of the Osaka Shipping Line were requisitioned for conversion to armed merchant cruisers (AMC)s, in anticipation of the likely thrust southward by the Japanese. The (the name ship of the class) and , both under construction for the route between the Empire of Japan and South America, started their rebuilds in 1941, and by the time they were commissioned, the 10,470-ton vessels were heavily armed. The main armament consisted of eight 140 mm/50 caliber guns, which were augmented by two 80 mm guns, and four 25 mm guns. There were four 533 mm torpedo tubes in twin mounts, and each vessel had two Mitsubishi F1M2 "Pete" Type 0 observation seaplanes, each armed with two fixed forward firing Type 97 machine guns, one flexibly mounted rearward-firing Type 92 machine gun and 120 kg of bombs. Initial deployment With their heavy armament, the two Japanese merchant raiders could overpower any smaller combatant or merchant vessel, and their speed enabled them (in combination with their floatplanes) to search large areas of ocean. In service, they were organized as the 24th Special Cruiser Squadron under Rear-Admiral Moriharu Takeda. Hōkoku Maru was modified to serve as Admiral Takeda's flagship with space for his staff of four officers and eighteen men. The 24th Special Cruiser Squadron departed Hiroshima Bay on 15 November 1941 under radio silence and blacked out at night to arrive in a standby position at Jaluit Atoll in the Marshall Islands. They departed Jaluit on 26 November 1941 to patrol the sea lanes between Australia, Samoa, Fiji, the United States, and the Panama Canal. The operational plan was for one ship to lie-to and drift while performing maintenance, as the other ship carried out a perimeter patrol searching for enemy shipping. The two ships would spend the hours of darkness within visual range; the ships then reversed roles the following day. Following the Attack on Pearl Harbor, the search objective changed from avoiding detection to locating enemy commerce. Following sunset on 12 December 1941, Hōkoku Maru stopped the 6,210-ton United States freighter Vincent bound for the Panama Canal from Sydney, Australia at 23 south, 118 west. The old freighter was sunk after taking her crew of 38 aboard the two raiders. The Japanese ships then left the area to avoid any response to Vincents radio SOS. Routine searching resumed on 23 December 1941. On 31 December, a seaplane from Aikoku Maru found and