"The Morse Code call letters, i.e., international call letters (?), were:
BS Bismarck
HP Hipper
LW Lützow
GU Gneisenau
PE Pelikan
PG Prinz Eugen
SC Scheer
SH Scharnhorst
TP Tirpitz
GS Admiral Graf Spee
BL Blucher

(Source: Übliche Kurzbezeichnung von Schiffen durch den Morseanruf [Commonly used short designation of ships for Morse hailing], in Paul Schmalenbach's "Schwerer Kreuzer Prinz Eugen") "

Morse hailing in this case means flashing light.

The wonderful book 'DEADLY STROKE' by Warren Tute, tell of the story of ORAN, a port on the North African Coast. After France fell to the Germans, Germany occupied the northern section of the country and put the Vichy French [collaborators] in charge in the South of the country.  Thus the whole country was governed by Axis power forces. The French Fleet sailed from their various ports South to Oran which was a well established French Navy base. Fearing that through the Vichy French, the Germans would get the French Fleet to add to its Fleet, the Allied powers gave the French Fleet Commander an ultimatum: either come over to the Allies side, or risk being sunk, by the Royal Navy, whilst inside Oran. The French refused to surrender to the Allies, and so the Royal Navy turned on the French Fleet and virtually destroyed it killing thousands of men, in, what the French would say, cold blood. One of the protagonists at that destruction was our Battle Cruiser HMS HOOD with her 15-inch guns. One of her 15-inch shells  exploded the after magazine of the French Battleship F.S.BRETAGNE which caught fire and sank within minutes killing 950 French sailors.  This became a grim "pre-run" of what was to befall Hood herself just ten months later.

[Portugal]