Suffren-class cruiser

Schematics of the Suffren class
Class overview
Name	Suffren class
Operators	The Marine Nationale ( French Navy)
Preceded by	Duquesne class
Succeeded by	Algérie
Built	1925-1932
In service	1930-1972
Building	4
Completed	4
Lost	3
Retired	1
General characteristics
Class and type	Suffren-class cruiser
Type	Treaty Cruiser Marine National designation 1925 Light Cruiser 1931 1st Class Cruiser
Displacement	10,160 t (10,000 long tons) (standard) 11,769 t (11,583 long tons) (Normal) 13,135 t (12,928 long tons) (full load)
Length	194 m (636.48 ft) overall 185 m (606.96 ft) between perpendiculars
Beam	19.26 m (63.19 ft)
Draught	6.51 m (21.36 ft) at normal displacement
Propulsion	6 Guyot du Temple boilers, 20 kg/cm2 (215°) plus two small coal/oil fired boilers 3-shaft single-reduction geared steam turbines for 88,768.8 shp (66,194.9 kW)
Speed	32 knots (59 km/h) (designed)
Range	1,876 tons oil fuel and 500 tons coal radius 4,600 nautical miles (8,500 km) at 15 knots (28 km/h) 2,000 nautical miles (3,700 km) at 11 knots (20 km/h) on cruise boilers 3,700 nautical miles (6,900 km) at 20 knots (37 km/h)
Complement	773
Armament	4 × 2 203mm/50 Modèle 1924 guns in Model 1924 twin mounts 8 × 1 Canon de 75 mm modèle 1924 guns on a model 1922 HA single mounts 4 × 2 Canon de 37 mm Modèle 1925 guns on single mount CA Model 1925 12 × 1 Hotchkiss M1929 machine gun on single mounts 6 × 550 mm (22 in) torpedo tubes Model 1925T triple mounts with 9 Model 1923D, Toulon torpedoes
Armour	Belt: 50 mm (2.0 in) Deck: 25 mm (0.98 in) Turrets and conning tower: 30 mm (1.2 in) Magazine box 50 mm (2.0 in) sides with 20 mm (0.79 in) crowns
Aircraft carried	2 GL-810 then Loire-Nieuport 130
Aviation facilities	2 catapults
Notes	all ships data for Suffren only, variations for others will be shown on individual ships pages

In 1925 there was a provision for a treaty cruiser of 10,000 tons based on the Tourville design. The General Staff changed a requirement focusing more on protection than speed. Machinery was reduced to three shafts with the corresponding weight savings put towards increasing the armour of the vessel.^[1] The change to a three shaft arrangement lowered the corresponding horsepower lever the 90,000 CV (chevaux - horses).* The initial vessel would retain the same armament as the preceding Duquesne-class cruiser. The hull and internal layout would also be very similar. The vessel would be the first vessel of the Suffren-class cruiser. Four vessels would be built over the next five years with incremental changes in each.

Initially classed as a croiseur Leger (Light Cruiser) all ships were reclassified on 1 July 1931 as a croiseur de 1ere classe (First class cruiser). The Marine Nationale did not have a vessel classification of heavy cruiser instead used croiseur cuirasse (armoured cruiser) and croiseurs legers (light cruiser) prior to the London Naval Treaty then croiseur de 1ere classe (First class cruiser) and croiseur de 2e classe (Second class cruiser) afterwards.^[2]

Design and description[]

Hull and Protection[]

The design of the Suffren class was based on the Duquesne-class cruiser light cruiser while maintaining the standard displacement of 10.000 tons. The hull maintained the high freeboard with the raised forecastle of all post-war cruisers with excellent sea keeping qualities. The hull design also kept the fine lines for the speed requirement complemented by the clipper bow with a gentle sheer and the marked flare keeping the forecastle dry even in heavy weather. The framing in a French hull was numbered from aft to stem, frame numbering was based on the distance from the aft perpendicular in meters.^[3] The longitudinal framing was used for cruisers throughout the interwar period. The hull was 185 meters (606 ft 11 in) between the perpendiculars with an overall length of 194 meters (636 ft 6 in) and a beam of 19.26 meters (63 ft 2 in). At her normal displacement of 11,769 tonnes the draft of the ship would be 6.51 meters (21 ft 4 in).^[4]

The protection was increased over the previous Duquesne class. The armour protection in the hull for the Duquesne class was only 370 tons whereas Suffern would have 670 tons.^[5] The upper deck was 25 mm (0.98 in) thick amidships with 25 mm (0.98 in) bulkheads running to within 3.18 meters (10 ft 5 in) of the sides enclosing the funnel uptakes and ventilation trunking between the main and first deck. The magazines were enclosed in an armoured box with 50 mm (2.0 in) sides and 20 mm (0.79 in) crowns, forward and aft bulkheads. The turrets and conning tower had 30 mm (1.2 in) plating. The roofs of both the turrets and range finders was 35 mm (1.4 in) of cast nickel. The steering gear was housed inside an armoured box with 26 mm (1.0 in) sides and an 18 mm (0.71 in) top.^[6] A Belt of 50 mm (2.0 in) made of non-cemented 60 kg steel was installed to a height of 2.6 meters (8 ft 6 in) and 1.0 meter (3 ft 3 in) below the waterline abeam of the machinery spaces in Suffren and Colbert only.^[7] The space between the machinery bulkhead and the inside of the hull was approximately 2.1 meters (6 ft 11 in). For Suffren and Colbert this space was filled with 500 tons of coal for the cruising boilers and therefore did not count against the standard displacement.

