Passage: Throughout August, small numbers of U.S. aircraft and their crews continued to arrive at Guadalcanal. By the end of August, 64 aircraft of various types were stationed at Henderson Field. On 3 September, the commander of the 1st Marine Aircraft Wing, U.S. Marine Brigadier General Roy S. Geiger, arrived with his staff and took command of all air operations at Henderson Field. Air battles between the Allied aircraft at Henderson and Japanese bombers and fighters from Rabaul continued almost daily. Between 26 August and 5 September, the U.S. lost about 15 aircraft to the Japanese's approximately 19 aircraft. More than half of the downed U.S. aircrews were rescued while the majority of the Japanese aircrews were never recovered. The eight-hour round-trip flight from Rabaul to Guadalcanal, about 1,120 miles (1,800 km) in total, seriously hampered Japanese efforts to establish air superiority over Henderson Field. Australian coastwatchers on Bougainville and New Georgia islands were often able to provide the Allied forces on Guadalcanal with advance notice of inbound Japanese air strikes, allowing the U.S. fighters time to take off and position themselves to attack the Japanese bombers and fighters as they approached the island. As such, the Japanese air forces were slowly losing a war of attrition in the skies above Guadalcanal.During this time, Vandegrift continued to direct efforts to strengthen and improve the defenses of the Lunga perimeter. Between 21 August and 3 September, he relocated three Marine battalions, including the 1st Raider Battalion, under Merritt A. Edson (Edson's Raiders), and the 1st Parachute Battalion from Tulagi and Gavutu to Guadalcanal. These units added about 1,500 troops to Vandegrift's original 11,000 men defending Henderson Field. The 1st Parachute Battalion, which had suffered heavy casualties in the Battle of Tulagi and Gavutu–Tanambogo in August, was placed under Edson's command.The other relocated battalion, the 1st Battalion, 5th Marine Regiment (1/5), was landed by boat west of...

Question: Why did the convoy need to bring 392 Seabees with them?
to maintain and improve Henderson Field