A purely maritime claim doesn’t have a statute of limitations (or, for you Louisianans, a prescriptive period). It has laches, which is kind of weird. Laches means that even if you’re past some deadline, you still get to bring a claim, it’s just that you have to prove the other side wasn’t prejudiced.
But congress can change that if they want to. As the Supreme Court said about maritime common law, “we sail in occupied waters,” where the occupier is, I guess, Congress.
Separately, you can bring a claim for salvage. Well, maybe. I mean, you can bring a claim for salvage if you render aid to a vessel in distress, and there are all these factors that come into play to figure out how much you get. It’s a purely maritime claim. You can’t bring a claim for life salvage. Save people from a sinking ship but leave the ship behind? That, my friend, gets you $0.* Congress didn’t like that so Congress passed a really narrow life salvage statute: if you save lives, and I save the boat, then you get a part of my salvage award. And Congress put a time bar: you have to do that within two years.
Does that two-year limit apply to pure salvage or just to life salvage? Courts have uniformly said that it applies to both. But it’s worth a shot at suggesting otherwise, and lo, the shot was made. Regrettably, the district court said “no, two years means two years” and it is under a statute of limitations, not laches. And the Fifth Circuit agreed.
*If we’re going to be economically rational about this, then there’s an easy answer. You have somebody’s life in your care, and that’s worth something, right? Typically, this is known as a hostage, and you are basically the Dread Pirate Roberts. But it’s against the law to hold hostages. Historically, that’s been a sometimes-impediment. Famously, it happened to Julius Caesar, who at that point was not quite so famous or else maybe the pirates would have thought better of it. Young Gaius Julius was indeed ransomed, then, being Caesar, he turned around and hunted down and killed the pirates. Occupational hazard I guess. Better to do the right thing.
For more on piracy, read this, which is great.