Not sure but it looks cool... Either a shelter or some sort of common area.

Let’s play a game! Let’s pretend you rented a giant yacht for the weekend somewhere warm. It’s one of those amazing boats that has a bedroom underneath and a fully stocked kitchen. So, you take your boat out into the sea for a sunset cruise and are drinking wine and beer and having a great time....

This is our shelter from our four day survival trip on a deserted tropical island off the coast between Malaysia and Thailand. We went here with nothing but a knife, a flint and a machete.

Three sailors are rescued from an uninhabited Pacific island by the US Navy after spelling out "help" with palm fronds.