Asked Fergalb why there was no such concept, and he encouraged me to start such a thread so here we go

I'd intend it (with the support of the mods) to be for random questions observations that maybe don't need an entire thread but a few posts might answer queries.
So I'll start it off as I'm a fair newbie.
I was reading the daily mail (I know!!!!) about the Costa Concordia being salvaged, and costing €500 million to do so, and then going for scrap.
Is there a rule/sailing/boating regulation that says you are responsible for the salvage of a boat in any/certain circumstances?
I'm curious as to how the company are spending this money to salvage the boat, and imagining it has to be due to regulation?