Companionway Hatch Trim

[cadteach]

I have recently purchased a Islander Bahama 30, our first ever boat. The sliding companionway hatch is fiberglass, with a single piece of teak trim on the face, toward the cockpit.

Where the teak trim attaches to the fiberglass, there is some old caulk or putty that is deteriorating. What should I use to re-fill this? It would just be to keep water from getting between the trim and the face of the fiberglass it mounts to

It looks more like putty than caulk that is in there, but I have no idea how old it is.