I’ve been noticing a lot of hard chines appearing on cutting edge open class sailboats. I’m wondering if any of the yachties on this board can explain their purpose (directional stability? release?) and if there is any useful application in surfboard design
No! Don’t buy chines boards. Buy domestic. Support your local boardbuilders. Thanks.
hahahahahahahahahahahah…fukn chines made boards are everywhere
efficiency heeled over and cornering?
http://www.pygmyboats.com/Comparison.htm
Becomes like a rail, dunnit?
I think the intended purpose of chines on surfboards is to decrease wetted surface when planing. The “double edges” on chines also act as release points for water, so less water wraps around the rail. To some degree, I also believe that the flat surface between the edges creates some lift when on rail, as the rocker makes that flat surface a new “bottom.”
I don’t think they work that well, however. How often are you planing flat at speed? Don’t fins create more lift? Isn’t one good, well placed and foiled tucked edge enough?
I’d love to hear some other theories…
Stewart, made(makes) a lot of boards with chines, in the 80’s they called them hydro hulls, there is some info on them in the George Oberlion book whose title I can’t call to mind right now (essential surfing, maybe) as it is early. I tried them once on a board I made and it was hella fast. I think you kinda need big thick rails to get much advantage out of them, but I don’t really have enough experience to know.
cheers
I think the intended purpose of chines on surfboards is to decrease wetted surface when planing. The “double edges” on chines also act as release points for water, so less water wraps around the rail. To some degree, I also believe that the flat surface between the edges creates some lift when on rail, as the rocker makes that flat surface a new “bottom.”
I don’t think they work that well, however. How often are you planing flat at speed? Don’t fins create more lift? Isn’t one good, well placed and foiled tucked edge enough?
I’d love to hear some other theories…
I’m reminded that almost all boogies have hard chines–Morey calls it a “vacuum rail”–I don’t know enough to know the top half of that rail, whether it’s curved to keep attachment or what–I think the overall rail must be fast enough–rail fins help the tail stay in–you rotate and play around with those surfaces to get your tail to cooperate with the midpoint rail–you drag your feet to keep a boogie’s tail in…
One of the most popular boards out there is the Walden Magic. It has chines from nose to tail.
Personally I like them, and have shaped them into most of my recent boards. As to what they do: I notice a little side-slip, which I like. And when done together with concaves, you can make ankle turns when you’re in trim.
As to the theory: here’s what I think. The flat surface of the chine allows water to travel over it with less drag than if it was convex like a rounded rail. If the outside of the chine (nearest the outside edge of the board) has a tucked under edge, then you get quick release off the rail. The board planes on the water and gets good speed. All the performance factors are influenced by every other aspect of the board, of course, but I like them chines. Especially with a combination of single concaves in the middle, morphing into double concaves in the tail. Fast and carvey.
Doug
“It takes a philosopher to understand a tax return. It’s much too difficult for a mathematician.” Albert Einstein
Bill Stewart Hydro Hull Design surfboards. I had a 9’4" one that went pretty good.
I was thinking more like, what would happen if you just left your rail bands without blending them, so you’d have 5 or 6 chines all around the rail? Would the board be real slippery? Loose? Too loose?
I was thinking more like, what would happen if you just left your rail bands without blending them, so you’d have 5 or 6 chines all around the rail? Would the board be real slippery? Loose? Too loose?
It could make you famous!!! We would be reading about you!
J/K
IMHO it would all depend on what kind of waves you used it in.
Bob McTavish already did them…He calls them zepplin rails. They showed promise but were such a pain in the ass to sand that he gave up on them. He hoped that molding technology might allow him to resurrect the idea…That was 3 years ago or so.