Abstract: A leg guide for use in a leg of a jack up unit adapted to provide sliding guidance of the leg during vertical movement of the leg. The leg guide has a first portion contacting an edge of a leg chord and a second portion contacting a face of the leg chord along a longitudinal plane opposite the contact plane of the first portion. The edge contacting guide has a deflecting guide unit, which uses a compressible member sandwiched between two rigid plates. As the leg moves, the teeth of the leg chord contact the edge guide unit, with the compressible member absorbing compressible loads acting on the leg chord. The second portion provides for a face plate mounted transversely to the edge contacting guide for reducing the build-up of horizontal moment acting on the leg chord during the vertical movement of the leg and for reducing bending moments acting on the leg.

Abstract: A leg guide for use in a leg of a jack up unit adapted to provide sliding guidance of the leg during vertical movement of the leg. The leg guide has a first portion contacting an edge of a leg chord and a second portion contacting a face of the leg chord along a longitudinal plane opposite the contact plane of the first portion. The edge contacting guide has a deflecting guide unit, which uses a compressible member sandwiched between two rigid plates. As the leg moves, the teeth of the leg chord contact the edge guide unit, with the compressible member absorbing compressible loads acting on the leg chord. The second portion provides for a face plate mounted transversely to the edge contacting guide for reducing the build-up of horizontal moment acting on the leg chord during the vertical movement of the leg and for reducing bending moments acting on the leg.

Abstract: The invention relates to mobile offshore jack-up structures and provides for a self-regulating jacking system for elevating and lowering of the legs and the hull. A central controller assembly regulates movement of each of the legs, depending on the relative speed of movement of each leg and inclination of the hull along two independent axes: forward-aft and starboard-port. Each chord of the supporting legs is inverter driven to ensure a bi-directional full rated torque control of the associated pinion assemblies at very low speeds. By regulating the relative speed of the leg vertical movement, the system monitors the hull inclination within allowable limits and prevents an excessive differential vertical travel of any of the leg chords, thereby minimizing a possibility of leg bending or jamming of the screw jacks of the jacking assemblies 30.

Abstract: The invention relates to mobile offshore jack-up structures and provides for a self-regulating jacking system for elevating and lowering of the legs and the hull. A central controller assembly regulates movement of each of the legs, depending on the relative speed of movement of each leg and inclination of the hull along two independent axes: forward-aft and starboard-port. Each chord of the supporting legs is inverter driven to ensure a bi-directional full rated torque control of the associated pinion assemblies at very low speeds. By regulating the relative speed of the leg vertical movement, the system monitors the hull inclination within allowable limits and prevents an excessive differential vertical travel of any of the leg chords, thereby minimizing a possibility of leg bending or jamming of the screw jacks of the jacking assemblies 30.

Abstract: A leg guide for use in a leg of a jack up unit adapted to provide sliding guidance of the leg during vertical movement of the leg. The leg guide has a first portion contacting an edge of a leg chord and a second portion contacting a face of the leg chord along a longitudinal plane opposite the contact plane of the first portion. The edge contacting guide has a deflecting guide unit, which uses a compressible member sandwiched between two rigid plates. As the leg moves, the teeth of the leg chord contact the edge guide unit, with the compressible member absorbing compressible loads acting on the leg chord. The second portion provides for a face plate mounted transversely to the edge contacting guide for reducing the build-up of horizontal moment acting on the leg chord during the vertical movement of the leg and for reducing bending moments acting on the leg.

Abstract: A brace assembly for truss legs of offshore structures is provided with a reinforcing sleeve mounted on the brace member in the portion of the brace member most prone to buckling under the force of horizontal moment acting on the brace member. The reinforcing sleeve surrounds the critical area of the brace member and provides additional load bearing capacity to the brace member. The reinforcing sleeve is made from a non-corrosive material having physical characteristics suitable to withstand the environmental forces in the location. The reinforcing sleeve may be installed at the shipyard when the offshore structure is manufactured or mounted on the existing rig by an easy retrofit not requiring towing of the offshore structure to the shipyard.