On December 26, 1943, when the 1st Marine Division went ashore at Cape Gloucester, on the northwest tip of New Britain, it was accompanied by the 19th Construction Battalion, whose mission was the building of roads for supplies and access during the assault, and the preparation of beaches and piers for landing craft.
Reconstruction of two enemy airstrips, which were the principal objectives of the attack and from which United States planes could continue raids against Japanese-held Rabaul and Kavieng, was carried out by the 1913th and 841st Army Aviation Engineer Battalions. The strips were captured by the Marines on December 30, and next day the American flag was raised over all Cape Gloucester.
Road construction, with necessary bridges, continued throughout the Seabees' stay. Pulverized volcanic slag produced a surface so hard that even after continual truck traffic, the tread of a large bulldozer did not cut into the surface.
A new method of "drilling" holes for blasting was developed on this work. A 75-mm armor-piercing shell, fired into a rock ledge by a General Sherman tank, left a hole about 10 inches in diameter and 10 feet deep which could be quickly prepared for a dynamite charge.
Waterfront construction consisted of a rock-fill pile-and-crib finger pier, 130 feet long and 50 feet wide, a 160-foot rock-fill approach jetty for a cargo-ship berth, landing-craft unloading pier, and a 350-foot seawall of piles and log-facing, backed with large boulders.
The 19th Battalion, the only Seabee group at Cape Gloucester, was attached to the First Marine Division and left with the division in late April for the Russells. During the first weeks, continuous enemy air raids resulted in 5 men of the battalion killed and 24 wounded.