Abstract: A first permissible operating range of the self-elevating vessel is determined based on a first structural analysis of the self-elevating vessel under a first set of conditions. A structural utilization ratio of the self-elevating vessel is determined based on a second structural analysis of the self-elevating vessel under first and second sets of conditions. Safety of lowering the self-elevating vessel from an elevated state to a first hull draft level is determined when the structural utilization ratio is less than a predetermined value. Safety of lowering the self-elevating vessel from the first hull draft level to a second hull draft level is indicated when positional displacement data obtained while the vessel is at the first hull draft level indicates that the positional displacement of the self-elevating vessel while at the first hull draft level is within the first permissible operating range.

Abstract: A dual tower rig includes a hull supported by one or more legs and includes a cantilever assembly coupled to the hull. Dual towers are supported by a skidding system that is coupled to the cantilever assembly. The towers are configured to conduct independent operations and are movable relative to each other and to the hull by the skidding system and the cantilever assembly.

Abstract: A first permissible operating range of the self-elevating vessel is determined based on a first structural analysis of the self-elevating vessel under a first set of conditions. A structural utilization ratio of the self-elevating vessel is determined based on a second structural analysis of the self-elevating vessel under first and second sets of conditions. Safety of lowering the self-elevating vessel from an elevated state to a first hull draft level is determined when the structural utilization ratio is less than a predetermined value. Safety of lowering the self-elevating vessel from the first hull draft level to a second hull draft level is indicated when positional displacement data obtained while the vessel is at the first hull draft level indicates that the positional displacement of the self-elevating vessel while at the first hull draft level is within the first permissible operating range.

Abstract: A dual tower rig includes a hull supported by one or more legs and includes a cantilever assembly coupled to the hull. Dual towers are supported by a skidding system that is coupled to the cantilever assembly. The towers are configured to conduct independent operations and are movable relative to each other and to the hull by the skidding system and the cantilever assembly.