The Lessons Learned from the Actions of Both Sides during the Battle of the Coral Sea

Author

A.N. Other

Subjects

Naval technology, Naval Intelligence, WWII operations, History - WW2

Tags

Battle of Coral Sea, Radar

RAN Ships

None noted.

Publication

June 2014 edition of the Naval Historical Review (all rights reserved)

By Midshipman Gerard G. Vejrych, RAN

 Gerard Vejrych was born in Canberra but raised in Suffolk, England. From an early age he aspired to pursue a career in military aviation and while with the Air Training Corps in 2007 was awarded a Royal Air Force flying scholarship. However after completing high school he joined the Parachute Regiment Reserve, serving with the 4th Battalion for four years. After completing a BSc in Aviation Technology with Pilot Studies at the University of Leeds he returned to Australia and applied to the Australian Defence Force as a pilot, and joined the RAN in 2013. He is currently awaiting commencement of his flying training. His pastimes and interests include skydiving, aviation, and keeping fit.

Introduction

Between 4 and 8 May 1942 Allied and Japanese naval forces attempted to engage each other in an area to the south of the Solomon Islands and Papua New Guinea, between the northeast coast of Australia and Vanuatu, known as the Coral Sea. During these engagements the Japanese invasion fleet, destined for Port Moresby, was repelled and Imperial Japanese Navy (IJN) forces in the area were significantly weakened.

Allied forces involved consisted of Task Forces 17 and 44. TF17 came under the command of Rear Admiral Frank J. Fletcher and consisted of the carriers US Ships Yorktown and Lexington with a total of 143 aircraft, five cruisers, and 11 destroyers, plus a number of support ships. TF44, commanded by Rear Admiral Crace, consisted of a joint Australian-American force based around HMAS Australia and two other cruisers and three destroyers, plus submarines and seaplanes. The Japanese force, part of the Fourth Imperial fleet under the command of Vice Admiral Shigeyoshi Inoue, consisted of the Fifth Carrier Division consisting of Zuikaku and Shokaku with 144 aircraft, nine cruisers, 14 destroyers, and a number of smaller gunboats and support ships. There was also the light carrier Shoho with 35 aircraft intended to give air support to the invasion 1.

This was the first naval engagement where all offensive actions were carried out by carrier-launched aircraft, with no direct action between surface ships. It was also the largest naval engagement to have ever taken place off the coast of Australia.

This essay will examine the actions of both sides which led to strategic victory for the Allies despite suffering a minor tactical defeat in terms of ships lost, along with the lessons subsequently learned from this battle.

Allied Intelligence

In April 1942, the Japanese Army and IJN started planning Operation MO; this was designed to gain control of Port Moresby and thus cut supply routes between Australia and the United States, effectively forcing Australia out of the war and allowing Japanese forces to concentrate their efforts on destroying the American fleet at Midway.

The Japanese planned to capture Tulagi in the Solomon Islands, before deploying the Port Moresby Invasion Group of troop ships and several cruisers with air cover provided by the carrier Shoho. This invasion force was to be protected from outside interference from the Allies by a second Japanese group; the Carrier Striking Force, which consisted of the carriers Zuikaku and Shokaku accompanied by an escort of cruisers and destroyers commanded by Vice Admiral Takagi 2.

At this time the United States Office of Naval Communications could decipher approximately 85 percent of the Japanese Codebook D. When the Allies intercepted a message ordering Zuikaku and Shokaku to Vice Admiral Inoue, commander of the IJN Fourth Fleet, they concluded that Port Moresby was the probable target. This was confirmed by Australian coast watchers who reported Japanese movements. As a result of this intelligence, the commander of the Allied forces in the Pacific, Admiral Chester Nimitz, was able to muster a task force of aircraft carriers and warships to oppose the Japanese invasion force.

Japanese Complacence

Until this point in the war the IJN had experienced overwhelming success in military operations in places such as Pearl Harbour and Singapore, along with the sinking of the battleship HMS Prince of Wales. This success led to a complacent attitude such that when it came to planning the invasion of Port Moresby, the Japanese considered that a single heavy carrier division, consisting of Zuikaku and Shokaku, would be sufficient.

In reality the Japanese found themselves fighting a joint American-Australian force consisting of the carriers Yorktown and Lexington supported by a large escort of cruisers and destroyers. It was only due to the fact that the US carriers Enterprise and Hornet had been engaged in the Doolittle Raid three weeks previously that they were not present for the Battle of the Coral Sea; the inclusion of these carriers in the Allied task force may well have led to the loss of both Japanese carriers³.

The Japanese plan, on occupying Tulagi, was to use this location as a base for their Mavis reconnaissance seaplanes; these aircraft had a range of over 4000 miles and were a valuable asset to the IJN⁴. When the Allies discovered that the Japanese had gained control of Tulagi a series of air raids was carried out. On arriving at the target the US Devastator and Dauntless dive-bombers found the harbour undefended and carried out their attack runs without receiving any serious anti-aircraft fire. The Japanese lost two destroyers, one cargo ship, four gunboats and a number of aircraft⁵.

Anti-aircraft Defences and Tactics

Due to the nature of the battle of the Coral Sea the anti-aircraft (AA) defences of both fleets played a major role. When attacking aircraft were able to penetrate the defences provided by the defending fleet’s aircraft, it was down to the ships’ AA weapons and the tactics of the ships’ commanders to manoeuvre their vessels to provide mutual fire support and avoid inbound bombs and torpedos.

