris Ostlind

    Chris Ostlind Previous Member

    You mean, when the foil exits the back side of a wave crest, crashes back down with the full weight of the boat on the horizontal foil and it has to reattach itself to the flow in order to restore lift?

    Yeah, there could be issues there.
  4. Capn Mud
    Joined: Apr 2008
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    Capn Mud Junior Member

    And the Russian Judge gives a 2

    Look at the amount of spray, wake and splashing going on!! Is it really being efficient or causing more drag? I guess testing would tell and also pics of the boat in the same breeze with or without it and see how much lower the boat would sit in the water and how much additional bow wave and wake the boat has without it....

    In any case - probably not for me - I still struggle to be pulling the daggerboard up on a run and remember to push it down again for the beat ;-)
  5. Capn Mud
    Joined: Apr 2008
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    Capn Mud Junior Member

    On the site under Research and Development some interesting, albeit very brief, information:

    Stage 4 - position very important "it was quite easy to reduce performance when basic elements were not working in an optimum environment"

    Stage 7 - 23 ft existing sportsboat used with it installed only on one side so performance could be directly compared tack to tack - up to 35% increase in performance.

    My question would be - how non-ideal do the conditions have to be to actually cause a reduction rather than an improvement?

  6. CT 249
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    CT 249 Senior Member

    One older UK sportsboat around 23' is the Hunter 707; it's 1.5% faster than a J/24. If this 23' sportsboat increased its speed by 35%, it would savage a J/125, and easily beat a 49er.......

    If the 23' sportsboat was a Melges 24 (PHRF 87) and its performance increased by 35%, it would equate to a PHRF rating about the same as a N/M Transpac 52; about a minute per mile faster than Randy Smyth's Farrier 25 tri; similar to the fastest of the 33' cats in the USA; about as fast as a C Class cat's PHRF.......

    Put it this way, there's only 47% speed difference between a Laser Radial and a 49er.....

    In other words, 35% is one hell of a big call.

    Why a centreboard stuck out to the side of a Melges would turn it into a machine that could beat bigger, lighter multihulls is an open question.
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