This arrangement was seen as more efficient, and was deemed adequate to meet anti-surface and anti-aircraft needs under most circumstances. The space saved from combining the two types of guns added to simplification of supply, increased deck armour coverage, stowage of other equipment, a larger light anti-aircraft battery, and other needs. Rather, they replaced them with turret-mounted dual-purpose guns that could be used against both aircraft and ships. Also, it was deemed unlikely that a battleship would be simultaneously facing both rushing destroyers and aircraft, and it would take up too much space to have separate types of guns to deal with both threats. They discarded the dedicated, anti-ship secondary batteries altogether, because a battle-line fleet would be screened against cruisers and destroyers most of the time. 58 inch).ĭuring World War II, the US Navy, Royal Navy, the French Navy, and the Imperial Japanese Navy combined the secondary battery with the heavy anti-aircraft guns, creating a dual-purpose secondary battery. The light A/A was dispersed throughout the ship and included both automatic cannons of 20mm to 40mm (.787 inch to 1.57 inch) and heavy machine guns of 12.7mm to 14.5mm (.50 inch to. Second World War-era capital ships had four classes of artillery: the heavy main battery, intended to engage opposing battleships and cruisers of 305mm to 457mm (12 inch to 18 inch) a secondary battery for use against enemy destroyers of 152mm to 203mm (6 inch to 8 inch) heavy anti-aircraft guns of 76mm to 127mm (3 inch to 5 inch), which could create barrages to knock out airplanes at a distance finally, light rapid-fire anti-aircraft batteries (A/A) to track and bring down aircraft at close range.

Heavy calibre meaning guns