The principal AA weapons utilised by both sides at this time were focused on defending against dive-bombers, firing at a high angle towards aircraft above the ship; the Allies used 5-inch 38 calibre guns, with a mixture of Browning .50-cal machine guns and Oerlikon 20mm guns for closer targets, while the Japanese used the Type 89 40 calibre guns along with Type 96 25mm heavy machine guns and 8mm machine guns.

During the Battle of the Coral Sea it became apparent that the American Oerlikons, while reliable and having a high rate of fire, did not provide the destructive power of the larger 40mm Bofors gun as fitted to some Allied ships. Due to this observation, US ships were subsequently armed with the Bofors from July 1942 onwards.

On 6 May Fletcher ordered Crace to take TF44 and act independently from TF17; this was a risky move as it put TF44 outside the protective air cover provided by the carriers of TF17. The next day Japanese seaplanes located the ships of TF44 and shortly after the radar sets on all three Allied cruisers picked up a formation of enemy aircraft closing rapidly on their position. As the aircraft started their attack run the ships of TF44 carried out evasive manoeuvres, these actions allowed Australia to avoid two torpedos and multiple bombs⁶. This action highlighted the effectiveness of the avoidance manoeuvres and AA tactics used by the Allies.

At 0820 on 8 May the scout aircraft from Lexington located Zuikaku and Shokaku, at 0822 a Japanese radio message was intercepted that Japanese aircraft had also discovered the location of the Allied carriers. Both sides launched aircraft to attack the others’ carriers at the same time, the opposing formations passing each other mid-air.

The Japanese carriers had split their formation with the carriers approximately 16 km apart, each accompanied by two cruisers and two or three destroyers. Each carrier was armed with 16 x Type 89 AA guns and 42 x 25mm AA guns, allowing them to put up a formidable amount of fire. As the Allied aircraft approached the carriers Zuikaku entered a squall and was unable to launch aircraft to counter the attackers. In addition the two cruisers assigned to defend Shokaku had also been positioned approximately eight kilometres away from the carrier. On sighting Shokaku the Allied dive-bombers and torpedo bombers started their attack, however due to the distance between the carriers and supporting ships they were unable to provide effective AA fire support to each other. Shokaku subsequently took two bombs on her flight deck, rendering her unable to operate aircraft; returning Japanese aircraft were forced to land on Zuikaku, with aircraft being pushed off the deck to make space for additional aircraft. As a result of this neither carrier was able to take part in the Battle of Midway a month later, which saw the Japanese suffer a disastrous defeat⁷.

Allied Radar

Meanwhile, the Japanese aircraft formations en-route to the Allied fleet were detected by Lexington’s radar system approximately 70 miles away; unfortunately a number of aircraft had just been recovered to the Allied carriers and were not ready to be launched, in addition the eight aircraft on Combat Air Patrol were low on fuel and were unable to confront the incoming Japanese aircraft. As a result only nine fighter aircraft were launched to defend the Allied fleet, with an additional 23 Dauntless SBD dive-bombers pressed into service as fighters against the Japanese aircraft⁸.

The Allied carriers also widened their formation to give them more room to manoeuvre, although this was at the expense of the effectiveness of the AA fire umbrella. Lexington was severely damaged after being struck by multiple bombs and five torpedos; she was subsequently scuttled by the Allies after a failed attempt to recover the ship to Pearl Harbour. Yorktown was slightly more manoeuvrable and was able to avoid torpedos and bombs aimed at her; in addition the extra cruiser in her escort provided additional AA fire resulting in the Japanese losing 20 aircraft in the engagement⁹.

Conclusion

The Battle of The Coral Sea was one of the first strategic victories for the Allies. Although the Allies lost a greater number of ships, the Japanese Port Moresby invasion force had been repelled leaving supply lines between the United States and Australia open.

The importance of Allied intelligence in this instance is obvious. Due to the ability of the Allied code breakers to decipher Japanese messages, a task force was able to be assembled and despatched to protect Port Moresby before the Japanese had a chance to establish themselves there.

Due to previous operational success in the Pacific arena, the Japanese had underestimated the Allied capabilities leading to the IJN confronting Allied forces on an equal footing. Although the Japanese won a minor tactical victory they were unable to gain control of Port Moresby and therefore failed in their aims.

Other aspects highlighted by both sides in this event were the importance of teamwork and tactics in anti-aircraft defences. By splitting their carrier formations the Japanese severely weakened their anti-aircraft firepower, such that the attacking dive-bombers were able to prosecute their attacks on Shokaku without major losses. Conversely the ships of TF44 were able to survive multiple attacks by Japanese dive and torpedo-bombers due to skilful ship manoeuvring and discipline of the AA gunners. This action also highlighted the need for increased AA firepower when defending against massed bomber formations.

The lessons learned by the Allies during the Battle of the Coral Sea allowed them to achieve victory at the subsequent Battle of Midway, and ultimately led to the defeat of Japanese naval forces in the Pacific theatre by the Allies.

Notes

1. Henry, C. Battle of the Coral Sea, Compendium Publishing: London, pp 18-24.
2. Lewis, R. The Battle of the Coral Sea, ANZAC Day 2002, p 13.
3. Parshall, J. Coral Sea, Midway and After, Wartime, Issue 59, p 8.
4. Henry, C., Battle of the Coral Sea, Compendium Publishing, p 46.
5. Office of Naval Intelligence U.S. Navy. The Battle of the Coral Sea, No. 855, p 9.
6. A.F., Coral Sea Log, p 55.
7. C., Air War Pacific, Crescent Books, p 75.
8. Henry, C., Battle of the Coral Sea, p 64.
9. Brown, D., Carrier Operations of World War II, Vol II, pp 55-6.

Bibliography

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