Its not the fiberglass
that is losing its luster, it is the gelcoat
which typically covers it as a finishing coat. Fiberglass can probably last forever if properly layed-up, finished and maintained (although after about 10 years it will likely need to painted, or refinished with gelcoat). Nevertheless, in terms of the structure, those are still HUGE ifs.
Many boats will suffer osmotic blistering below the waterline, which can be a time-consuming and expensive repair. Some is largely cosmetic, although if left unattended, it will become structural. Many boats will also suffer delamination
has been allowed to permeate the core
(and yes, virtually all FRP boats have a balsa, or foam core
in the decks, most all in the hull
above the waterline and many below). This is a structural issue and repairs
are even more time-consuming and expensive.
Yes, these things can be repaired and many boats with proper repairs
are more sound/durable than they were originally (especially if the bottom was peeled and covered with an epoxy
barrier coat, which is less water
permeable than gelcoat
; or, in the case of deck delamination
, had the outer or inner glass laminate removed, the core replaced, and new glass laid over top with all machine screws/bolts 'potted' with epoxy
before bedding in order to stop water migration into the core.
The end result - regardless
of the age of the boat, get a good independant surveyor