Page 1 of 2 1 2 LastLast
Results 1 to 7 of 8
  1. #1

    Why not a DDS for foiling?

    Just spent a few hours looking at DDS http://www.dynamicstabilitysystems.com/ and I wonder why not try to do something like that? that is use a lifting self-stabilizing foil midway the hull instead of what we are using.

    Examples are impressive, from the the 6.5 mini https://www.youtube.com/watch?v=fY9IRxXTBZo, to the Q23 https://www.youtube.com/watch?v=I6zDWXc0jCw to much bigger sailboats.

    Why not? (it is a question) you can keep the fin and leave to the forward DDS foil to lift you (partly or completely) out of the water ...

    Click image for larger version. 

Name:	13641278_1071618336256339_8258772430621982466_o.jpg 
Views:	64 
Size:	67.4 KB 
ID:	15919
    Last edited by duzzi; 29th January 2018 at 07:05 AM.

  2. #2
    Senior Member
    Join Date
    Jan 2008
    Posts
    1,363
    Quote Originally Posted by duzzi View Post
    Just spent a few hours looking at DDS http://www.dynamicstabilitysystems.com/ and I wonder why not try to do something like that? that is use a lifting self-stabilizing foil midway the hull instead of what we are using.

    Examples are impressive, from the the 6.5 mini https://www.youtube.com/watch?v=fY9IRxXTBZo, to the Q23 https://www.youtube.com/watch?v=I6zDWXc0jCw to much bigger sailboats.

    Why not? (it is a question) you can keep the fin and leave to the forward DDS foil to lift you (partly or completely) out of the water ...

    Click image for larger version. 

Name:	13641278_1071618336256339_8258772430621982466_o.jpg 
Views:	64 
Size:	67.4 KB 
ID:	15919
    Essential for that system to operate is a heeling force. ( Google Bruce Foils for explanation)
    Basically on a board with opposing fins (akin to Hydrofoil principle) one fin will always give negative lift. That's fine on yachts, dinghies etc because its force can be made to correlate with and oppose healing moment. On a board one rail will simply sink.
    I messed about trying to build a gybing system ( ie fins allowed to pivot , tips effectively down wind) but centre of lift was unstable...
    I do think its the future tho..one day..

    The picture of the dinghy" foiling" is operating effectively on inverted T foils , with each " wing" protruding for gunnels. Two problems.
    A) You are still limited by fact its a T foil with its limitations. ( it all breaks surface fairly simultaneously, needs to break surface gradually...giving constant overall lift.
    B ) A board sails flat. In the picture healing is opposed by weight of dinghy and sailor..we dont transfer healing moment to board, we deal with it via harness , UJ prevents any healing force getting to board.

    On current constant lift foiling systems all depend on the necessary evil of healing moment. Yes,with many systems its not absolutely constant and crew have to adjust ballast etc to keep vessel balanced. But basically foil has to lift same weight of boat at 15 knots as it does at 50 kts..Thats impossible with T foils...

    Have a look at Bruce foil developments. ( Bruce foils have been with us years...before we were even windsurfing I,d guess)
    Last edited by Alphie; 29th January 2018 at 08:57 AM.

  3. #3
    Senior Member
    Join Date
    Jan 2008
    Posts
    1,363
    The system I toyed with..

    Imagine a formula foil hanging down that could pivot ( in a fore aft plane) rather than being solid. As you begin to sail fin will pivot upwind and board slip down ( because of leeway) The fins movement would be stopped at 45 degrees. You now have an angled , constant lift foil under board. At 45 degrees half fins lift would be opposing leeway and half opposing load.
    Now imagine two such fins, either side of board. Both fin tips would be upwind and both oriented to give lift opposing weight. ( if they pointed other way they would give negative lift because of leeway)
    Now as speed increases fins start to lift board free of water, as they do less foil is presented to water.. they become constant lift foils. That's the theory..making it work is another issue.
    Ps ( I tried to patent above idea, thought it was original and mine. Its neither.)
    PM me if you want any info.
    Last edited by Alphie; 29th January 2018 at 09:15 AM.

  4. #4
    Senior Member Navegante's Avatar
    Join Date
    Dec 2010
    Location
    40 48'N 14 26'E -Western Med - West South Atlantic
    Posts
    2,953
    Because in windfoiling the current Setup is simple and fixed.
    There’s still possibly much room to improve in foil efficiency but largely that is it and as such will remain.
    Windsurf boards with their u-joint mast do not lend themselves to more complex handling foil mechanics and moving parts as a fixed rig craft does where the helmsman is sitting or hanging from a trapeze.

    Possibly someone may come up with a foil lifting force trim system such as on the Moths.
    However this is accomplished also by the longitudinal trim applied by feet pressure on the board.

  5. #5
    Senior Member
    Join Date
    Jan 2008
    Posts
    1,363
    Quote Originally Posted by Navegante View Post
    Because in windfoiling the current Setup is simple and fixed.
    There’s still possibly much room to improve in foil efficiency but largely that is it and as such will remain.
    Windsurf boards with their u-joint mast do not lend themselves to more complex handling foil mechanics and moving parts as a fixed rig craft does where the helmsman is sitting or hanging from a trapeze.

    Possibly someone may come up with a foil lifting force trim system such as on the Moths.
    However this is accomplished also by the longitudinal trim applied by feet pressure on the board.
    Yep, any system for boards would have to self adjusting / totally natural in operation. The best Moth systems are brilliant both for use and operation. ( One I had a good look at tiller rotated for trim control and as much as it worked great it certainly wasn,t intuitive or natural..

    I,m using ( attempting ) to use NP alufoil on an old Carve..seems ok but thinking of a dedicated foil board...what are you using ?
    Was thinking of a board that would be great early planer but then capable of foil use..Very nearly bought JP SLW...( 2018 ,s and I believe late 2017's are foil ready)

    BTW
    Planning on being in Leucate for mid April. �� ( All being well !!!)

  6. #6
    Senior Member Navegante's Avatar
    Join Date
    Dec 2010
    Location
    40 48'N 14 26'E -Western Med - West South Atlantic
    Posts
    2,953
    I am using the Houe Tiny 110 with XLW and LW Vini foil. Very well balanced.
    And recently I got the Goya Proton 116 foil ready
    For overall do it all travel board. Took it to South Africa
    But we had wind for windsurfing everyday so did not use it with the foil.

    Whatever board you get it needs to work well as a conventional windsurf board.
    So if you have a foil assembly with fixed length fuselage you need to see what dedicated board is sold to use with that and get whatever other affordable board you find that has very near the same proportions such as length from the mast track to the foil/fin box to have very near the same balance of forces as with the purposely built board/foil.

    Yes April I’d be likely near by for Leucate
    Cheers

  7. #7
    Senior Member tooold2dance's Avatar
    Join Date
    Nov 2006
    Location
    nice house with horses, cats dogs, and bride. USA
    Posts
    6,233
    The l shaped foil in photo looks like it might deal with pesky kiters.

    About to make my 2nd mini foil, so i find this interesting. But dont think it’s workable on board


    K4 Fins 4Boards TRI-sails Sailrepair




Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •