Repair of aluminuim mast section.

[Mudisox]

The waves caused by the latest storm made buoy pennant of my mooring break the roller fairlead and also make the 12mm chain jump out of the s/s "groove" and score the alloy section of the front crossbeam of my catamaran. It is an old, thick section but grooves of 3mm have been made, with a little bit of identation.
The construction is such that removal of the beam and replacement is not possible without major destruction and also sleeving is out. However the s/s Pulpit construction is strong and will probably takes most of the loading.
S0-- What do I use to fill and fair, ensuring good adhesion to aluminuim, and hopefully returning some of the strength?

 

[vyv_cox]

I suggest that it is going to have to be a sleeve, but one with a cut in it so you can get it over the existing beam. Riveting it in place will increase the thickness and strength.

It is quite difficult to get any filling and fairing products to remain attached to a flexing member like this. Epoxies and polyesters will pop out over time. You need something like Sikaflex 291 beneath your sleeve to give adhesion and flexibility, plus to keep the water out to prevent future corrosion.

 

[merlin3688]

I agree with the above, not sure what cat it is but you may find the same beam section still available, Sailspar used to make many cat masts and beams so they may be able to help you. The sleeve would need to be a good fit to do any good.

 

[alahol2]

Our Iroquois crossmember suffered from severe corrosion where the pulpit was rivetted on. The solution was rivetting on a large sheet (not quite a full sleeve) of stainless then rivetting on top of that. I would think a similar solution would suit your problem. PS the stainless sheet can be highly polished which makes it look less like a repair. PPS ensure lots of Duralac between the ally and stainless.

 

[merlin3688]

The Iroquois had a beam made by Sailspar, from memory E100, an oval section and not available any more. I think they still maybe could help wit the above. Lots and lots of Duralac if fitting anything stainless or you will have an even bigger problem!

 

[wklein]

Our Iroquois crossmember suffered from severe corrosion where the pulpit was rivetted on. The solution was rivetting on a large sheet (not quite a full sleeve) of stainless then rivetting on top of that. I would think a similar solution would suit your problem. PS the stainless sheet can be highly polished which makes it look less like a repair. PPS ensure lots of Duralac between the ally and stainless.

That is a good idea, would stop similar problem happening in future.