To improve the strength at a butted part of a thick plate and a thin plate, and, in particular, to keep the strength at a corner part of a hatchway of a hull.
A joined structure is provided with a thin plate part 1c in which an edge part of a thick plate 1a is of the same thickness (t) as that of a thin plate 1 as far as the position slightly away from a joined part J on the thick plate 1a to form a corner part of a hatchway of a deck of a hull, and a part 1e in which the thickness is gradually increased to the thickness T of the thick plate body. Even when the stress concentration is generated due to the geometrical discontinuity at the boundary of the thin plate part 1c with the gradually- increased thickness part 1e, the structure is favorable in terms of the strength compared with the conventional structure because the corner part is away from the joined part J.
TOZAWA HIDE