Fixing fibreglass to fibreglass hull

[Pongo145badger]

Hi All
I have a Tohatsu 4.2m RIB which I want to fix a fibreglass box to. Bit ignorant on how to fix to the fibreglass floor of the boat. The fibreglass box contains the fuel tanks and is not presently fixed at all. Wedged it in place for a recent outing but the crew member complained! (It doubles as a seat)
Do I use self-tapping stainless bolts or resin or both?
Can't see any access to below the fibreglass floor of the boat.

Thanks in advance,

[Sonar]

the better way I have found rather than using screws through the deck is
Can always be removed if you need to at a later date..

Can be used even if the decking is damp.

Sticks Like 290ml Clear - Toolstation

Or marine sikaflex

[Pongo145badger]

Many thanks Sonar

[Poly]

Sonar, are you suggesting sticking a box that someone sits on down with just sticks like sh*t? I'd suggest the op reviews the old maib report on rib seat detachment which was assembled badly...

For strength glass it in.
If bolts are easy to use then go that way.
For future flexibility marine sika and self tappers.