Battle of the Coral Sea and Its Impact on SubSoWesPac

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Since 03-15-05

In May 1957, two San Diego based subs finishing up a routine WesPac cruise paid a courtesy call to Brisbane, Australia. My boat, USS Diodon (SS-349) in company with USS Caiman (SS-323), was to represent the US during Australia’s celebration of the 15th anniversary of the Battle of the Coral Sea (3 – 8 May 1942). The Australians were eternally grateful to the US for turning back the Japanese in this battle, as they had feared the imminent threat of occupation by the Japanese. Suffice to say we were welcomed with open arms by the folks in Brisbane, many that clearly remembered the circumstances.

Years later, this encounter piqued my interest, so much so that I researched the events of the famed battle. I found much had been written about the Battle of the Coral Sea itself, but little had been said about its effect / impact on the US submarine (SubSoWesPac) operations based in Australia. Although no submarine force was directly involved in the Coral Sea battle, the ramifications of the out come of the battle on the submarine force were tremendous.

The Japanese controlled the north coast of New Guinea, and desperately wanted to capture Port Moresby on the south coast of the island as that would give them control of the southern periphery of the Greater Asia Co-Prosperity Sphere established by the Japanese strategists. It naturally follows that it would also be a major port of debarkation for the intended invasion of Australia. Port Moresby would be another Truk or Rabaul, which were major supply bases in the southwest Pacific for the ever-expanding Japanese Empire.

In spite of controlling the north coast of New Guinea, the Japanese could not go overland to Port Moresby on the south shore because of the rugged, mountainous terrain. This meant the invasion had to be from the sea. The code-breakers (FruPac) intercepted and decoded enough information to realize that the heavy concentration of naval activity at Rabaul could only mean they were headed for Port Moresby via the Coral Sea.

Admiral Nimitz dispatched the carriers Lexington (CV-2) and Yorktown (CV-5) and their associated task forces to oppose any such invasion. The carriers Hornet (CV-8) and Enterprise (CV-6) were also directed to the area, but they were too far away and arrived on the scene after the battle was essentially over.

The Japanese had three forces, a carrier force, a covering force and a landing force. The carrier and the covering force’s objectives were to screen and protect the landing force. It was these two forces which encountered the Yorktown and Lexington forces.


The battle, which ensued, was unique in that it was fought strictly with carrier air power from both sides. No major ship of either Navy directly engaged another ship – the fleets were over the horizon from each other often in the 200 to 300 mile ranges. This was a “first time” occurrence for this type of battle. Here-to-fore broad sides and battleships were the rule. Neither side had a clear strategy, but both were developing one in real time.

The US lost the carrier Lexington, the oiler Neosho and the destroyer Sims. The Yorktown was heavily damaged and 31 planes were lost in combat and another 35 went down with the Lex. The Japanese lost the carrier Shohu and the carrier Shokaku was damaged. Other loses included a cruiser, 2 destroyers, a cargo ship, 4 gunboats and 104 planes.

Most analyses of the battle rate the battle as a toss up – probably heavily weighted by each side’s loses or damage to carriers. I have come to another conclusion, however.

By thwarting the Japanese attempt to occupy Port Moresby, they did not gain control of the sea between New Guinea and Australia and consequently gave up the attempt to invade Australia. In so doing, this assured that the submarine forces of SubSoWesPac established in Brisbane and Perth/Fremantle remained secure.

Had this not been the outcome, the whole operational strategy of the southwest Pacific would have been different. The Japanese controlled all the Philippines, Marianas, Gilberts, Marshalls, Carolinas and Solomon’s. The US’s only recourse would have been to put all submarines under ComSubPac and operate out of Pearl. The associated extended transit times to war patrol areas would have favored the Japanese especially when there weren’t enough Gato class boats at this time which could make the transit – only 4 Gato boats were in commission at the onset of the war. The older class boats didn’t have the range or endurance. The whole complexion and duration of the war would have certainly changed, albeit in favor of the Japanese.

Therefore, in the eyes of this submarine veteran, the US came away as the winners of the Battle of the Coral Sea – Australia was never occupied and the subs attached to ComSubSoWesPac operated at a much higher efficiency level in spite of the continued torpedo problems yet to be identified and resolved.

Don Messner

Qualified in Submarines on USS Diodon (SS-349)