The Battle of the Coral Sea

Author

A.N. Other

Subjects

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

Tags

New Guinea, Aircraft carrier, Battle of Coral Sea

RAN Ships

HMAS Hobart I, HMAS Australia II

Publication

June 2015 edition of the Naval Historical Review (all rights reserved)

 MIDN Lachlan Montgomery joined the RAN in February 2014 coming from a family of five in Ringwood Victoria. His father is a serving member of the Victorian Police Force and his mother an office manager at the Ringwood High School. He enjoys running, computers and flying with the career goal to become an Aviation Warfare Officer.

 Introduction

The Battle of the Coral Sea was a series of naval engagements off the north-east coast of Australia between the 4th and 8th May 1942. It is considered by many to be the turning point of the war against the Japanese. The Japanese advance on Port Moresby in Papua New Guinea was the precursor to the first aircraft carrier battle, in which the Japanese Fleet was badly damaged and forced to withdraw.The Battle of the Coral Sea resulted in Australia being released from the immediate threat of invasion by the Japanese, and prevented Australia from being isolated from its American allies. It also resulted in the Americans maintaining naval superiority of the Pacific region. The battle paved the way for a decisive Allied victory at the Battle of Midway just one month later, and hence is an extremely important event not only in regards to the survival of Australia, but to the downfall of the Japanese war machine. The aim of this essay is to discuss the lessons learnt from the Battle of the Coral Sea by examining the following points in addition to the involvement of the RANand the significance of the battle to Australia. These are divided into the following aspects:

1. The influence of carrier air power upon the battle,
2. The influence of intelligence upon the conduct of the battle,
3. Claims of tactical defeat and strategic victory,
4. The strategic impacts upon events ashore in New Guinea, and
5. The involvement of the RAN and the significance of the battle to Australia.

Precursors to the Battle of the Coral Sea

The great war between the US and Japan opened in a totally unexpected manner. The destruction of much of the United States Pacific Fleet at Pearl Harbour was a huge blow to their tactical capability. However, as a result of all its Pacific aircraft carriers not being present at Pearl Harbour during the attack, the United States considered how to use these ships to reverse the Japanese expansion across the Pacific. (Stille).

Stillestates that as a result of the Japanese success at Pearl Harbor, air power was now considered a dominant factor in naval warfare. In order to avoid being totally defensive in the face of an unstoppable Japanese carrier force, the United States began a series of carrier strikes in the Central and South Pacific. These proved somewhat ineffective, but forced the Japanese to postpone their proposed Port Moresby operation. When the Japanese were ready to move on New Guinea in the South Pacific, two of the US Pacific Fleet Carriers had been deployed to conduct a raid on Tokyo, meaning the US could only send two carriers to the South Pacific to counter thepredicted Japanese offensive. With part of the Japanese Carrier Force committed to join theSouth Pacific operation, history’s first aircraft carrier battle seemed imminent.

The influence of carrier air power upon the battle

Millot (1974) contends that the war in the Pacific led to a new kind of warfare – one which relied on the use of air power. In fact, the Battle of the Coral Sea was based around a type of warfare where the opposing carrier groups never sighted nor fired upon each other.

The Carrier Air Groups of both sides were primarily made up of three types of aircraft. These consisted of fighters, dive bombers and torpedo aircraft, forming a ‘Combat Trio’ with the goal to project overwhelming force upon the enemy ships. As a primarily carrier only battle, these aircraft would prove vital to the attack of enemy forces – a new kind of ‘Over the Horizon warfare’ emerged.

The Japanese and Americans had very different aircraft design philosophies as seen below in figure 1.

As shown above, the Japanese utilised lightweight, manoeuvrable and fast aircraft with high rates of climb. This came at the cost of reduced pilot protection, armour and special features such as self-sealing fuel tanks. The Americans however, had the slower, heavier Wildcat, inferior in almost every way to the Japanese Zeros apart from its stout construction. This interesting comparison proves the uniqueness of each carrier force and a few of the strengths/weaknesses of each.

Overall, the Battle of the Coral Sea had the strategic effect of ‘promoting’ the aircraft carriers’ importance to naval warfare, and thus resulted in a dramatic increase in numbers of these ships produced. It also essentially removed the battleship from the elevated position it held as the ‘flagship’ of navies worldwide and presented air power with utmost importance for future naval engagements. The Battle of Midway which occurred in early June 1942 is proof of this.

The influence of intelligence upon the conduct of the battle

Intelligence proved vital to the outcome of the Battle of the Coral Sea. As an over the horizon carrier battle, seaplanes were the primary method of predicting the next moves of the enemy forces. Australia played an important role with intelligence. Coastwatchers were on the job, spotting Japanese seaplanes as they departed their forward bases at Lae and Salamaua on the north eastern coast of New Guinea. The Australians observed the routines of the Japanese and hence discovered they had begun to mass air and sea power in the area – pointing to an attack on Port Moresby. This knowledge was a contributing factor to the American deployment of sea power to the area in anticipation of a clash (Hoyt).

Signal interception was also a means of intelligence prior to the battle. A joint USN/RAN Unit known as Fleet Radio Unit Melbourne (FRUMEL) played an important role in the Battle of the Coral Sea. US Naval Intelligence was able to decode Japanese naval communications and as such was almost as well informed as to what was being planned as Japanese commanders were (Straczek). On 13 April, the British intercepted a Japanese message stating that the ‘Fifth Carrier Division’ was en-route to the area. Upon receipt of this intelligence from the British and confirming its authenticity, the US deployed all four of the Pacific Fleet’s available carriers to the area. Only two of these carriers, USS Lexingtonand USS Yorktownwere able to make it to the area of operations in time due to USS Hornetand USS Enterpriseconducting a raid on Tokyo. Interestingly, the Japanese believed only one American carrier was in the area of their planned operation, and did not expect such a strong carrier response to their invasion until it was well underway. This perhaps had a serious effect on Japanese performance during the battle, as they hadn’t expected the large American force present during their operation.

