Goofs

Liam Redmond plays the part of "Chief Engineering Rating\\C.E.R. WATTS." However, on at least two separate occasions both the ship's Captain Ericson (Jack Hawkins) and later Coxswain Tallow (Bruce Seton - 11th Baronet of Abercorn) clearly call him WATSON.

Just after the repair in the Mediterranean is completed and Compass Rose gets underway, another ship can be seen on the horizon.

When the captain says things like "Steer one six O" and "Very Well", that is not what a real Royal Navy captain would say. The Script should have said "Steer one six zero" and "Very Good". "Very Well" is a US Navy expression...

The U-53, a type VIIB u-boat, was sunk on 23 February 1940 in the North Channel by HMS Gurkha, not late in the war. The same fictionalised name was used for the U-boat which effected the unwanted 1943 German rescue from an Adriatic island in another British film, Don't Panic Chaps (1959).

The ship used to represent HMS Compass Rose in the film is actually not a pre-1940 Flower-class corvette. Those corvettes had mast before the bridge. The modified Flower-class corvettes which were developed and ordered after 1940 were slightly larger, slightly better armed and the mast was moved behind the bridge.

In any scene where the A.S.D.I.C. is being used and strikes a target, the rate of A.S.D.I.C. pulses increases the closer to the target the ship gets. There is no reason that the A.S.D.I.C. pulse rate would increase, as they are set at a certain frequency that would only be changed by the crew, not by distance to target.

The phonetic alphabet for B in The Royal Navy is "BRAVO". Not "BAKER" as stated in the film. BAKER is used in the US NAVY. Not so, during the period in which the movie is set, the Royal Navy used the "Able, Baker, Charlie..." phonetic alphabet. It was much later when the NATO "Alpha, Bravo, Charlie..." phonetic alphabet was adopted.

Some depth charges are clearly labelled "INERT FILLED."

The ship used for HMS Compass Rose is clearly too old to be a brand new ship.

When Compass Rose is undergoing repairs and attacking the first submarine, land comes and goes around the ship; one minute they are relatively close to land, the next out of sight of any.

When Compass Rose is halted for repairs, one of the engineers is hammering a bolt and making a lot of noise. The engineer opposite then turns a large spanner, but the bolt head also rotates. Without anyone holding the other end, it will never tighten.

At the end of the film Ericson mentions that Lockhart never gained any medals and yet Lockhart clearly has medal ribbons on his uniform.

Lt.Cdr. Ericson (Hawkins) sitting alone in his cabin, hears a commotion on the deck above, as the ship leaves port for the first time. He glanced upwards, then looks at his left wrist while pulling back the sleeve of his uniform jacket as if to check the time, but there is no watch visible on his wrist.

When the Compass Rose is disabled and preparing for the night while the repairs are underway, the captain orders the utmost silence be kept to avoid detection by an enemy sub. On the other hand, the ASDIC has been merrily pinging away all the time for hours on the stationary ship, which submerged subs can of course hear across great distances.