Japanese icebreaker Ōtomari

The Ōtomari (大泊) was an icebraker of the Imperial Japanese Navy (IJN) serving during the 1920s through World War II, the only ship of her class. She was an only icebreaker as warship in the IJN.

Background
Ōtomari was planned as one of the Kamoi-class oilers under the Eight-eight fleet plan at first. However, Nikolayevsk Incident changed her future. IJN was not able to dispatch their warship to Nikolayevsk which froze, because they did not have an icebreaker. All Japanese civilians were killed by terrorist in this incident. Japan was afraid that this dire disaster occur once again, because the Russian Civil War continued in this time. Japan built only lead ship about the Kamoi-class oiler. Other 5 vessels, they rearranged a budget and built three oilers (Ondo-class), one food supply ship (Mamiya), and one icebreaker (Ōtomari). As for Japan, the icebreaker architecture was the first experience. IJN began by observing a sample of neighboring various countries, They decided to make a model of the Russian icebreaker Dobrynya Nikitich. The IJN hurried work of Otomari, because they wanted her until Winter 1921, she was completed from a building start in only four months. She was assigned to Ōminato Guard District and took northern patrol duties, and continued being active for her life. In World War II, the IJN planned her succeeding ship Esan (恵山, Project Number J23, 6,800 tons standard) under the Kai-Maru 5 program in 1942, because Ōtomari was old and small, however, Esan was canceled in 1943.

Service
Ōtomari acted in Sakhalin, Kuril Islands and Sea of Okhotsk between all time except maintenance. In July 1945, she sailed to Yokosuka Naval Arsenal for maintenance. However, she was not able to take maintenance because Japan was surrendered. Japan was going to employ her as repatriation transport, however, it was given up, because her boiler was worn out. She was scrapped in March 1950.