Saturday, February 06, 2010

Preparations for front beam mount lamination

When several tons of forces from the 200% buoyancy floats (from my target sailing weight of around 700 kg) are distributed to the main hull, primarily trough the front beams, a lot of reinforcements are needed.  The paths to pick up and distribute the loads are carefully engineered and the appropriate warnings regarding the necessity of following the designer's instructions exactly are clearly visible in the plans.  The UD and DB needed for the front beam mount lamination, not including the flange in the bulkhead opening, are now cut. I usually reduce the fabric weight by around 40% from the specified glass weights for 'R' designation, but in these areas, where parts of the hull will be non sandwich, I use a relatively heavier fabric to make sure the laminate is thick enough to give reasonable stiffness.  This also adds extra strength to these critical areas, as well as adds a safety margin that might be needed as glass and carbon fibres are mixed (the glass might not contribute until the carbon breaks).  Carbon beam mounts were so much more expensive due to one of Farrier Marine's sub contractor's pricing that I did not find it cost effective.


I finished making the moulds for the forward recesses. The front side is actually an "inverse recess", as it mostly protrudes from the hull.  Hence, the mould is also inverse from the others.

Port front beam mount recess moulds in place


And the inside getting ready for lamination, here showing the starboard front face of the bulkhead and beam mount. White outline suggesting the fabric overlap.

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