Let’s for the sake of argument assume that it’s a well known fact that flex is good. Let’s also assume that the purpose of the flex is to alter the rocker for sharper turn while maintaining high speed when going straight.
Questions:
Where would you want the apex of the rocker flex to be located?
How do you put the flex in the board where you want it?
On a ski/snowboard the sidecut together with the foil and sharp edges coupled with the weigt/g-force of the rider controls the amount of flex. Due to the sidecut the ends will flex due to high load when put on an edge. As the middle point (and the full length of the edge) touches ground this stops the flex.
On a surfboard there are no such control points. Basically the surfboard has a fairly uniform pressure from the water. So how do you tune the flex?
start with something flexible and then stiffen it in the places you dont want as much flex , those places would be the areas of highest load in certain situations …coz if the flex is to much the curves change to the extent that they become unworkable …
as an example ive been working on something new lately , got way more overall flex happening more from the center of the board but proportionatly less at the tail in comparison to my known flex ratios …
took off on a juicy wave where the bottom fell out so the drop was real fast , when i hit the bottom all my weight was on the front foot , i felt the board flex and the rocker increased at the centre ,it slowed because of the new curve and threw me off the front …
so now i know with this particular construction technique to handle a bigger range of condititions , i must decrease the flex in the middle 1/3rd of the board …
so even tho water may have a fairly uniform pressure , the riders pressure changes depending on the circumstances …
every material has its own unique set of flex properties and rates of flex returns …
which means every construction must be tuned to suit the materials involved …
just make it and see , then work from there …if the performance never comes after every possible adjustment , write it off and go back to what was previously the best combo and start again …
Take a look at the thread called “Flex Materials” I remember writing about how a snowboard sidecut works…A surfboard may not have a parabolic sidecut to help it flex but remember the medium is different. You can dig a surfboard rail deeper into water then you could with a snowboard or ice for example, Powder riding snowboarders incorporate different designs and flex patterns…From my experience I would say flex is important uniformally where the board is in contact with the water during the turn, depends alot on how you ride, what you want to accomplish, and what kind of wave you are riding. The back 1/3 of the board is probably a good place to start experimenting as water flows off the tail and most of the pressure is put on the back foot during a turn…
If you were using epoxy, could you pour a softer epoxy resin on the last foot of the tail to get a more flexible area in it? would they bond together well enough or would the tail just snap where the two resins meet?
I wonder if bonding would be as good with a softer epoxy.
In poly resin, we used vinylester for it’s softness, but then it dented and delamed.
You can always reinforce the area of the joint with more glass.
Problem with flex boards is the overlaps don’t flex, the foam sandwich flexes unevenly, and flex board should be purely multiple layers of glass and resin, no foam…and they still stress fracture after repeated usage.
Take a look at the thread called “Flex Materials” I remember writing about how a snowboard sidecut works…A surfboard may not have a parabolic sidecut to help it flex but remember the medium is different. You can dig a surfboard rail deeper into water then you could with a snowboard or ice for example, Powder riding snowboarders incorporate different designs and flex patterns…From my experience I would say flex is important uniformally where the board is in contact with the water during the turn, depends alot on how you ride, what you want to accomplish, and what kind of wave you are riding. The back 1/3 of the board is probably a good place to start experimenting as water flows off the tail and most of the pressure is put on the back foot during a turn…
Had a look at it that tread, problem is a completly disagree with you in most regards to how the snowboard/ski sidecut/flex work. You’d be amazed how well a snowboard that ride good on hardpack work in deep fluff. An extremly stiff snowboard with more than normal sidecut made for extreme carving should in theory not work well in powder. Well, it does!
I do agree that a sidecut won’t be practical in a surfboard, but I think it has more to do with the shape of the wave and how the rail digs into the wave. A sidecut will never fit well in the pocket.
I wonder if the reason the most load on the backfoot during a turn has to do with the way a surfboard is constructed and if this could be changed if the construction was different.
A stiff snowboard with a wider outline will work well in powder, but not a flexier smaller board made for more freestyle riding…I don’t think you really disagree, as much as don’t uderstand, look at the original snowboards made by Jay Burton and how they progressed. Look at the outline on a Burton fish. What I was saying is the edges aren’t made to “catch” up front and back although it is an inherent characteristic of the design, the sidecut is designed so that when the board is flexed there is more active edge so you can hold an edge during a turn. Totally agree that a snowboard side cut would never work on a surfboard, I was just talking about it from a flex standpoint.
i remember this one time this season I ducked under the ropes and snowboarded down this glade in about 3 feet of fresh powder, my board rode alright, a wood core freeride board…not too stiff but not real flexxy either, but if I was about to go ride backcountry powder I would use a powder board or maybe even something like yours made for carving they do go well in powder…
Also most of the weight is on the back foot during turning a surfboard because that where the fins are.
