7'0"balsasandwich riding impressions.

General Discussion
1

Have been riding my 7’0" balsasandwich for a while now and thought I’d share what I’ve felt about the board so far.First a little about the design, It was design as a “Funboard” kind of thing.

board is 49cm wide 6cm thick. Noserocker 11.5 cm tailrocker 8.5 cm. The bottom contour is flat and rocker is staged. As you can see in the rocker photo the rocker has a very flat section in the middle. this flat part was put in for more speed and it sure did work, I have reached speeds I’ve never experienced before. Fins on the bigger side with a typical trifin setup. Dont know if anyone else has noticed the same thing but i think a trifin setup on a balsacomposite “feels” like it has less drag than in conventional boards. Dont know if it’s the material of board that makes it so or if it’s the way I foil my fins. toe in is pointed 5 cm off nose. I have pinched my rails very low this time to see what happens. First time out was in knee to waist height surf. paddle was nice and takeoffs were really nice, I was really suprised how fast it was but had some difficulties to get the board turning,couldn’t really tell anything more than it was faster than any other board I’ve ridden.

Second time out was in blown out shoulder to headhigh fast steep beachbreaks. the low entry didn’t

quite like the steep faces but once you where up it was ok. Still struggling on how to turn the board.(was turning it like a shorter board) After a few waves I was able to turn the board to get where i wanted and managed to go vertical up the face but it (or I)didn’t manage to get down to the bottom again cause of the low entry. Couldn’t really feel that flex that me and others are looking for, only when you pumped the bord really hard you could feel some “flexreturn”. The bord feels very stiff outside the water but when in water and tap on the tail you can see the board go boing,boing which looks like some flex to me. The board really likes those days when it’s big and mushy. feels like I can do anything on those waves, the board is still going where others boards would loose speed. so you can go far away from the whitewater and come back with a nice long cutback thats feels forever. I am happy with the board except that I should have flipped the nose a little bit more and offcourse want some more of that flex return.

Forgot to mention the glassing schedule, It’s #1.5EPS 4oz under and over 3mm balsa on both deck an bottom and three 5mm strips for rails. Think I should have made it 2mm deck and 1.5mm bottom and two strips 5mm rail for more flex.

Jimmy yoshio shibata.



2

nice jimmy

thanks for the report.

give it some time and it should get better.as per thread on sunnova outline

its a really nice looking board .

jimmy try less glass underneath .also lower density eps

pm me if ya wanna chat about it

3

Hi Jimmy,

At first I though the rocker was really low, but after I converted it to inches it doesn’t really sound that bad. Nose would be about 4 1/2" and tail rocker is about 3 3/8". As you say a little more flip in the nose would help in steeper waves, live and learn. However, it’s propably faster and a better paddler with this rocker although a little flip in the last foot or so would probably not hurt the speed too bad. For me I would not have used a staged rocker for a board of that length. I think it makes the foot placement more critical. Foot placement is critical enough with a thruster setup and I tend to have a hard time finding that sweetspot for turning on a board that’s longer than the average thruster. But that’s me. Stick with it, and you’ll figure the board out.

I really like the outline. The board looks GREAT. How much does it weight?

regards,

Håvard

4

great stuff …thanks a lot for posting that Jimmy !

I like the good practical “this does that , but I wonder what would happen if I tried…” type posts here .

Very informative !

And , please keep us updated on your next surfs on it , any more new things you notice !

cheers !

ben chipper , west oz

5

You really look like your getting the board building dialed in!

Quote:

Couldn’t really feel that flex that me and others are looking for

I’ve got a few ideas (does this surprise anyone) on why your not feeling the flex. The first thing is that your board is still too overbuilt to easily feel flex. I think that the flex is a balance between the waves energy and the energy you put into the board (pumping). The glass job seems too much. On a 9’ board I’m getting away with 2b2 on the bottom and 2b4 on the deck and most importantly only a single strip of 4 oz on the rail (I’m guessing that your glassing traditionally so you would have 8 oz). You could also thin out (make less tall) the rails. The wideness of the rails doesn’t effect flex the way that the tallness does (try bending one of your deck strips of balsa if you stood it on end). My rail suggestions (thin & less glass) will make a bigger difference in flex than the glassing schedule. As your rails get thinner you are going to need extra wood elsewhere to regain the ability to store energy and rebound from flex. I’d take all this advice with a grain of salt, but its how I think it all fits together.

