DISCLAIMER: This is an AFTER ACTION REPLAY of a GAME and not a history of the real Battle of the Coral Sea.
DISCLAIMER 2: Yes, past experience shows that the above disclaimer is necessary - see the preceding Battle of Wake Island replay report.
In mid-April, 1942, a number of indicators began to suggest that the Japanese were preparing to renew operations along the Kokoda trail in the Owen-Stanley mountains, with the goal of capturing the vital Allied base of Port Moresby on the south-eastern tip of New Guinea. Signals analysis showed that the Japanese were massing a large number of transports at their forward base in Rabaul, and it soon became clear that a major seaborne invasion force was being prepared to mount a landing near Port Moresby in support of the Kokoda trail offensive, presumably to kick off some time in early May.
In response, the decision was made at Pacific Fleet headquarters to rush all available US carriers, under the command of Vice-Admiral (VADM) Matthew 'Bull' Shirley, to the region to counter the invasion. The stage was set for the second great carrier engagement of the Pacific war.
Shirley's simple but high-risk plan was predicated on his and other Allied commanders disappointing experiences with land-based reconnaissance aircraft support during prior naval battles against the Japanese. Shirley reasoned that if he couldn't rely on his patrol planes to find enemy ships, and if his mission was to stop the invasion of Port Moresby, then he'd just go where he knew he could find the enemy invasion transports: the Japanese base at Rabaul.
On the other side of the Coral Sea, Shirley's counterpart, VADM Jimmu, commander of Japanese naval forces in the Southern Region, also had a fairly straightforward plan. Once his invasion force was assembled and the landing forces embarked, he would move his supporting naval forces (centered on the modern fleet carriers Shokaku and Zuikaku, and the light carrier Shoho) down from the main Japanese base at Truk, passing through the northern end of the Solomon Islands chain, and screen the movement of the invasion convoy as it sailed to Port Moresby by placing his task force to the south of the transports intended track, interposing himself between them and anticipated American carriers he calculated would probably be coming up from their base in New Caledonia in response to his movements.
Embarked aboard the carrier Yorktown, with the carrier Lexington in close support, Shirley arrived in the northern Coral Sea during the night of 03May, and transited the Jomard Passage just after midnight. Though his high speed transit to get into position had gone undetected, it left many of his ships, particularly the smaller escorts, low on fuel.
VADM Jimmu was similarly having fuel concerns, and at dawn he paused his task force on the eastern side of the Solomon Island chain for several hours to conduct refueling operations from a pair of oilers. This delay would have ramifications in the upcoming engagement later that day. Jimmu, however, expected that one or more American carriers might already be operating in the area, and accordingly had dispatched the seaplane tender Kamikawa Maru ahead of his main body to scout the area with her floatplanes, and hand ordered an arc of long-range flying boat patrol planes to sweep the approaches to the area. However, he erroneously predicted that the Americans would not have their ships up in the northern Coral Sea until mid-day or later, and as a result his patrol plane sweep was too far to the south to spot the US fleet at daybreak.
The Battle of Coral Sea proper began shortly after dawn on 04May, when a large raid of nearly 80 planes struck Port Moresby. The attack was part of Jimmu's plan to begin reducing the main Allied airbase in the area in preparation for the invasion that was to follow. A fighter sweep of some 40 Zero fighters preceded the main strike group and made short work of the weak Australian Combat Air Patrol (CAP) that was still struggling for altitude when the raid began. The Betty and Nell bombers that followed inflicted substantial damage to the base, including destroying several hangars with over a dozen Allied aircraft still inside. Japanese losses to Allied anti-aircraft fire and the few CAP fighters that survived the initial onslaught were negligible. Another bomber raid a few hours later succeeded in demolishing the airfield control tower, but by that time the base commander had wisely dispersed the remaining aircraft into the fringes of the jungle lining the runway and no further planes were lost on the ground.
The damage at Port Moresby's airfield could easily have been far worse, but fortunately two squadrons of B-26 bombers and a squadron of escorting P-39 fighters, had been launched on a pre-dawn raid against the Japanese fighter strip at Buna, and so the runway aprons were nowhere near as full of parked aircraft as they might have been. The B-26s managed to badly crater the Buna runway, and there was insufficient time for the Japanese ground crew to fill in the holes before their fighters returned from the recent attack on Port Moresby; several Zero fighters were destroyed while trying to land, effectively doubling the losses suffered from the raid on Port Moresby.
Buna was not the only Japanese airfield hit that morning. USAAF B-17s, operating out of Cairns, Australia, bombed the airfield at Lae, but failed to achieve any significant results. And shortly after the Japanese raiders departed Port Moresby, the base commander scraped up what few serviceable airframes he still had that were operational and sent them off against the Japanese base at Gasmata, where they failed to achieve any noticeable results.
