The Battleship Richelieu

Visualization 3D Andrzej Sobucki and Piotr Forkasiewicz

Model of the Richelieu’s hull, based on the previous Dunkerque and Strasbourg design, was extensively tested in the Paris Model Basin. Information thus collected allowed for slight modifications of the design, which was promptly sent for completion. Traditional riveting as well as electric welding techniques were used during construction of the hull which considerably shortened the process. The hull was divided into 21 watertight compartments. The “F” compartment located in front of the first main battery turret is worthy of mention as it was filled with water-exclusion material “Ebonite Mousse” based on rubber foam. Richelieu had a flush deck with slight break of poop. The main battery turrets “I” and “II” were located in the forward section. Behind them there was a forward superstructure and a huge structure of the mast integrated with a smokestack characteristically bent toward the stern. The Richelieu’s propulsion plant included four Parsons-Rateau steam turbine sets with the total designed power output of 150 000 SHP located in two machine rooms – fore “L” and aft “N”. Each of the sets was composed of low, middle and high pressure turbines for forward gear, as well as low pressure turbines for reverse. Steam was provided by six Sural-Indret (Norguet) water-tube boilers located in threes in two boiler rooms – No. 1 in the “K” forward section and No. 2 in the “M” aft section. Each turbine set propelled a shaft through a single-stage transmission gear. It is worthy of mention that none of the two machine rooms was not divided with a transverse bulkhead into two separate compartments, as was the case in other heavy units in other navies. Thus, even a single hit in one of the machine rooms could cause their destruction or flooding, which would result in loosing half the power. The same was true as far as boiler rooms were concerned.
Both 230 V and 460 V (powering the main battery turrets equipment) direct current was provided by two sets of turbo-generators, each made of four 750 kW generators. The turbo-generators were located in the forward section of the “O” compartment, directly behind the aft machine room. Three generators, 1000 kW each, powered by diesel engines were located in the “H” compartment located between the main battery turrets “I” and “II”. Two small diesel generators, 150 kW each were on the main deck as emergency power source. Total power output of power-generating units aboard the Richelieu was 9300 kW.

The Oerlikon battery (Nos. 42 to 50) mounted in front of the main battery gun Turret I. Visualization 3D Andrzej Sobucki

Armour protection scheme was one the most effective ever designed for a battleship commissioned in the interbellum period. It was designed to withstand impact of 38 cm projectile and 500 kg bomb dropped from 5000 metre altitude. Vertical protection was provided by 131.45 m long (54.2 % of the overall length) side armour belt made of section armour plates installed at 15.14 degrees. They were of homogenous height of 5.96 m and width of 2.5 to 3.05 metres. Their thickness was 330 mm which gradually decreased to 170 mm at the lower edge. Three armoured transverse bulkheads were installed inside the hull, two at each end of the armoured citadel and one at the stern protecting steering mechanism. Apart from that, the battleship’s hull had no side protection, neither in the bow, nor in the stern section.

Table 4. Characteristics of the battleship Richelieu after modernization in the USA
Standard displacement    42 875 tons
Full-load displacement     47 721 tons
Length overall    247.0 m
Waterline length    242.0 m
Waterline beam     33.08 m
Full-load draft (battle)    10.58 m
Main battery     Eight 380 mm guns in two quadruple turrets
Secondary battery    Nine 152 mm guns in three triple turrets;
Six 100 mm guns in three twin turrets
Anti-aircraft battery    Fifty-six 40 mm Bofors guns (14 x IV, 11 x I)
Fifty-two 20 mm Oerlikon guns (41 x I)
Seaplane    Three Loire-Nieuport 130 aircraft
Catapults    Two
Speed    32.6 knots
Power output     147 950 SHP (max. 177 540 SHP)
Fuel capacity     6 796 t max
Main side belt     330 mm sloped at 15.5°
Upper armour deck    170 mm (over magazines)
150 mm (over machinery)