23rd-24th March
As night falls the two cruiser forces are still manoeuvring for advantage. The Japanese are trying to get into a position for a night attack, while the Allied force is trying to slip along the coast to get at the invasion convoy. A strike is attempted on the Japanese at 1730 from HMS Colossus, but was unable to find the force; the ASV-equipped plane leading the strike had equipment failure, and the rest of the strike did not spot the Japanese beneath the cloud cover. With the Japanese force now lost, HMS Colossus is ordered to fall back on the main fleet. However her earlier attacks on the Japanese cruiser force have given away her approximate position. At 1715 (while her own strike is on the way to the estimated position of the Japanese cruisers) a large enemy raid is detected closing from the north-east. This is a surprise to the plotting crew, who had not been expecting a strike from that direction. It is in fact a strike from the three IJN light carriers comprising the cover force for the invasion fleet; this force had been detected earlier by a USAAF aircraft yesterday, and Somerville is intending to attack it. Due to a mishap, the report of the force had been missed by Colossus and her destroyer escorts.
The incoming attack consisted of 24 torpedo planes and 20 dive bombers, escorted by 16 fighters. As the Colossus was also covering the Allied cruiser force, she only had 14 fighters available, although all of these were either airborne or launched before the enemy raid arrived. Ironically this raid had been spotted by a Catalina on its way west, but it had been assumed it was headed towards Somerville's main carrier force, who were preparing to launch their own strike against the covering force, having spent the day closing the range.
The FAA fighters tried to engage the raid, in particular the dive bombers (felt to pose the greatest risk to a light carrier), but the Japanese escort fighters closed to protect them. In the ensuing fight 10 Sparrowhawks were shot down for the loss of 4 dive bombers and 7 escorting fighters. Another dive bomber and three torpedo planes were shot down by the AA fire of the carrier and her escorts. Despite radical manoeuvring, the Colossus was hit by four torpedoes, one of which failed to explode. The damage caused by those that hit was enough to force her to a halt as her both her engine rooms started to flood. This abrupt stop actually helped her evade the first of the dive bombers, who were unable to compensate for the sudden loss of speed, and six huge plumes of water rose into the air in front of the listing carrier. Despite all her AA could so, the remaining 10 dive bombers dove down to deliver their 500lb bombs. The ship was hit three times, all three bombs penetrating her hanger. Two burst in the hanger itself (fortunately empty of planes), the third penetrated into the forward engine room (the light carriers had no hanger deck armour), where it exploded, wrecking the equipment. Colossus was left heavily on fire and listing from the water flooding in through the torpedo holes.
Even as the Colossus was being attacked, the main British strike was on its way. The force was centred around the fleet carriers HMS Illustrious and HMS Implacable, and the light carrier HMAS Melbourne. Their strike consisted of 24 SeaLance torpedo planes and 24 Cormorant dive bombers, escorted by 20 Sparrowhawks. Somerville intended to follow up this attack with a night strike, but this would not be prepared until after dark (he did not want armed and fuelled planes on deck or in the hanger with a possible inbound Japanese airstrike). The strike arrived at the Japanese carrier force just after sunset.
The Japanese force was centred around three light carriers (despite the reports, they were only escorted by heavy cruisers, not battleships). These were the carriers Takasaki and Tsurigisaki (converted into carriers as part of the response to the increased RN carrier program in the late 30's), and the CLV Taiyo. between them they carried over 80 planes. The carriers were escorted by four cruisers and 8 destroyers. The incoming strike was not spotted until it was ten miles away from the carriers, the fading light having made the raid commander decide to go straight in. Due to the fighters sent off to escort the raid on Colossus, the force only had 14 fighters available, and due to the short warning time only 9 were in the air when the strike arrived. The defenders were immediately attacked by the Sparrowhawks, preventing them from closing with the attacking planes, and only one torpedo plane was lost to the defending fighters. All 9 of the Japanese fighters were shot down for the loss of six Sparrowhawks.
The attacks were lead by the torpedo planes. One was shot down on its attacking run, and another forced to drop its torpedo and turn away by the AA fire, but 21 SeaLance remained. Without enemy fighters to worry about, the swept in on the first two carriers in a classic hammer and anvil attack, hitting the Takasaki with three torpedoes, and the Tsurigisaki with one. These were not the new Mk XV aerial torpedoes, but even so the hits crippled the two Japanese ships. Even as the torpedo planes swung away, the dive bombers were falling into their near-vertical dives. Most of the planes were attacking the two already-damaged carriers (the third carrier, Taiyo, was some distance away and had been missed in the hurry to get the attack in before dark). The Cormorants were carrying 500lb bombs due to the range (the strike had been launched at near to the maximum range, as the Japanese force was under observation by ASV-equipped RAF planes which had been able to guide it in), but these were more than adequate against the poorly-protected converted carriers. The Takasaki, already reeling and listing from the torpedo hits, and with no fighters to worry about the Cormorants could take their time. Three bombs hit the Takasaki, leaving her blazing in the falling night, and four exploded deep inside the Tsurigisaki. Ten minutes after the raid, the Tsurigasaki exploded, sinking soon after. She would be joined in an hour by the Takasaki, her converted hull unable to take the damage from torpedoes and bombs.
The remaining 6 dive bombers headed for the Taiyo, which had been finally been spotted. The light was failing, and the dive bombers did not manage to get any hits, although the reported the carrier as 'damaged', having mistaken a couple of close misses as hits. The planes made it back to their carriers after dark, landing safely as, despite the risk of submarine attack, the carriers used landing lights for help the planes land safely.
To the south, the invasion convoy had made landfall late in the afternoon. The Dutch commander of the defences had decided to let them land then counterattack, a decision later criticised by the Imperial commanders. As a result by sunset some 4,000 troops had got ashore (although with little equipment), only resisted by local light forces. The Dutch commander reported he would launch an attack on the beachhead at 0700 the following morning.
Unknown to the Japanese, Somerville had a second carrier force off Java - the two fleet carriers HMS Ark Royal and HMS Bulwark. This force was south of the island, and had been steaming east all day at 25 knots, putting it in range of the Japanese landing by 1800. The force had not been detected; the Japanese reconnaissance was concentrated north of Java, as they had indications of a carrier force there, and their intelligence led them to believe the RN only had the ships available to form one force. This would lead to one of the FAA's trademark night strikes. At 1900 the first strike set off, led by the ASV-equipped Spearfish, followed an hour later by the rest of the planes. As the Japanese had no night fighter capability as far as the RN knew, the strikes were unescorted. The first that the Japanese knew was when their frantic unloading of their ships was suddenly illuminated by flares dropped by the raid leaders. The only defence of the ships was by wild and ineffective AA fire, as the torpedo planes bore in to attack the transport ships. The second strike, by the remaining torpedo planes and the dive bombers, was even easier - by now the Japanese defence was erratic and uncoordinated, the sea and the remaining ships lit by the burning hulks left by the first strike. By the time the last of the planes were recovered to the carriers, only three transports were left, and the aircraft had also sunk two cruisers.
The Japanese now had only 6,000 men ashore on Java, with only limited equipment and ammunition.