Can a crack at the foot of a mast be fixed?

[thinwater]

These are nearly always cause by internal expansion, either from corrosion between the spar and plug or ice. Yes, there are horizontal forces and yet it needs fixed, but the cause is almost certainly expansion rather than rigging and sailing forces. These are orders of magnitude different. Many repairs are possible.

Note: If it could have been ice, add a drain. However, ice generally causes cracks a little higher up that that.

 

[lw395]

In my case the cause was corrosion. The foot of the deck-mounted mast was closed-off with a cast aluminium bung and there was no effective means of drainage so water had collected there and the resultant corrosion and swelling split the mast at its weakest points: where the rivets holding the bung in place were.

I have a dinghy mast where the rivets have corroded, allowing the mast foot to twist in the section. The cast plug is slightly tapered, and you can see where the extruded section has started to spread. The design is a water trap. Everything is stacked against it, but to be fair, it's 20 year old racing kit and with a bit of TLC it will do more years yet. I'm going to replace the rivets with rivnuts and screws, so it can easily be removed and re-sealed from time to time.
It's amazing the stuff you find inside spars, dirt, ends of rivets, dead insects, bits of string....