The process was further expedited by employing cargo nets to move cargo unbroken from the ships to the beach. Once unloading was completed, Wilkinson then took his ships out of the area out of fear of an overnight attack by Japanese surface ships. The unloading continued the following day under air attack and ground fire from Japanese in the beachhead area. The Japanese airbases at Kahili and Kieta on Bougainville, and nearby islands of Buka and Balalae, had been knocked out before the invasion, but were soon repaired and used for night bombing attacks. The shallow water prevented LSTs from beaching closer than from the shore. Ramps had to be constructed to allow them to unload.