Invasion of Tulagi (May 1942) - Aftermath

Aftermath

On 5 May, Kikuzuki slid off of the shore of Gavutu and sank in Tulagi harbor, a total loss (09°07′S 160°12′E / 9.117°S 160.2°E / -9.117; 160.2). Tama Maru foundered two days later. The other surviving, damaged Japanese ships were able to reach Rabaul and Kavieng for repairs. Hagoromo Maru and Noshiro Maru #2 joined the Port Moresby Invasion Group. On 10 May, as Okinoshima participated in the first Japanese attempt to take Ocean (Banaba) and Nauru Islands, titled Operation RY, she was sunk by the submarine USS S-42 off New Ireland (05°06′S 153°48′E / 5.1°S 153.8°E / -5.1; 153.8). A total of 87 Japanese naval personnel died in the 4 May air attacks on Tulagi, and 36 of the landing troops were seriously injured.

The lost Yorktown TBD aircrew reached Guadalcanal after drifting in the ocean for three days. A Roman Catholic missionary took them to Martin Clemens who arranged for a boat to take them to San Cristobal. From San Cristobal, another boat took them to the New Hebrides and from there they eventually rejoined U.S. forces.

After striking Tulagi, Yorktown rejoined with Lexington, and the two carriers engaged the rest of the Japanese forces involved in the Mo operation from 6–8 May in the Battle of the Coral Sea. In the battle, Lexington was sunk and Yorktown was damaged. The Japanese suffered Shōhō sunk, a fleet carrier heavily damaged, and heavy losses to their carrier aircraft and aircrews. Fearing more damaging attacks from Allied land-based aircraft or warships and unable because of their aircraft losses to provide adequate air cover for their naval surface forces, the Japanese turned back from their planned assault on Port Moresby with the intention of trying again later. The next Japanese seaborne attempt to take Port Moresby, however, never happened, mainly because of their navy's defeat in June at the Battle of Midway. Instead, the Japanese decided to try to take Port Moresby in an ultimately unsuccessful overland attack along the Kokoda Track. The failure to take Port Moresby in May 1942 would have significant and far-reaching strategic implications, many of which involved the small Japanese naval base at Tulagi.

Despite the damaging air attacks to their ships and landing forces, the Japanese proceeded with the construction of the naval seaplane base at Tulagi and Gavutu, receiving more shipments of troops and construction workers over the next several months. The base was soon operational with aircraft from the Yokohama Air Group which conducted air reconnaissance patrols throughout the surrounding area beginning on 6 May. On 27 May, the Japanese inspected the Lunga Point area on Guadalcanal as a possible location to build a large airfield. On 13 June, the Naval General Staff approved the construction of an airfield at that location and on 19 June, Admiral Inoue toured the site in anticipation of the airfield construction effort. The next day, Japanese troops began clearing the area of brush, and on 6 July, a 12-ship convoy delivered 2,000 Korean and Japanese construction workers plus 500 Japanese naval combat troops to conduct the airfield construction effort in earnest. The coastwatchers on Guadalcanal and Allied air reconnaissance observed the Japanese airfield construction efforts. Allied Catalinas and B-17s based at Port Moresby, Efate, Noumea, and Espiritu Santo frequently bombed the Japanese bases on Guadalcanal, Tulagi, and Gavutu over the next several months, but without causing significant damage. Several Japanese float fighters and one Allied bomber were destroyed in aerial combat during the missions.

The Allies were greatly concerned about the Japanese airfield construction effort on Guadalcanal because, when completed, the aircraft operating from the airfield would be a significant threat to Allied operations between Australia, New Zealand, and the U.S. The two strategic victories for the Allies in the battles of the Coral Sea and Midway provided an opportunity to take the initiative and launch an offensive against the Japanese somewhere in the Pacific. An Allied plan to attack the southern Solomons was conceived by U.S. Admiral Ernest King, Commander in Chief, United States Fleet. He proposed the offensive to deny the use of the southern Solomon Islands by the Japanese as bases to threaten the supply routes between the U.S. and Australia, and to use them as starting points for a campaign. His goal was to neutralize or capture the major Japanese base at Rabaul while also supporting the Allied New Guinea campaign, with the eventual goal of opening the way for the U.S. to retake the Philippines. U.S. Admiral Chester Nimitz—Allied commander-in chief for Pacific forces—created the South Pacific theater—with U.S. Vice Admiral Robert L. Ghormley in command—to direct the Allied offensive in the Solomons.

The failure of the Japanese to take Port Moresby and their defeat at Midway had the effect of dangling their base at Tulagi without effective protection from other Japanese bases. Tulagi was four hours flying time from Rabaul, the nearest large Japanese base. On 7 August 1942, 11,000 U.S. Marines landed on Guadalcanal and 3,000 U.S. Marines landed on Tulagi and nearby islands. The Japanese troops on Tulagi and nearby islands were outnumbered and killed almost to the last man in the Battle of Tulagi and Gavutu-Tanambogo while the U.S. Marines on Guadalcanal captured the airfield at Lunga Point without significant resistance. Thus began the Guadalcanal campaign that resulted in a series of large, combined-arms battles between Allied and Japanese forces over the next six months which—along with the New Guinea campaign—would decide the fate of Japanese efforts to secure the southern frontier of their empire in the Pacific.