Currently working on a hpsb and I want to get the most flex out the tail. I’m curious what fin systems impacts flex the least? I’m thinking glass on, although, all the extra cloth back there may stiffen things up more than boxes or plugs. What do you think?
Just a guess, I have no scientific evidence to prove it....
glass ons would seem to be best, and my second best guess would be FCS plugs.
I also remember seeing an ad or something by FCS showing a diagram of more natural flex properties with fcs plugs as opposed to a box system like futures.
an FCS ad saying that their fins flex better than the opposition ??? well it must be true then .. sorry for the sarcasm but I bet the other fin companies might say that their fins have better flex....fibreglass fins have great flex, even foil them thinner in the tips, you could use thinner stringer, possibly even no stringer or the tapered or 2 split stringers for different flex, plenty of options but it is choosing the right one for the board and surfer......
I'd think that any of the 'boxes' would tend to stiffen the section of the tail in which they were mounted... the longer the box, the stiffer the result. It would seem that FCS plugs would be the least stiffening but Bert Burger claimed at one point that adding FCS plugs ruined the tail flex in one of his compsand boards. I think he felt that locking the bottom skin to the deck skin inhibited the sheer effect of light weight EPS foam but I often wondered if rails and tail blocks didn't tie things up equally tight?
I would have to think that a glass on fin would add some stiffness as well.
Possibly the least stiffening fin system would be a minimally glassed-on layout with cutaway bases? 4 Way Fin Systems with their single tab fin attachment would likely be about the same.
These thoughts are in regards to tail flex rather than fin flex.
structurally
boxes do not flex.
flats flex well.
they dont flex as well
when on edge.
even the fin on edge will
move the flex perpendicular to the
flat board flex instigating an alternative flex
we could call twist.To maximize flex, even the fin
at all even glassed on diverts or perhaps compounds the planing
vehicle -surfboard- dynamic.This may be splitting hairs but we should
call a spade a spade.soSoSO… howzat for a little brain push-up?
…ambrose…
3/4’’ thick finless boards
FLEX like a … mother.
can we call it an omo?
Yes we can.
thin flat deck (rail to rail, no dome) + lots of deck rocker = more flex (& more breakage)
.02 from backyarder
FCS Fusions and Lokbox. Plugs lock the bottom and deck together. Also go to the Coil thread and check some of the foil views of their boards and note the scoop in the deck rocker near the tail. There are other factors that make them flex as well as they do but thats obviously part of it.
dd
The best flex would be a version of Surfoil’s induction setup. Short of that I think that using a high density insert and routing the base of a full-tang fin into that without adding any extra exterior glass fillet would be the next best thing. No matter what, where the base of the fin meeds the bottom of the board is going to cut into the flex.
[quote="$1"]
an FCS ad saying that their fins flex better than the opposition ??? well it must be true then .. sorry for the sarcasm but I bet the other fin companies might say that their fins have better flex....fibreglass fins have great flex, even foil them thinner in the tips, you could use thinner stringer, possibly even no stringer or the tapered or 2 split stringers for different flex, plenty of options but it is choosing the right one for the board and surfer......
[/quote]
Hi pridmore,
what I meant was the system itself, not the fin. Something about the plugs allowing more natural flex patterns. I understand that a company will advertise anything that separates its product from the competition whether it be true or false, and the average person just assumes that it is true. I'm not saying that it is true, but I just thought I'd throw it out here for discussion :)
On a side note, I'm not a fan of the fcs plugs cause it seems to be the system I fix the most, but I like the fusions alot
thanks
yeah.... I use FCS plugs and have no problem at all with them, my glasser insists he puts them in the best way possible...have had extremely good results as far as no plugs breaking out but I also do see and hear of alot of plug issues with them...I am not syaing they are the best but I use em coz the fins are by far the most popular here in Oz and as I said, great record with them so far....but the flex thing may be different all togtether... be keen to see what choice is made with this board and hope to see pics and ride reort as it becomes reality, would be interesting thread.....
fins and fin systems need to be attached to the underside of the deck !.........think about it...
yep....
Kayu, you havent been having any battles on RS with the crazy Jesus looking guy ( his name evades me atm ).....those forums are lifeless of late....
Please elaborate Kayu.
