Lovely picture. 20 mm Flak (AA-Quick Fire gun) this was the basic light artillery for all the Wehrmacht, Army, Air-Force and Navy. On the ships these were all over the decks. All the ship's complement were assigned to defening the ship, cooks, writers, stores accountants, administrative crews and other supporting personnel in the ship had to carry out duties in defending the ship. Thus, many ship mates had to follow courses and advanced training in managing A.A. guns (signified by Sonderabzeichen), but the main Artillery was left to the specialists, as were torpedoes, asdic, radar, engines management and other operational branches. War ships did not carry passengers, only complement - men with a military duty.