Rich from exporting coffee and rubber in the years leading up to World War I, Brazil bought a modern fleet in Great Britain including the scout cruisers Bahia and Rio Grande do Sul, based off the Royal Navy's Adventure-class. Modernized during the interwar period, Bahia was able to escort convoys with her new anti air and anti submarine weapons. It is believed that during gunnery practice one of these anti aircraft guns was accidentally fired into a depth charge rack, causing the explosion that resulted in the loss of the ship in July 1945.
In 1940 Koln was fitted with a helicopter landing platform on top of the aft superfiring turret. This could accommodate a single Flettner Fl 282 Kolibri, or Hummingbird, the first series production helicopter. She went into combat in this configuration in Operation Beowulf, a joint German Finnish invasion of the western coast of Estonia designed to destroy any Soviet warships in the area and support the infantry assault. During this operation Koln failed to engage any surface ships but did provide naval gunfire support and survived an encounter with the Soviet submarine Shch-322.
One of four ships of the Kountouriotis class, modification of the Italian Dardo class of destroyers (the Greek ships substituting two dual-barrel turrets for four single mounts), Ydra was built during a period of peace between Italy and Greece. Ydra also witnessed some of the first hostilities between Italy and Greece in July of 1940, when she was attacked by Italian aircraft sent in response to the British warships operating in Greek waters. When war broke out, Ydra shelled several Italian harbours unopposed in the Straight of Otranto; the German intervention and the arrival of the Luftwaffe would see her demise. On her way to rendez-vous with the submarine Papanikolos and the cargo ship Marimesk, she was sunk by part of a passing flight of German bombers near the island of Legousa.