How strong are the mooring points on your boat.
- Thread starter Ross
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BTW as we all know from the "mast up vs. mast down" storage questions the spars add little windage....
Think this boat would have been heeling like this in 45 knots without a spar...?[/quote]
Not sure where folks get the idea a spar adds "little windage?" I had the opportunity to take a course with an aerodynamics researcher in undergrad school. He did a lot of work on jet engines, but had assorted grants from the DOD also looking at noise reduction for sub control surfaces, etc. There is a huge amount of "drag" created by a cylindrical object in a flow stream. If you don't think so stick your arm out the window of your car at 45 mph and see how hard it is to hold it. The separation of the airstream and the resulting vortices created from the remixing of the air downstream cause huge amounts of drag and thus the heeling moment so well demonstrated by MainSail in his post. Well worth doing some reading about this subject for those interested. Modern racing boats now incorporate airfoil shaped spars that rotate to try to keep the airstream attached and laminar flow over the sail. I saw many racing trimarans in Newport in the 80's with this kind of set up.
Think this boat would have been heeling like this in 45 knots without a spar...?[/quote]Not sure where folks get the idea a spar adds "little windage?" I had the opportunity to take a course with an aerodynamics researcher in undergrad school. He did a lot of work on jet engines, but had assorted grants from the DOD also looking at noise reduction for sub control surfaces, etc. There is a huge amount of "drag" created by a cylindrical object in a flow stream. If you don't think so stick your arm out the window of your car at 45 mph and see how hard it is to hold it. The separation of the airstream and the resulting vortices created from the remixing of the air downstream cause huge amounts of drag and thus the heeling moment so well demonstrated by MainSail in his post. Well worth doing some reading about this subject for those interested. Modern racing boats now incorporate airfoil shaped spars that rotate to try to keep the airstream attached and laminar flow over the sail. I saw many racing trimarans in Newport in the 80's with this kind of set up.
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