On 6 January, the Japanese convoy carrying Okabe's force set out for Lae from Rabaul. Forewarned by Ultra, USAAF and RAAF aircraft spotted, shadowed and attacked the convoy, which was shielded by low clouds and Japanese fighters. The Allies claimed to have shot down 69 Japanese aircraft for the loss of 10 of their own. A P-38 pilot, First Lieutenant Richard Bong claimed three, becoming an ace. A RAAF Catalina of No. 11 Squadron RAAF under the command of Flight Lieutenant David Vernon made a night bombing attack on the convoy which sank the transport "Nichiryu Maru". Destroyers rescued 739 of the 1,100 troops on board, but the ship took with it all of Okabe's medical supplies. Another transport, "Myoko Maru", was so badly damaged at Lae by USAAF B-25s that it had to be beached. Nonetheless, the convoy succeeded in reaching Lae on 7 January and landing about 4,000 troops. In all, the Allied Air Forces flew 416 sorties.