Construction of a PT-boat base on Puruata Island was undertaken by the 75th Naval Construction Battalion, with help from the 71st and 77th Naval Construction Battalions. A wooden pile pier was built, along with crash boat and fueling piers, and 18 small-boat moorings. Base facilities included accommodation, mess halls, five steel-framed warehouses and an emergency hospital. The main medical facility was on Bougainville, and built by the 36th Naval Construction Battalion. It consisted of 70 Quonset huts and a mess hall, with accommodation for 500 patients. The inland road network was the responsibility of the US Army engineers, particularly the 117th Combat Engineer Battalion. They cut supply roads through the jungle. It was found that underneath the deep top soil was volcanic sand, which was suitable for road surfacing. A three-span bridge was built over the Koromokina River. Base development work was completed by July 1944, and the last naval construction battalion, the 36th, departed in August. Construction Battalion Maintenance Units 582 and 586 arrived in May 1944, and took over maintenance of the base facilities.