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We use West System epoxys for their high strength and adhesive values.
It also fully protects the boat against water absorption and it can not develop the dreaded Osmosis.
We choose ATL Composite’s resin systems for their superior quality, reliability and value for money.
Having worked closely with the ATL Composites team and their products for many years, we know we can stand by their material solutions, and rely on great service should something unexpected happen.
We prefer Colan brand cloths for their quality and low resin absorption, custom made for Schionning Marine at six (6) stitches per square inch for easy wet-out and rounding corners.
This may not seem important but when working with a material for an extended period of time, the small things make all the difference.
The core choice is usually quite confusing. Cores have different capabilities and properties, and their benefits I feel are utilized fully in our catamaran designs. A quick look at their abilities:
Balsa has very good values and we can produce a shell using a very light laminate. It will be very stiff and very resilient to fatigue.
It has exceptional qualities including very high compression strength, extremely good sheer capabilities and fantastic sheer stiffness.
Compressive strength is the resistance to collapsing when pressure is applied perpendicular to the surface as when pushing directly onto the material with the point of your finger. Balsa is far stronger than Foam (80kg/cubic metre) in compression.
Balsa is also very strong in shear. This is when the core sample is held flat between your hands, one hand slid one way and the other slid the opposite way, when the core tears through the middle the core has failed in sheer. The amount of stretch you feel before the core shears is shear stiffness. To compensate for sheer weakness the core is made thicker. So 13mm Balsa may be equal in sheer to 19mm Foam.
(80 to 200 kg/m³)
There are many boats sailing that are built from foam as it’s mechanical properties are good for boat building.
The end result using foam core amounts to a very similar total boat weight. Professional builders can achieve a good result but usually use vacuum bagging and very good molds to achieve this.
Balsa can absorb water. It needs extreme neglect to rot (very unusual). Water soaks along the end grain quickly. It travels very slowly across the grain. We use balsa under the waterline especially because of it’s high compression strength for beaching etc. any core type must be sealed. Damage to all cores results in the same sort of repair. Notice a damp spot remaining when drying out to anti-foul… simply grind back the surface glass exposing the core, dry it out and re-glass – it’s that easy.
Timber cores are cheaper than Foam in most cases.
A light, high tech cat returns a far better (often 2 – 3 times) re-sale than lower tech materials. Often saving $10,000 on materials initially, loses $200,000 on re-sale – a serious reality.
Our boats can be built using Balsa, Foam or Western Red Cedar. Combine strength, stiffness, lightness and cost, with ease of use – it just makes good sense!