La genèse de l'Ark Royal, porte avions de 22 000 t.
Les premières études d'un porte-avions moderne sont entreprises en 1930, pour augmenter le nombre d'avions embarqués en réduisant les distances de décollage et d'atterrissage de ceux-ci, on combine l'utilisation de catapultes et de brins d’arrêt, pour le stockage des avions deux hangars superposés permettent a l' Ark Royal
de transporter 72 avions. Cependant, le développement d'avions plus gros et plus lourds pendant la construction du porte-avions induit une réduction de leur nombre de 50 à 60 unités. Les hangars d'aviation sont placés à l'intérieur de la coque, ils bénéficient ainsi du blindage de 114 cm; trois ascenseurs permettent la manutention des avions entre les hangars et le pont d'envol.; les Britanniques se préoccupent de la protection passive de leurs porte-avions d’escadre, le pont d'envol est blindé.Ces caractéristiques se retrouveront sur les porte-avions suivants.
remarquez les extrémités des catapultes à l'avant
La poupe de l'Ark Royal
; remarquez l'important porte à faux du pont d'envol à l'arrièreHistorique:
est mis sur cale le 16 septembre 1935 chez Cammell Laird à Birkenhead; il est lancé le 13 avril 1937; il entre en service le 16 novembre 1938; des le 25 septembre 1939 , l’Ark Royal
participe au sauvetage du sous-marin HMS Spearfish
endommagé et échoué sur des récifs dans le Kattegat;,en décembre 1939, il est engagé dans la poursuite du cuirassé de poche allemand l’Admiral Graf Spee
dans l'océan Atlantique sud; il participe plus tard en 1940 aux opérations de la campagne de Norvège, le 13 juin 1940, l’Ark Royal
lance une attaque aérienne sur Trondheim (Norvège) ; en mars 1941, l' Ark Royal
essaie en vain d'intercepter les deux cuirassés allemands Scharnhorst
qui rentrent à Brest d'une croisière dans l'Atlantique, il les repère mais ne peut gagner une position d'attaque; ses avions Fairey Swordfish parviennent, fin mai 1941, à immobiliser le Bismarck
en en bloquant le gouvernail, à 600 km de Brest, le Bismarck
est écrasé le lendemain par l'artillerie de la Home Fleet. Retourné en Méditerranée, l’Ark Royal
est torpillé, le 13 novembre 1941, par le sous-marin U81;
il chavire le lendemain et coule, il n'y a eu qu'un seul mort, l'équipage ayant pu etre secouru par les destroyers Légion et Laforey.Le naufrage de l'Ark Royal; recherche des causes du chavirage,
(article en anglais):
Le 14 novembre 1941, l'Ark Royal
torpillé la veille par l'U81
sombre; la gite augmente progressivement quand elle atteindra 45° il chavirera
sombrant vu de l'arrière, le destroyer HMS Légion recueille l'équipage, il n'y aura qu'un mort
HMS Ark Royal
was torpedoed by U-81
. A single g7e torpedo struck the ship on the starboard side, abreast of the Island. This position was the worst possible: being dead amidships, it was where the list caused would be greatest, and its position relative to the transverse bulkheads was such that four main compartments, plus over 106 feet of the ship's starboard bilge, were immediately subject to flooding.
The enemy torpedo was running very deep, and at the time there was some speculation that it might have used a non-contact (magnetic) exploder. This was later discounted on the grounds that the damage inflicted by the hit was not as extensive as would have been expected for an under-the-keel hit, nor was it of the type typical of such hits.
The explosion opened a hole 130 feet long by 30 feet deep, the size being increased by the time taken to bring the ship to a halt, which resulted in additional hull plating being peeled off. The starboard boiler room, air spaces, and oil tanks were flooded, as were the main switchboard and the lower steering position. The starboard power train was also knocked out by the hit, but the port and centreline trains kept functioning.
Some of the torpedo blast vented upwards through a bomb trunk forward of the Island. The ship whipped violently with the explosion, which caused the fully-loaded torpedo-bombers on the flight deck to be hurled into the air; however she showed very little shock damage internally, and her masts remained standing. She immediately took on a 10 degree list that increased to 18 degrees within 20 minutes.
Due to the flooding of the switchboard, communications within the ship were lost, which explains the delay in bringing the ship to a halt. At this point the Captain decided to evacuate the ship. All personnel were withdrawn from the machinery spaces and assembled topside in order to determine who should leave the ship and who should remain on board. As a result of this action, damage control measures were only initiated 49 minutes after the hit, the flooding having been uncontrolled for this period. During this critical period, the centreline boiler room started to flood from below. During the evacuation of the machinery spaces several covers and armored hatches were left open, allowing the flooding to spread further than otherwise would be expected.
As the ship listed further, water came in through the uptakes of the starboard boiler room, flooding over into the centreline, and later into the port, boiler rooms. This flooding further reduced the area through which the funnel gasses could escape, causing severe local overheating and fires.
One hour and 19 minutes after the torpedo hit, all power within the ship failed. Meanwhile, most of the crew had been ordered to evacuate the ship. Those that left the ship included the entire staff of shipwrights and key members of the electrical staff, depriving the damage control crews of much-needed expertise. There were still further delays before the repair crews returned to the machinery spaces and attempts at counter-flooding started.
Only half of the available compartments on the port side were flooded (which reduced the list to 14 degrees), because there was a lack of specialist expertise in the damage control parties. To make matters worse, the flooding valves were not then closed, so the water in the counterflooded units was gradually expelled as more water entered the starboard side of the ship.
Flooding and the loss of feedwater had already shut the ship's power-plant down. Since all the generators were steam-powered, this deprived the ship of electrical as well as motive power. The ship's engineers fought to get the plant back on line despite the rising floodwaters. They won that battle five hours and 34 minutes after the torpedo hit when the portside boiler room was lit off.
However, by that time, the list had increased to 18 degrees and the flooding was starting to spread across the ship's boiler room flat. This was an uninterrupted compartment running across the whole width of the ship, making the entire area of the machinery spaces vulnerable. The efforts made by the engine room crews to restore power were futile. The boiler room flat flooding forced the plant to be shut down again.
Progressive flooding now caused the list to increase rapidly. The list reached 20 degrees 11 hours and 4 minutes after the hit and touched 27 degrees an hour and a quarter later. At this point, the abandon ship order was again given. All crew were off the ship at 0430hrs, 12 hours 19 minutes after the hit, at which time the list had reached 35 degrees. HMS Ark Royal capsized and sank at 0619hrs, after the list reached 45 degrees.
After the Second World War, the loss of Ark Royal was investigated. The conclusion drawn was that, on a target of 22,000 tons, the provision of an effective anti-torpedo scheme was difficult. However, when a comparison with the Yorktown was held, it was demonstrated that it was possible, and that the Yorktown had only sunk when all her reserve buoyancy had been exhausted. The primary cause of the loss of Ark Royal was therefore held to be the inexperience and poor judgement of those responsible for damage control. Proper measures were not undertaken in good time, nor was action to tow the ship to Gibraltar, less than 25 miles away, undertaken promptly.
The Investigation also concluded that there were a variety of design factors contributing to the loss:
- The uninterrupted boiler room flat was a significant error: it was immediately rectified in the Illustrious and Indefatigable classes.
- The adoption of a double hangar had forced the use of cross-deck uptakes low in the ship, adding to vulnerability.
- The reliance on steam generators was also an error: diesel generators were retrofitted to the armoured carriers.
- The power train design itself was strongly criticised.