Jeff Chandler was originally offered the role that went to Cary Grant, but chose to work on The Jayhawkers! (1959) instead. Grant himself was at first reluctant to take it, knowing he was much too old to play a wartime captain.

In the film the submarine is on a constant quest to reach a submarine repair ship to restore her operational status again. In real life Tony Curtis served on the submarine repair ship USS Proteus during WW2. It was alleged his enlistment in the Pacific Submarine Force was inspired by the film Destination Tokyo (1943), starring Cary Grant.

The "sinking" of a truck was inspired by a real incident that happened in 1944. On August 9, USS Bowfin (SS-287) followed four Japanese ships into Minami Daito Harbor. She fired her six bow torpedoes at the moored ships, hitting three and sinking two of them, but one torpedo went astray and hit a pier. A bus parked on it was blown up and thrown into the water by the explosion.

Some of the plot points of the movie were based on real-life incidents. Most notable were scenes set at the opening of WW II, based on the actual sinking of the submarine USS Sealion (SS-195), sunk at the pier at Cavite Navy Yard, the Philippines; Cmdr. Sherman's letter to the supply department on the inexplicable lack of toilet paper, based on an actual letter to the supply department of Mare Island Naval Shipyard by Lt. Cmdr. James Wiggin Coe of the submarine Skipjack (SS-184); and the need to paint a submarine pink, due to the lack of enough red lead or white lead undercoat paint.

Lt. Barbara Duran (Dina Merrill), the love interest of Tony Curtis' character, is portrayed in the 1977 television series remake Operation Petticoat (1977) by Curtis' daughter, Jamie Lee Curtis.

Continuity

When Holden is stealing the pig, he falls down in the mud and clearly gets the seat of his uniform muddy. Yet when he is climbing into the truck, the trousers are clean.

During the New Year's Day celebration the sub is pink. However, in the night scene immediately following the sub is gray again.



Factual errors

Barbara tells Nick that his features of dark hair and blue eyes are dominant characteristics. Blue eyes are not dominant, but recessive.

After the nurses are picked up and being brought below, one of the nurses hits the collision alarm. When explaining that she hit the button she points to the red handled alarm button. The red handled alarm button on U.S. Submarines is the General Alarm no the collision alarm. The nurse should have pointed to the green alarm handle.

All ship's logs are property of the U.S. Navy. They are kept by the Navy for a number of years and then are kept by the National Archives.

When Lt. Commander Sherman is talking to Captain Henderson they mention the submarine tender Bushnell as being in Darwin, Australia. That is not correct as the Bushnell had been transferred to duty as a Hydrographic Survey ship and renamed Sumner AGS-32 in 1940. The closest submarine tender was actually USS Canopus AS-9, which was in the Cavite Naval Yard.



Incorrectly regarded as goofs

Lt. Holden is seen uniforms with a single bar on the collars. The single silver bar is the Navy insignia for the Lieutenant Junior Grade. This appears to be Holden's rank. In shots with his dress uniform he has one broad and one thin stripe on the shoulder boards also indicative of Lt. JG.



Revealing mistakes

In the opening sequence of sea life, the string holding up the crab is visible.

During an air raid, several bombs go off near a truck Tony Curtis is driving. A cloud of smoke is shown coming up vertically at the driver's door while the background scene shows the truck is moving at a high speed. The wind created by the truck's forward motion should have blown the smoke horizontally.

In several of the shots looking through the periscope, a piece of the black matte is missing and moving around.



Miscellaneous

Off and on throughout the film, Lt. Cmdr. Matt T. Sherman wears what appears to be a signet ring on the third finger of his left hand.

Nicks uniform is correct. He is a junior grade Lt. not a full Lt. He correctly has a single silver bar.

When Admiral Sherman first sits down at the desk, as he is about to open the log book and reminisce, the desk has nothing on it (at 4:19 to 4:39) but when the camera changes to looking over his shoulder (at 4:41) there are eyeglasses on the desk, next to his left shoulder.



Anachronisms

The map on the wall of the office where Cary Grant and his superior are discussing the damages the submarine suffered during the Japanese raid at the beginning of the movie is clearly a mid '50s world map. The borders of European countries are clearly post war and the same about India and Pakistan that didn't exist as countries in 1941.

Nick Holden tells Matt Sherman that the boys up in Las Vegas would say he is trying to make his point the hard way. Sherman later repeats this to someone else. In 1941, while it existed and had gambling, Las Vegas was not yet the gambling and entertainment center it is known for. It was a small dusty town that was mostly a rest stop on the way to Southern California. People might know of it, and specially navy servicemen might know of it since they would stop there on their way to the Pacific, but it wouldn't have been a standard cultural reference as it would be in the 1950's and beyond. In 1941, Reno, NV would have been a more appropriate reference as it was better known as a place to gamble and vacation.

When Lt. Holden tells the Marine guard about the "blackout regulations," he says the order came from Adm. Nimitz. If this is set in mid-December 1941, Adm. Nimitz wasn't commander-in-chief, yet. He took command on 31 December 1941.

There is a Leica M3 camera hanging on the bulkhead of Lt. Holden's stateroom. That model was released in 1954.

A late 1950s vintage car - possibly a Dodge or Chrysler is visible through an open door in one of the rooms at the naval base.



Audio/visual unsynchronized

When the station wagon crashes into the limousine, the sound of the crash comes just before the actual collision.



Plot holes

When Major Heywood is talking to Lt Commander Sherman on her arrival on the submarine, several ships can be seen in the background. If real, these would have been more appropriate transport for the nurses.



Character error

At the end of the movie, as then Admiral Sherman steps off the Sea Tiger, and he's greeted by his wife and two boys, the first lad says "Hi Mr. Grant".. but Grant picks up the pace like no errors had been made, and, of course you immediately have the bus pulling away with the car attached to it. Few people catch the boy calling him Mr. Grant--but it's there.

When Stovall goes up on deck for watch and forgets his binoculars, Sherman goes to Stovall and Holden's shared quarters to retrieve them for Stovall. When Sherman ultimately leaves their quarters to head back up on deck, he does not have the binoculars with him.