The photo above is a Twiggy Mk1 from France

This presentation documents the construction of a modified version of Lock Crowther's famous Twiggy Mk 2 trimaran

Sunday, February 14, 2021

Crossbeam Construction

above the bench on the shelf are clear cedar strips 13/16" x 1.5",
already scarfed together to form 30 foot lengths, 40 of them altogether
On the bench is a full length (30 foot) curved web cut to shape for the front face 
of the beam, scarfed from 8' lengths of  1/2"ply

30 custom clamps used to clamp 5 strip lamination
onto the edge of the web,
one clamp per foot

5 strips laminated onto one web edge

it helps to have 2 people to speed up the application of epoxy
to both sides of all 5 strips, the web, and clamp them all in place 
before the epoxy hardens

2nd row of clamps ready to laminate 5 more strips on the other 
edge of the web 


over 60 clamps altogether


the 2nd row of laminated strips clamped in place


leave the strips in the clamps overnight to fully cure the epoxy

clamps removed, leaves a "U" shaped flange,
reinforcement ply is laminated in places where the mounting bolts will
pass through the beam.

the ends of the beam taper with 2 layers of 1/2" ply reinforcement 
where the floats will connect














 

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