It is not unusual for older fiberglass boats (and not so new, amzingly enough) to develop wet coring, particularly in the transom and engine stringers. Below is one such case. We have also done the same type of work on a Commander 30, basically the same as this, only it was a Commander.
1996 Bayliner 3258 Avanti
There is a growing "restoration/renovation renaissance" of fiberglass boats across the country and this project is an example. This is a major renovation project on a 1996 Bayliner 3258, pictured below. Many people have the same loyalty to their fiberglass boats as wooden boat lovers do. Projects on this vessel include a new cabin door, some window replacements and repair, hull gelcoat repairs, transom core replacement, new engine stringers and side shelves, swimstep repair, transom door modifications, bottom paint, hull buffing and some additional interior projects. New electronics, fuel management system, etc. were installed by Jordan Morse.
As you'll see in the before pictures below, the transom core , engine stringers, and engine compartment side shelves were completely saturated and rotten. Again, Joel's experience and skills in composite boat building came into use in a major way. As you'll see, new stingers were built from scratch, as were new shelves and transom core, all of which were coated, glassed, primed and gelcoated.