Barracudas on Formidable being armed with 1600lb AP bombs during August 1944 strikes against the German battleship Tirpitz (Operation ‘Goodwood’: strikes on 17 July and 22, 24 and 29 August). The aircraft in the background are US-supplied Corsairs. In addition to her anti-aircraft battery, in resisting the Fleet Air Arm attacks Tirpitz fired both her 15in and her 5.9in LA guns in barrage mode, with time-fused HE ammunition (German accounts give the numbers of rounds fired). (David Hobbs)
Unfortunately for the Royal Navy, by about 1935–6 it seemed that a future war might well be fought in European waters, where an enemy could deploy large numbers of aircraft at shore bases. No naval dive-bomber force could neutralise those bases, although it turned out that intense air attacks could shut a few of them down for brief periods. Since the Royal Navy could not secure air superiority under these circumstances, it adopted armoured flight deck (actually armoured hangar) carriers whose limited aircraft capacity was devoted entirely to strike aircraft. A carrier facing air attack would strike all of her aircraft below, into the armoured hangar. Fleet anti-aircraft guns would be the sole defence. It seems to have been assumed that this was a reasonable choice, that British anti-aircraft gunnery would make attacks on the battle fleet difficult at best. In practice the Royal Navy was unwilling to depend entirely on its guns, so it continued to buy small numbers of fighters – adapted Gloster Gladiators and then the purpose-built Fairey Fulmar. It is not clear whether those responsible realised that the advent of radar would soon make shipboard fighters effective.31
By 1944 the Royal Navy had a fully effective dive bomber in the form of the Fairey Barracuda, and it was used in 1944 strikes against the German battleship Tirpitz. On 3 April (Operation ‘Tungsten’) forty Barracudas in two waves escorted by eighty-one fighters) achieved complete surprise. The ship had just been repaired after damage by midget submarines in 1943 (she was about to run speed trials, one anchor having been raised). Surprise was complete, partly because the radar recently installed in the area was not yet operational. The attackers divided into groups from the two quarters and from ahead, attacking nearly simultaneously. The ship’s smokescreen was very thin, her foretop completely exposed to provide an aiming point. The fighters strafed the ship to suppress anti-aircraft fire (many of the ship’s anti-aircraft guns were unshielded, the shields ordered much earlier not yet having been delivered), and the Barracudas attacked using 1600lb AP bombs, 500lb SAP and also medium-capacity (HE) bombs; there were also a few 600lb depth bombs. The first strike scored nine hits and a profitable near-miss (all with 500lb SAP); the second (also 500lb SAP), five hits and three near-misses, the reduction being due to a thick smoke cloud generated after the initial attack. Unfortunately the ship was not seriously damaged. Bombs were released from too low an altitude (the Germans claimed 300ft to 1500ft) to penetrate the ship’s armoured deck (initial British reports claimed that bombs were dropped from 2500ft and 3500ft).
DNC later pointed out that even when dropped from 3500ft, a 1600lb AP bomb would only just penetrate the ship’s armour deck over the machinery, where it was thinner than over the magazines; a bomb dropped from 2500ft should not have penetrated the armour deck. Only two of the bombs reached the armour deck; two others bounced off the 2in upper armour deck, and one lodged halfway through it. The greatest damage was done by a bomb (probably 1600lb AP) which struck the water near the ship, penetrated the side plating under the armour belt, and detonated near the main torpedo bulkhead. Unfortunately there was no significant damage to machinery or armament, and the ship was ready for sea again in about a month: hence a second series of raids mounted on 17 July and on 22, 24 and 29 August (Operation ‘Goodwood’). Against these raids the Germans used observer posts some distance from the ship to trigger adequately thick smokescreens and anti-aircraft fire. Even so, an eighty-plane raid mounted on 24 August managed to score two hits (out of 23 AP bombs dropped: 18 × 1600lb AP, 5 × 1000lb AP) with AP bombs plus two (and one possible and one probable) out of ten 500lb SAP bombs. One of the AP bombs hit the port side of the upper deck abreast the forward conning tower and penetrated through the armour deck to the lower platform (inner bottom).
The D3Y (‘Val’) was the stablemate of the B5N torpedo bomber, and as such fought at Pearl Harbor and in the earlier carrier-vs-carrier battles. It was unique among its generation of Japanese carrier aircraft in having a fixed undercarriage. It was built to a 1936 (11-Shi) specification, and performed carrier qualification trials in 1940. The normal load was a single 250kg (550lb) bomb on the usual dive-bomber crutch; two 60kg bombs could be carried on wing racks outboard of the dive brakes. The contrast between the 250kg warload and the typical 800kg warload of a torpedo/level bomber reflects the vast difference between an aircraft stressed to pull out of a more or less vertical dive and one which would deliver its weapon in level flight. Maximum speed was 232kts, and normal range was 730nm. (Philip Jarrett)
The D4Y Suisun (‘Judy’) was in effect the stablemate of the B6N, the standard Japanese dive bomber of the latter stages of the Pacific War. Like its predecessor the D3A ‘Val,’ it was designed to deliver a single 250kg bomb, a considerably lighter weapon than that wielded by US Navy dive bombers. However, like other Japanese carrier attack aircraft, it had a considerably longer range. It was conceived in the wake of unsuccessful tests of the German He 118 in Japan. The He 118 demonstrated high speed but it disintegrated in flight. The D4Y was designed to an experimental 13-Shi (1939) specification calling for a speed of 280kts (cruising speed 250kts) and a range of 800nm, the latter not matching that of the torpedo bomber, but still quite long. Range without a bomb load was to be 1200nm. On this basis the D4Y outperformed all other carrier dive bombers in service during the Pacific War. Unusually for Japanese carrier aircraft, the D4Y was powered by an in-line liquid-cooled engine, in this case a license-built version of the German DB 605. The only other carrier attack aircraft with this type of engine was the British Barracuda. The US Navy rejected such engines on the ground that they were too vulnerable to battle damage, even by a stray bullet; it preferred the much more rugged radials. Prototype performance was very impressive, but simulated dive bombing revealed unacceptable wing flutter, and production aircraft were used for carrier-based reconnaissance. The dive-bombing problem was finally solved and D4Y accepted as a dive bomber in March 1943. Thus it had missed the early carrier battles, but was available in numbers for the battle of the Philippine Sea – in which it was not nearly fast enough to evade US fighters. Among other sacrifices made for speed was any form of protection. The engine itself caused problems, and in May 1944 tests showed that a radial-engined version had about the same performance. (Philip Jarrett)
The Germans claimed that this was the first time the British had dive-bombed with 1600lb AP bombs. The post-war British analysis concluded that the 1600lb AP bombs were quite capable of penetrating the ship’s deck armour and causing vital damage and flooding if they were released from a sufficient height, and in sufficient numbers. That a dive bomber could deliver such a weapon effectively meant that the distinction between dive bombers, which in the past could destroy only lightly-armoured ships (including carriers), and torpedo bombers, which could sink capital ships, was being erased.
Had the bomb detonated, the main fire control rooms, switchboard rooms, etc