Hey, Tell me, Cant, that's the angle of the fin in relation to the bottom plane of the board, right-- How does it affect board performance. I see very steeple canted fins on bonzers but seldom on other boards. I have my own ideas about how it affect performance but I'd like to hear the voice of experience if it's available. Mahalo, Rich p.s. I see Mavericks is trying to go this morning. Maybe with the afternoon tide they'll be paddling in.
>>> Hey,>>> Tell me, Cant, that's the angle of the fin in relation to the bottom plane > of the board, right-- How does it affect board performance.>>> I see very steeple canted fins on bonzers but seldom on other boards. I > have my own ideas about how it affect performance but I'd like to hear the > voice of experience if it's available.>>> Mahalo, Rich>>> p.s. I see Mavericks is trying to go this morning. Maybe with the > afternoon tide they'll be paddling in. Yea cant is the angle from the bottom and toe in is the angle in relation to the nose.I would like to know more about this stuff myself.All I can do is guess.I can remember building fish shapes back in the late sixties and the fins were straight both ways.Now they do it different.Beats me....R.B.
>>> Yea cant is the angle from the bottom and toe in is the angle in relation > to the nose.I would like to know more about this stuff myself.All I can do > is guess.I can remember building fish shapes back in the late sixties and > the fins were straight both ways.Now they do it different.Beats me....R.B. Cant is angle from an imaginary horzontal plane perdendicular to the stringer. If it was relative to the bottom contour, you'd end up with more cant on tails with vee and less with concaves.
>>> Cant is angle from an imaginary horzontal plane perdendicular to the > stringer. If it was relative to the bottom contour, you'd end up with more > cant on tails with vee and less with concaves. Since the side fins are foiled to the outside adding cant moves the force vector generated by the airfoil above the horizontal plane. Though it’s slight, theoretically it would add a bit of lift to the tail. More so I could see it playing a role in turning; both by creating a smaller cross-sectional area to turn against and since you lean into a turn the cant would help keep the force vector of the inside fin from going below the horizontal (dragging the board under water) and help release the effect of the outside fin sooner. These thoughts are all taken from my knowledge of fluid dynamics, not surfboards. Unfortunately we never studied any surfboards in my classes. I’m sure someone on here can (and will) correct me if I’m wrong. Cheers,
>>> Since the side fins are foiled to the outside adding cant moves the force > vector generated by the airfoil above the horizontal plane. Though its > slight, theoretically it would add a bit of lift to the tail. More so I > could see it playing a role in turning; both by creating a smaller > cross-sectional area to turn against and since you lean into a turn the > cant would help keep the force vector of the inside fin from going below > the horizontal (dragging the board under water) and help release the > effect of the outside fin sooner. These thoughts are all taken from my > knowledge of fluid dynamics, not surfboards. Unfortunately we never > studied any surfboards in my classes. Im sure someone on here can (and > will) correct me if Im wrong.>>> Cheers, Alright cut the crap guys.I,m an old geezer and this tech stuff flys over my balding head.Tell me this...if I cant the fins more outboard what will it do?If cant em inboard what will it do?Also if I change the toe in what will it do?Make it simple...kinda like talking to a child so I can understand.Thanks....R.B.
Ya..I was thinking what Rook said!
>>> Alright cut the crap guys.I,m an old geezer and this tech stuff flys over > my balding head.Tell me this...if I cant the fins more outboard what will > it do?If cant em inboard what will it do?Also if I change the toe in what > will it do?Make it simple...kinda like talking to a child so I can > understand.Thanks....R.B. The more toe,and cant the shorter the turning radius is(turns quicker)and it will also create more vaccum,giving more lift,unfortunately it also slows the board down,like a parachute. The straighter the fins, the faster there are,but they turn like crap.Herb
OK. here is my .02 worth. This all revolves around my messing around with twin fins on older Fish outlines. My old Sunset Cliffs shape twin had two parallel-to-stringer and zero cant. It was stiff and tracked for my average conditions. When I stumbled through the door here at Swaylock's back some 2-3 years ago I was searching for fin specs. In time I found that with the right cant angle helped in getting that wide 17" tail over on the rail. The toe-in stuff just allows you to control the turn radius, more toe-in=tighter arc. Now for a question. I'm going to make my son a new grom type board, 5'6- 5'8 chip etc. I'm thinking that with the lighter weight of the rider and the really shortened rail line then the fin placement (tri-fin) needs to be adjusted, further back it would seem. What kind of numbers are some of you using in these really short shortboards? In other words, trailing edge to tip for Center and Side fins? Tom S. > Alright cut the crap guys.I,m an old geezer and this tech stuff flys over > my balding head.Tell me this...if I cant the fins more outboard what will > it do?If cant em inboard what will it do?Also if I change the toe in what > will it do?Make it simple...kinda like talking to a child so I can > understand.Thanks....R.B.
>>> Since the side fins are foiled to the outside adding cant moves the force > vector generated by the airfoil above the horizontal plane. Though it’s > slight, theoretically it would add a bit of lift to the tail. More so I > could see it playing a role in turning; both by creating a smaller > cross-sectional area to turn against and since you lean into a turn the > cant would help keep the force vector of the inside fin from going below > the horizontal (dragging the board under water) and help release the > effect of the outside fin sooner. These thoughts are all taken from my > knowledge of fluid dynamics, not surfboards. Unfortunately we never > studied any surfboards in my classes. I’m sure someone on here can (and > will) correct me if I’m wrong.>>> Cheers, -- You`re right... more cant + more speed = more lift. In fact, after a certain velocity, the tail will start to rise and handling becomes a serious problem. Combine cant with edge fins which are only foiled on the outside/flat on the inside, plus toe-in and you have a configuration that`ll always be trying to crank around and back up the face. The built-in dilemma with thruster fin set-ups is the fact that at any given time, two of the fins are in directional opposition to the (inside edge) engaged fin. Lots of drag means lots of control in this case, but also a significant loss of top end... one of the primary reasons these designs must continually be pumped rail to rail in order to maintain and develop speed. Small, active "paddle fins" (twist/flex concentrated in the narrow base) really help in resolving the common problem of three, stiff base thruster fins all working against each other.
>>> OK. here is my .02 worth. This all revolves around my messing around with > twin fins on older Fish outlines. My old Sunset Cliffs shape twin had two > parallel-to-stringer and zero cant. It was stiff and tracked for my > average conditions. When I stumbled through the door here at Swaylock's > back some 2-3 years ago I was searching for fin specs. In time I found > that with the right cant angle helped in getting that wide 17" tail > over on the rail. The toe-in stuff just allows you to control the turn > radius, more toe-in=tighter arc.>>> Now for a question. I'm going to make my son a new grom type board, 5'6- > 5'8 chip etc. I'm thinking that with the lighter weight of the rider and > the really shortened rail line then the fin placement (tri-fin) needs to > be adjusted, further back it would seem. What kind of numbers are some of > you using in these really short shortboards? In other words, trailing edge > to tip for Center and Side fins? Keep it simple Tom.Build the kid a baby single finn egg.People are finally discovering that you dont have to thrust a single fin......R.B.>>> Tom S.
Ok Gentlemen: All things being equal-- same board, same fin, same toe in. One rail fin is tilted off verticle 4 degrees out from center, another 16 degrees out from center. How does the two differ in performance? Better Surfin', Rich
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