HMS Repulse

Repulse, 1939. Rangefinders, searchlight and anti-aircraft artillery stands can be seen

Machinery installed on Repulse remained unchanged throughout her service life. The huge boiler room (over 58 m long) housed as many as 42 Babcock-Wilcox boilers distributed among six compartments. There were 3 boilers in compartment A, seven in compartment B and eight in each of the stern compartments (C, D, E and F). The boilers generated steam for four Brown-Curtis turbine units located in two engine room compartments. The turbines drove four-bladed propellers via main drive shafts. The ship’s machinery developed 112 000 SHP (112 400 after modifications) which translated into a top speed of almost 32 knots. Following various refits which significantly altered the hull’s hydrodynamic characteristics and increased the ship’s weight (addition of armor plating and installation of anti-torpedo bulges) the battlecruier’s top speed dropped to a little over 28 knots. Repulse featured a set of auxiliary generators delivering a total of 750 kW. Two of the generators were piston-powered (200 kW each), one was a turbine powered set (200 kW) and one was a hydraulic unit (150 kW). In total the machinery weighed in at 5 100 t. The ship carried 720 t of boiler water and 150 t of potable water.

Protection
In keeping with an adage: “speed is armor” Renown class battlecruisers featured limited armored protection which was to be offset by a powerful propulsion system. The Battle of Jutland proved beyond any doubt that the concept was fundamentally flawed (the British lost three battlecruisers in the engagement). Later attempts to provide the ships with improved armored protection were, unfortunately, not entirely successful.
When Repulse first entered service her citadel featured very thin 6” side armored protection, which was also very narrow (only 2.74 m with the lower section extending just one and a half feet below the waterline). The armor belt was only 4” thick in the area around turret A and 3” thick around turret Y. 2” armored strakes were located directly behind the main armor belt. Upper sections of the hull’s sides were protected by 1.5” armor plating. The front of the citadel was protected by a 4” bulkhead set at an angle (upper and lower edges were closer to the stern of the ship, while the mid section extended towards the bow). The stern bulkhead was 3” thick. Horizontal protection was based on two decks: lower deck (beginning at the lower edge of the main side armor belt – 2.5” thick and increasing to 3.5” above the steering gear compartment) and main deck (upper edge of the main armor belt, 0.75” to 3” thick). Upper and forecastle decks featured lighter protection (up to 1.25”). The main battery turrets and barbettes were better protected (but only just!): the turrets were covered by 7” to 11” plates (4.25” on their roofs), while the barbettes had 7” armored protection in the upper sections and 4” plating around the lower sections. Sides of the conning tower were protected by 10” armor, while the roof and floor featured 6” and 3” protection, respectively. Armor protection particulars can be found in the tables. Below the waterline the ship’s hull was protected by anti-torpedo bulges, which additionally provided storage for fuel oil. Directly behind the anti-torpedo bulge, in the amidships section, was a narrow air-filled compartment enclosed by two thin, longitudinal bulkheads. The design weight of the entire protective armor was 4 770 t.

The cross section of the Repulse’s hull. Clearly visible are 6” and 9” armor belts, 4” armored strakes, as well as lightly armored forecastle, upper and main decks. Additional “blisters” were added to the original anti-torpedo bulges. The new additions were split inside by a single longitudinal bulkhead and covered the 9” vertical armor. There were two additional, thin longitudinal bulkheads behind the bulges with empty space between themRepulse’s armor was modified and upgraded on several occasions during her 25 years of service. Some of the most significant modifications included increasing the main armor belt thickness to 9”, increasing the side armor plating between the main and upper decks to 6”, addition of 2” plates to the armor strakes above the ammunition magazines and 1” plates to the main deck, as well as the installation of much beefier anti-torpedo bulges, which covered the main armor belt. From 1936 Repulse featured strengthened lower deck protection (up to 3.5”) and additional plating on the main deck (up to 5.75”).

 

Armament (1916)
6 x 15’’/42 (381 mm) Mk I installed in Mk I* turrets (3 x II)
17 x 4’’/42 (102 mm) BL Mk IX on Mk I mounts (5 x III, 2 x I)
2 x 3’’/45 (76.2 mm) 20cwt QF HA Mk I on Mk II mounts (2 x I)
2 x Hotchkiss 3-pdr (1.85’’/40. 47 mm) QF Mk I on Mk I mounts (saluting guns)
5 x 0.303’’ (7.7 mm) Maxim machine guns (5 x I)
2 x fixed underwater 21’’ (533 mm) Mk II torpedo tubes (2 x I)

Armament (1936)
6 x 15’’/42 (381 mm) Mk I installed in Mk I* turrets (3 x II)
12 x 4’’/42 (102 mm) BL Mk IX on Mk I mounts (4 x III)