First off good story,
God knows i am not a expert on writing (far from it)but I'll try to give you some feedback.
The only thing i could say is the ending seemed a little rushed. There's not a whole lot of detail between Beattis coming out of the water. No wait she had a flare gun? Do they all carry flare guns incase of something like this? seems kind of parinoid.
Those are the reactions going through my head when i read the end.

Hope that helps a little.
DoH