To correct the defect in a conventional ship through part for an impervious fence, wherein water containing oil, the red tide, water-bloom, and the like passes through the impervious fence through clearances due to the presence of clearances at both end hinge parts and the lower part of a door body in a biparting type, and the presence of clearances at connection parts between the door body, and a frame member and a rail at a side part in a vertically sliding opening/closing type.

An impervious curtain 8 of structure and material that can follow the movement of the door body 7 when opened/closed is mounted between both sides of the door body 7 of the ship through part 2 for the impervious fence 1, and the impervious fence 1 adjacently connected to the door body 7. The movement of surface layer water divided by the impervious fence placed in between can thereby be completely intercepted except when the door body 7 is open, to obtain an effect of completely preventing the inflow and diffusion of oil, the red tide, the water-bloom, and the like, which is the original purpose of the impervious fence 1.