Guadalcanal Campaign - Initial Operations

Initial Operations

The 11,000 Marines on Guadalcanal initially concentrated on forming a loose defensive perimeter around Lunga Point and the airfield, moving the landed supplies within the perimeter and finishing the airfield. In four days of intense effort, the supplies were moved from the landing beach into dispersed dumps within the perimeter. Work began on the airfield immediately, mainly using captured Japanese equipment. On August 12 the airfield was named Henderson Field after Lofton R. Henderson, a Marine aviator who was killed during the Battle of Midway. By August 18 the airfield was ready for operation. Five days worth of food had been landed from the transports, which, along with captured Japanese provisions, gave the Marines a total of 14 days worth of food. To conserve supplies, the troops were limited to two meals per day.

Allied troops encountered a severe strain of dysentery soon after the landings, with one in five Marines afflicted by mid-August. Tropical diseases would affect the fighting strengths of both sides throughout the campaign. Although some of the Korean construction workers surrendered to the Marines, most of the remaining Japanese and Korean personnel gathered just west of the Lunga perimeter on the west bank of the Matanikau River and subsisted mainly on coconuts. A Japanese naval outpost was also located at Taivu Point, about 35 kilometres (22 mi) east of the Lunga perimeter. On August 8, a Japanese destroyer from Rabaul delivered 113 naval reinforcement troops to the Matanikau position.

On the evening of August 12, a 25-man U.S. Marine patrol, led by Lieutenant Colonel Frank Goettge and primarily consisting of intelligence personnel, landed by boat west of the Lunga perimeter, between Point Cruz and the Matanikau River, on a reconnaissance mission with a secondary objective of contacting a group of Japanese troops that U.S. forces believed might be willing to surrender. Soon after the patrol landed, a nearby platoon of Japanese naval troops attacked and almost completely wiped out the Marine patrol.

In response, on August 19, Vandegrift sent three companies of the U.S. 5th Marine Regiment to attack the Japanese troop concentration west of the Matanikau. One company attacked across the sandbar at the mouth of the Matanikau river while another crossed the river 1,000 metres (1,100 yd) inland and attacked the Japanese forces located in Matanikau village. The third landed by boat further west and attacked Kokumbuna village. After briefly occupying the two villages, the three Marine companies returned to the Lunga perimeter, having killed about 65 Japanese soldiers while losing four. This action, sometimes referred to as the "First Battle of the Matanikau", was the first of several major actions around the Matanikau River during the campaign.

On August 20, the escort carrier USS Long Island delivered two squadrons of Marine aircraft to Henderson Field, one a squadron of 19 F4F Wildcats and the other a squadron of 12 SBD Dauntlesses. The aircraft at Henderson became known as the "Cactus Air Force" (CAF) after the Allied codename for Guadalcanal. The Marine fighters went into action the next day on the first of the almost-daily Japanese bomber air raids. On August 22 five U.S. Army P-400 Airacobras and their pilots arrived at Henderson Field.