Semi-submersible vessel, method for operating a semi-submersible vessel and method for manufacturing a semi-submersible vessel

摘要

The present invention relates to a semi-submersible vessel comprising at least one lower hull section (22) which defines a first water displacing volume; a support structure (24) connected to the at least one lower hull section (22) and extending upward from the at least one lower hull section, wherein the support structure (24) has a waterplane area which is substantially smaller than the waterplane area of the at least one lower hull section; a deck structure (26) connected to the support structure (24), wherein the deck structure (26) is provided at a distance above the at least one lower hull section (22); a ballast system for controllably varying the draft of the vessel such that at a first draft (30) the at least one lower hull section (22) may be provided at least in part above the water-line and at a second draft (28) the support structure may be provided at least partly below the water-line; wherein the assembly of said at least one lower hull section, said support structure and said deck structure comprises structural reinforcements, such that the vessel is sufficiently strong to substantially safely survive a storm at the first draft (30). The invention further relates to a method of operating such a semi-submersible vessel.

主权项

1. An autonomous, self-propelled semi-submersible vessel comprising:
at least one lower hull section which defines a first water displacing volume, the at least one lower hull section comprising a propulsion system and a dynamic positioning system using propulsion and/or thrusters to control horizontal positioning of the autonomous, self-propelled semi-submersible vessel; a support structure connected to the at least one lower hull section and extending upward from the at least one lower hull section wherein the support structure has a waterplane area which is smaller than the waterplane area of the at least one lower hull section; a deck structure connected to the support structure, wherein the deck structure is provided at a distance above the at least one lower hull section; and a ballast system for controllably varying the draft of the vessel; wherein the vessel is designed and constructed to be operated at a number of different predescribed drafts which are specified for that vessel, the predescribed drafts comprising:
an operational draft for carrying out an operation,a transit draft for travelling large distances, anda survival draft for surviving a storm; the semi-submersible vessel having structural reinforcements configured for operation of the semi-submersible vessel at the survival draft, in which survival draft the at least one lower hull section of the semi-submersible vessel is partly above a waterline.