aloha
ok here’s a wide open new thread…
had a thought this morning regarding flex and wanted y’alls thoughts…
say you have the following options:
a. somewhat flexible board with flexible fins
b. somewhat flexible board with stiff fins
c. somewhat stiff board with stiff fins
d. somewhat stiff board with flexible fins
which one would you likely prefer assuming all other variables remain constant?
which one would you least likely prefer?
all input is welcome,
cheers
B.
But I’m heavy - 205# or so. And I surf mainly single fins.
Too many flex fins give up midway through a turn and slough out water. I can actually feel them lose their drive & start to drift. Instead of flexing to the point where they snap back like they’re supposed to, they flex to a place where they lose grip. No good. The G IVa and the Velzy Classic are horrible this way.
B.
B.But I’m heavy - 205# or so. And I surf mainly single fins.
Too many flex fins give up midway through a turn and slough out water. I can actually feel them lose their drive & start to drift. Instead of flexing to the point where they snap back like they’re supposed to, they flex to a place where they lose grip. No good. The G IVa and the Velzy Classic are horrible this way.
Yeah, you really need a flex fin with a hard limit on the flex…
I like stiff carbons
I like big fins (GRs Simon’s, MRs, TC1’s, Vectors, FG7s)
But I ride more off my fins than my board except bottom turns and roundhouses where it’s all about the rail
Stiff and small if I’m going to use more of the board than the fins to do my work…
Oh yea I usually ride bigger boards too 7"0 -7’6"
I’m 5’8"
but I’m heavy footed in my style
flex fins require a more subtle and fast approach
than just jammin it and laying all on the line with every turn…
thats my problem too, then ? i weigh 215 and have a 8.5 tk flex on a 7 ft egg and haven’t been liking it and have tried all different fin positions.
I liked it better with a wide based fin I made. I would say that would be a stiff board with a stiff fin.
I would like to make a 6’8" balsa single fin egg shape and use one of those rotating fins.
So would you call the rotating fin a “flex fin” or a “stiff fin” ?
as a general rule I like C.
although I’d note there are other options, eg., I have had good results with a stiff center fin and flexible rail fins. This tends to overcome that “sloughing off” tendency and loss of control that flexy fins can have.
Tails should should flex and snap back as they are loaded and un-loaded. You want to be able to force more rail rocker as you drive hard into a turn. At the same time you want the tail rocker to spring back to it’s shallower unloaded rocker quickly and smoothly. Stiff fins and secure attachment methods allow you to more efficiently transfer the torque from the fins through to your boards tail. It’s all about smoothly and predictably being able to transfer the power flowing around and past your fins and tail area to redirect your mometum to where you want to go.
What about a flex bias fin. I just read about them and they sound interesting. You would use a non flexy epoxy on one side (like RR 2000) and flexy epoxy (like RR 2020) on the other. They are supposed to bite when you want them to and get out of your way when you don’t want them.
Man, I was a proponent of flexible fins after a magic board I had, had flexible glass in fins. I then was on a mission to make sure this “Magic” fin setup was on all my boards. I then went to Surfco and found some flexible fins and VOILA!!! All my other boards turned to DOGS!!!
I think all boards are a combination of all factors blending together. Rocker, rails, etc combined with fin placement and flex all combined in a Muligan stew with the waves on hand… Some boards work better with stiff fins and some with more flex but also depending on wave conditions…
Middle of the road is where most surfers will end up so they will not end up like me where I am a total fin whore trying all kinds of combos in all kinds of conditions… For those of you that need a predictable ride, DON’T BE LIKE ME!!! FINS ARE THE DEVIL!!! Ahhhhhhhhhhhhhhhhhhhhhhhhhhhhh!!!
For all others, let the mad scientist in you flourish… Buwahahahahahahahaha!!!
Just a few of my fin fetish/SICKNESS exposed…
So would you call the rotating fin a "flex fin" or a "stiff fin" ?
It has optimized flex. You can tune it by changing $1 bumpers instead of $45 fins. But it has other advantages over flex fins, too.
doesn’t have concave on low pressure side
has firm end-stop
turn is restricted to toe-in
has pre-load - a force that must be exceeded before the fin will turn
The last is real important. It lets the flex be relatively smooth across a broad range of forces without oscillating.
thanks blakestah… definitely sounds like the ticket. i love the single fin flow and with the rotation sounds like you lose the downside of single finning. ie., slippin out.
will it work on any shape, or is it best on certain shapes ?
and I imagine I could make a fairly stiff board and not try to engineer a “magic” balsa flex board.
What seems so sweet about the rotating fin rather than flex fin is you get the action all the way down at the base too. A loaded up flex fin has a big twist in it from top to bottom (assuming it has rake) and the tip can flex so far as to lose its grip, not very hydrodynamic. The rotatin system stays straight and sleek both top to bottom and front to back, just changing rotational direction.
Of the choices I’d also go for B. I’d go even more middle of the road actually, with both board and fins in the some what flexy category. I like a big side fin to work off of.
thanks blakestah.. definitely sounds like the ticket. i love the single fin flow and with the rotation sounds like you lose the downside of single finning. ie., slippin out. will it work on any shape, or is it best on certain shapes?and I imagine I could make a fairly stiff board and not try to engineer a “magic” balsa flex board.
I spent some time/energy getting to a good shortboard shape. It ends up being like a single-fin board outline with the wide point a little further back, and a little more rocker. The flatter rockers common on shortboard singles seemed too stiff for the rotating fin - it lets the tail move easily into the early portions of the turn and you don’t need to get your weight as far back to make it turn.
I don’t ride longer boards in small waves, I imagine the same principles would hold…but you never know what you’re going to find.
Please note that it is no substitute for rail fins. They still provide aspects of performance a rotating single cannot. But the rotating single compares VERY favorably to other singles.
so would having some flex in the tail aid the pivot fin ?
and does flex in the tail do as much good for a single fin as it does for a thruster ?
so would having some flex in the tail aid the pivot fin ?and does flex in the tail do as much good for a single fin as it does for a thruster ?
??? I don’t know. I’d be willing to bet, however, that flex in a finbox or fin provides an order of magnitude more benefit than flex in a tail. Just a hunch.
well, what I was thinking was that I like a little lower tail rocker for catching waves and speed and your fins like a little more rocker. so if there’s some tail flex at the right time to make the fin work right then you have the best of both worlds right ? is that how it works ?
so anyway, you probably need to adjust the “bumpers” to match the flex in the tail, i guess.
a. somewhat flexible board with flexible fins
which one would you likely prefer assuming all other variables remain constant?
For me, none of the above. I prefer zero flex in the board, and zero flex in the fin. That way I’m assured that what I feel the board doing on a wave is a result of the shape and contours I had created, and not some variable over which I had little or no control.
More sober wisdom from Bill Thraikill. Thank you, Bill. Mike