In the scene where the ship is underway and at general quarters, several shots of the bridge show that there is no one at the helm (steering the ship).
The captain accidentally leaves the switch of the PA system on while he and Roberts have a confrontation in the captain's quarters. But when the captain has a seizure, Roberts flips a switch to turn on the PA system to page the doctor to come to the captain's quarters, even though the PA system had not been turned off.
The shore patrol arrives with a truckload of guards to restrict ship's personnel from leaving "The Bucket" and Schlemmer drives a motorcycle off of the dock. Before he does so, he passes the ship and the truck and all the shore patrol personnel are missing.
When Ensign Pulver is supervising a supply transfer, his uniform shirt is heavily sweat-stained. But when confronts the captain shortly afterward, his shirt is spotless.
When Roberts is talking to the sailors inside after his confrontation with the Captain about his letter requesting a transfer, all the sweat stains on his shirt have disappeared.
Lt. Girard uses military time incorrectly while talking with Ens. Pulver. She says "the shore boat will be at the dock at 1800 minus ten. No one would say it that way. The correct way to say that is 17:50 hours (said as seventeen fifty hours.
Several mentions are made regarding the "Congressional Medal of Honor", this is not the correct title for the award. It is known as the Medal of Honor, and while it may be awarded by congress, it has also been awarded by presidents.
Chief Dowdy's working uniform aboard ship during that time would have been dungarees with a CPO cap. Chiefs didn't start wearing khakis as a working uniform aboard ship until later. Also note that none of the enlisted sailors had their rating/rank on their sleeves of the dungaree working uniform. This also didn't occur until later on.
The Reluctant is a Camano-class cargo ship an AKL type ship. It was controlled by the army. And crewed by the United States Coast Guard. Not the United States Navy as shown in this film.
There is no way Ensign Pulver could have been aboard the ship for fourteen months without being seen by the Captain. He would have to report to him when he first came aboard, and as an officer, he would be expected to stand watches.
As the drunk sailors return from shore leave, the same shot of the truckload of men is used twice.
When Mister Roberts finally leaves the U.S.S. Reluctant by seaplane, the plane makes a 180 degree turn to the left and makes a close fly-by along the starboard side of the ship. This shot was not taken from the plane; it was taken from a camera boat passing the ship. You can see the wake from this boat at the left side of the screen as it meets the side of the Reluctant at the waterline.
When Ensign Pulver is talking to Lt. Gerard in the hospital, through the window to their left you see a blue automobile pass by in the distance. It is obviously a 50's style automobile although the film is set during WWII.
The radio shown in the officer's quarters is a 1946 or 1947 Zenith model.
As Ensign Pulver tries to climb the stairs after blowing up the laundry room, you hear him calling out to someone and whistling at the same time.
On more than one occasion, Ensign Pulver's lips don't move when he sings his little song.
(at around 14 mins) While looking through binoculars, Insigna says there's a white flag flying on the island but his lips don't move.
Camera shadow falls on Doc when he gets up to go to "check on hypochondriacs."
When Pulver meets captain for the first time in their discussion on the deck it appears the boom mike that's above their heads at the end of a support pole encased in a blimp is casting a shadow on the bulkhead. (A blimp being an open air chamber surrounding a mic creating more space between wind and the mic capsule to keep the rumble from being picked up on the recording.)
Although the trailer states that the file was shot "in the Romantic Islands of the South Pacific", the location shots were actually in the Hawaiian Islands, in the North Pacific.
Just before Roberts leaves the ship Dolan tells him the Captain has had a new palm tree dug up and placed a 24-hour guard around it. But when Pulver later goes to throw the palm overboard, there is no guard anywhere near it.
When the captain is trying to find out who threw the palm tree overboard, the 1 Main Circuit (1MC the term for the shipboard public address circuit) is used incorrectly. People keep flipping the announce switch back and forth, but it has no effect (everything said is heard over the entire ship).