In the early part of 1945, monsoonal weather in Darwin reduced the number of missions flown by No. 76 Wing. On the night of 5/6 April, three Catalinas kept watch on the Japanese cruiser , which was subsequently struck by Allied bombers and sunk by submarines. During the month, the Catalinas mined Hong Kong harbour, as well as targets on the coast of mainland China, flying up to sixteen hours per mission. On 26 May, they undertook the RAAF's most northerly operation during the Pacific War, against Wenchow. The same month, Group Captain Stuart Campbell, former leader of No. 42 Squadron, took over command of the wing. In May–June, reinforced by a detachment from No. 11 Squadron, No. 76 Wing flew mining and bombing missions in support of the forthcoming Operation Oboe Six, the Battle of North Borneo, and Oboe Two, the Battle of Balikpapan. Before Oboe Six, while some of the Catalinas concentrated on mining the approaches to Surabaya harbour, others bombed airfields in Java and Celebes in concert with RAAF B-24 Liberators. The Catalinas and Liberators combined again in the lead-up to Oboe Two to raid any Japanese airfields that could threaten Balikpapan, in some cases bombing the same target around the clock, the Catalinas by night and Liberators by day.