. The ships' maximum speed would have been about 23 knots. Housing the main armament in triple turrets was new to the Royal Navy though British companies had been involved in the production of triple-gun turret designs for other navies. The choice of a high muzzle velocity with a relatively lighter shell was taken from the German practice; it ran counter to previous British guns such as the BL 15-inch Mark I gun of 42-calibre length which were lower-muzzle-velocity weapons firing heavy shells. Armament The N3 design mounted nine 45-calibre BL 18-inch guns in three triple-gun turrets, designated 'A', 'B', and 'X' from front to rear. The guns had a maximum elevation of 40°. As none of these guns were ever completed and test-fired, sources differ on their exact specifications. Naval historian John Campbell quotes the projectile weight as fired at a muzzle velocity of , but Alan Raven and John Roberts cite a shell fired at a muzzle velocity of . The maximum penetration of those guns at zero obliquity would have been 36.82 inches (935.3 mm) of armor for a muzzle velocity of 2,700 fps, that is based upon the USN Empirical Formula for Armor Penetration, in theory that would have made those guns the most powerful naval weapons in the world, surpassing the penetration power of the 460 mm guns found on the Yamato. The N3s carried a secondary armament of sixteen BL 6-inch Mk XXII guns in superfiring twin turrets. Four turrets were sited around the forward superstructure and four at the stern. The guns could elevate between –5° and +60°. They fired projectiles at a muzzle velocity of . Their maximum range was at 45° elevation. Their rate of fire was five rounds per minute. An anti-aircraft battery of six QF 4.7-inch Mk VIII guns was included. They had a maximum depression of -5° and a maximum elevation of 90°. They fired a high explosive shell at a muzzle velocity of at a rate of eight to twelve rounds per minute. The guns had a maximum ceiling of , but an effective range of much less. The ships were intended to carry four 10-barreled mountings for the QF 2-pounder gun (commonly known as a pom-pom), two abaft the funnels and two at the stern. Each barrel was provided with 1300 rounds of ammunition. The gun fired a shell at a muzzle velocity of to a