Reinterpreting the rules of the Washington Naval Treaty, the STNC decided to change and improve the level of protection on the next cruiser of the series, Foch. The interpretation was for Washington standard displacement to mean a peacetime load versus what would be required for a full wartime load. With the concept of shells striking the sides above the shallow armoured belt being able to penetrate to the machinery spaces, it was decided to do away with the belt and replace it with an armoured box around the machinery. The sides of this armoured box was 54 mm (2.1 in) with the deck above of the armoured box was 18 mm (0.71 in). The bulkheads of the box varied in height from 5.5 meters (18 ft 1 in) to 6.1 meters (20 ft 0 in). The protection on the sides of the magazines was increased to 54 mm (2.1 in) with all other protection remaining the same.^[8] The last cruiser of the program, Dupleix would be protected along the same lines as Foch.but with a slight increase. All longitudinal bulkheads were increased from 54 mm (2.1 in) to 60 mm (2.4 in) on the magazines and machinery spaces. The main deck over the machinery spaces was increased from 18 mm to 60 mm (2.4 in). The upper deck however, was decreased from 25 mm (0.98 in) to 22 mm (0.87 in). The magazine crowns were also increased to 30 mm (1.2 in).^[9]

Machinery[]

The propulsion system was changed from the four shaft arrangement of the Duquesne class to a three shaft arrangement in the Suffren class. Three single reduction gear Rateau-Bretagne steam turbines with six Guyot du Temple small tube boilers built by Indret rated at 20 kg/cm2 while operating at 215° Fahrenheit would produce 90,000 CV (chevaux - horses)* on three shafts to achieve a designed speed of 32 knots. The forward boiler and engine rooms would be the same as in the Duquesne class. The forward engine room would drive the wing shafts. The aft boiler rooms and turbine would be inline driving the center shaft. Each boiler room would have only one boiler.^[10] Between the forward engine room and the aft boiler rooms two smaller coal/oil fired boilers would be installed in Suffren and Colbert only. These smaller boilers would be connected to the center line turbine for low speed cruising and were known as cruising boilers. The six main boilers would be oil fired with a maximum load of 1,876 tons of oil giving an endurance of 4,600 nm at 15 knots and 3,700 nm at 20 knots. For Suffren and Colbert carried 640 tons of coal for the cruise boilers and would provide another 2,000 nm at 11 knots. Twin side by side rudders were installed abaft between the shafts. To reduce the tactical radius of the vessels the centerline skeg was removed in the first three vessels (Suffren, Colbert and Foch) though it was reinstalled on the fourth unit (Dupleix).^[11] They were considered good sea boats and responsive to the helm at speeds above 10 knots.^[12]

Armament[]

The requirement for main the armament of eight 203-millimetre (8 in) guns housed in four lightly armoured turrets with 120 rounds per gun and with maximum magazine storage of 150 rounds per gun during wartime.^[13] The weapon used was the 203 mm/50 (8 in) Model 1924 naval gun. The guns were mounted in four Cruiser Two Gun Turret Model 1924 providing a separation of the axis of the guns by 74 inches. The turret was plated with two sheets of 15 mm high tensile steel plate riveted together placed on all sides and roof for armour protection of 30mm. The mount provided an elevation from minus 5 degree to plus 45 degrees with an elevation rate of ten degrees per second. The mount could be trained to plus or minus 90 degrees from the centerline of the vessel with a train rate of six degrees per second. The guns could be loaded at any degree of train but only between minus 5 and plus ten degrees in elevation. The loading cycle started with the rammer cocked by the recoil of the guns. A dredger hoist brought the shell and two half charge bags to the breech. The rammer drove the shell into the breech with the powder being loaded by hand. The breech would close and the gun would be fired. The guns could maintain a rate of fire of four to five rounds per minute.^[14][15]

For the secondary armament, Suffren was to maintain the eight 75 mm/50 (2.95 inch) model 1924 naval gun on single Model 1922 gun mounts placed in the same positions as the Duquesne-class cruiser.^[16][17] Starting with the Colbert it was decided to upgrade these weapons with the 90 mm/50 (3.5 inch) Model 1925 gun on Model 1926 single mounts. The 90 mm guns replaced the 75 mm on Foch and Dupleix as well and would be mounted in the same positions as the 75 mm guns. For Dupleix the mount was changed to the Model 1930 dual mount thereby reducing the number of mounts from eight to four.^[18]

