hi everyone how are we all doing
lets say i have a local custom shaped board at 85L
and a production board at the same volume of 85L
my question is...
will these boards have the same float
even though the production board has a breather screw and the custom board is a glass board
do the two types of construction using different materials have the same float
i have two boards in mind but wont mention them yet as i dont want to discrimenate yet because of brands
what are your opinions on this

volume - weight = boyancy... however that is assuming the water has a density of 1kg/L as in pure fresh water... not sure wat the specific gravity of salt water is... so this would make the boyancy more...

If both boards are the same weight they should have similar floatation

that was my kinda thought
the two boards i were refering to,
the custom board has:

closed cell foam (doesnt take water in)
Divincell sandwich bottom
with divincell blocks in mast and fin areas
fixed in with polyester or epoxy resins
and a timber veneer sandwich deck

and of course the production board is a DRAM
The Dyneema Reinforced Airex Model construction is a sandwich construction described as "bullet-proof" by the US magazine Windsurfing. Using an Airex sandwich core combined with military grade glass, D-RAM boards feature the use of wood under the heels for impact resistance as well as Dyneema in impact-exposed areas of the board. Dyneema is a fiber engineered to provide a remarkably high specific strength and high impact energy absorption properties. The fibers are manufactured in a unique gel-spinning process that align the molecule chains into a parallel orientation. The resulting strength, high elongation-to-break ratio and a sonic velocity of over 10km/s combine to give a sandwich laminate capable of absorbing high levels of impact energy. Dyneema is used by the US Department of Defense in their bulletproof vests for ballistic energy absorption.

the custom board weighs 6.9kg
and the production board 7.3kg

i may reveal the two boards soon after some more ideas have been posted

My 2 cents worth.
Volume is always a bit tricky. I had a shaping program that would give you volume from the boards dimensions, but I thined the rails down quite a lot and the volume was unchanged so I lost confidence in it.
When we built Hardies board, we weighed the foam after it was shaped, assuming a reasonably consistent density we could then work out the volume of the inner core, we just had to add the extra divinycell thickness to it. But without actually doing a displacement measurement I don't know how acurate we were.
A friend bought a production board with 85l marked on it, but was told by the retailer it was actually 90l, showed him some emails from the manufacturer to prove it. So yes, don't expect too much accuracy from volume statments.

(PS There's only one custom board I know of like you describe, and it won't be epoxy resin. Great boards thou.)

And yet another point, (wish I could think of all of this before I post)
easiest way to deal with board's weight is to include it in the total weight to be floated, i.e. 100l board floats 100kg (yes in fresh water),
but board weight must be included it that 100kg!!

Board weight is another area of variability, most production boards are quoted without any fittings. So when you work out floatation don't go by quoted weights, weigh it! with fin, mast base, footstraps etc.

I am so silly... Hey it's rock, not Dr Fizz
One last thing from me, it is about float, not just buoyancy... This has something to do with where you stand on the board, theoretically, a 100l board will float 100l less the board weight; but, if the weight is not directly over the most buoyant part of the board, or is not distributed evenly, then it's goin' to sink or the weight will fall from the board

hi everybody
rooster is onto it
thanks all for your posts
let me see if i can explain myself properly, im wanting an 85L wave board for 15knots and 5.8m sail, so the whole purpose is a stable board, early planing and fun wave riding
first i was wanting a FISH and was chasing a starboard but then i saw the stone fish and have seen a few of his boards around and heard nothing but good things about them, i also think they look good
---------starfish----------------stonefish
volume---86L---------------------86L
length---239cm-------------------235cm
width----57.3cm------------------57.5cm
tail-----43cm--------------------40cm
weight---7.3kg-------------------6.9kg
sails----4-6m--------------------up to 6m

qiven these dimensions id rather support a local shaper anyday over a million dollar mass production company
but saying that i want performance
does the stonefish have the right float i am after with the materials its made from
if i get both boards, put them in the water and stand on them one at a time, will i tell the difference of float
is the last final finish the same materal used on surfboards (glass)
i hope im not puting anyone under the microscrope and pointing the finger because thats not my intension
its the performance of different materials used in constructing these boards
it could be any local shaper its just im trying to decide between these two awsome boards
sorry i hope ive made myself clear maybe too clear maybe im too particular, curious and a bit picky
anyway... oh and also another question damn im a goose what does the fish tail do that a square/pin/round tail doesnt

Lauriew

quote:

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Originally posted by lauriew

In terms of the local board containing closed cell foam that doesn't absorb water, I am intrigued as there are only 2 core materials that fit this bill, polyurethane doesn't absorb water and extruded polystyrene doesn't absorb water. Nobody in their right mind would use polyurethane as its too heavy,
Lauriew

---

Almost right, Mark Stone has managed to persuade Burford blanks to make a supper light version of polyurethane, his boards are coming out with comparable weights to production boards. The locals in Geraldton certainly give them a good work out, and seem to be happy with them.
A few of the regular posters to this forum, that I know of, also swear by them. (cory, king of the point & last but indeed not least, Hardie)

The biggest downside from my point of view, is the size/shape limitation imposed by the blank itself

So does that mean that he uses polyester or are they still epoxy? Also, does anyone have any tech data on these blanks cause its got me interested now. BTW I promise that I don't wanna use the foam for anything to do with surfing, windsurfing or kiting so theres no need for trade secrets.

