Mast compression

[geem]

Time has come to stop ignoring the mast compression on my 1978 Moody 39.
There was always a bit of a dip in the deck locally around the mast base, but following a rig tune up and Atlantic crossing it had become more pronounced.

I'm assuming that I need to remove the mast, cut open the deck, remove top layer of GRP, and remove the compressed material underneath. I'm assuming it will be ply.
Then reinstate using thickened epoxy and perhaps starboard. Replace top deck layer, and make good the cut lines with gelcoat filler.

Anything likely to catch me out?

Can you,observe the deck below the mast internally? Worth checking here to see if the issue is definitely failed ply within the grp. We had failed ply on our previous boat. There was a 1" thick piece of marine under the mast. We cut out the grp to expose the ply. I could scoop out the ply with a spoon.
To cure the problem, we laid up a sheet of epoxy and glass to about 5 or 6mm. Let it cure then cut it in to squares the size of the void under the mast. We laid in the grp sheets with epoxy thickened with colloidal silica until it was up to 1" thick, then replaced the section of deck we had removed.

It was totally solid and never going anywhere after that.
If you are in Grenada, there is a fishing tackle shop in the Carnage that sells a very good construction epoxy. It's a 1:1 mix and viscous. Extremely strong and way better than the West system in my opinion. Being 1:1 it's super easy to mix out small quantities.

 

[Kelpie]

Can you,observe the deck below the mast internally? Worth checking here to see if the issue is definitely failed ply within the grp. We had failed ply on our previous boat. There was a 1" thick piece of marine under the mast. We cut out the grp to expose the ply. I could scoop out the ply with a spoon.
To cure the problem, we laid up a sheet of epoxy and glass to about 5 or 6mm. Let it cure then cut it in to squares the size of the void under the mast. We laid in the grp sheets with epoxy thickened with colloidal silica until it was up to 1" thick, then replaced the section of deck we had removed.

It was totally solid and never going anywhere after that.
If you are in Grenada, there is a fishing tackle shop in the Carnage that sells a very good construction epoxy. It's a 1:1 mix and viscous. Extremely strong and way better than the West system in my opinion. Being 1:1 it's super easy to mix out small quantities.

Which shop is that? I'm up in Carriacou at the moment but will be back in Grenada (Woburn) when I tackle the repair.

I've already got a good supply of epoxy and silica, left over from building the dinghy.

As far as I can tell, the only problems are within the plinth itself. But I'll be taking a very close look at the whole area. It's pretty disruptive to drop headlinings etc, I'll need to earn some brownie points before I go turning the boat upsidedown.

 

[geem]

Which shop is that? I'm up in Carriacou at the moment but will be back in Grenada (Woburn) when I tackle the repair.

I've already got a good supply of epoxy and silica, left over from building the dinghy.

As far as I can tell, the only problems are within the plinth itself. But I'll be taking a very close look at the whole area. It's pretty disruptive to drop headlinings etc, I'll need to earn some brownie points before I go turning the boat upsidedown.

Its opposite where the fishing boats and Rum Runner day charter boats tie up. I think there is a cash machine next to it. Blue writing on the signage but can't remember the name.

 

[Kelpie]

Its opposite where the fishing boats and Rum Runner day charter boats tie up. I think there is a cash machine next to it. Blue writing on the signage but can't remember the name.

In St George?

 

[geem]

In St George?

Yes