In the opening battle scene, the colliding boats explode before they hit each other.
When Jeffords inspects the crew for the first time, the shadows change direction between shots.
As they approach the harbor/arsenal near the climactic scene it is still daylight (maybe twilight) but when they pass into the harbor 5 seconds later it full dark night.
In one of the battle scenes in the submarine pens, Jeffords and Yacov, in shooting at attacking German soldiers, are at crossfires with each other.
The women wear clothes that were obviously in fashion at the time the movie was filmed (~1970) rather than 1942.