channel island flex bar multi-foam boards

General Discussion
1

sandwich core of 2lb eps w/ divinycell in the middle? interesting. but do surfboards really flex that much? i know there’s some serious discussion on the subject. i don’t ride light weight HP short boards so if i’m ignorant, so be it. on the shorter boards i have (5’8 and 5’10" not uber-light glassing and groveler thick/wide) i can’t push on them and see any really visible tip-to-tail flex like i can w/ a ski/snowboard (which bends and snaps back like a leaf spring). how much can a hpsb flex? 1/8"? 1/4"? the damping characteristics are interesting though.

what do you guys think?

2

Hoops! You open the wrong door! From what i know surfboard flex is more a vibrating problem than a quasi static one like ski or body board. For me projection after turn because of board return is a mythe because board don’t flex so much and because flex appear between opposites forces, or when surf there are zéro to really short distance between opposites forces so board need to be really flexible to noticeably flex in quasi static way. A pendoflex tail can flex. There are dynamics vibrations where stiffness, damping, weight play that create the feel of board.

3

Rarely is so much boolshit crammed into such a short video…well done , but I doubt too many will swallow it.

4

Sadly, Kayu, too many WILL swallow it.          It promotes a myth, that boarders on being a religeon.       You are correct about how much has been crammed  in there.      The true believers are lineing up, as I type this.        It seems that ‘‘pop’’ is the new ‘‘twang’’, eh?

5

Comment directed @ readers:

Thickness affects stiffness (stiffness is related to the cube of thickness).  Material properties affect stiffness.  Flex is affected by length too.

3-4 Gs can be exerted on a surfboard during a hard bottom turn.  Assuming a surfer weighs 160 lb, what is the measured distance of static deflection for the nose and tail tips relative to the midpoint for a 480-640 pound weight place centrally on a surfboard’s deck distributed over an 18" distance?  Simple data to collect as a relative reference point for discussion and comparisons of surfboard flex.  Obviously static flex is not the same as dynamic flex, but some empirical data are better than no data – data are not affected by beliefs.

I defer to George Gall’s (PlusOneShaper) – engineer and mathematician surfboard builder – discussion about flex at the following links (last half of first link and first half of the second link):

http://www.swaylocks.com/comment/497273#comment-497273

http://www.swaylocks.com/comment/497387#comment-497387

 

6

third membrane in the center of a composite beam increases global stiffness.

adding deck springer increases local stiffness.

board stiffer with same glass.

using what is basically a d-cell springer protected from impacts and buckling by its interior location may add longevity.

except that the impact/ding resistance is no better (same skin).

arguments can be made for taking structure in conventional monocoque direction for efficiency, versus building strength into core for longevity.

Pro: Adds stiffness and buckle resistance.

Con: Adds weight without increasing ding resistance.

More than one way to skin a cat.

7

The big names have to do something to keep their marketing teams happy.  Latest and greatest is the unattainable carrot dangled from the stick.

 

I ride relatively flex free HWS’s, and find them more predictable and chatter free.  Weighing 200+ lbs  and a front footed style, I find foam boards too squishy underfoot,  No pop or squirt or twang for me, just an overdampened suspension with too much travel, like an offroad suspension used on a stock car.

 

But my HPSB days are long behind me.  I just want to catch waves easily, go fast and turn hard and throw buckets until I die and I want a board that i can develop a long lasting relationship with, not something destined for the landfill.

 

Watching the recent J bay contest when it was smaller, I could see some of those guys on some waves actively tictack hopping trying to get that twang and pop generating speed right after takeoff.  Looked forced and hyper and unrewarding and only marginally effective.

 

One 9’3"  old school pintail LB I have was about to snap in half or thirds.  I routed 1/4 inch deep over stringer, deck and hull.  laid 6 oz under 3/16" thick cedar planks 3.5 and 5 inches wide and glassed over.  Super I beam effect.    Super thin tail got another  unequal length tapered stringer inlaid on each side of fin box.

Flex much reduced, weight increased.  i though all this Work would possibly make board ride like shit and all this effort in vain.

 

First wave after this I beam rebuild, had me laughing like a maniac.  Heel side bottom turns with every ounce thrown into them yielded a significant increase in  projection and a predictability the board lacked before the I beam rebuild significantly limited flex.

 In my opinion, for my style and weight and desires, less flex is more rewarding, but I am certainly interested to see where those in the know can and will take Flex in the future with different materials and methods.

