Repair worn out masthead hole

[ckeijser]

How would you repair this?

Halyard attachment at masthead of my 45 ft cat. The hole that holds the shackle for the main halyard is worn out. Mast comes off next week. How to best repair this?
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[captainjay]

What brand of mast? Several manufacturers have bolt on mast heads/cranes. It might be easier to replace the whole crane. Otherwise you will need to weld it and redrill. This will effect the anodizing.

[rom]

That looks like a poor way to attach a halyard. Mine is attached to a pin that is integrated in the mast head. Just to say if replacing the head completely you may look for a more robust system.

[hellosailor]

That looks like a hole that has worn out into a slot?

Happens with aluminum masts, metal fittings or even synthetic lines can cut the aluminum. I would look for a couple of piece of stainless plate, maybe 1/8" or 3/16" thick, have them bent to match the curve of the mast, one on each side. Then have them drilled out, one big hole in the center to "replace" the slot in the mast, and some smaller holes around the edges so you can have them pop-riveted to the mast. Appropriate rivets to prevent galvanic issues with the two metals, and between the plates and the mast.

Or, of course, you could tap the mast and screw the plate down, if you or the machinist got together with the mast.

No biggie. Just lap a plate over each side, don't worry about welding on the mast.

There are actually stainless plates sold for small masts, to reinforce in-mast halyard exits that have been chewed out the same way. Slap 'em on, pop rivet, problem gone.

[Terra Nova]

Through-bolt a stainless padeye to the mast. Attach the shackle to the padeye.

[Bean Counter]

Drill another hole higher up and put a long, rated shackle in it.

[Cheechako]

Cant tell what's going on for sure, but a doubler on the outside, made of aluminum is an option, that would get the thickness closer to the shackle width also. If it's a wrought aluminum welded masthead (appears it may be) you can weld up the hole and weld a doubler on the outside giving 2 x the bearing area for that pin.

[ckeijser]

Thank you for your replies and suggestions. I eventually fixed it by addein gsmall stainless steel plates on both sides, bolted through.

[a64pilot]

Well, that ought to work and seems to certainly be stronger and more wear resistant than original.