The reconstruction reduced Renown's machinery from 42 boilers to eight while retaining four Brown-Curtis turbines and 120,000 shaft horsepower. Ten twin 4.5-inch dual-purpose mounts replaced a mixed battery of 4-inch and 3-inch weapons, and three octuple pom-poms strengthened close-range air defence. The work increased belt protection, retained substantial deck and turret armour, removed the torpedo tubes, and added a catapult with floatplanes. Deep-load displacement rose by nearly 4,000 tons, yet the official loss was only one knot. Royal Navy speed figures were conservative, and ships chased by Renown did not regard her as slower. The reconstruction added protection, anti-aircraft firepower, and aviation facilities while preserving the speed that defined her operational value.
Chapter · 25:25-30:20
Rebuilding Renown without sacrificing speed
Renown's major reconstruction replaced 42 boilers with eight, improved protection and anti-aircraft armament, and officially cost only one knot.