The sidecuts are also combined with different thicknesses and materials, stiffer between the feet and more flexy to the tips, not to leave out the lengthwise torsional aspect as well. Doesn’t that also have something to do with it?
Is there actually a seam in the board? From the 3rd pic, the side view of the fin system/tail, it looks like there is a crease or seam and the tail is actually a seperate piece. Is that so?
Aqua, the tail is laid up carbon fibre . it is joined to the board with a rubber hinge , but the hinge is really stiff so I think the lay up glass over it as well . there is a closed cell eps foam over the top of the finished product. The long and the short is it is a seperate piece. to get a flextail on a board is an extra $300 so there must be a heap of work going into it.
A stiff snowboard with a wider outline will work well in powder, but not a flexier smaller board made for more freestyle riding…I don’t think you really disagree, as much as don’t uderstand, look at the original snowboards made by Jay Burton and how they progressed. Look at the outline on a Burton fish. What I was saying is the edges aren’t made to “catch” up front and back although it is an inherent characteristic of the design, the sidecut is designed so that when the board is flexed there is more active edge so you can hold an edge during a turn. Totally agree that a snowboard side cut would never work on a surfboard, I was just talking about it from a flex standpoint.
i remember this one time this season I ducked under the ropes and snowboarded down this glade in about 3 feet of fresh powder, my board rode alright, a wood core freeride board…not too stiff but not real flexxy either, but if I was about to go ride backcountry powder I would use a powder board or maybe even something like yours made for carving they do go well in powder…
Also most of the weight is on the back foot during turning a surfboard because that where the fins are.
Slightly off topic, but…
IMHO flex in a snowboard is there more to keep the load on the edge than anything else. The edge is on the snow at all times, albeit with more force near the center when not leaning all that much over which is propably why you can get it to turn less then the radius of the outline. I think the most important aspect of the flex in a snowboard is to distribute the load on the edge evenly. The edge will always limit or control the flex if you will since it is always in contact with the surface. To flexible though and it will get too much load in the middle and bend too much in the middle->washout. Too stiff and the nose/tail will be on the snow but not the middle during a hard turn → washout. Obviously must be tuned to style of riding and weight. Also, a snowboard on hadpack doesn’t need to flex all that much to carve. At 45 degrees it only need to bend as much as the actual sidecut to keep center and endpoints at the snow. This will result in a sidecut radius turn as long as the sidecut is tuned to the flex.
In powder IMHO other effects start taking over. You’re right, area matters more than anything else(I loved the early 90s when everybody else was on those 140 long boards made for spinning. No powder for them, more for me). I think you could ride snowboard that is 100% stiff and without sidecut as long as you have a setback stance which will create torque when you lean over and create a sideway force. Skies used to be like that and it was still possible to do turns on them. This is much the same way as a surfboard works with a setback stance and a template that narrows at the tail. Which is why the burton fish makes sense too(nice one, hadn’t seen that before). The fin(s) is under the back foot to bring back control.
Which get’s me thinking why do I worry all that much about flex at all if there are other things that matter much more?
Bert,
interesting about the board folding in the middle and throwing you off. I’ve experienced that a plenty in wet deep snow on a snowboard… I guess I’ve missread one of you post some time ago, because I thought you ment that a surfboard should bend the most in the center which didn’t make all that much sense to me.
There are snowboards made with little or no sidecut that are stiff and do ride off the tail…I’ve never rode one personally but have seen plenty of them. Why bother with flex if other things matter more? Well its another dimension to the design, if you have a board with outline, and fins dialed in, then go to flex to tune your ride. If the other aspects aren’t tuned rigth, then you’re absolutely rigth you should worry about tweaking other things rather then flex. You can ride an aboslutley stiff surfboard too, it would be quick to edge and responsive…but you won’t be able to use that energy transfer that flex allows…
Sorry - To lazy to do the work, but there was thread on the “Swizle(sp?) stick” Full side cut surfboard, works w/out fins too. And the snow board thing… Come on it’s been hashed out before. I’ve ridden all kinds of snowboards made several myself in the late 70’s-early 80’s - and all kinds of shapes work in powder. Flex… Listen LeeDD, good luck getting something that will last. (If I had a good digital camera…)