SHIP'S HATCH COVER Russian patent published in 1999 - IPC

FIELD: shipbuilding; hull structural members, superstructures, etc. SUBSTANCE: at least part of boundary line of section is made in form of fragment and/or combination of fragments of oblique taper section of right circular cone at boundary of front and/or rear side of at least one layer and/or at least one of vertices of at least one of layers of section. Angle of at least one of vertices of at least one of layers of section may be lesser than 180 deg. At least one of layers may have varying thickness. Thickness of at least one of layers increases from one edge of section to other. It may increase or decrease from inner part of section towards at least one of edges. Thickness of least one of layers may repeatedly increase or decrease or change repeatedly and intermittently. Over part of length , boundary line of at least one of sides of at least one of layers may be convex or concave relative to center line of section of layers; it may be also stepped. At least one edge of cover may have bend or partial bend at repeatedly changing concavity, opposite concavity inclusive. Over part of length, such line may have at least one projection or at least one recess. At least one of vertices of cover section may be provided with at least one recess or one projection. Thickness of cover may have at least one discontinuity. Discontinuities may be repeated and intermittent. EFFECT: improved service characteristics. 21 cl, 18 dwg