A membrane welding device guide system according to the present invention comprises: an anchor strip arranged on an insulation wall which configures an insulation system of a liquefied gas storage tank; a stud integrally formed with the anchor strip, the center of the stud deviating from a welding line of the anchor strip; and a guide rail which is coupled to the stud to form a path of an automatic membrane welding device for welding a membrane to be stacked on the insulation wall. Therefore, the present invention allows membrane welding to be easily performed and allows a membrane welding device to be stably guided.

An additional chamber to watercraft that adds both volume and curvature to other compartments or components of the watercraft that are essentially flat is described. The additional chamber provides for modular construction of watercraft for creating volumetric space as well as a curved surface to the outer portion of the watercraft. The chamber advantageously increases the aesthetic appeal of the watercraft as well as provides a surface on which water is discouraged from pooling or collecting on. Various watercrafts having such a chamber are also described.

A first and a second tubular member are welded to opposite sides of a stiffening ring in order to obtain a double-segment. Further segments can be added to form a tubular multi-segment with stiffening rings in between adjacent tubular members. The resulting multi-segment is used as a tubular buoyancy module in a floating offshore structure.

A first and a second tubular member are welded to opposite sides of a stiffening ring in order to obtain a double-segment. Further segments can be added to form a tubular multi-segment with stiffening rings in between adjacent tubular members. The resulting multi-segment is used as a tubular buoyancy module in a floating offshore structure.