VADM Shirley's small piecemeal raids that morning were part of an overall scheme to throw the Japanese Southwestern Air Command into disarray, hopefully distracting the Japanese as his carriers snuck into range of Rabaul. The plan apparently worked, at least to some extent, for as these various air formations were busily attacking one another's bases, Shirley's carriers were able to get within 40 miles of his launch point without being detected.
But then things began to go frightfully awry. At around 1030, a pair of Jake seaplanes were launched from Kamikawa Maru on a routine patrol to check around Woodlark Island and the Jomard Passage for the presence of Allied ships. Around 1215, about halfway into the flight to their patrol zone, an observer aboard one of the Jakes spotted a small group of ships far to his north. The Jakes continued on their route towards Woodlark Island, but transmitted a brief radio message: 'Unidentified ships, possible carrier, 200 miles west of Buka.'
Receipt of the Jake's sighting report aboard Zuikaku, VADM Jimmu's flagship, sent a current of panic through his staff: American carriers within striking range of the vulnerable transports anchored in Rabaul, what air units were available to hit them before they could attack'
Unfortunately for Jimmu, a quick examination of the aviation status boards revealed the grim answer: there were few Japanese air assets available to respond to the threat. Most of his land-based aircraft were either unready for immediate action or still in the air returning from the morning's air raids on Port Moresby, while the Japanese carriers were out of range of all but the longest-legged of their planes due to the decision to refuel that morning. After a hasty consultation with his air operations officer, and realizing that there was little likelihood of hitting the American flattops before they could launch against Rabaul, Jimmu adopted a conservative approach to the situation. He ordered the few available land-based air units (mostly fighters and a handful of Nell bombers) to fly against the American ships, and launched two squadron of Kate torpedo planes (armed with bombs to extend their range), from his carriers to augment the attack. At the same time he ordered his carriers to close on the Americans at flank speed, and directed the airfields ashore to ready the returning bombers as soon as they recovered ' whatever survived his initial blow would be obliterated in the subsequent second strike that afternoon.
Onboard Yorktown, VADM Shirley was unaware his force had been spotted. The only indication the Americans had of any Japanese naval activity in the region was a sketchy report from the submarine USS Trout that they were preparing to engage a large transport or auxiliary ship south of New Ireland. Even had Shirley had known that Trout's target (which she sank) was the seaplane tender Kamikawa Maru, it's questionable whether that information would have altered subsequent events.
Regardless, at roughly the same time that Jimmu's staff was frantically trying to find some way of stopping him, the American carriers began launching a massive strike, of nearly 120 planes, against the transports they believed were in Rabaul harbor. The strike arrived over Rabaul at 1345 and found the roadstead filled with over 20 Japanese transports sitting at anchor and no Japanese fighters in the skies. Though Japanese anti-aircraft fire was moderately effective, shooting down a dozen US bombers, it did little to reduce the devastating effects of the raid. In the end, 11 of the Marus were sunk outright, and four more foundered over the course of the next few days due to extensive damage. But more importantly, four batteries of artillery and over half of the troops comprising the Imperial Japanese Army's elite Ichiki Detechment, went to the bottom with those transports, and with them any hope of a seaborne invasion of Port Moresby.
Jimmu's ad-hoc strike began arriving over Shirley's carriers around 1500. For a strike comprise of air units from so many sources (three different land bases and two carriers), the Japanese navigation was remarkably good: only a single small group of Zeros from Buna failed to locate the target. Because the strike arrived at roughly the same time as the American strike planes from Rabaul were returning, radar operators onboard Yorktown and Lexington became confused and fighter direction of the sizeable CAP that Shirley had had up was poorly executed: many patrolling US fighters were shot down before they were even aware their carriers were under attack. Amidst the confusion, US anti-aircraft fire was completely ineffective, but the confusion extended both ways and the piecemeal Japanese level bombing efforts similarly failed to achieve any hits. VADM Shirley's sigh of relief was audible to everyone on the YORKTOWN's flag bridge as the last of the attacking Japanese planes departed the area, but his relief was to be short lived.
Back aboard the carrier Zuikaku, VADM Jimmu evidenced little disappointment over the results of the unsuccessful strike on the American carriers. He had anticipated that such a hastily organized attack would not achieve much, and in fact was quite pleased that his fighters had managed by all accounts to shoot down so much of the American fleet's air cover. In his desire to close on the now vulnerable American carriers faster, Jimmu ordered his operations officer to suspend zig-zagging. It was a perilous decision, for it allowed the submarine USS Cuttlefish, which had been paralleling the Japanese fleet's course, to line up a snap torpedo shot at the light carrier Shoho. The torpedoes missed, but the incident served to make Jimmu realize that he might still lose this fight: he directed the fleet to resume zig-zagging.
