sail track

Being careful not to cut into the carbon mast section, cut the ends of the track back either side of the damage with a hack saw. Next cut as much of the broken track off between the saw cuts as you can and then carefully file anything that remains just down to the carbon. Cut a new piece of track to fit the gap and carefully radius/smooth all the cut edges of the sail track so that they don't damage the bolt rope tape as it slides up and down the mast. Degrease all surfaces with some acetone or similar.

To stick the section of track back on, use something like Plexus MA310 <http://www.ldcsailing.com/?searchStr=plexus&x=0&y=0> which is a self mixing, two-part methacrylate adhesive, that has a working time of between 15 & 18 mins and reaches 75% of is ultimate strength in 30-35 mins at approx room temp. It's worth noting that LDC will effectively lend you the applicator gun (£37.48 - refundable) so you only have to buy the adhesive and nozzle, currently £13.78 & £0.96 respectively.

Before you apply the Plexus it's worth putting masking tape about 2mm outside of the areas to be bonded (mast & sail track) as this will help produce a tidy repair as you can simply wipe any surplus adhesive away and peel the tape off whilst the Plexus is still soft.