Meanwhile, at around 16:00, the 13th Infantry Regiment reached a mangrove swamp on the bank of the Barike River, where they began to assemble for the attack on the beachhead.Rentz, Marines in the Central Solomons, p. 83 The rear area of the U.S. beachhead consisted of many spread out camps and facilities that were mainly occupied by logistics, support and technical troops. Throughout the night of 17–18 July, formed into small section or platoon-sized groups, the Japanese succeeded in infiltrating and attacking several isolated outposts in the American rear areas, which were hastily defended by small groups of support troops. Over several hours, they carried out minor raids against supply dumps and engineer depots, and ambushed medical parties, inflicting many casualties on the American forces. During the confused fighting, the Japanese raiders destroyed vital telephone switchboards in an effort to disrupt communications. Nevertheless, the US forces were able to maintain communications with their supporting artillery battalions through a single telephone and throughout the night the artillery liaison officer called down heavy barrages from offshore batteries in response, some within of the divisional command post.Miller, Cartwheel: The Reduction of Rabaul, p. 136
