Having patrolled the Buka-Kilinailau Channel for 17 days, on 7 December, Kennedy decided to patrol the direct route between Truk and the Shortland Islands for a few days. This proved fruitless, and "Wahoo" returned to her former hunting grounds, the Buka-Kilinailau Channel. On 10 December, while making her return trip, "Wahoo" ran across a convoy of three heavily loaded cargo ships escorted by a destroyer. She chose the destroyer as the first target, but proved unable to attain a firing position. Instead, she fired a spread of four torpedoes at the largest tanker, from a range of . Although three hit, it took two hours for "Kamoi Maru" () to sink. The destroyer got too close and "Wahoo" started down before another attack could be launched. The destroyer dropped approximately 40 depth charges, none close. Rather than use the new SJ radar to mount a second attack, which might well sink the freighter (then stopped to pick up survivors), and possibly even the destroyer, "Wahoo" let them go on a northeasterly course and moved into a new area.