The medium anti-aircraft armament was augmented with 37 mm/50 (1.46 inch) model 1925 guns in Model 1925 single mounts. Suffren would carry eight whereas the remaining three would only have six. With an elevation only to plus 85 degrees they had a slow rate of fire, 15 to 21 rounds per minute therefore were not effective against modern aircraft when installed.^[19] Starting in 1943, these guns would be replaced with single 40 mm Bofors on Suffren only as the equipment became available. To complete the light AA armament it was intended to install four single 8 mm Hotchkiss machineguns on the quarterdeck just aft of the last 203 mm turret as in the Duquesne. However, it was recognized that these weapons were ineffective against aircraft of the period so they were replace by twelve 13.2 mm (0.5 inch) Model 1929 machineguns. Two would be mounted forward on the lower bridge wings and the other four in place of the 8mm machineguns. These guns would be mounted in twin mountings.^[20] For Colbert, Foch and Dupleix it was intended that the forward machine guns would be quad mounts. The mounting was unavailable and only ‘’Courbert’’ had them installed in 1941. In 1943 they were replaced on Suffren only by 20 mm Oerlikon cannons based on the availability of the equipment.

For torpedoes two launchers Model 1925T for 550 mm torpedoes were fitted to port and starboard. When in the locked position the starboard launcher faced forward and the port launcher faced aft. The tubes could be trained and fired either locally or from the armoured conning tower. The ships initially carried the was the 55 cm (21.65 inch) 23DT, Toulon torpedo. Nine torpedoes were carried, six in the tubes with three spares.^[21] The torpedo tubes were landed on Suffren only between 1943 and 1945.^[22]

Aircraft[]

Two catapults would be installed on these vessels. Two Gordou-Lesseurre GL-810 float planes would be shipped. On Suffren the catapults were installed between the aft funnel and the main mast. For the remaining three the catapults would be moved forward to be between the funnels. Two aircraft would be carried until 1937 when the catapults were removed for modification. Once the modification was complete the catapult was reinstalled with a Loire 130 float plane. Suffren would land her catapults and aircraft between 1943 and 1945.^[23]

Ships[]

History[]

Suffren was first to enter service in 1929 joining the First Light Squadron at Toulon. Colbert, Foch and Dupleix would also join the First Light Division at Toulon upon completion. In 1934 Suffren along with the two Duquense class cruisers would be reassigned to the Third Light Division. All would remain there in Toulon until 1939. In June 1939 Suffren departed for French Indochina to relieve the cruiser Primauguet.^[26] With the outbreak of war in September Suffren patrolled the South China seas on the lookout for German merchantmen. In November she went to Singapore to aid in the escort of an Australian troop convoy to Colombo. She continued to escort convoys in the Indian Ocean until the end of April 1940. In May she returned to the Mediterranean to be assigned to Force X at Alexandria. Here she made two sorties against the Italians but no targets were found. With the French armistice in June 1940 she was demilitarized along with the other units of Force X. Colbert, Foch and Dupleix joined Force X at Dakar in late 1939 and patrolled the mid-Atlantic searching for the Graf Spee and German merchant vessels. The three returned to Toulon in January 1940. In June 1940 they along with Algerie bombarded Genoa and Vado. At the time of the Armistice were based at Toulon. All three were scuttled there in November 1942. Suffren returned to the Allied cause in May 1943, sailed for Dakar for blockade patrol in the Atlantic. Underwent a major refit in 1945. Her last operations were during the restoration of French control over French Indochina. Placed in reserve in 1947 and used as a training hulk. In 1962 she was renamed Ocean then stricken in 1972.

Notes[]

• all ship statistical data from French Cruisers 1922 - 1956 (Jordan & Moulin, Chapter 3, The Suffren Class, Design and Construction, Building Data and General Characteristics: Suffren and Colbert) unless otherwise noted
• French sources do not use shaft horsepower rating for the power output of their machinery. Instead the term 'chevaux' (CV) or horses is used. To convert the French measure to SHP multiply the CV value by 0.98632 to find the true SHP value. Jane's did not do this nor has many of the English language sources. The reference French Cruisers 1922 - 1056 shows the horse power values as only CV and gives the value for conversion to SHP used in many sources.

References[]

Bibliography[]

• Jordan, John & Moulin, Jean (2013). French Cruisers 1922–1956. Barnsley, UK: Seaforth Publishing. ISBN 978-1-84832-133-5.
• Whitley, M.J. (1995). Cruisers of World War Two – An International Encyclopedia. London, UK: Arms and Armour Press. ISBN 1-85409-225-1.
• McMurtrie, Francis E. (1940). Jane’s Fighting Ships 1940. London, UK: Sampson Low, Marston & Company, Ltd.

External links[]

Wikimedia Commons has media related to Suffren class cruisers.

• 203 mm/50 (8in) Model 1924 naval gun
• 90 mm/50 (3.5 inch) Model 1926
• 75 mm/50 (3.0 in) Model 1922 naval gun
• 37 mm/50 (1.46 in) Model 1933 naval gun
• 13.2 mm(0.5 in) machinegun Model 1929
• French Pre-war Torpedoes