Hi Matt
Another hint in the riddle:
Reynard the Fox (Reinhard der Fuchs), see [bestiary.ca]

U-255's commander Reinhard Reche compared himself with this fabulous animal with the same name as himself, and used the fox in his emblem.

Thee three later commanders of U-255 kept the same emblem.
The second commander was Erich Harms who had been 1WO under Reche. Harms later commissioned U-3023, and used the emblem once more.

Cheers
Vidar