Using a foil to fly a hull, rather than a whole boat?

Discussion in 'Multihulls' started by Emerson White, Feb 1, 2017.

  1. Emerson White
    Joined: Aug 2012
    Posts: 95
    Likes: 7, Points: 8, Legacy Rep: 61
    Location: Nordland, WA, USA

    Emerson White Junior Member

    So only purpose built foiling racers are really capable of foiling under sail, can't just slap foils on a regular racer and hope for the best. The vast majority of purpose built racing catamaran can fly a hull too. Cruisers built like wedding cakes will never fly a hull and there are racer/cruisers in the middle, some of which can fly a hull in the right conditions.

    As I understand it flying a hull is advantageous for two reasons, it reduces wetted surface area, and it reduces the influence of wave interference between the hulls. So what I'm wondering about is if a foil could be used on a windward hull not to lift the whole craft out of the water, but just to tip the balance and lift that windward hull out. I'm curious it the benefits of flying a hull would outweigh the induced drag from the foil and I'm curious if the wave pattern of the foil would miss the second hull or if it would just be more of the same with interference off the two hulls.

    If anyone has any thoughts or if there is anything like this out there I'd be very interested.

  2. Doug Lord
    Joined: May 2009
    Posts: 16,679
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    Location: Cocoa, Florida

    Doug Lord Flight Ready

    windward foil

    Probably more trouble than its worth just to lift the windward hull(which the rig wants to lift anyway). And potentially dangerous since the lift will be reducing righting moment.
    One possible workable solution might be a foil with a surface sensor set for a particular windward hull altitude after which it automatically begins to develop downforce adding to righting moment.
    Again, I'd say it's more trouble than it's worth for this particular application.
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