well done and effective
For many movies, you have to be in the mood for what you are about to see. I sat alone in the dark, and got swept away in the horror. The movie was very tense! And I just let it flow. I didn't waste time thinking of what they should have done. They were screwed by careless bad luck. And only fortunate luck would save them. So, I think for those who complain about the pacing, the situation, the acting and dialog - it wasn't your night to watch this, or it wasn't your movie.
I thought it did everything I expected it to do. I was entranced, and glued to my seat. And I was fine with the dialog. With the hopeless panic and acute stress, I thought it sounded real.
I had a friend who was once sailing off the coast of Costa Rica with his GF. Their boat started taking on water. After a day of seeing no one, he jumped in the water and started swimming. It took two days, but he made it to land. When a boat took him back out, they found his boat - but the GF was never seen again. It was such a sad story, weighing heavily on him.