I have the opportunity to purchase this GOB for about 4k. I have been on it and gone thru the boat fairly well; without having it surveyed. I took a number of pictures and have found out the following things that need to be done. Other than these things the boat is in pretty good shape. First i have not been able to find anything on a Columbia 25. Is there such a model or is this really a 24 or a 26? The rudder has cracked gelcoat near the stern that is coming off. It has been reccomended that I sand or break off the gel to look at the fiberglass matrix. If that is fine it is fine. Worst case scenario, replace the rudder. Goss Foam is the best known company for this @ about $400. Any feedback on this? Headliner is loose in spots; simply screwed to battens glued to the underside of the deck. How do I fix this? There is moisture inside. The windows need to be recaulked. I have read several articles about this in Good Old Boat and this emms to be something I can do myself. Any help on this would be appreciated. Fuel tank is very rusty. If it is not rusted through or should I just get a new one? Any ideas on cost and where?