Jack wrote; >Not to get into the nits too far, John, but do you think that applies to skegs >as well? My Pintail's stock skeg is basically slab sided with the edges >bevelled off, but there's certainly no attempt to have the shape be a foil. I >use the skeg deployed at about 30 degrees when I'm lazy and want the boat to >do part of the tracking, and deployed more when I'm surfing down following >seas; it does develop a lot of chatter when it's down more than 20 to 30 >degrees. Would fairing it out to more of a foil decrease the vibration? > I don't consider it nit at all. Consider first that when the apparent wind comes from the side the boat makes leeway. When it makes leeway the skeg makes an angle of attack with the water. For flat plates an angle of attack greater than two degrees can initiate stall and once the skeg stalls the lateral resistance can decline and leeway will be increased. In short, the skeg becomes less effective once it stalls. If the skeg has a foiled shape it can produce lift that will help reduce leeway and will not stall at the lower angles of attack the skeg encounters. (lower than rudders) Leeway tends to be rather large for kayaks (relative say to sailboats or displacement power boats) because they have so little underwater profile. An interesting option that I have experimented with involves mounting a fixed skeg just aft of the center of buoyancy. This reduces leeway and, consequently, weathercocking. Its location at the center of buoyancy which becomes the pivot point in a turn has little effect on manoeuvrability. The added resistance does not fall into the "very noticeable" category (depending upon skeg size). The huge advantage to my mind would be the lack of complexity in drop down skegs or rudders. In some boats the center mounted skeg may even come out of the water in a leaned turn. Once I get a good feel for the proper size on my boat I intend to have one cast in aluminium so it will also serve as protection for the bottom. Cheers, John Winters Redwing Designs Specialists in Human Powered Watercraft http://home.ican.net/~735769/ *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************Received on Sat Nov 21 1998 - 05:22:27 PST
This archive was generated by hypermail 2.4.0 : Thu Aug 21 2025 - 16:30:01 PDT