6

Bert mentioned that he uses 80’s style tail rocker which is about 3.5cm to 5cm, your tail rocker at 8cm seems significantly different, perhaps less tail rocker would force it to flex more

7

Was out today in a-framing nice beachbreaks chest-shoulder high.

I’m getting things dialed in and feel very comfortable with my board now.

was able to do long drawnout bottom turns(kind of like snowboardcarving turns).

Haavard, i dont think the staged rocker is that tricky with foot placement as you say,

but that maybe because I’ve been riding it for a while now. sorry but don’t know how much it weighs, dont even own one of those bathroom scales. I guess a bit over 3 kilos.

Silly, I really want to try out the lower densities but my eps supplier doesn’t have the light stuff in big blocks right now. The only make em when they get big orders they say.

they told me the #1.25 eps was available so think I’m gonna get that.

DanB, I agree with you that the board is overbuilt for my weight. the first balsasando I made was with the #1 eps and could easily feel the flex. But even though I cant feel that flex like the #1 eps stuff It’s still super smooth and it’s getting better and better every time i surf it.

I do handlayups but try to tune flex there as well, I only have 8oz where I want and the rest is only a layer of 4oz so dont think thats a problem, think I’m going too thickbalsa on the deck with my #1.5 eps. Do you think it’s possible to get the same flex patterns as #1eps when using #1.5eps?

Burnsie, could be right. Guess I have to make one to find out.

Jimmy yoshio shibata.

8

how does it feel

taking off

bottom turning

in the tube

reos …backhand

   ...forehand ?

how do the fins feel ? …do you have a closeup shot of them , please ., Jimmy ?

cheers mate !

ben

p.s. - it’s a bit of a pity that you and ‘Susej’ [Pete] live so far apart, eh ? …I bet he would be interested to try one of your boards … and possibly vice versa , too ? (Maybe the user known as ‘Toshi’ is also in Japan , yes ?)

9

nice work jimmy …

dan made some real valid points , my first impressions of the shape was a board that did drawn out down the line trims , had a tendancy to over shoot the pocket when trying to hit the lip and likes the open face best , feels more comfortable with weight placed forward to find that sweet spot for speed , will still hook hard and tight off the back foot with effort , but will wash off speed quick unless right in the pocket , doesnt like to have to much weight placed on the tail for extended times , just quick jabs on the tail making sure its as close to the pocket as possible , keeping all the weight on the front rail after coming off the top and entering the next bottom turn with weight forward , keeping the back foot light until there is opportune time to jam it in …

having to keep the weight forward on the sweet spot and after re-entries , adds to that sense of not enough nose rocker …

looking forward to the next one off the line …

dan !! what was the verdict with those 2 longboards??

regards

BERT

10

no jimmy IMHO

i dont think going thinner on balsa deck is the real solution

it what gives a compsand its spring.

berts mentions a balance of glass and lower density eps.

a 7ft board with 3mm deck should flex sweet unless you have

  1. too much glass under bottom skin

  2. bottomskin overlapping rails

  3. too much glass on rail

  4. eps is to high density

  5. core is too thick

a compsand blank is easy to flex until you but the top skin on

so the deck stiffens it up

but thats what you want!

just not too much

in saying that though there doesnt seem to be alot in it

stay tuned

i wrecked a board so i could figure out stuff

il post my finding when i thought about it more

i will remake it and give it a new life

11

ben,

taking off feels like it catches waves early…good.

bottom turning…feels long and drawn out but this depends on how YOU turn it.

in the tube…no tubes yet.

reos…feels…like reos.

the fins…I’m no fin expert but feels less like less drag.

and here’s a finpicture for ya.

Jimmy yoshio shibata.


12

Bert I am really impressed how you explain the board…dont know if i’m that a good surfer to tell if all you said is right but I agree with many things.

Will come back with more reports.

Jimmy yoshio shibata.

13

I did some thinking after reading your reply and think your right about the deck balsa.

I think I have too much glass under my balsa and too high density eps.

am looking for lighter glass and eps right now.

Thanks for your advice.

Jimmy yoshio shibata.

