I first saw this in the 1960's and revisited it some fifty years later.
Of course it is of its time. It combines a story based on fact that is compelling and courageous, with a modest budget. The special effects are clunky, the costuming erratic, and armoury dubious, but it doesn't really matter. The story is well told, and dramatic. Submarine movies are at their best underwater where the claustrophobic drama is intense, and at their worst when that leaves them with nowhere to go. Here, fortunately the climax is on the surface, and incidental gems like a passing German patrol vessel playing music loudly also take place topside.
The portrayal of toffs in charge and salt of the earth ranks grate a little now, but John Mills is a sound, reflective toff.
Modern adrenaline junkies will not be impressed, but the simple heroism and determination portrayed is as impressive now as it was then.
