The cabin is a GRP moulding formed and then lowered onto the side ledge of the hull. Some months ago we spent some time levering the two pieces apart and filling them with sealant before bolting them back together again and covering them with a plywood deck.
Anyway the surface above the cabin is in very poor condition. It is a real source of leaks as there are numerous fittings which bolt through allowing water to enter. This has been one of the major causes of the water leaking into the boat.
In the past people have tried to cure this by putting fibreglass resin over the whole thing which gave it it’s white colour. This has crazed and split making the whole thing even worse.
The deck is actually made up of three parts. The fibreglass moulding which is then covered with plywood and then strips of teak have been put on top. This teak layer has had the fibreglass put on it because the teak was moving. This by the way was the wrong thing to have done. The more the water got in the more the plywood core has rotted away.
We started to remove the planking at the weekend and found that the plywood was so poor that we could hoover it with our trusty vacuum cleaner. There was almost a half inch gap (12 mm to the millenniums amongst you) between the teak and the fibreglass because the plywood has rotted away. What is more instead of sealing each plank with a flexible compound someone used epoxy resin which has cracked and let even more water through.
Time for a complete rethink and so first things first remove the lot down to the GRP.