Why Was the Boat EMPTY?? (And Other Confusing Parts)

I am shocked at how many good reviews this got (82% fresh on Rotten Tomatoes). This is one of the most confusing and badly acted films I've seen in my life.

Triangle tells the story about a group of young adults who seems to be rich enough to sail a massive yacht for a weekend getaway. One of the adults is the main character- a woman who seems paranoid all the time. It's either excessive bad acting or she just comes across annoying. Either way she is not believable or sympathetic. There's a storm that capsizes the boat but somehow everyone survives except Heather- who mysteriously disappears.

But there's hope. Out of nowhere, a big cruise ship comes out of the mist and somehow the crew manages to get onboard rather easily. The problem is - no one else is on board. Kind of impossible, but apparently that's the case. The boat is old fashioned, like it was made in the early 1900s. Everything started to make less and less sense, like the main character finding her house keys. And blood showing up. And suddenly the main character starts killing her friends. And then gets caught in some sort of time warp.

1. No one has mentioned the boat or how it got there? It was one big empty vessel. Why was it empty? Was this just a key to her being dead already?

2. Why didn't she just shoot herself vs trying to shoot everyone else? When I say shoot herself I mean literally take the gun and blow her own brains out.

I don't want to give away anything else, but if you're a fan of a good plot with solid acting, this one is a big fat miss. My friend, Helen, also didn't understand it. She's in her 50s and me in my late 40s. We sat knitting for the second half, occasionally looking up at the screen but mostly became uninvolved.

Anyone else agree this might be the most head scratching plot in the past twenty years?