plans for the defence of the Philippines included suicide attacks, which began in October.41 A British official account published in April 1945 described the initial attacks as long-awaited, presumably on the basis of intelligence. material. Kamikazes were accompanied by conventional attackers following the cautious tactics of the previous period.
The Japanese equivalent of the German guided bombs was the manned Okha, shown here surrounded by Americans to give an idea of its size. Unlike the German bombs, Okha was unjammable. On the other hand, it was no easier to control, and it had to be released in just the right place to have a good chance of hitting its target. (Philip Jarrett)
Initially Kamikazes were all aircraft of current combat types, typically carrying 250kg bombs (some carried 500kg bombs). Bombs were usually retained, but in some cases they were dropped before the crash. Usually aircraft also carried drop tanks, either to increase range or to increase fire damage. Most sinkings were caused by fire rather than explosion. These aircraft could not penetrate armoured decks, but they could cause great fire damage. Since US carriers had wooden flight decks (on thin steel plating), a Kamikaze could crash through into the hangar deck below. It could ignite gassed-up aircraft already loaded for strikes (big US rockets did considerable damage to a US carrier under these circumstances).
While the supply of existing aircraft was being run down, special Kamikaze aircraft were being built. Some were cheap wooden versions of existing types (one crude wooden aircraft was all-new), but there was also the rocket-propelled MXY-7 Ohka (‘Baka’) launched as a stand-off missile by a larger bomber.42 The first seen in combat were two launched at the destroyer Stanly while on picket duty on 14 April 1945. She splashed one, and the other clipped the flag on her after stack and blew up in the water. Both were hit repeatedly by 40mm fire. Another was launched by an army ‘Helen’ bomber off Okinawa on 18 April against the minesweeper Jeffers at a range of 14,000 yds from an altitude of 4000ft. It accelerated rapidly to 450kts on a course aimed straight at the ship. The missile was shot down by 20mm fire, hitting the water 50 yds on the port beam. ‘Baka’ attacks were always co-ordinated with conventional attacks. The destroyer Mannert L. Abele, on picket duty, splashed a ‘Val’ with the aid of LSM 189, which was assisting on her picket station. Then two ‘Zekes’ attacked. One was shot down, but the other hit her with a bomb, breaking her keel. Immediately afterwards a ‘Baka’ hit her starboard waterline. The destroyer broke in two and sank at once.
A survey of damage showed that carriers were always the primary targets, although the Japanese expended considerable effort attacking the destroyer pickets stationed between Okinawa and the fast carriers. Carriers were so large that a Kamikaze was almost certain to hit unless it suffered severe structural damage. Two of every three aircraft attacking carriers managed either a hit or a damaging near-miss. Overall, carriers were judged more susceptible to damage than any other type. Battleships were the most successful in destroying Kamikazes. The very low success rate of merchant ships indicated that in the late stages of an attack the target ship was its own primary defence – and that a determined suicide pilot would hit if not destroyed. Tabulated data showed that nearly 80 per cent of Kamikazes were killed not by proximity-fused 5in/38s but by automatic weapons (50 per cent by 40mm, 27 per cent by 20mm). In non-suicide attacks, 5in/38s were credited with 34 per cent of kills. Against Kamikazes, proximity fuses were responsible for 56 per cent of kills by 5in guns; in non-Kamikaze cases that was cut to 37 per cent. That was unfortunate, because 5in guns were the main hope of destroying Kamikazes far enough away that they could do no damage. Their poor performance was attributed to failure to open fire at maximum range, and also to failure to use a sufficient proportion of proximity-fused shells. The 5in guns did better against non-Kamikazes because they opened fire at longer range and they expended more ammunition, as they had more time to fire. Since many aircraft taken under fire never reached attack positions, the rising number of rounds fired per aircraft shot down was considered acceptable.43
It was clear that the 40mm gun was the star of the anti-Kamikaze effort, and through 1945 the US Navy enormously increased the number of such weapons. The fleet was much less impressed with the 20mm, the general view being that it did its damage at such short range that a Kamikaze would often still crash into the ship. One destroyer officer wrote that the main value of the 20mm was as a warning: when they opened fire, it was time to evacuate machinery spaces. However, figures showed that the 20mm was still effective, and it was retained as far as possible.44
Kamikaze tactics were not standardised, but all of that cautious probing before the Philippine Sea apparently taught the Japanese a great deal about how the US Navy used radar. The battle of the Philippine Sea itself taught them that inexperienced Kamikaze pilots should do whatever they could to avoid US fighters. Tactics could exploit both weaknesses of search radar (nulls at high altitude and limited capacity at low altitude) and difficulty in detecting targets overland; and weaknesses of the raid tracking and related fighter direction systems. For example, a CIC could track only a limited number of raids accurately enough for fighter control, so splitting up attackers could saturate a CIC.45 As of March 1945, Kamikazes worked singly, or in formations of up to three; there was some slight evidence of co-operation by as many as six aircraft, but this was nothing like the numbers working together in conventional attacks. The Japanese also learned both to mimic US IFF and to trail US strike aircraft home. The latter tactic was so successful that special fighter sections (Tomcats) had to be assigned to examine home-bound formations visually and shoot down Japanese aircraft among them. Kamikazes were usually escorted by fighters.
Final attacks varied widely. By March 1945 there seemed to be five main alternatives. One was a near-vertical dive from high altitude, in effect a dive-bombing attack without a pull-out. A second was a low-level approach followed by a pop-up and a steep dive, to frustrate close-in fire.46 A third was a shallow glide, from an altitude as great as 20,000ft. The British observed that this particular type of attack was difficult to engage by long-range armament. A fourth exploited the fact that ships’ anti-aircraft batteries were typically divided along the sides. An aircraft might approach from one side at low altitude, within close gun range, circle the ship, and attack from the other side. The commonest tactic was an attack along the centreline of the ship from astern by a single aircraft. It was easiest for the pilot to hit the ship, as he had the largest possible target, yet he faced the minimum number of anti-aircraft guns.
The Kamikazes emphasised the great difference between hitting the oncoming aircraft and demolishing it thoroughly enough that what was left of it would not badly damage a ship. This distinction applies to current anti-ship missiles.
Anti-Submarine Attack
Nearly all submarines had to charge batteries on the surface, and they could make good a reasonable distance only on the surface. They were reasonably invisible to any but the nearest surface ships, but they were easily seen from the air. The usual defence was a crash dive, but many First World War submarines could not dive very suddenly. For them an anti-aircraft gun might mean survival. In some navies submarines had more powerful anti-aircraft guns than most surface warships. Most Second World War submarines mounted a few heavy machine guns, but they relied mainly on crash dives. That was one reason US and Royal Navy submarines had air-search or air-warning radar. The Germans, however, lacked the necessary technology, and also feared that Allied antisubmarine aircraft might home on their radars. They tried to provide submarines with receivers which could pick up the emissions of Allied radars on board anti-submarine aircraft. The failure of this equipment led them to equip some U-boats, which they called ‘Flak U-boats’, with unusually powerful anti-aircraft batteries, with which they hoped to fight off air attacks. These weapons had no special fire-control equipment, and they proved ineffective. The ultimate defence against air attack was not to surface at all, which is why the Germans introduced the snorkel in 1944 (it bred a new kind of attack using sonobuoys and homing torpedoes).