14

hi yoshil

i hope danb pipes in here

i really feel that pre treatment and glassing of the skins before attaching to the blank,

is the solution to a lot of problems

i imagine you can achieve really waterproof board with very little resin and cloth.

this seems to me to be the key to controling flex.

i also think in the unlikely event of breaking a compsand

it will be the bottom that fails in compresion

the skin delams from the core and then the board fails

however the deck can remain unaffected

compsands skins, as i build them,are far stronger in tension then they are in compression

i feel an desire to work out how to improve this situation

and when i do ,i feel it will solve other probs

maybe the blank needs to be in 2 pieces so the bottom and top skin are independent.

that way it may relieve the compressive load on the bottm skin. by kinda of sliding between the two core pieces

bert says

a strong board is a board that can flex

i feel this this suggests to me a strong board is a board that can handle large compressive forces

on the bottom skin.

we gotta think outside the square here

i could be way off

so correct me if im wrong

15
Quote:

ben,

taking off feels like it catches waves early…good.

bottom turning…feels long and drawn out but this depends on how YOU turn it.

in the tube…no tubes yet.

reos…feels…like reos.

the fins…I’m no fin expert but feels less like less drag.

and here’s a finpicture for ya.

Jimmy yoshio shibata.

thanks for that Jimmy !!

good to hear how you feel it rode , please update when you get some tubes ? or good forehand and backhand reos and cutties on it ?

I like the fins , too !

…what wood did you use ?

cheers !

ben

16

im bumping/hijacking this thread

anyone want to comment on my current theory

anyone?

17

hi silly, i think you are right when you say making the skins separate is way to go,what do you use as a pre treatment?

i am not sure when you say the bottom being under compression ,i would have thought it can only be under tension under normal riding conditions,pete

18

well until now ive just been sealing with resin before i lam

but i intend to make up a balsa sheet and heat it up then paint it with a flexible epoxy that has been thinned with solvent

if i do both sides i would hope to get full saturation into the wood

anyone else tried this method.

i know the bottom is in tension when youre surfing sure.

im talking about when a board is broken

its natural for a bottom skin to fail in compression as well

if you look at a damaged compsand.at a bottom skin that has failed in tension

what does it look like ?

i imagine it would be a fairly clean tear

if it was to fail in compression it would delam from the core and buckle away from the foam.

when nev was showing off berts boards

he was jumping on them upside down

why?

he was putting the bottom skin under compressive stress!

and indicating it to be a show of strength

why? if a board is not exposed to those forces anyway

whats the point of doing it?

its like having a bullet proof board . whats the point cuz no ones shooting at superbank yet

what say he put the board bottom down on a log and had some one jump either end

ie put the deck into tension

Im pretty sure there would be no dramas there, becuase of the outward curve of the deck.

it should bend a fair way without failing as well.

at the point of failure,

would it break/tear clean or would it buckle away form the core?

see what im sayin. because of the opposite curves ,the skins behave in different ways under similar forces.

a deck failing under tension would behave differently to a bottom skin failing under tension

and vice versa.

i think the compsand surfboard no matter how you build them have good strength in regards to forces of tension on the skins.

there weaker under compressive forces .and i think that is the key

they need to flex both ways

i know we disscussed this but

who can flatten out there boards upside down without damage?

i built 2 so far that can be safely jumped on without damage

one i jumped as high as i could on it and it only got a tiny little tear on the rail

another one i jumped on buckled

why?

the skins was the same thickness but the one that buckled had more glass on the outside and the bottom skin overlapped the rails.

so one board is extremely durable to compressive forces and the other isnt at all

why?

i basically built them the same,except for those few differences. they both have concave decks.

19

paul, i have only ever seen boards that buckle on the deck when they break and i think that has as much to do with the deck being crowned ,probabally a flat or concaved deck would bend a bit more before breaking these being poly boards, i have not seen a composite board broken yet,pete

20

HA! I was having a discussion recently with someone else…

if you used high density balsa on the rails,

why would you need glass there? just pre-t it and brush on some resin after shaping them…or very minimal glass with some flexy resin…

ooh

btw, i have done what you suggested…and then did water soak tests…and guess what…very little absorption…but it felt more brittle so a flex epoxy would be the go

wrt this construction, a lot of guys are ignoring shape effects, and thats a shame…you seem to be buckin the trend…good onya mate

if I didnt have so many other projects going on I’d try to build another BCS…youve got me tempted.

Soooo…whats the theory?

HA!