As I was cleaning and bleaching the cockpit and compartments, I looked under the rear seat and noticed a crack in the fiberglass base of one of the rear seats. This particular seat is a cantilever base and is part of the rear "U" shape seating.

Here is the general location of the problem and a closeup of the crack on the base of the seat (below)

Whatever the weight capacity of the seat is, obviously it has been exceeded at some point.

I decided to fix it by adding some more fiberglass on both sides of the base. Here is a picture of the seat removed (below Left)  The entire seat assembly looks quite complicated to remove, so I would have to patch the cracked area as best I could from inside & outside the fiberglass base, and what was accessible.

I ground into the gelcoat and roughed up the inside area as well. Here is a picture of the outside area after fiberglassing. I used 2 layers of 1708 cloth on both sides of the damage area with Vinyl Ester resin. Hopefully, it provide enough strength.

Since I was not able to disassemble the seat to expose the area further, I had to make do by masking the seat back. 

I took a closer look at the seat cushion . . . Seems to have a crack in the wood sub-straight (below)  So, it looks like a chain reaction break may have occurred at some point during the boat's life.

I decided to mend the cracked plywood with a few layers of fiberglass, and maybe even form a stiffener in the fiberglass. My plan was to get the fiberglass all set up and then lay a big heavy 'thing' on the seat bottom to bring it back fairly straight so it could set up.

I laid the seat across some saw horses and did the fiberglassing thing, formed the stiffener and then cover it all with some plastic wrap.

Then I looked around the garage and found the perfect 'heavy thing' . . . a Piece of a steel i-beam. It seemed to do a nice job of straightening the seat base.