When the scuba divers are rising to the surface (from the underwater camera shot), the water depth appears to be over 25 feet, yet when the camera angle changes to above, the divers immediately stand up after surfacing.
At the start of the film, the landing boat has ten people in it. Moments later Lt. Quinlan says the boat is bringing more supplies. This is the same landing boat. How could it have gone back to the seaplane so fast and returned? Also the amount of people has increased. One Seaman too many.