巴士海峽
The submarine returned to the Luzon Strait, where she found the variable currents in the two main channels (Bashi Channel and Balintang Channel) made keeping trim very tricky. On 28 October she was attacked with no effect (beyond a little fright for her lookouts) by an anti-submarine aircraft. For the next two weeks, in constantly poor weather, "Halibut" found no enemy shipping except the hospital ship "Hikawa Maru", which could not be attacked.