A mast with a history is this particular Finn one, being my first ever carbon mast, so sentimentally I wanted to try and resurrect it.

Back in the days when we all had alloy masts and those must have carbon ones were just too expensive, a group of us Kiwi Finn sailors got together to design and build carbon masts.  A layup was professionally designed to mast bend figures from a variety of alloy masts, a mould constucted and 3 masts built.

We experimented with the first mast using an internal sail track but discarded this idea as too hard.  I bought this first mast and later ground the track out (leaving a "U" shaped section) on top of which a new sail track  was simply glued. Used this mast for many a year till I sold the boat. 

This is the moment of the masts' demise, Kevin Stone at the 2006 Nationals in Thames with the end of the mast stuck in the mud and a howling 25 knotter pushing the mast deeper into the putty.

First step is to glue the various pieces back together. As a normal epoxy adhesive would be too brittle for this application, we used some HPR 5 rubber toughened epoxy adhesive from Adhesive Technolgies Ltd.

It is black, it is sticky, it is messy, but it has that shear resisting strength we need to stop the splits from opening up further.

Everything was lofted up straight and level on lump of 50x25mm straight edge, the sail track lined up internally with an aluminium rod, and two pieces of wood profiled to the shape of the mast/sail track intersection before we set to with the sticky stuff.

The mast was glued up and positioned correctly before making fast by tightly wrapping packaging tape around the construction.  As epoxy will not stick to the plastic packaging tape it is used whenever we want to isolate holding material from the substrate.

The profiled pieces of wood were glued to the mast to keep everything straight and lined up for the next step.

The plan is to fix the break in two steps. First is to place a patch over the front face off the mast.

With the glued on support structure holding the mast in alignment, the top face was scalloped out to a distance of 150 mm each side of the break and to a depth of just a millimetre at the break point.

The scallop was filled with carbonfibre layers in the following radial pattern. 4 at 45 degrees, 4 at 135, 4 at 0, 1 at 30, 1 at 120, 1 at 60, 1 at 150, finished by another 4 at 0 degrees. All tightly bound down with peel ply to force the layers together and remove excess resin.

With the support structure cut away the sides are ready to be joined as per the method used on the top face.

The reverse curve from the mast to the sail track was left with the core in place to provide a flat face for extra strength over the break. 

It is intended to fill the rest of the reverse curve with filler to make the mast into a semi wing shape.

While the splits were glued together originally, they were further strengthened and secured by lighty scalloping out and laying 1 layer of carbon at 90, two at 45 plus two at 135 degrees over the length of the splits.

With the front and the sides completed, the side walls of the sail track had become pretty thin and weak.  These were then reinforced with carbon pads and the whole break area covered with double bias carbon cloth.

This layer of cloth will act as the sacrificial layup when it comes time to fill and fair the mast. All that remains to do is clean up the track, replace the fittings, halyard and take it for a sail (with fingers crossed).