On 04/09/2020 18:30, Kathy A Yarbrough wrote:
I have a hairline crack in my fiberglass tub. It is very small. Could it
leak down o to the floor below?

Depends on whether it goes all the way through. It might just be in the
gel coat, in which case it probably won't leak. You can do a temporary
fix on the inside with PVC electrical tape (or the wider, thicker stuff
if it is too big). If it does go right through, but is not flexing too
much then there are various ways of patching the outside. Easy ones
include Denso Tape (or Sylglas) and Flashband.