Foil Assist Monohulls

Discussion in 'Sailboats' started by Doug Lord, Jun 14, 2018.

  1. OzFred
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    OzFred Senior Member

    Most of the features in the DSS patent abstract are consistent with nearly every hydrofoil (lifting, stowed and deployed conditions, protrude outward, etc.), the fact that the Sailing Booster claims similar features is not remarkable. There are many examples of stabilising fins on ships and submarines that fit most of the same criteria, but you wouldn't consider them DSS ripoffs.

    The novel (i.e. patentable) part of DSS is in the detail, not the general application of a moveable hydrofoil as a stabiliser or lifting surface.
     
  2. CT249
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    CT249 Senior Member

    I wonder whether this was the first foil assist mono racing class. The lift off the centreboard was one of the major factors in sailing these Division II boards, once the Grand Prix class of windsurfing and later used as the basis for the Olympic Lechner. Upwind it was critical to "rail" them by tilting them to 25 degrees or so. The railing put the centreboard into a position where it lifted the board quite significantly, and sailing them in many conditions was in essence a matter of balancing between rig, hull and CB in roughly equal parts. I think it was the importance of centreboard lift that means that when a longboard windsurfer sailor gets onto a full foiler it can be a very familiar feeling. It's interesting that two older former longboard windsurfers, AMAC and Goughy, both got on the podium at foiling Moth worlds.

    I did a couple of races against the world's top two seahuggers Moths (Mark and Les). I was out of practice and using a less optimal (flatter) 7.4 IMCO sail but the board was equal to about 6-8 knots and faster in the brief puffs. They were able to roll an IC upwind in moderate to fresh breezes and vanished downwind, sailing to a yardstick of about 95 I think. Now of course they have no chance against a Moth in anything over a consistent 6-8 knots. Lovely boards and now having a small resurgence. I gave my first one to a mate (who still has it) when I got the bronze medal winner's Olympic board. Now another Olympic medal winner I know is joining our club and we may get a local Div 2 reunion going when we're not Lasering or playing A Cat v F18.

    [​IMG]

    [​IMG]
     
  3. OzFred
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    OzFred Senior Member

    You might be right about that. I once met a guy on the RQ ramp who made carbon fibre fins for his son's sailboards. He said he made them very flexible so they would bend to provide vertical lift. It was a challenge to make them bend but not twist

    PS. My first Moth was a Thorpe Axeman with aluminium wings (but fortunately a carbon rig, I swam a lot). :)
     
  4. Doug Lord
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    Doug Lord Flight Ready

    =====================
    It's an attempted rip off no ifs, ands or buts.......
     
  5. Skyak
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    Skyak Senior Member

    Yes, patents protect the novel device. The stuff thrown in explaining what good things you get out of that device are of no consequence legally.

    From what I can see, the pivot down foils would not be a violation of the DSS patent because DSS is about how the foil slides out of the hull and in what position.

    We should have a forum for "Boat Design IP" and how to handle it, respect it, and profit from it. Doug is not the only one with misconceptions.
     
  6. Doug Lord
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    Doug Lord Flight Ready

    I have no misconceptions about patents -the DSS patent in particular. I've worked on patents researching them, writing them and getting a few for over 40 years with guidance from one of the best patent attorneys in the US. I can assure you that the "Sailing Booster" is an attempted rip-off of DSS up until the point it is sold-then it is an actual ripoff!

    DSS system for IMOCA 60's-covered by DSS patent:
    DSS IMOCA foils.jpg

    DSS system for Quant 23-covered by DSS patent:
    DSS- frm hugh.jpg
     
    Last edited: Jun 29, 2018
  7. Tink
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    Tink Junior Member

    As above the claims (big 13 at top of page) are the only part of the patent with any legal importance. The claims are rather specific narrowing the scope of the protected idea and making it easy to work around.

    If claim one has said something like a ‘a sailing vessel with a board projecting out of the hull at an angle plus or minus 60 degrees from the horizontal at rest’ and then become more specific latter on it would have been strong. I suspect the prior art has driven them to such a narrow set of claims.

    https://patentimages.storage.googleapis.com/3b/04/65/edda9bc741beb9/US7644672.pdf

    There is a ton of prior art and I am not going read them all, this one is poorly translated but from a scan read covers the essential operation of DSS. There are many pictures but a this one show a stabilising foil sliding through the hull.

    Google Patents https://patents.google.com/?q=lifting&q=hydrofoil&q=vessel&q=position&q=sailing&before=priority:20060407&scholar&page=4

    https://patentimages.storage.googleapis.com/f5/e8/97/988229d8c74421/FR2542274A2.pdf
     

    Attached Files:

  8. OzFred
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    OzFred Senior Member

    In deed, there is a French patent listed by the DSS patent as prior art. Figure 1 looks remarkably like the DSS configuration, it's a pity the translation is so poor and there aren't more diagrams.

    french patent 2 877 311.png

    This version of the DSS patent has hyperlinks to the cited patents: US7644672B2 - Monohull sailing vessel having a lifting hydrofoil - Google Patents https://patents.google.com/patent/US7644672B2/en#patentCitations

    Those that are translated are hard to read, there are links to the originals.

    PS. This is not to say I think the DSS patent is invalid, it's only to show that there are quite a few similarities between the various patents. Those similarities don't necessarily make any one a "ripoff" of another.
     
  9. Tink
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    Tink Junior Member

    The DSS patent is very narrow, here are a few of the clauses of claim 1 and all the following claims link back to claim 1

    (e) wherein the lifting hydrofoil when in the deployed position is oriented at a predetermined angle of attack to a fore and aft plane of the vessel, the predetermined angle of attack being between about 2 and 6 degrees;
    (f) wherein the lifting hydrofoil when in the deployed position is oriented at a mean angle of between about 5 and 20 degrees to a horizontal plane when the vessel is in a non-heeled state so that the lifting hydrofoil is substantially parallel with the water plane when the vessel is heeled to a normal optimum sailing heel angle;
    (h) wherein the lifting hydrofoil has an exposed span that is greater than about 7% of a height of the tallest mast of the vessel, the height measured from the water plane


    It doesn’t take much imagination to design I system that works like DSS but outside these claims
     
  10. OzFred
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    OzFred Senior Member

    Indeed, per the second foil on Wild Oats XI (WOXI), which they stated was not DSS, though their first foil was developed in collaboration with DSS (the company). It is hard to imagine a more similar foil that isn't "DSS" within the definition of the patent (and it has not been reported that DSS sued the owners or designers of Wild Oats' second foil for infringing the patent). Just about everyone called it "DSS" anyway.

    At least it gave Doug a get out of goal card, he could claim that WOXI's foil was rubbish (hence its removal) without moderating his claims regarding the magic of DSS foils. :)
     
    Last edited: Jun 30, 2018
  11. Tink
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    Tink Junior Member

    Maybe the second WOXI foil was only 6.999% of the mast height and didn’t work because of this
     
  12. Dolfiman
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    Dolfiman Senior Member

  13. Doug Lord
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    Doug Lord Flight Ready

    Thanks for the news, Dolfiman! "Foil assist" is more and more popular-and successful.........

    " His uber-modern IMOCA 60 sometimes even semi-foiled and reached top speeds of 28 knots."
     
  14. Doug Lord
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    Doug Lord Flight Ready


  15. CT249
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    CT249 Senior Member

    To put it in context, though, the foil-assisted 60 footer was only an hour ahead of a non-foiling 56 footer after ten days of sailing. Although there was a crew difference to complicate matters, given its extra size the 60 footer should have been much further ahead.
     
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