Commandant Teste was a large seaplane tender of the French Navy () built before World War II. She was designed to be as large as possible without counting against the Washington Treaty limits. During the Spanish Civil War, she protected neutral merchant shipping and played a limited role during World War II as she spent the early part of the war in North African waters or acting as an aviation transport between France and North Africa. She was slightly damaged during the British bombardment of the French Fleet at Mers-el-Kébir in July 1940. Commandant Teste was scuttled at Toulon when the Germans invaded Vichy France in November 1942, but was refloated after the war and considered for conversion to an escort or training carrier. Neither proposal was accepted and she was sold for scrap in 1950.
Design
After the completion of aircraft carrier , the Marine Nationale desired another aviation vessel, but the lack of another hull that could cheaply be converted made another aircraft carrier too expensive. It settled for a seaplane carrier () that could act as a mobile aviation base and support seaplanes for a specific attack. The ship was restricted to a maximum size of at standard displacement, which prevented her from counting against France's Washington Treaty capital ship allocation (she could not have been counted as an aircraft carrier, because she did not meet the Washington Treaty requirement for aircraft to be able to launch from the ship and land back on). This also served to keep her costs relatively low.
Description
Commandant Teste was long overall. She had a maximum beam of and a draught of . She displaced at standard load, at normal load and at full load.
Because of the ship's high profile, there were concerns about her stability in bad weather as she had a significant amount of weight mounted high in the ship; notably her catapults, cranes and anti-aircraft guns. To increase her stability, two lateral tanks were fitted with a pressurized butterfly valve connecting them so that water could flow between the tanks to counter her rolling motion. On trials in 1933, the system was judged successful as it deadened the ship's roll by 37–65%. However, maintenance of the system proved to be problematic as the tanks were difficult to access.
Propulsion
Commandant Teste had a two-shaft unit machinery layout with alternating boiler and engine rooms. Her Schneider-Zoelly geared steam turbines were designed for . Four superheated Loire-Yarrow small-tube boilers powered the turbines at a pressure of at a temperature of . These were the first superheated boilers in the Marine National and required some modifications after the ship's trials. The two in the forward boiler room were oil-fired, but the other two could use either fuel oil or coal. Commandant Teste had a designed speed of , but she exceeded during sea trials on 23 July 1933. of fuel oil was carried as well as of coal. This provided a range of at or at using only coal. Two 300 kilowatt (kW) turbo generators provided electricity at 235 volts. Three 150 kW diesel generators were fitted to provide power while in harbor.
Armament
Commandant Teste was originally going to carry a mixture of or anti-surface and anti-aircraft (AA) guns, but this was changed before construction began to a homogeneous main battery of twelve Canon de Modèle 1927 45-caliber dual-purpose guns on powered single mounts. Five guns each were mounted on the fore and aft superstructures and two were mounted between the catapults. Their elevation limits were −10° to +85°. Their rate of fire was 10 rounds per minute. They had a maximum range of about with a armor-piercing shell at a muzzle velocity of . 280 rounds were provided for each gun, including 40 star shell rounds and 19 tracer rounds.
Eight /50 cal semi-automatic AA guns were carried by Commandant Teste. Two each were fitted on the fore and aft superstructures and four on platforms around the single funnel. 4,000 rounds were carried; 500 rounds per gun. The guns could depress 15° and elevate to 80°. They fired shells at a muzzle velocity of . Their effective anti-aircraft ceiling was less than .
Six twin Hotchkiss Mitrailleuse de Modèle 1929 machine gun mounts were also fitted, two mounts were positioned on the bridge wings, two on the upper funnel platform, and two on the stern. 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 .