It was at night and sal hints that their navigation systems are GPS based. While I think you have a 100% valid point, maybe no one was paying attention trusting the nav.They're in the middle of the open ocean and both ships are the size of a building, visibility has to be like 5-10miles out there, GPS is no excuse.
Any way, I am just glad it wasn't some sort of missile or mine attack. Hopefully just stupidity.