We have a 1985 Hunter 31. I am continually amazed at what I learn about this boat as the days go on. I would like to share the following and seek advice at the same time.Our boat is sitting in the cradle for the winter. On the weekend, on the advice of a maring surveyor, we were making a drain hole in the bilge, which will allow the bilge to drain IF water gets in during the storage time. This hole is enlarged on the outside and a stainless sleeve is installed, then a drain plug inserted. A number of other boat owners in our marina have done this as well. However as I began to drill a small hole in an otherwise completely dry blige, water began to seep into the bilge. It was black, had an extremley bad odor and almost filled the bilge. Of course once the hole was through the hull, it drained out. We have been complaining of a bad odor in the boat for 3 years and the odor of this liquid had a striking similarity to the one complained of. The surveyor said that there is a "second" skin under the interior skin and it is this area which was filled with water and goop! We have flushed out this cavity and have put javex in of a couple of days. Has anyone else had this experience or offer some comment on what we have found. HELP!!