1. Design
    General characteristics  Propulsion  Armament 

2. Service

3. Notes

4. Bibliography

Pluton was a fast minelaying cruiser built for the French Navy in the late 1920s. She was also able to carry 1,000 troops on her mine deck as a fast troop transport. Shortly after completion she was modified and became a gunnery training ship, replacing the elderly armored cruiser {{Ship|French armoured cruiser|Gueydon||2}}. Shortly before the beginning of World War II, she reverted to her original role and most of the gunnery training equipment was removed. She was sent to Casablanca, in French Morocco, when the war began to lay a minefield, but the order was cancelled a day later and she was ordered to disembark her naval mines. She exploded while landing her still-fuzed mines on 13 September 1939.

Design

The Marine Nationale decided to build a fast minelayer as part of its 1925 Naval Programme after the British {{HMS|Adventure|M23|6}} made her debut in the early 1920s. Pluton was similar in many respects, also being armed with four single destroyer-caliber guns, but was smaller and faster. She could also be used as a fast transport for up to 1,000 troops. The sides of the mine deck were normally open to the weather, but metal panels could be used to close it off when carrying troops.^[1]

General characteristics

Propulsion

Armament

The four 138 mm 40-caliber guns were on M1924 mounts with gun shields. Two guns each were fore and aft in superfiring positions on the centerline. Their elevation limits were -10° to +35° and they had a 270° arc of fire. Their rate of fire was a nominal eight to nine rounds per minute, but proved to be considerably less in service. They had a maximum range of about {{convert|18200|m|yd|abbr=on}} with a {{convert|40|kg|lb|abbr=on}} shell at a muzzle velocity of {{convert|700|m/s|ft/s|abbr=on}}. 150 rounds were provided for each gun. One powder and one shell magazine served each pair of guns, each of which had their own individual hoist.^[7]

Ten 37 mm/50 cal semi-automatic AA guns were carried by Pluton. Two were fitted on the foredeck, six amidships between the funnels and two on a platform at the stern. 10,000 rounds were carried with 144 rounds in ready-use boxes near each gun.^[7] The guns could depress 15° and elevate to 80°. They fired {{convert|0.725|kg|lb|abbr=on}} shells at a muzzle velocity of {{convert|810|m/s|ft/s|abbr=on|0}}. Their effective anti-aircraft range was less than {{convert|5000|m|sp=us|0}}.^[8] All of these guns—except for the pair on the stern—were removed shortly after Pluton was commissioned in 1932.^[9]

Twelve obsolete {{convert|8|mm|in|3|abbr=on}} Hotchkiss M1914 machine guns were carried in six twin mounts. Two mounts were on top of the bridge, two atop the after boiler room ventilator housing and two just forward of the tripod mainmast. 48,000 rounds were provided for them. They were removed shortly after Pluton was commissioned in 1932.^[9]

Service

She entered service with the French Mediterranean Fleet in 1932. Pluton experienced many teething problems, particularly with the machinery. Shortly after she was commissioned the Navy decided to give her an extra role as a gunnery training ship and she entered Toulon Dockyard for the necessary modifications on 24 October 1932. Quarters for 40 men were added on the mine deck. Most of the 37-mm AA guns and all of the 8 mm machine guns were replaced by four 50-caliber 75 mm Canon de 75 mm Mle 22 or 24 AA guns and 12 {{convert|13.2|mm|in|2|abbr=on}} Hotchkiss machine guns on six twin mounts, two mounts where the 37 mm guns had been mounted on the foredeck and four between the funnels.^[11] The 75 mm guns had a maximum depression of 10° and a maximum elevation of 90°. They fired a {{convert|5.93|kg|adj=on|sp=us}} shell at a muzzle velocity of {{convert|850|m/s|ft/s|abbr=on}} at a rate of fire of 8–18 rounds per minute and had a maximum effective ceiling of {{convert|8000|m|ft|abbr=on}}.^[12] The Hotchkiss guns had a cyclic rate of fire of 450 rounds per minute, but the practical rate was between 200 and 250 rounds per minute to allow for reloading its 30-round magazines. They had a theoretical ceiling of {{convert|4200|m|ft|abbr=on}}.^[13] A simple fire-control director was added for the 138 mm guns and 15 additional rangefinders were installed for use by the Rangefinding School.^[14]

In 1936, an experimental twin 13.2 mm gun mount with a gun shield was added between the starboard 75-mm guns and more rangefinders were added to bring her total up to 31. Her boilers and condensers were repaired in a refit between 25 November 1936 and 13 March 1937. Later that year Pluton had a major refit that involved repair of her turbines, replacement of her 138 mm fire-control director by one of the type used by the {{convert|8000|t|LT|abbr=on}} light cruisers and the transfer of the foredeck 13.2 mm machine guns to positions on the forward superstrucut. Her last refit, from 15 November 1938 – 15 February 1939, retubed two boilers, enclosed the AA director to protect it from the weather, improved the remote control of the 138 mm guns and added gun shields to each of the twin 13.2 mm mounts.^[15]

As war approached, it was decided to retain her as a minelayer and most of the extra fire control equipment was removed. She was transferred to Brest as part of the reorganization of the 5^e Escadre. She sailed for Casablanca, French Morocco on 2 September with 125 Bréguet mines embarked. She was ordered to lay a defensive minefield there on 4 September, but this order was rescinded the next day, after the mines had already been fuzed, and the ship was ordered to disembark the mines. While landing the mines on 13 September one of them exploded, destroying the ship and killing 186 people. A further 73 crewmen and 47 others were injured and significant damage was caused by flying debris.^[16] One gun and some armor was salvaged during the war, but demolition work did not begin until October 1952 and was completed by July 1953.^[17]

Notes

Bibliography

• {{cite journal|last=Guiglini|first=Jean|author2=Moreau, Albert |year=1992|title=The First Light Cruisers of the 1922 Program: The Minelaying Cruiser Pluton, Pts. 1–2|journal=Warship International |publisher=International Naval Research Organization|location=Toledo, OH|volume=XXIX|issue=2–3| pages=152–173, 225–43|issn=0043-0374}}
• {{cite book|last=Jordan|first=John|title=The Minelaying Cruiser Pluton|editor=Preston, Anthony| publisher=Conway's Maritime Press|location=London|year=2004|series=Warship|volume=2004|pages=21–28| isbn=0-85177-948-4}}

• John W. A. Scott
• John Washington Baird
• John Washington (disambiguation)
• John Washington (football player)
• John Washington Rogers, Jr.
• John Washington Steele
• John (washroom)
• John Wastell
• John Waterbury Cudlip
• John Waterhouse (astronomer)
• John Waterhouse (disambiguation)
• John Waterhouse (violinist)
• John Waterlow
• John Waterman Arnold House
• John Watermann
• John Waters (assistant director)
• John Waters (British Army officer, born 1935)
• John Waters (director)
• John Waters (journalist)
• John Waters Kirwan
• John Waterson (physicist)
• John Waters: This Filthy World
• John Watkins Brett
• John Watkins (cricketer)
• John Watkins Crockett