[paulk]

Henry Scheel did a lot of research and experiments developing his keel, both tank testing and on full-sized boats. The fact that he was able to patent it lends credence to the idea that it is different from other shoal-draft designs. The fact that a reputable (and conservative) outfit like Tartan saw fit to pay Scheel a royalty for using his design instead of having their in-house designers come up with something cheaper that they could tout as a "manta-wing-super-shoal-performance keel" -- the way some builders do -- also points to it outperforming other shoal keels. There are always trade-offs. A ''real'' wing keel might work better than a Scheel keel for upwind legs, but it will likely have more wetted surface, and so be slower downwind, where the wings won''t be as useful. I also read about people with wing keels going aground in mud or on sandbars and having the keel act like a huge arrow, keeping them stuck when a simpler shape would have been able to twist off. If you had a centerboard, you could lift it and be off, but you trade space in the cabin, and possibly more things to break, like pivot pins and pennants. If you want performance, look at the racing boats and go for deep draft. If you need shoal draft, you are not going to get the performance. You have to decide the balance that suits your needs.