Here's a post I made on another forum - you may find it helpful:
I know this topic has been covered a bit, but I spent last weekend in my anchor locker and I'll be spending much of this weekend in the same place. So, I thought I'd hit this horse one more time and reiterate the importance of properly sealing hardware.
I knew about these spots when I bought the boat last year, but I've waited until now to repair them. A good section of the foredeck forward of the bulkhead needed to be replaced, as did a smaller section near the anchor locker. The foredeck was inundated with water from a deck plate and the waste pumpout fitting. The area around the anchor locker was damaged by the hinge screws.
Here's the cross section of deck with the deck plate removed:
I did this from below so as not to ruin the deck finish. Here's the first cut:
Here's the exposed core with the lower skin removed. Note the two pieces of wood right in the middle of the deck. This came from the factory as there was no indication of a previous repair in this area. An old foredeck cleat had two fasteners through the wood (see the epoxy plugs), but the other two were through regular balsa. It's strange and I'd love to why these two pieces are here. Did TPI run out of balsa?
I don't have any photos showing the new core exposed as I laid up the new core and replaced the lower skin in the same operation. I wasn't about to touch my camera. So, the two photos below show the lower skins replaced. In the anchor locker photo, I put that brace back for the picture. There were three braces in place while the epoxy cured.
Since these photos, I've water washed the repair to remove amine blush, sanded the area, and solvent washed it.
This weekend, I'm going to grind the seam back several inches on each side and reinforce with two layers of tape. Eventually, I'll repaint both lockers with Bilgekote, but that will be done later.
This work could have easily been avoided if the core was isolated from these fittings with thickened epoxy. Before the new hardware is installed, all fasteners or through-deck hardware will pass through the epoxy, not the new balsa. I omitted a lot of the core in the area where the deck plate passes through and I'll ream out the area around the waste pump out fitting. Fasteners will be installed in the standard way - potting the overdrilled holes with thickened epoxy and drilling and tapping the holes for the fastener.
The first time I did a recore from the inside I made a few mistakes. The largest mistake was not sufficiently preparing the braces for shoring up the new core. This time around, all of the braces were cut and set near by, so that went much, much easier.
Another difference is that I was able to reuse the bottom skin. On the Triton, the skin was not salvageable so I just laminated a new lower skin. I had some issues with trying to install pieces (particularly the biax) that were too large and therefore were a real challenge to keep from falling back off the overhead surface. It went a lot easier when I started using smaller bits of glass.
This time, the old skin was replaced. However, I'm not convinced that's really the best way. You still have to clean and prep the old skin, it has to go back in precisely the same location (meaning your going to hold in place until the epoxy kicks and you can add the braces), and you'll still have to grind and glass the cut seam. It seems that with that much effort, it may be easier just to lay up new glass.
The only minor downside this time was gluing myself to the drop cloth. Last time I stuck the back of my head into fresh glass, so things are improving with practice. No haircuts needed (yet).