FLEX??
If you are thin down there, where you should NOT be thin, perhaps laying in some Xmat, or similar, should be done now.
I would lay the cloth along the hull interior up onto the bulkheads so that the hull is tied one side to the other - and made thicker.

Tying the boat together with those small blkhds makes a very STRONG 'I-beam' structure.

Consider doing this where the ballast ends also.