1.

The lifeboat did belong to a shipwreck victim who had simply happened to come across the island by pure chance. Landing on the shore, he left the boat (which was obviously too heavy to carry around) and went to look for some kind of food and water sources. The severe climate may have been too much for him to handle, and he could have collapsed and died elsewhere on the island whilst doing this. As stated above, the team that found the boat didn’t have time to search much further than the shore where the boat was, so this seems like a logical explanation. There are still several questions remaining, though. Were there any shipwrecks in the general vicinity of the island at the time? If so, why didn’t anyone come forward to claim the boat and say it was from their ship? Where did the boat disappear to? Maybe the boat somehow floated back out to sea, or simply sank into the lagoon. Unfortunately, there is no real way of knowing.