Shortround6
Major General
As far as the high-lighted section goes, there was very little that was unorthodox or novel except for 3 things?How did each country's destroyers compare at the outbreak of the war, was there any that had unorthodox solutions and others which had solved problems in a clever way
1. The Japanese use of oxygen fuel torpedoes. But they used the same torpedoes in Cruisers.
2. The use of high pressure steam in the German and American navies. But again, in each navy the use of high pressure steam was navy wide, not destroyer specific.
3. The use of high angle main guns in the American and Japanese destroyers, but again the Americans were using the same gun in every ship that was big enough.
The Japanese used a different 5in gun on their battleships and cruisers. The 'declared' DP guns used in most of the Japanese destroyers were sometimes replaced by the some 5in guns used by the Japanese on the large ships. Much like some British Tribal's replaced one twin 4.7in mount with a twin 4in mount to improve AA the Japanese replaced one twin 5in/50 mount with the twin 5in/40 mount for better AA, which should tell us all we need to know about the AA capabilities of the Japanese 5in/50 gun and mounts.
The use of specialized AA weapons or the dedication of destroyers to a single role (AS for example) came after the outbreak of the war.