I have seen items recovered from beneath the sea using pairs of inflatable bags tethered together with under-slung straps. I therefore conclude that these bags must be made of a strong fabric.

Therefore, is it not possible to weld a sub-structure in the hull of the half submerged cruise liner to encase an inflatable bag to seal the large hole, then pump out the remaining sea water and tow the stricken liner off to a harbour?