A semi-submersible (semisubmerged ship) is a specialised marine vessel utilized in a number of precise offshore roles these as offshore drilling rigs, protection vessels, oil production platforms, and significant elevate cranes. They are made with superior balance and seakeeping features. Other phrases incorporate semisubmersible, semi-sub, or just semi.
1 of the most unusual conversions and updates is Noble Drilling’s EVA-4000 style and design, which, at first, was a shallow-h2o submersible. This triangular submersible was a complete redesign and turned into fourth- and fifth-technology semis. VDL and age are poor definition parameters for technology designation simply because some next-technology units have greater VDLs than some fourth-technology units and simply because age variants inside of a technology, primarily fourth technology just after update, can change extensively.
Fifth-technology units commonly have incredibly substantial VDLs, significant marine-riser pressure, hook load rankings of one.five million lbm, substantial deck place, significant-strain [seven,five hundred-psi working strain (WP)] mud pumps, and comprehensive mud-solids regulate programs.
A spar is a sort of floating oil platform ordinarily utilized in incredibly deep waters, and is named for logs utilized as buoys in shipping and delivery that are moored in location vertically. Spar production platforms have been created as an choice to regular platforms.
A spar platform is made up of a substantial-diameter, one vertical cylinder supporting a deck. The cylinder is weighted at the bottom by a chamber filled with a materials that is denser than h2o to decrease the center of gravity of the platform and provide balance. Spars are anchored to the seabed by way of a unfold mooring system with possibly a chain-wire-chain or chain-polyester-chain composition.
There are three most important kinds of spars the vintage spar, truss spar, and cell spar. The vintage spar is made up of the cylindrical hull mentioned above, with the significant ballast at the bottom of the cylinder.
A truss spar has a shorter cylindrical “difficult tank” than a vintage spar and has a truss structure connected to the bottom of difficult tank. At the bottom of the truss structure, there is a relatively compact, square shaped “delicate tank” that homes the significant ballasting materials. The the vast majority of spars are of this sort.
A cell spar has a substantial central cylinder surrounded by smaller sized cylinders of alternating lengths. At the bottom of the longer cylinders is the delicate tank housing the significant ballasting materials, related to a truss spar. There is at this time only a single cell spar in operation.
Post time: Nov-12-2016