De Guichen-class cruiser

## Guichen-class cruiser

6 x II - AAG 37mm/70 Mle. 1935 in mounts ACAD

6 x II - AAG 13.2mm/76 Mle. 1929

4 x II - torpedo tubes for torpedoes 23DT Toulon

25mm hull and deck plating

40mm torpedo bulkhead

**OVERVIEW**

The *Guichen*-class was a planned class of two light cruisers of the French Navy, designed in 1931. When designed, the type would have been one of the most modern cruisers in the world. The designers envisioned a light crusier type warship equal to heavy cruisers in protection, however the cost of building such a cruiser of this tonnage with 152mm guns was unappealing to the French senior admiralty. Despite reaching an advanced stage in design, the project was terminated before any orders where issued.

**DESIGN**

The *Guichen-*class was designed to displace 10000 tons standard, built in accordance to the London Naval Treaty. The class would have been 182 m long at the waterline, a beam of 19 m, and standard displacement draught of 6.15 m.

The hull was of a flush deck design and the ship generally resembled the Algerie-class in appearance and size. The forward section of the ship was dominated by a tall, tower like bridge with integrated conning tower and single main gun director, with a large open deck amidships aft of the narrow single trunked funnel. The ship's main deck amidships between the raised primary battery turrets was entirely covered with a secondary deck, mirroring practice from *Bougainville-*class avisos.

The main arnament was to consist of twelve 152mm guns placed in four turrets, with a high angle capability, similar to the turrets used on the *Richelieu*-class battleships. Secondary armament consisted of twelve 100mm guns in six twin turrets. Anti-air weapons where twelve 37mm and twelve 13.2mm weapons placed in six twin mounts. The 37mm "ACAD" mounts featured gun directors for the automatic weapons which improved their efficacy greatly. Four sets of twin tubes where also carried for 533mm torpedoes, located amidships. The ship was to carry four *Gourdou-Leseurre GL-832 HY* floatplanes, with 3 planes being stored in an unusual hangar below the superstructure deck amidships, complete with a carrier style elevator to raise planes. Most of the ship's boats where stored on the roof of the hangar, nestled between a single large rotating aircraft catapult.

The ship would be protected by an external armored belt with a thickness of 100mm over machinery spaces and 140mm over magazines. The main armoured deck was 65mm thick, with a 25mm weather deck extending the length of the ship. Turret faces and barbettes where protected with 140mm thick armor; the secondary battery was only provided with splinter proof protection. Underwater protection was of the form of a 1-meter deep fuel-oil filled hull void with a 40mm thick holding bulkhead extending from the ship's bottom to the main armoured deck forming the outside of the machinery spaces.

Propulsion was originally designed to be 14 diesel engines grouped in sets of 2 or 4 in an 'X' configuarition on 4 shafts, however this was later increased to 16 engines grouped in 4 sets of 4. Engines where 6000 hp Sulzer types similar to engines used on submarine *Pascal*. Engines would have declutcable in pairs for maintainance or economical cruiser. With gearing losses maximum continuous shaft horsepower was anticipated to be 84,000 shp, enough for a maximum speed of 31.4 knots, however at maximum RPM the engines would have delivered 105,000 shp at the shafts, sufficent for 33.15 knots. Due to the diesel propuslion, the design's crusing range at 15 knots would have been over 15,000 nautical miles; a conventional oil-burning steam turbine plant would have only a crusing range of 8000 nautical miles.

**SHIPS IN CLASS**

Two ships where planned, *Guichen* and *Jurien de la Gravière*, however neither was selected for construction and design work did not proceed any further than pre-final designs. The names where previously used on French protected cruisers in the 1890s. *Guichen* was to be named for Admiral Comte de Guichen, a French admiral in the 18th century, and *Jurien de la Gravière* forEdmond Jurien de la Gravière and his father, Pierre Roch Jurien de La Gravière.