dont do it
fiberglass is not too forgiveing and its best to get
some professional fibergalss reapir guy out there
to figure out what to do...
I wont even touch putting handicapped grab bars in a fiberglass
unit becausse you need wood backing behind where you want to install
the bars ,,,, then when you tighten down the screws to the wood
most fiberglass will compress and crack from the stress of being
squeezed down....
then you got a big mess on your hand...
proceed with caution