Lauriew

Hey Greeny. I used to have a Stonefish around 90-95 and a good mate had a Starboard fish 95. Totally different boards in feel. His would plane a little quicker but its top end wasn't great. My stoney was an awesome junkie surf board and pretty good at floaty jumps.
If you are considering getting one made, Mark makes an Evo type board as well. I tried one last time I caught up with him, and they kill the production models.
As far as strength goes they are bulletproof. I weigh 107kgs and no matter how hard I tried could'nt break mine. "King of the point" is rumoured to have done one of the biggest jumps anyone has seen at a recent Gero comp. and he still struggles to break his boards. He is not a small lad either.
Good luck in your selection

Hey Laurew
I must be out of my mind as I have used both extruded styrofoam and ultralight polyurethane to make sandwhich sailboards with. I don't have much tech data on the materials just some experience, usually a shaped blank made out of these 2 materials weighs about 2kg (about 30kg per cubic metre)where as a polystyrene blank is usually about 1kg. Extruded styrofoam will absorb under 1% water if submerged as per their data sheet. I experimented a long time ago by submerging pieces of each foam in water and food colouring for a week. Only the surface of the extruded foam had food colouring in it but with the polyurethane the colouring went into the foam, I have repaired urethane surfboards and have been able to squeeze water out of the foam, so if you put a hole in a urethane board it may absorb a very small amount of water.Due to Dow chemicals NEW enviro friendly process extruded styrofoam now weighs 35% heavier
Infact I've got a polyurethane blank in the vacuum bag right now should be ready to turn off soon, then I can go to bed.

Both Stoney and Mike make some great boards - no doubt about it - especially if you are after something tailored to what you want.

There are also some great production boards out there too. I wouldnt say that either "KILL" each other by comparison.

At the Wave Nationals with some real good sailors there was a good representation of Evos (Ben Severne , Scotty) and some representation of Stoney's Boards (Jaeger). Glen Alexander (Greeen Head air master)has been doing some of the most insane awesome sailing to be seen on the West Coast on one of Mike's Blue Juices. Mike puts alot of love into his creations so i thik they have some built in karma too.

I just get a little suss of people saying this new board is 100 times better than that one etc. It loses credibility. most improvements made in boards tend to be evolutionary rather than revolutionary.

There are plenty of average sailors out there on awesome boards making them look very ordinary.

In terms of float - 2 boards at the same volume but with different nose and tail widths will ride very differently. The wider tail / nose board will be able to hold alot more sail and will plane up alot earlier. The narrower version will probably feel better when it gets real windy and a 4.2 needs to be used. This is why a board like the EVO 74 can actually carry a 5.7 ! But an Acid 74 would struggle with the 5.7 - but feel great on the 4.2 !

Also - no boards are bullet proof. Some good jump landing technique will solve most problems. Remember your board cost you alot and is a performance hull - treat it with care and learn to spear your jumps or come in tail first. Nothing is flattie proof !

Also remember when chasing a wide style wave board like a fish - check that it has good vee through the tail as this allows you to roll it from the bottom turn rail to the top turn rail as you hit the lip (which is the whole point of having a wave board !)If your board is too flat in the back , with a wide tail ,then your reo action is gonna be stiff and you will not be digging the board. This is the whole secret to a good fish design - Tail width PLUS vee. THIS IS VERY IMPORTANT !

Hope this helps you see the facts through the hype.

woops, my mistake...

sorry.

Hmm! excelent post mattress buster especially the vee in the tail bit.
What can I say but even better post by dave.h thanks dave.h

As Glen is now sponsored by Delta I wonder if he was useing a Delta production board in the comp.Because at home in Greenhead he seems to be using Blue Juice boards. Was it really a production Kinetic used in the competition? or a custom painted up as a production? I ask as there seems to be some marketing hype around such as I believe that Scott M Isn't actually using an "off the shelf " production Evo
but a hollow made version of the Evo's .
Even Jesper Orth has been seen a few years ago on a New Zealand brand Carbon Art board painted up as one of the Starboard Acid's.
Wasn't Ben Severne using a Stone board painted up as Starboard at Dutch Inn last year?
Are the Starboards that Mark Stones son Jaeger uses really production starboards?
I'd really like to know the real facts to cut through the marketing hype.
Can anyone clarify this for me?????