Yep, the word Sinnbild is good, but here in Germany its better to say
Turmzeichen (transl. Conningtowersign). A lot of German WWII Subs have this signs on her Towers. But i miss them on the American WWII Subs, maybee the "Redfin" is one of them.
Greetings to L.A. and
Good Hunt 