Therefore it can be said that intelligence had a significant impact upon the conduct of the battle, primarily involving American predictions of Japanese movements, and the subsequent deployment of carrier groups to the area. We must also not forget that the Japanese intelligence in this situation was inferior to that of the United States, demonstrated by their underestimation of US carrier power in the region. This is a vital lesson in the importance of intelligence in this kind of ‘blind’ warfare.  (Straczek & Hoyt).

Claims of tactical defeat and strategic victory

There is no doubt the Battle of the Coral Sea had a heavy impact on both the Americans and the Japanese, but who really won? There are claims of a tactical defeat along with strategic victory from the American point of view. Stille states that the battle has correctly been described as a strategic American victory. The Americans had, for the first time, repelled a Japanese attack and subsequently prevented the Japanese sea-borne invasion of Port Moresby. This attack was Japan’s best chance at taking the port and airfield, and hence posing a major threat to Australia’s security. The failure of the sea approach resulted in the later failed attempt to take the port by land over extremely rough terrain. So in the sense of a wide viewed approach, the United States had a strategic victory during the Battle of the Coral Sea.

Some possess the view that whilst a strategic victory, the battle was a tactical defeat for the US Navy. This can be attributed to the fact that whilst sinking only a light Japanese carrier Shohoand damaging a fleet carrier Shokaku, the US Navy lost Lexington, one of its four operational fleet carriers. Observing from an isolated perspective, this ‘tactical defeat’ could be considered true, however looking back to the broad strategic overview, this is not accurate, as the primary Japanese goal of achieving carrier dominance over the Americans had failed. Therefore it is apparent that whilst some considered the battle an American tactical defeat, the disabling of a large portion of the Japanese Carrier Force paid rich dividends for the American position in the Pacific.

Strategic impact upon events ashore in Papua New Guinea

As previously mentioned, the halt of Japanese naval advances on Port Moresby resulted in a land campaign over increasingly difficult terrain. This Japanese attempt proved to be unsuccessful, meaning that Port Moresby remained under Allied control. Resultantly, Australia was protected from the threat of invasion. It can be said that the Battle of the Coral Sea had a huge impact upon events ashore in Papua New Guinea, not the least of which was the survival of Port Moresby. Had this important port been taken in a Japanese naval assault, the enemy would have aimed to cut off Australia and its important contribution to the war effort. The consequences of this occurring would have been disastrous to Australia.

The involvement of the RAN and the significance of the battle to Australia.

The Royal Australian Navy had a significant involvement during the Battle of the Coral Sea. A Support Group attached to Task Force 17, the American Carrier group, consisted of HMAS Australia and HMAS Hobart as well as several USN ships. This group was headed by Rear Admiral J.G Crace of the Royal Navy. After being split from the carrier force to cover the Jomard Passage and intercept the Japanese invasion force as it exited, the support group became the target of heavy bombing and strafing attacks. After repelling these attacks, the group was free to intercept the Japanese invasion force. However Admiral Inouye, in charge of this invasion force, reversed his ships whilst they clarified the sightings of ‘battleships’ in the area. Had Crace’s ships not been detached from Task Force 17, the Japanese force would have been able to enter Port Moresby, resulting in grave consequences for the Allies.

As mentioned previously, Australia was a vulnerable target which relied greatly on Port Moresby for its security. The Battle of the Coral Sea resulted in Australia being protected from the threat of imminent invasion and supply lines between the United States and Australia remained open. It was also the first time Australian ships had been involved with a major US carrier group, a proud moment in history indeed. (Jacobsen).

Conclusion

Many lessons were learnt from the Battle of the Coral Sea, the first of which being the immense importance of air power in future naval engagements. As a new kind of ‘over the horizon’ warfare had emerged, it became apparent that aircraft would be vital to the success of any kind of naval warfare from that point onwards. Intelligence also proved to be an extremely important factor in deciding the victor in naval engagements. The Americans having effective intelligence prior to the Coral Sea battle meant they were able to deploy their carriers to the area, possibly changing the tide of the war in the Pacific. Despite losing a quarter of its carrier strength, the US had a strategic victory during this battle, one that assisted their position for later conflicts in the Pacific region, particularly the Battle of Midway. The Coral Sea battle held significant strategic importance insofar as control of Port Moresby being maintained by the Allies and in regard to the security of the Australian mainland. The Royal Australian Navy’s contribution, although small in the scheme of things, was significant and contributed to the final result not just during this battle but throughout the Pacific War.

Bibliography

Frame, T., The Battes that Shaped Australia. St Leonards: Allen & Unwin, 1994.

Hoyt, E.P., Blue Skies And Blood – The Battle of the Coral Sea. New York: iBooks, inc., 1975.

Jacobsen, M., The Battle of the Coral Sea 1942– Conference Proceedings 1992. Sydney: Australian National Maritime Museum, 1993.

Macdougall, A., Australia’s Navy. Waverton: Waverton Press, 2005.

Millot, B., The Battle of the Coral Sea. United States of America: Naval Institute Press, 1974.

Stille, M., The Coral Sea 1942 – The First Carrier Battle. Great Britain: Osprey Publishing, 2009.

Straczek, J., Battle of the Coral Sea. [Online]  Available at: https://www.navy.gov.au/history/feature-histories/battle-coral-sea[Accessed 7 October 2014].