[jessriedel]

They almost never charge. But contrary to lutorm, they could. I recall at least one story of folks who were extraordinary negligent in getting stranded in national parks and were charged for a very large helicopter search and rescue operation. I can't find the correct article for victim rescue operations, but I assume the same reasoning applies as in the Law of Salvage where someone who rescues cargo is entitled to reward even if they don't sign a contract:

http://en.wikipedia.org/wiki/Law_of_salvage

However, this article uses the recent example of the Carnival cruise rescue to give some very good arguments why the Coast Guard is so reluctant to charge.

http://gcaptain.com/cost-rescue/

(Note that Carnival has not charged for using their cruise ships to pick people up in the past.)

[lutorm]

You mean the coast guard or a random other ship?

There are no corresponding rules for rendering assistance to people on land, so I'm not sure the NP comparison is valid.

I definitely had the impression that, like the article you linked, there was a "maritime tradition that holds that the duty to render assistance at sea to those in need is a universal obligation of the entire maritime community". Maybe they can try to recoup their costs later, but that was not my (uninformed) impression. Or maybe things are different in national vs international waters?

[soneil]

International waters makes less difference than people tend to believe. In international waters, your vessel is held to the laws of it's flag country.

It's not lawless - it's just confusing because different vessels are held to different laws.

[lutorm]

This can for a fact not be a complete truth, because some ferries have to wait to reach international waters before opening the tax free shops (back in the day when there were such things, I guess). If they were always held to the laws of their country, why would it matter where they were?

[jessriedel]

The fact that you have a duty to do something doesn't mean you aren't also entitled to compensation afterwards for risks and costs you encountered. See the first paragraph of this article for an explicit discussion:

http://www.jstor.org/discover/10.2307/1288377?sid=2110519172...

The only thing thing I can't rule out for sure is that government salvors are somehow not entitled to compensation in international law even when private salvors are, but that would be pretty weird. In any case, it's definitely not true of "the entire maritime community".