I just played through this again after trying the remake just to compare. Noticed something and wanted to comment on it's implications for the future of the story... but doing it on that thread is premature (it's not caught up to the right point yet) so I figure I'll say it here and we can have a theoretical discussion.
So, at the end of Ch 5, right before Day 23, we get a quick scene of the girl Cindy (who the MC mistook for his wife at the resort while super drunk and fucked), where she is feeling sick in the morning before school. (Probably it's too soon for morning sickness but whatever.) Why would we need to see this scene, when it looks like we're gonna be stuck on the island forever? I wonder if the MC's indiscretion with Cindy is going to save them (but send him to jail.)
Brother-in-law failed to send a distress call correctly so no one is going to be looking for them until the boat rental is up. But by the time that happens, the shit will have hit the fan at BIL's workplace and the cops will be looking for him. So when they fail to return the boat, people are gonna think they fled and so the search will most likely focus on where they could have fled
to instead of if they could have sunk in the storm.
2 weeks after the manhunt is on (assuming 1 week boat rental), the reason for Cindy's unexplained illness will be discovered, her parents will lose their shit and an investigation into her rape (because technically it was statutory even if she was into it) will begin and eventually collide with the manhunt. Nothing about this would point them to the sunken ship scenario, but after 2 weeks of fruitless searching at foreign ports, maybe the injection of Cindy's parents' anger into the investigations will trigger a re-evaluation of everything and maybe someone will think of the storm then...