[quote="$1"]
yep....
Kayu, you havent been having any battles on RS with the crazy Jesus looking guy ( his name evades me atm ).....those forums are lifeless of late....
[/quote] Yeah Mark, haha! he does serve a purpose as entertainment I suppose....
[quote="$1"]
Please elaborate Kayu.
[/quote] It explains itself.......glass-ons were ok pre-lightweight foam and pre-superlight glassing, but modern requirements for hpsb have changed that. The tranverse alignment of 2 rail fins between leading and trailing edges will negate any flex in that area (and area of extra reinforcement ) , so the board will only flex in front and behind the alignment of fin bases. Maybe just a hair brained idea , but I am experimenting..........
hi , i like yout thoughts kayu, its something i have been thinking about for awhile but as yet hav/nt done anything about ,
it seems sort of obvious that the posistion of your feet will determine where the board has movement , whatever fin arangement you have will keep that area lock solid stiff ,your front foot is on the thickest part of the board which has to be an area of least flex so the board can only have any real chance of movement somewhere between the two posistions ,
i have wrote on here several times that my son has broke a lot of boards just in front of the forward fins which shows to me that the board was flexing in that area but in the end over flexed the strength of the materials ,
the flatness of the deck side from the tail to where the nose starts to curve up also has a detrimental effect because the glass is in tension, if you believe that the tail trys to flex downwards away from the deck .
i say believe because thats what i see from my own obsevations , you are pressing down on the tail in bottom turns and powerful lip turns ,the area between your feet is the fulcrum ,the tail is flexing down and returning,
how much flex ? i have tested loads of boards for tail flex , clamp or weight the board to give a 2 ft over hang of the tail ,i just use the rocker bed i have , use a spring balance to pull down on the tail against a tape measure and record your numbers , you will be suprised in the difference between similar boards ,
a good guide i have found to be somewhere near is a tail flex in pounds what the board has of litres in volume , so an average hpsb of 24 litres you want the tail to flex around 24 pound to pull it down i inch ,
its harder to achieve than it seems because you dont really know what you have got until the board is done ,
most things that you want to have movement in is built in somehow but boards just seem to rely on a bit of luck and hope ,
what i have been thinking about and as yet have/nt done anything is to put one or more corrugations across the board from rail to rail right between your front and back foot , carbon would be the best because of its spring in that application and then covered with glass , if the grooves where two inches or so wide and taken right down to the centre of the rail line then the rail can bend without being in too much tension ,
if you intially aimed for slightly too much flex glass can be added when the board is finished and the tail flex tested so it can be fine tuned to your individual liking,
the front foot area can have added glass to prevent denting but would/nt impact on the tail flex so in theory you could have solidly glassed board but with the tail flex of a lightly glassed pro board ,
i know people like coil are useing different combinations of fabrics to achieve the same end results but you should be able to get there with a different line of thought ,
pete
Pete , I don't ride flex boards personally.....I mean most boards have flex naturally (to some degree) increasing toward the tail as they get thinner....I'm no expert , just playin around , but I see it as being more about the recoil itself , rather than the amount of flex you can biuld into a board.A more powerfull surfer will need less flex to get better projection.......the experiments I'm doing are more a by-product of a fin system I been using......like an interesting tangent .......yeah , carbon equals reciol
hi kayu, i often read about recoil or springback but it goes hand in hand with flex , you can only get less and less out of something , a ruler over the edge of a desk is a good example , if you could take pics in slo mo when you bent and released the ruler the hight the ruler bounces to will get lower and lower until it stops,
a boards tail is the same ,if it takes 30 lb effort to bend it one inch its recoil will be slower than a tail with 40 lb to bend one inch , a bow is the same ,all things equall a bow with a higher draw weight will fire the arrow further only because its recoil is quicker ,
a board ca/nt be made that has a fast recoil but is easy to flex the tail , the faster the recoil needed the stiffer in flex terms the tail needs to be ,
it sounds so easy but in reality is harder and i think thats where good sufers have the most advantage ,under volumed boards that are thin ,powerfull bottom turns and top turns that can flex the board and provide recoil ,once you add more foam for the average surfer and a more relaxed way of surfing you are/nt going to really take any benefit because the board is just unable to flex as much , pete