I’d forgotten about the coconut, but I remember the albatross. They tore it apart and ate what they could, I think it may have been the first food they caught, then left the carcass in the bottom of the raft. One of them woke up during the night and saw something glowing in the raft. Turned out to be the flesh of the bird. Then they all wondered if they’d poisoned themselves, until they figured out that the bird had been eating phosphorescent sea creatures which then permeated its flesh.
Indeed it does exist. Some life rafts are equipped with portable solar stills and/or desalination tablets.
Even better: an EPIRB
I came to post the Rose Noelle. Guys were adrift on upturned boat for 119 days. But I see that someone has beaten me to it. I think that is the longest mentioned so far.
Unless you count Shackleton and his men on the Endurance. Not strictly a life raft, but between having their boat stuck in ice, setting up camp in the ice when their boat was crushed and floating about in their life boats trying to get to elephant island, the men did not touch land for 18 months.
The problem with any kind of search at sea, it is just about impossible to spot anyone or anything from the air, it’s just too vast. “The Raft” guys were even lucky enough to have a spotter plane fly in their general area, but it didn’t spot them, but unlucky enough to lose virtually everything in the plane - it sank too quick. They likely would have had at least some rations and water onboard, not to mention a thermos of coffee, ciggies and, by god, bourbon. So, they went from “Gee, I wish the matches didn’t get wet. Well, we’ll get picked up in the morning” to “Boys, there goes our one and only chance at rescue.” After all, there was a war going on.
There are portable, hand-held sea-water desalinators that come with life-boat survival kits. The problem at sea w/out fresh water is eventually psychosis takes over, and the unfortunate victim suddenly believes it’s perfectly OK to drink seawater, and goes swimming off for the coke machine juuust over there… not. cool. at. all.