VADM Shirley began withdrawing his carriers southwards at high speed, hoping he could get beyond the limits of Japanese land-based bombers before dusk. It was an unrealized hope. By 1600, Japanese ground crews, working at a fevered pace, had managed to get a squadron of Nells, armed with torpedoes, ready to launch. Coordinating closely with Jimmu's air staff, the Nells took off slightly before carriers Zuikaku and Shokaku began launching their remaining Kates, so as to synchronize their arrival over the American carriers simultaneously. Because of Jimmu's order to resume zig-zagging, the Kates would be flying at extended range and so had to be armed with bombs again, instead of their more effective torpedoes.
Superb navigation again enabled all the Japanese strike waves to locate their targets, and at 1740 their attack began. Their fighters having been blasted from the skies during the earlier raids of the afternoon, the American carriers were nearly defenseless. The land-based Nells concentrated on Yorktown, steaming several miles astern and to the north of Lexington. Anti-aircraft fire from Yorktown's escorts was ineffective, and the Nells were able to set up a deadly 'anvil' attack (making their approach runs from both Yorktown's port and starboard bows at the same time, to make it difficult to comb the incoming torpedoes), but as the Nells came in closer Yorktown herself was able to splash several of the attacking bombers. By skillful maneuvering, the ship was able to avoid all deadly inbound 'fish,' although one torpedo did pass down her port side so close that Yorktown's bow wake was seen to push it aside slightly as it zipped past.
The elation on VADM Shirley's flag bridge over Yorktown's emerging unscathed from the attack was short lived, and the Admiral and his staff were in excellent position to see what happened next. Ahead of them they watched mutely as twenty-four Kates, in near perfect air-show formation and unfazed when AA fire from Lexington's escorts flamed several of their number, release their bombs with surprising precision on the hapless 'Lady Lex' below. Great white geysers from numerous near misses surrounded the Lexington, and observers began to hope she might escape being hit, but then a blast of flame erupted just behind her conning tower as a 250 kilogram bomb struck a clump of parked planes stowed on deck by the after elevator. Secondary detonations of bombs cooking off on the parked aircraft caused further damage, including rupturing the main aviation fuel transfer valve on the flight deck; burning avgas began cascading down the open aircraft elevator shaft into the hangar deck below, touching off more bombs and torpedoes on aircraft stored down there. Within 10 minutes, Lexington's entire aft end was a twisted mass of flaming wreckage and the dying ship began to list heavily to starboard. Witness to the entire affair, Shirley reluctantly ordered Lexington abandoned and continued his flight to the south.
Almost as a side note to the turn in fortunes, a dusk air raid against the Japanese airfield at Lae, by Port Moresby based B-26 bombers, and B-17 heavy bombers out of Cairns, managed to miss the drop point entirely and drop their ordnance in the New Guinea jungles, over a mile from the intended target.
Knowing that there would certainly be more Japanese air attacks to come, VADM Shirley now became desperate. He sent all his remaining Wildcat fighters up on CAP and, hoping to avoid having Yorktown share Lexington's fate of being caught with readied aircraft on deck, hastily ordered all his carrier based bombers to conduct a strike at nearby Buna airfield. As an afterthought, he also directed what remaining land-based bombers were still operational at Port Moresby to support the raid on Buna. The ensuing raid on Buna did major damage to the base but had minimal impact on the subsequent course of the battle as there were only a few Japanese fighters still stationed there.
Just before sunset another swarm of Japanese aircraft struck Shirley's task force, this time focusing their entire effort on Yorktown. The remaining Wildcats did good service, splashing a number of Betty bombers carrying torpedoes before they were in turn shot down by escorting Zeros. But in the end, poor Yorktown had to endure the attentions of a dozen Bettys and Nells with torpedoes and over twenty Kates conducting level bombing runs. Though AA fire was good, downing eight Japanese planes, it was not enough. Yorktown, caught in an 'anvil' between Bettys and Nells lumbering in on her, took a torpedo hit on her port bow that flooded her forward fire room, ruptured several fuel tanks, and bowed her port shaft.
With Yorktown now limited to only 12 knots, a speed that rendered her incapable of conducting air operations, Shirley realized that she had become more of a liability than an asset. Without an operational aircraft carrier, Shirley knew that the best chance he had of deterring the Japanese from attempting a landing at Port Moresby with their few remaining transports would be to lure the Japanese fleet within range of aircraft based in Australia and then dash in to engage the transports with his small force of cruisers. Shortly after sunset he transferred his flag to the heavy cruiser USS Portland, detached Yorktown with a pair of destroyers to make her way as best feasible to the dubious safety of Port Moresby, and headed south at high speed. There he remained for the rest of the battle, under the relative safety of the airbases along Australia's northeastern peninsula.
