Shockwave core

Hello,

F18 rules

D.3 HULL SHELLS
D.3.1 MATERIALS
(a) The hull shells shall be built from polyester or vinylester resin, glass
fibres, core of PVC or balsa or felt. The combination of wood-epoxy,
injected plastic, which shall not be altered, other than locally for fittings,
and passage of equipment and normal reinforcement. Epoxy glue is
permitted for joining components. Every material that is not expressly
permitted is prohibited.

Since the world there's some rumorous about shockwave..

Shockwave core is Corecell.
Corecell isn't PVC or balsa or felt
So Corecell is prohibited in F18 rules.
Corecell marketing is that it is a better alternative to PVC.


World Council will discuss it in December.
But racers and members of F18 associations aren't aware of that.
It is an important matter, It is not normal that it stays in the secret of the Class dinosaurs.

What are you thinking about ?

Me : It's cheat, and cheat musn't be present in F18, hulls with Corecell musn't be race in F18.

What a troll. Anonymously register today just to post that?

The Technical Committee has already addressed the issue and made recommendation to Council for next month's meeting in Paris. You can rest assured that the Council has the health of the Class, fairness, and the current Shockwave owners' concerns in mind. I expect a good and balanced outcome.

Correct behavior would be to protest all the Shockwave present at a race you're in. Not post anonymously.

You'll probably win the protest. And lose some friends!

Guessing at the solution...

Assuming this effects all shockwaves and not a couple of "specials"

1. Grandfather existing boats (you can guarantee most the sailors don't know they were cheating).
2. Remove builder's right to self certify
3. Ban all unsold/unfinished boats from F18 class events.

I've known about this since the worlds, but honestly, who cares?
As long as the new boats ard built according to the rules I dont see the big deal, it is not as if its owners are deliberatly breaking the rules or anything.

We dont even know how much of the material is involved, it could be just the boards or something.

What bothers me more is cowards who create accounts just to post sh1t about the class!

Sounds like the builder should have their license revoked. How many of these boats are out there?

Shockwave, would you care to enlighten us as to which corecell foam you refer to and what that foam is made of?

The corecell literature for the A-foam refers to it being better than two forms of PVC foam. Can you confirm that this foam is not just another PVC variant?

Cheshirecatman

My chemistry isn't good enough to expain the difference between PVC foam and Corecell (SAN foam). The advantage of corecell is basically that it has higher elongation to failure figures which means it will withstand impacts and damage better. It also can be very easily heat shaped allowing for a closer fit to the hull and therefore less resin or bog in the structure. Given all F18s are heavy the only real advantage with corecell is its "ruggedness" A brand new boat with PVC or SAN foams will be very similar. But if you're looking at 5 year old second hand boats in 4 years time the odds are the Shockwave will be in better nick. In the early 90s when the F18 rule was written SAN foams where more much expensive, this it less so these days. As I stated above there is no reason to kick the corecell boats out of the fleet. Just make sure no more are built.

Mater is here

With corecell it's possible to build hulls with a better moment of inertia.
Less weight everywhere for the same strength, at the end only add more weight on the middle.
Corecell isn't pvc.

From Corecell datasheet
It’s styrene acrylonitrile (SAN) polymer base gives it unique processing and in-service properties.

Corecell is stronger in shear than PVC so a thicker foam can be used.
Given equal skins of lay-up on each side, thicker foam gives a stronger stiffer structure.

75 kg/m3 Klegecell R shear strength = 1.0MPa (PVC)
80 kg/m3 Divinycells H shear strength = 1.0 MPa (PVC)
A450 Corecell (81 kg/m3) shear strength = 0.8MPa

1.Do these foams have similar compressive strength?
2.In general are these foams similar for fatigue: cyclic shear load and cyclic compression?
3.After a number of years could the foam become thinner?
4.Does cyclic loading affect the foam's adhesive (resin or epoxy) ability to adhere to the exterior skin?