Retractable Lifting Hydrofoil

Discussion in 'Sailboats' started by Doug Lord, Oct 16, 2005.

  1. Doug Lord

    Doug Lord Guest

    A bit ago I mentioned the idea of a small boat using a form of on-deck movable ballast in combination with a ballasted daggerboard and possibly a rudder T-foil.
    And a while back I wrote about the kFOIL- an idea to use as a lateral resistance solution for canting keel boats-the following is the only version of the rendering of the kFOIL that I can access now:
    http://www.sailinganarchy.com/editor/2004/edword_october2004.htm

    So what if you combined the kFOIL idea AND the on deck movable ballast idea in an 18 footer or even on a boat like Pterodactyl(see below). The kFOIL would lift up (opposite to its original conception) and would probably work best(if at all) as a partial lift foil so there was no necessity for an altitude control system. The on deck movable ballast would be critical to keep the boat mostly level so the foil could work and the kFOIL would allow the hydrofoil to disappear when not needed.
    The following is a Pterodactyl, a Bethwaite /Billoch designed "Maxi Skiff" with on-deck movable ballast and a fixed keel:
    http://www.sailinganarchy.com/fringe/2005/images/billochcut.jpg
    -----
    Any thoughts on the combination of the two ideas and the use of a PARTIAL LIFT hydrofoil?
     
  2. NiklasL
    Joined: Apr 2004
    Posts: 36
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Stockhom, Sweden

    NiklasL Student member

    Lead + hydrofoil

    Areu going to fly this boat i think it will be difficult with lead to have high speed.
     
  3. Doug Lord

    Doug Lord Guest

    Lead + Hydrofoil= speed?!

    Actually, it depends on a lot of factors. Look at the speeds of the Open 60 and Volvo 70 mono's off the wind. They may be candidates for the type of partial lift foil I was suggesting but I'm convinced that ,more than likely, the two boats(hybrid monohulls) mentioned in my previous post would benefit from the application of a well designed hydrofoil system-partial lift or full out flying-18' or 60+'. Just a guess but a reasonably well informed one.
    Don't think of the movable ballast that both those boats use in terms of "lead"; think of it in terms of x pounds of righting moment on a giant Moth-like sailing machine....
     
  4. NiklasL
    Joined: Apr 2004
    Posts: 36
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Stockhom, Sweden

    NiklasL Student member

    Usage

    Im not the expert, but I'm curious.

    If you want to use the Kfoil then u have to use flap on the keel to get a force component not pulling the boat slightly down into the water. Unless u can tilt the Kfoil to be vertical when used.

    Why not just use 1 or (2 assymetric) retractable centreboard instead?

    About the movable ballast on deck, I love it.

    /Niklas Lundberg
     
  5. Doug Lord

    Doug Lord Guest

    lifting kFOILâ„¢

    Niklas, the kFOIL was originally conceived of for use on a canting keel to provide the extra lateral resistance needed as the keel cants. In this application it would be used on a fixed keel similar to the one on Pterodactyl and the foil would lift up instead of down (as it would when centered in the original design). Of course, in the original use on a canting keel, the foil would never be deployed with the keel vertical and parallel with the mast.And in the "Maxi Skiff" application that's the only time it WOULD be deployed!
    The idea is to come up with a retractable main foil for light air. But the actual design would have to look at whether or not the bulb on a "Maxi Skiff" was big enough to "hide" the main hydrofoil. There are other solutions to retracting the foil on a monofoiler if that didn't work.....
     

  6. NiklasL
    Joined: Apr 2004
    Posts: 36
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Stockhom, Sweden

    NiklasL Student member

    Ok cool!

    There was some discussion about this in another thread, so I guess you extracted i here.

    I think this kind of boats 18 & bethawites, could benefit from a bowfoil, to reduce wetted surface, and retract it just like Those patrolboats did when there is no wind.

    Otherwise I hope you could form a think tank with those connected to the boat type your aiming at.
    Student. /Niklas
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.