As reports of the various afternoon and evening air strikes trickled in aboard Zuikaku, VADM Jimmu became increasingly confident that he had turned the tide of battle. With one Yankee carrier sunk and the other damaged (which he was positive he would be able to locate and sink the next day), he believed that a reduced scale amphibious landing near Port Moresby might still have a good chance of succeeding once he had driven the paltry remaining Allied forces from the area so that his carriers and cruisers could devote their full attentions to supporting the landings, thereby making up for the troops and equipment lost aboard the transports sunk at Rabaul. It was a bold idea that should have succeeded, but luck has a way of upsetting bold ideas.
Yorktown had barely cleared the Jomard Passage at daybreak on 05MAY; it was there that a Mavis flying boat found her. By that time, Jimmu's carriers were well within optimal range of all their aircraft. At 0645, without any fighter cover and only a pair of escorting destroyers in company to provide anti-aircraft support, slow and unresponsive to her helm from the damage she'd received the previous day, Yorktown's fate was sealed. A swarm of 30 Val dive bombers descended upon her and a half-dozen hits left the doomed ship aflame and slowly going down by the bow. The escorting destroyers took off the survivors, scuttled the once proud ship with torpedoes, and fled the scene at flank speed.
While Yorktown was suffering her fate, a series of strange events occurred that effectively ended the Coral Sea battle. An Australian Catalina patrol plane out of Port Moresby stumbled across the main Japanese carrier force about a half-hour after sunrise and radioed back a sighting report to RAAF headquarters in Brisbane. Acting on his own initiative, and without consulting VADM Shirley, the RAAF Northeastern Regional Commander, Vice Air Marshall Sean Joshua, ordered a squadron of USAAF B-17s out of Cairns to cancel their planned late-morning raid on Buna and instead proceed to the last known position of the Japanese carriers.
At 0915 the heavy bombers arrived at the position and found it obscured by low broken cloud cover. After a cursory and unsuccessful search, the mission commander, LtCol George Chelsea, aborted the mission and ordered the flight to return to base. Approximately 20 minutes later, through a break in the clouds, Chelsea's tail gunner spotted the main Japanese fleet. Chelsea hurriedly reformed his group and began a bombing run over the enemy force. The high altitude bombers caught the Japanese totally by surprise; indeed, there was almost no AA fire and the first indication that the force had they were under attack was when geysers from misses began spouting up in the midst of their formation.
The B-17's bombing was wildly inaccurate, most bombs missing by over a half a mile, but a single 500 Lb. armor-piercing bomb somehow managed, almost by accident, to hit Shokaku just above her port quarterdeck. It penetrated the flight deck and passed through the hanger into the number 2 machinery room below before detonating. The explosion destroyed the portside main reduction gear and started a fire that raged for several hours, gutting the ship's interior communications switching room and the auxiliary equipment room that serviced the aircraft elevators. Although Shokaku's structural integrity was not seriously compromised, her ability to conduct air operations was severely impacted and her speed limited to a maximum of 16 knots.
With Shokaku's communications suite in disarray, VADM Jimmu was forced to shift his flag to Zuikaku. As Jimmu departed the ship, Shokaku's Captain was heard to remark, 'Well, there's a lucky break!' (referring to Jimmu's reputation as a bit of a Jonah of ill-fortune, having had three successive flagships sunk from under him during the Battle for Wake Island).
The sudden reversal of fortunes left VADM Jimmu stunned, and the previously aggressive commander seemed to lose his nerve. For the remainder of the day he kept his forces carefully positioned well outside Allied air strike range, conducting desultory air searches against the possible threat of a third US carrier, while his land-based air power continued to pound Port Morseby's defenses. The few surviving Japanese transports sortied from Rabaul in the late afternoon, steaming back and forth across the northern end of the Coral Sea, but always remaining carefully outside Allied bomber range. Eventually, around midday on 06MAY, VADM Jimmu ordered all ships to return to port.
Jimmu's stated reason for calling off the operation was that the risk of losing his only remaining operational fleet carrier to Allied land-based airpower, in order to support an amphibious landing that had been relegated to little more than a diversionary effort, was strategically unsound. He and the Imperial Navy had won a glorious victory for the Emperor by sinking two US carriers at the cost of damage to only one of theirs; if the Imperial Army wanted Port Moresby so badly, they could win a glorious victory on their own by taking it without having the Navy suffer pointless losses.
On the other hand, although VADM Shirley had managed to deter the Japanese from invading Port Morseby, it was at a terrible cost. Though recalled to Pearl Harbor for a formal board of inquiry for losing Lexington and Yorktown, he was exonerated and returned to command. However, his reputation was badly tarnished, and the press took to changing his moniker from 'Bull' Shirley to the less imposing 'Steer' (a steer being a castrated bull).