A sudden hole appearing under the ship is a very effective way to create a hell of an amount of damage, and unfortunately can and does happen naturally all the time. The deciding factor appears to be two converging wave patterns and what determines the damage is related to the how the basic wavelength of each pattern relates to the size of the ship and where the convergence takes place on the ship.
My old man [Marine Chief Engineer] had very personal experience of this in the south pacific in transit from Fiji back to Oz on his BP Tanker in the early '80's. One quiet sunday morning, about half way back to Sydney, in his words - they fell into a hole in a nearly flat calm ocean which broke piping off from the fo'csle all the way back to the pump room justb ahead of the accomodation and in the engine room broke all three of the auxiliary "Percy Paxman" diesels and their attached generators free from their bases, wrecking the coupling on the running unit. The main engine mounting plate got cracked and the bow plating got split so badly he had to weld shut some watertight doors until they were able to limpback into port in Oz as none of the pumps on board coul keep up with the flooding rate. It took a fortnight's work in Sydney to get the ship fit for travel to Keppel in Singapore where they had another three week's in dry dock to repair the worst of the damage. His take on it was that if they'd been hit slightly further back, he'd have been lucky to have been paddling.
His bright side was that he did manage to get across the Sydney Harbour bridge a couple of times without having to pay the toll and he developed a liking for a particular restaurant in Singapore that he was very disappointed to learn, years later from me that it was now a block of flats after I visited for my work.