 

The claims in the linked video raised my eyebrow more than once, but not in curiosity.  Kind of like when someone claims their MPGs are 50% higher than the EPA estimates for that vehicle.

 

 

 

8

Marketing . there always has to be something new to sell boards , no proof required .

9

So the designers at Channel Islands finally got around to reading the Burt Burger thread on swaylocks.  Divinyle cell! what a creative idea!  Their next version will be to put the divynlecell on the deck for impact resisitance, and give it a cool name, like toughlite or something.

I really do like them inovating to make a better board, but whenever credit is taken for someone else’s creativity, it bugs me.

10

I was just having a long hard think about flex a couple of days ago, so to see this thread pop up is interesting.

 

All that talk about flex, expecially in the tail area.  Big manufacturers dont tent to carry ribz carbon past the fin area on the bottom because they say that the tail area needs more flex.

BUT…   then they install future fin plugs or FCS2 plugs which on a 5 fin option board would cover almost all the tail area. I assume these plugs would have little or no flex, ??

Co-incidence or not the best board that I ever owned had Future fin system, also it was probably the second lightest  board that I have ever owned… flex or weight or a combination, but probably wouldnt have had much flex on the tail area due to the fin plugs?

Just to add, the video seems to make no sense at all, in the past I always heard that it was the foam degrading through too many flex cycles which caused boards to lose their ‘pop’, not the stringer, also certain blank manufacturers say that boards flex is improved when the core is softer than the outer areas of the blank.   It certainly seems like they just make it up as they go along and change the ‘science’ when it suits them.

11

I like the idea.

It looks ok to me.

The vertical flex bar, and the addition of carbon here there and everywhere.

radical blank set up.

 

12

…after watched the clip, several things come to mind:

-All these things can/could happen only due to be from a big name brand (from California). Read Sunova…

-The shaping room with dust ¿? makes me laugh.

-The guy is good and down to earth to sell the product.

-The idea is good

-Some things that he says are right for small HP boards, not for big bulky boards.

-try to avoid the hype mumbo jumbo to see the possibilities

 

13

Multi foam is an interesting thing to play with. I know there is a definate difference between two of my boards that are super close to the same shape but one is a staight eps blank the other is eps in the center with 20 mm cut off the rail all the way around, some salvaged red cedar veneer as rail stringers and then some PU rail off cuts as a rail band and a wood tail block. The multi foam board has a much more energetic ride it seems faster in and out of turns.

Why? wood works? eps pu combo? Im not sure.

Why did i make it that way? it was suposed to be a compsand but i got impatient and wanted to use scrap materials. Why not?

Note, that I tried very hard to avoid the marketing terms (parabolic stringer, twang, zip etc)

 

What their stuff does? Meh I dont have the back yard tech to pull it off but it it seems a tad over done, but I would surf one if I could get one for free.

14

I’ve ridden a few of them. Boards are light and lively, and the center sandwich dampens the typical feel of eps/epoxy, and makes them feel underfoot like a poly board. I like them a lot.  

15

You really well explain the problem. If you do a 3 point flex test, board on tail and nose, you in middle, you can measure static flex of boards and compare. I do it for 5 years with about 100 boards of different tech, really instructive. But when you surf, most of time water push under you feet there are no to short distance between opposit forces, and deflexion become realy small.

16

You got it, it change dampening blank properties, wich is sometimes a problem with EPS core and light build.

17

But they will not like them because they will feel stiff under foot, hard to dent, plus if they make them well they will be too durable, not good for business !

18

this is my question too and why i originally posted the video. the video discusses tail flex and snap off a loaded bottom turn…similar to how one describes a ski or snowboard working. i can’t believe that there is any significant flex going on back there that actually provides significant spring. like i asked originally, what would it flex? 1/8" or 1/4" at most? considering how little board is in the water on a bottom turn and how easily water can be pushed (even at speed), by the time you unweighted out of the bottom turn, the energy in a 1/4" of flex would be completely dissipated, wouldn’t it?

as for damping characteristics they’re claiming, those all seem fine/accurate. the flex/spring seems impossible to me.

19

Regardless of marketing, I feel it’s an advancement in construction at the production level. I’m surprised at all the negativity to that.  I personally welcome advancements in design and construction. 

20

You’re en right all improvement are good. For sure they have a bit to massive marketing but barron flex, it’s the origin tech from barron in NZ seems an improve tech depend of price…