Friday, August 22, 2014

Further pix from Cornwall

Yesterday, Martin Scott teased us with a single photo of his Mistral.  This morning he provided several more pix showing the boat at various stages during construction.

This shot shows us why this type of construction is referred to as "stitch and glue".  One "sews" the two sides of the boat together with either copper wire or nylon zip ties and then pulls the skin panels into shape, usually around the main bulkhead.  Once the shape has been optimized, by locally loosening or tightening wires as required, fiber glass tape wetted out with epoxy resin is laid over the inside of the seams.  Once the resin cures the wires on the external side are trimmed off and an additional layer of glass tape is applied to the outside of the seams.  One can think of the adjustment of the tension on the various wires, to achieve the desired shape, as similar to the process a bicycle mechanic goes through while truing a spoked wheel.

Here, the skin panels have been pulled up around one of the bulkheads.  The ratchet strap is a convenient way to adjust tension while tweaking the the shape before permanently glassing bulkhead in place.

The main bulkhead and center board trunk.  The strips of laminated timber on either side of the trunk help establish the shape of the keel line.  I like the IMCA Moth insignia applied to the bulkhead.  Nice touch.

Copper wire "stitching" along the keel line on either end of the center board trunk.  The prop and shaped piece of wood, like the laminated timbers in the preceding photo help define the shape of the keel's rocker.  Many Mistrals have an awkward knuckle in the bottom aft of the trunk which is created when the skin panels are being tortured into place.  This one will not!

More details of the bracing Martin employed in insure the hull will be twist-free when finished.

The bow after the wires have been cleaned off and the outside layer of glass tape applied.  Hopefully Martin will keep us updated as construction moves along!