The invention relates to a method of constructing and launching an offshore semi-submersible platform, comprising: a) making said semi-submersible platform in a dry environment by dividing it into a plurality of sub-assemblies each of which comprises at least one of the floating columns and at least one semi-arm of a respective lower structural connection arm; b) providing each sub-assembly in a dry environment with at least one temporary thrust box; c) separately launching in water the individual sub-assemblies; d) adjusting for each sub-assembly the ballast of the respective temporary thrust box so as to obtain a balanced floatation of the sub-assembly; e) bringing the sub-assemblies at the free ends of the respective semi-arms close to each other two-by-two until they are aligned; f) connecting the temporary thrust boxes to each other two-by-two; g) welding the free ends of the semi-arms together; h) removing the temporary thrust boxes.

The invention relates to a method of constructing and launching an offshore semi-submersible platform, comprising: a) making said semi-submersible platform in a dry environment by dividing it into a plurality of sub-assemblies each of which comprises at least one of the floating columns and at least one semi-arm of a respective lower structural connection arm; b) providing each sub-assembly in a dry environment with at least one temporary thrust box; c) separately launching in water the individual sub-assemblies; d) adjusting for each sub-assembly the ballast of the respective temporary thrust box so as to obtain a balanced floatation of the sub-assembly; e) bringing the sub-assemblies at the free ends of the respective semi-arms close to each other two-by-two until they are aligned; f) connecting the temporary thrust boxes to each other two-by-two; g) welding the free ends of the semi-arms together; h) removing the temporary thrust boxes.

A cargo hold having a plurality of spaces, which are formed by a longitudinal bulkhead and a transverse bulkhead intersecting each other and store crude oil, comprises a void space located at least one corner among corners formed by intersection of the longitudinal bulkhead and the transverse bulkhead, wherein the void space has one side end and the other side end sealed by and fixed to the longitudinal bulkhead and the transverse bulkhead, respectively, thereby forming an empty space inside the bulkheads. The vessel cargo hold prevents a danger, such as fire and explosion, which may occur during the maintenance or repair of the vessel cargo hold for storing crude oil, and decreases work or the like required for the maintenance or repair of the cargo hold.

Disclosed is a heat-insulation system for a liquefied natural gas cargo hold, which comprises a primary sealing wall, a secondary sealing wall, and a secondary heat-insulating layer, and is applied to a liquefied natural gas cargo hold. The heat-insulation system for a liquefied natural gas cargo hold comprises a collar stud installed on a line on the upper surface of the secondary heat-insulating layer where an anchor strip is installed.

A fabrication system (100) for the manufacture of a support frame (10) for a pressure vessel (12). The support frame (10) is fabricated from a plurality of sub-elements (202, 204). The fabrication system comprises a jig assembly (300), a clamping system (400) mounted on the jig assembly (300) and the jig assembly (300) being rotatably mounted about a rotation axis (302), and extending out radially from the rotation axis (302) to an outer edge (304). A plurality of workstations (600, 602, 604) are arranged around the outer edge (304) of the jig assembly (300), located and configured to perform operations on the sub-elements (202, 204). The plurality of workstations (600, 602, 604) are mounted in a fixed position, the jig assembly (300) being rotatable about the rotation axis (302) relative to the workstations (600, 602, 604).

The invention relates to a pressure hull for human occupancy, which is manufactured using an additive manufacturing process. This results in increased structural integrity and safety for the occupants of the pressure hull.

The invention relates to a pressure hull for human occupancy, which is manufactured using an additive manufacturing process. This results in increased structural integrity and safety for the occupants of the pressure hull.

Assembled submarine hull steel components, each steel component having a chemical composition consisting of, in weight percent:
0.030%C<0.080%
0.040%Si0.13%
0.1%Mn1.4%
2%Ni4%
Cr0.3%
0.30%Mo+W/2+3(V+Nb/2+Ta/4)0.89%
0.15%Mo0.89%
V+Nb/2+Ta/40.004%
Nb0.004%
Cu0.45%
Al0.1%
Ti0.04%
N0.0300%
impurities resulting from the production operation, said impurities including
B0.0005%,
P+S0.015%,
the balance being iron, the chemical composition complying with the condition:
410540C.sup.0.25+245[Mo+W/2+3(V+Nb/2+Ta/4)].sup.0.30460.

An approach for assembling a maritime vehicle includes forming a keel panel from a single sheet of metal, forming a first side panel from a single sheet of metal, forming a second side panel from a single sheet of metal, and forming a lip member. The first side panel and the second side panel are temporarily coupled with the lip member. The keel panel is secured with the first side panel and the second side panel using a cold joining process.

An approach for assembling a maritime vehicle includes forming a keel panel from a single sheet of metal, forming a first side panel from a single sheet of metal, forming a second side panel from a single sheet of metal, and forming a lip member. The first side panel and the second side panel are temporarily coupled with the lip member. The keel panel is secured with the first side panel and the second side panel using a cold joining process.