Despite the damaging air attacks to their ships and landing forces, the Japanese proceeded with the construction of the naval seaplane base at Tulagi and Gavutu, receiving more shipments of troops and construction workers over the next several months. The base was soon operational with aircraft from the Yokohama Air Group which conducted air reconnaissance patrols throughout the surrounding area beginning on 6 May. On 27 May, the Japanese inspected the Lunga Point area on Guadalcanal as a possible location to build a large airfield. On 13 June, the Naval General Staff approved the construction of an airfield at that location and on 19 June, Admiral Inoue toured the site in anticipation of the airfield construction effort. The next day, Japanese troops began clearing the area of brush, and on 6 July, a 12-ship convoy delivered 2,000 Korean and Japanese construction workers plus 500 Japanese naval combat troops to conduct the airfield construction effort in earnest. The coastwatchers on Guadalcanal and Allied air reconnaissance observed the Japanese airfield construction efforts. Allied Catalinas and B-17s based at Port Moresby, Efate, Noumea, and Espiritu Santo frequently bombed the Japanese bases on Guadalcanal, Tulagi, and Gavutu over the next several months, but without causing significant damage. Several Japanese float fighters and one Allied bomber were destroyed in aerial combat during the missions.