The invasion force was indeed on its way to its targets, Guadalcanal, Tulagi, and the tiny islets of Gavutu and Tanambogo close by Tulagi’s shore. The landing force was composed of Marines; the covering force and transport force were U.S. Navy with a reinforcement of Australian warships. There was not much mystery to the selection of the 1st Marine Division to make the landings. Five U.S. Army divisions were located in the South and Southwest Pacific: three in Australia, the 37th Infantry in Fiji, and the Americal Division on New Caledonia. None was amphibiously trained and all were considered vital parts of defensive garrisons. The 1st Marine Division, minus one of its infantry regiments, had begun arriving in New Zealand in mid-June when the division headquarters and the 5th Marines reached Wellington. At that time, the rest of the reinforced division’s major units were getting ready to embark. The 1st Marines were at San Francisco, the 1st Raider Battalion was on New Caledonia, and the 3d Defense Battalion was at Pearl Harbor. The 2d Marines of the 2d Marine Division, a unit which would replace the 1st Division’s 7th Marines stationed in British Samoa, was loading out from San Diego. All three infantry regiments of the landing force had battalions of artillery attached, from the 11th Marines, in the case of the 5th and 1st; the 2d Marines drew its reinforcing 75mm howitzers from the 2d Division’s 10th Marines.
The news that his division would be the landing force for Watchtower came as a surprise to Major General Alexander A. Vandegrift, who had anticipated that the 1st Division would have six months of training in the South Pacific before it saw action. The changeover from administrative loading of the various units’ supplies to combat loading, where first-needed equipment, weapons, ammunition, and rations were positioned to come off ship first with the assault troops, occasioned a never-to-be-forgotten scene on Wellington’s docks. The combat troops took the place of civilian stevedores and unloaded and reloaded the cargo and passenger vessels in an increasing round of working parties, often during rainstorms which hampered the task, but the job was done. Succeeding echelons of the division’s forces all got their share of labor on the docks as various shipping groups arrived and the time grew shorter. General Vandegrift was able to convince Admiral Ghormley and the Joint Chiefs that he would not be able to meet a proposed D-Day of 1 August, but the extended landing date, 7 August, did little to improve the situation.