Do fin boxes dampen flex relative to glass-ons, or does the fin and fillet on a glass-on provide similar dampening?
I guess the question is: Is there a significant difference between the flex charachteristics of glass-ons and boxes?
Depends on who you talk to. I’ve always liked fin boxes better because of adjustability. For me any difference between the two is minimal in comparison to changing fins. Lot’s of the world tour guys use glass ons but then you see Slater with boxes and it’s pretty obvious a personal preference.
Another variable is how they’re glassed on… whether you run the patches all the way up the fin, or only up the base… how much roving… etc.
I think the old FCS two-tab fins flexed more at the base than the full tab fins in other systems, all other things held constant. Whether that’s a good thing or bad thing is a personal preference, and matters little, as Greg said, when you just keep changing fins until you get what you like the feel of best.
You all have seen enough boards snapped at the front of the fin box, the very design of the box itself is an I beam type, the first place it can release any energy placed on it is at the front and rear.
Like Greg says, change the fin, change the ride, I showed Greg one of my boards and told him it rode completely stiff, hard to control, I had G5 FCS on it as side fins, his first words were, “fins are too big”, made a set of glass ones of my template, ripped the very next wave one it.
I am currently shaping a flextail hi-performace shortboard with a vanishing, tapered stringer. The stringer tapers from 1/4" at nose to 1/8" at disappearing point, which is about 18" from the tail of the board. Dims on the board are 6'0" x 18 3/8" x 2 5/16". Template taken from a HP quad fish, so wider tail than your normal shorty with a diamond tail.
Same question as above, but in a specific context. 4 probox plugs vs. 4 glass-on bamboo fins in a flextail board...how will this affect flex?
Thinking of routing out a small channel under the fins and connecting that channel between each fin cluster, filling with roving and glassing on a fin patch over that, then glassing on fins so they flex as one unit per side...thoughts?
Here are some pics of the board, I laminated the bottom last night in a 'Juvenile Garibaldi' color scheme...rails and end of tail got kinda muddy, but the colors sure popped like I wated em to!
you'll never get two fins to flex as one unit unless the whole board in that area flexes and the fins stay ridgid in relation to the board... imagine a u-beam...i think thats what you're trying to make by routing that channel...if you clamp the bottom of the u-beam to your work bench and then press against one of the sides of the u...the other side won't notice...no communication...you'd have to make a box...connect the tips...
i was such a cheap bastard as a student that in order to make my own boards i had to salvage finboxes from snapped boards...ever done that? you'd be amazed how much effort it takes to get one of those boxes out...i'd very much doubt it if the box delivers any more flex than a glass-on...what might add to the percieved flex is that fins never sit completely snug in their boxes...there's always a bit of play...so in that light your glas-on might feel stiffer (or as mentioned earlier somewhere because of the added laminate on the sides of the fins but that changes the whole game: you're simply dealing with stiffer fins, it has nothing to do anymore with the attachement to the board)
play with your fins: use boxes
(a trick for super tight boxes: rout your holes, set your fins up like you'd be glassing them on (but now with the fin tabs in the routed holes) and then pour in (good) epoxy, then drill a small hole and tap some thread into it for your little screw) (don't forget to wax your fins,and fill the little indentation for the screw to catch on) or they'll stay stuck) (and cure your epoxy, usually an hour or so at 50 celcius does the trick...and makes all the difference!) (one downer: the thread in the epoxy won't last super long) (if you're a king handy man and this board turns out to be magic: upsize the hole and put in a little stainless or titanium tube, then thread...ohyesss)