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

FIELD: shipbuilding: hull structural members, superstructures, etc. SUBSTANCE: laminated cover of ship's hatch has at least two layers in cross section. Boundary line is made in form of fragment 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 layer of section of at least part of boundary line length. 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 portion of section to at least one of edges. Thickness of at least one layer may increase or decrease repeatedly and intermittently. Over part of length, boundary line of at least one of sides of one layer may be convex or concave relative to center line of section of layer; it may be stepped as well. At least one edge of material may have bend and/or partial bend with repeated change of concavity, opposite concavity inclusive. Over part of length, such line may be made with one projection or with one recess. At least one of layers may be made from metal. EFFECT: improved characteristics of cover. 24 cl, 21 dwg