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Doug Halsey

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About Doug Halsey

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  1. One of the components of a daggerboard's drag is induced drag, which increases in proportion to the lift squared. Sharing that lift with the rudder will reduce the total induced drag of the two foils (for the same reason that (2 * 0.5^2) < 1).
  2. A friend of mine who used to own a Rave modified it to allow him to control the foils manually in a similar way. I've emailed him about this boat, but have yet to hear back from him. I'm interested in what he thinks of it.
  3. It seems a lot like the Rave: WindRider Rave - The Future in the Past
  4. This OK Dinghy was the last all-wood boat that I owned, back in the days when even the spars were wood.
  5. Here's a scene from Alamitos Bay (Long Beach), taken in about 1973. Could that be the same 5.5? (There couldn't have been that many, right?)
  6. At least one of those (Einstein) was a sailor. I'm not sure how great though. Albert Einstein, Sailor - National Maritime Historical Society (seahistory.org)
  7. They were around a little before the 50's (not quite competitive though). Robert Gilruth: The First Foiling Catamaran-1938 | Foiling Week™
  8. I was trying to explain what would happen to the board's load if you tried to make the flow on the hull symmetrical. Even with zero leeway, the load on the board would cause some asymmetry in the flow over the hull.
  9. Everybody here seems to be assuming that it would be optimal to have the hull going straight through the water, but that isn't true. If you did manage to achieve that situation, the daggerboard would have a very unfavorable spanwise loading that tapered to very small values at the intersection with the hull, with extra twist drag, and higher loadings down low, causing earlier stall. The smallest drag would occur with a much smaller amount of asymmetry than required to get the hull going straight. An analogous situation occurs in determining the optimum loading of a fuselage in a
  10. If you have the option to use asymmetric boards, the question is how much asymmetry you need, rather than whether it should be symmetric versus asymmetric. The answer to that depends on what CL you are trying to optimize for, and what extremes you are allowing for. Here are some calculations to start you thinking about that.
  11. If you're interested in landsailing, check out NALSA home
  12. Moths had sleeve-luff sails before cams were invented. (I'm not saying it was ideal though). Here's mine in 1968 (sail by Australian Garry Fogg)
  13. I've been on the verge of posting something like this, but have managed to resist the temptation. But it raises the question: Is it possible for someone to edit their earlier posts? Seems like it would be a good idea.
  14. There are Moths & A Cats (& a few others) in Southern California. You might consider joining the West Coast Moth FB group. https://www.facebook.com/groups/694829203913174/
  15. Maybe it stands for "Fiberglass" & he's wants a fragile boat that requires a lot of repairing.
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