Is it possible to repair a mast?

[--ice--]

I recently purchased a very cheap Hurley Alacrity. It came with a mast and main, but no boom or head sail.

I had a few bits knocking around and managed to locate a boom and today I managed to do a dress rehearsal in order to see what the state of things were and what I was short and what needed replacing.

Just as I finished for the day, I noticed a small whole about 4-5mm in diameter that had corroded through the mast, further visual inspection shows that the area to the one side of the mast has suffered minor deterioration of aluminium but the rest of the mast seems to be sound.

I have swung off the shrouds, fore and aft stays and it hasn't managed to snap (I know my 115kg isn't anywhere near the stresses that sailing creates) but it hasn't shown any signs of giving way.

Can the affected area be repaired, sleeving perhaps??

Any suggestions would be gratefully appreciated!!

 

[ianat182]

The make of mast, the location of the corrosion and hole, and type, or serial no ,or label would help. Photo here helpful.
If the hole is in a high stress area of the mast, or where it may have been in contact with fittings, is it likely to repeat contact when repaired.
Perhaps a fitting has been removed from that position or a halyard chafed the area.
Normally such a hole could be drilled out an aluminium primer painted and a large Pop rivet inserted.
Presumably the anodising surface has been damaged, this can be protected to some extent with a thin film of epoxy resin. I've used polyurethane varnish on a dinghy mast before but having spilt some epoxy on metal unknowingly and later tried to remove it.......!

Sleeving the mast may present problems. If using unanodised aluminium sheet the new material will not have any protection and its surface will corrode;it will also need some primer between it and the original surface, and you'll be drilling more holes for rivets or S/tapping screws, and if the sleeve is of a thin stainless sheet.

We often need to drill holes in masts to permit cables and sheaves to be inserted and these can be quite long and large, so I can't think that the size hole mentioned will be too serious a wound.


ianat182

 

[Yacht Yogi]

Mast repairs

Aluminium masts can be repaired by riveting aluminium plates and patches or even cutting out a damaged section and riveting in a new piece using aluminium plate buttstraps. It is fairly common to see masts made from several sections rivetted together (such as on the Elan 310).

However, a certain level of knowlege of stress and strength is required in order to be sure that the repaired mast is strong enough. If you have never done any stress calculations then I would suggest you seek advice from a rig-shop or mast builder or maybe a local surveyor can put you in touch with somebody.

Most rig designers or aircraft stress engineers could design you a repair but they will need to look at it and take a few measurements. I would expect to see some 5082 or 6061-T4 aluminium plate patches held on with a several rows of Monel rivets. Some chromate or zinc-based primer and JC-5 jointing compound will be used to preclude corrosion from the joints.

Initial concern would be how widespread is the corrosion? If there is a hole in the mast wall then how much more corrosion is there inside that you can't see? There are devices around for checking this kind of thing; you just need to ask around until you find somebody who has one.

There is no reason why you cannot make a simple and effective repair yourself using simple hand tools and a pop-riveter. You just need to get some advice on what size to make the repair to fix your particular problem.

have fun and good luck.