This is the aluminium beam at the front of the boat. I've hacked away some of the material that was bonding it into the hull. It was partly solid polyester resin, with some glass/resin on top. It didn't work as a seal. Water was able to penetrate along the beam and reach the plywood bulkheads inside the boat that support the beam. The ply has softened to the extent that I have had to remove it all, and will replace it soon. Not a big job, but it is essential that that plywood is intact. I'll replace the polyester around the beam with epoxy, but since I doubt even epoxy would seal the beam due to differences in the rate of expansion/contraction with temperature change between the beam and the hull, I'll also add a thick layer of Sikaflex round the join. The Sikaflex is flexible enough to accommodate the differences.
This guttering around the inside of the forward hatches allows the hatches to be flush with the deck, which is a nice tidy setup, that allows any green water to quickly go over the side of the deck rather than piling up against an upstanding hatch edge. But still some water managed to find its way into the hatch, so I've raised the edges of the guttering with epoxy and glass, and then sanded it down bit by bit until the hatch is once again flush with the deck, but there is only a very small gap between the bottom of the hatch and the top of the guttering. Only a small amount of water can now get past the edge of the hatch , and the size of the guttering and drains ensures it will drain away before the next wave sends more water over the deck. This job took quite a lot of time and effort - it involved going into the hatch, pulling the lid over and marking where the edge of the guttering needed sanding down, then trying the hatch lid on again, then more going inside, marking etc.
There may be times when water is frequently sprayed over the deck. If even a little of it gets inside, it would accumulate and the forward section of the boat would lose buoyancy.... anyway, this fix should solve that issue.
Now, back to the sanding....