Natural weakening in deck under stanchion bases

The deck around many of my lifeline stanchion bases looks like it's weakened. The deck moves when I push and pull hard on the stancions. There isn't any fiberglass cracking that I can see, but the deck just seems to have lost its rigidity. Is this normal wear and tear for a 40 year (#354) J/30? What have others done to repair/improve it? Extra glass? Extra large backing plates?

Wet core is not a factor with these bolt hole placements.

I have read every post here with the word "stanchions" in it.

Like many boats, #357 had this same issue before I purchased her. The PO had Waterline Systems address this by using a top side G10 stiffener plate that spread the load out. Over the years however, there was water infiltration from a path formed between the top and bottom skins in that area in your picture which has no core. This path caused wet core near a couple of these stanchion bases which I later repaired by recoring from the top, then applying AwlGrip & Griptex. This improved the stability of the stanchions. In your case, I would be curious if there was any wet core in that area or delamination, which you might detect with a moisture meter, hammer and maybe a core drill sample from the bottom side. If it turns out to be sound and dry, you might be able to restore some structure with a G10 plate glassed onto the bottom skin.

GL,

-Chris

The core was good, though I didn't follow what you meant about how water could get into the core since these stanchions don't penetrate the core there. At any rate, I added a fix that is similar in concept to yours except by reenforcing with plywood and new glass. (Photo is pre-sand and gelcoat, of course ;))

We'll see how that works.

Hi, I had similar so when I replaced my stanchions I used G10 for backing. Used the same size as the original backing plates.... but G10 is far stonger than anything else. You can get it a Grainger. Its fiberglass pressed in high tensile strength for insulation? Commercial applications. Must be cut by a shop saw and drilled... none of my hand tools would get thru it.