航海法や工場法の適用を受けない船であったため

'The Crab Cannery Ship' (Kani Kosen) is an immortal masterpiece of Japanese proletarian literature written by Takiji Kobayashi in the early Showa period. The Hakuko Maru, a crab cannery ship that set sail for the freezing seas of the Kamchatka Peninsula, was a huge 'prison' in a lawless zone exempt from the application of navigation and factory laws, where laborers endured harsh work in a dark, unhygienic ship bottom called 'kusotsubo' (shithole).