Character mistake: Error in reading of the "sextant." Mark is somewhere at 33°, but Stallone said 30° 22 minutes. I suppose they thought there were 60 minutes between marks 30 deg and 40 deg (actually there are 10°) and calculated the difference at 22 minutes.
Factual error: When Ray figures out he is on the ship, he makes it back to his cell, creating a flood along the way, he then swims through a lot of water. When he returns to his water drenched cell and escapes with Victor, his clothes are bone dry.