Story leaves a few questions unanswered

This story is not very clear and doesn't seem to answer everything.
For one thing how did Jack manage to survive the sinking of the sub?
Did he jump off the sub or desert it?
Or did the captain of the sub leave him out on deck delibrately while
he went below to go underwater?
And if he did manage to get off the sub then he must have been rescued
by someone.
Or else how could he end up being the sole survivor?
If his memories slowly came back to him then he should have been able to
recall this.

Also I got the impression that this was a haunted submarine.
But if it was a ghost submarine then it seemed all too physically real.
How would an entire naval crew be able to board a ghost?
Also at the end it was revealed that the submarine itself named the "Scorpion"
had sunk back in 1943 and was lying on the ocean bottom.
And had been down there all that time.
So if that was the case then what was that sub that surfaced at the beginning of
the film?

The events that were occuring on the sub were a repeat of what happened back in
1943.
What was Lt.Jack Hardy doing back in 1943 that caused the captain to punish
him?
Did he try to sabotage the mission then and if so why?
The whole plot seems convoluted.

If anybody has some answere feel free to enlighten me here.


It is difficult to free fools from the chains they revere.

Voltaire