Abstract: A mechanical connector provided with a thread on substantially matching frustoconical surfaces extending between two sets of metal nipple seals is upgraded with an ability to transfer torque structurally in addition to friction, which is solely utilized to transfer torque in traditional connectors. Other than zero-pitch angle threads can be also effective in novel connector configurations. High torsional and bending load capacities are achieved structurally by use of: splines, dog-clutch teeth, fitted pins, keys, and/or interlocked thread systems, all used in isolation or in arbitrary combinations. Novel tapering of box and pin surfaces, fin and/or sandwich stiffeners and/or fairings, are provided to optimize loading in all regions of connectors and to meet specific design objectives. Thread angle mismatching between box and pin threads is introduced. Optionally assembly/disassembly fluids that solidify at least in some ranges of design temperatures can be used.

Abstract: This invention builds up on technical features and on the industry experience with the use of Merlin® family connectors. In addition to friction, structural means utilized in order to transfer high torsional loads include: dog-clutch like teeth, fitted pins, keys, splines and interlocked thread systems, all used in isolation or in arbitrary combinations. Static and fatigue bending load capacities of the connectors remain high, while the axial load capacities may or may not be high, depending on the design requirements. Connectors according to this invention can be built as new, carefully optimized designs. In some cases upgrading existing Merlin® family connector designs to increase they torque transfer capacities may be also feasible.

Abstract: This invention introduces three-dimensional (3D) damper arrangements that are used to suppress dynamic motions of a subsea line like a riser, on which the dampers are installed. Damping surfaces (shapes) are mounted on the line so that their combined drag per line unit length dampens motions in 3 mutually perpendicular directions: axial, in-plane (IP) and out-of-plane (OOP). 3D suppression is provided by integral 3D dampers or by combining IP-OOP dampers like strakes with neighboring axial dampers. Increased line motions suppression is achieved by decoupling, particularly on dampers mounted in regions of high line curvature and/or small effective tension. This invention also presents Short Lazy Wave (SLW) configurations of rigid catenary risers, which are also used to suppress dynamic motions. 3D dampers can be used together with SLWs. Motion suppression is introduced to reduce dynamic stresses and to increase fatigue life of the lines.

Abstract: Dynamic motion decoupling is effected by using buoyancy on catenary lines. Novel dampers can additionally be used on the buoyancy, weights and/or in other locations used to increase the suppression effectiveness and/or in order to reduce the number of buoyant devices used. High curvatures of lines may be utilized in some configurations. This invention can be used on new designs and it is also suitable for retrofitting on existing lines. The original line configuration may or may not be modified. In some configurations, along segments of slowly varying slope, buoyancy and/or dampers can be installed on relatively long line segments.

Abstract: Dynamic motion decoupling and damping is achieved with the use of mass, added mass, buoyancy, submerged weight and drag in arbitrary locations on catenary and/or tensioned lines. The original line configuration may or may not be modified. Novel, drag and added mass enhancing devices effective in all directions can be used to increase the suppression effectiveness and/or in order to reduce the number of devices used. This invention is suitable for use on new designs and it is also suitable for retrofitting on existing, already installed lines.

Abstract: Dynamic motion decoupling is effected with the use of mass, added mass, buoyancy, submerged weight and drag in areas of relatively low tension. High curvatures of lines on some configurations, together with their low slope may be utilized. The original line configuration may or may not be modified. Known motion suppressing device designs can be used. Because of the low slope on some configurations, said motion suppressing devices can be installed on arbitrarily long line segments to achieve objections required. Novel, drag and added mass enhancing devices effective in all directions can be used to increase the suppression effectiveness and/or in order to reduce the number of devices used. This invention is suitable for use on new designs and it is also suitable for retrofitting on existing, already installed lines.