Concentric thread mechanical connectors have been developed and qualified to ISO 21329 for offshore pipelines and risers. The connector design consists of a conical box and pin with interlocking concentric grooves and redundant metal-to-metal seals. Instead of make-up by screwing, it is designed to "snap" together under simultaneous axial clamping and hydraulic pressure in the thread annulus. After make-up, the connector cannot unscrew, back-off or loosen under dynamic loading and/or thermal cycling. Concentric thread connectors have been used in various tubular applications for more than 20 years. However, recent ISO qualification tests and modern FE analyses have been used to identify and design significant improvements. These improvements include: preloading of ID and OD abutment shoulders; elimination of a small gap at the connector ID; elimination of hot spot stresses; and lockout of any box-pin slippage due to extreme torque loading. In addition, smaller (6-5/8-in) concentric thread designs that are integral to high strength pipe are available. The improved concentric thread design has approximately 10x more fatigue life than a field-welded pipeline. It is also leak-tight and stronger than the pipe body in destructive testing, i.e., bending, tension and hydrostatic pressure to failure. These improved connectors enable pipeline construction with lighter, high-strength steel, or with corrosion resistant cladding. Since connected pipe joints are completely fabricated onshore, special materials and fabrication processes have no impact on pipelay rates. The improved concentric thread connector is now qualified and project ready for deepwater Steel Catenary Risers, Oil Offloading Lines and subsea pipelines in locations such as the Gulf of Mexico, West Africa, Brazil and the North Sea. Also, pipelay with concentric thread connectors may be done faster with lower cost modular systems in lieu of mobilizing welding pipelay vessels with high cost day rates.

This paper presents a newly developed Floating Regasification Unit (FRU) concept for LNG import in the US Golf of Mexico (GOM) region. The FRU can be converted from a Suezmax tanker and has a turret mooring system. One of the key technologies of the FRU concept is the Side-By-Side (SBS) mooring between the FRU and the LNG Carrier (LNGC) for offloading. The mooring lines and pneumatic fenders between the two vessels should be able to restrain the relative motions to ensure the safe transfer of LNG. Advanced hydrodynamics modeling techniques have been applied, which include full hydrodynamic interactions between the FRU and the LNGC with full QTFs considering the shallow water effect. The anchor legs are modeled as dynamically, fully coupled to the turret and the FRU. The feasibility of the FRU concept is established for LNG import in the GOM, with a variety of workable water depths ranging from 40 meters to more than 100 meters with an uptime exceeding 98%. Analysis results demonstrate the significance of hydrodynamic interactions between the two vessels in close proximity arrangement.

Until recently, the feasibility of connecting Steel Catenary Risers (SCRs) to monohull FPU / FPSOs (Floating Production Units / Floating Production Storage Offloading) had not been proven for deepwaters offshore Brazil. Extreme deepwater applications have required the use of steel risers to avoid hydrostatic collapse. Since SCRs are usually limited by fatigue, due to seabed interaction in the Touch Down Zone (TDZ), the effect of monohull vessel motions on SCR fatigue life had been an issue to be resolved. In the past, only semi-submersibles had been considered for these Brazil applications. Today it can be shown that spread-moored ship-shapes are sufficiently stable for the connection of several large diameter SCRs.

This paper was s e w e d for presentation by the OTC Program Commitfee following review ofinfortnation contained in an abstract subm'med by tha author(s). Contents of the paper, as presentad, have n d been reviewed by the Offshore Tedrndoey C c n f~ and are subject to axrection by the author(s). The material, as presented, does n d necessarily refled any positii of the ORshon, Technology Conference or its off-.Electronic reprodudion, distribution, or stwage of any part of this paper tor commercial purposes without the winen consent of the Offshore Technolagy Conference is prohibited. Permission to repodurn in print is restricted lo an abstract of not more then 300 words; illustrations may not be copied. The abstred must contain conspicuous acknwledgment of where and by whom the paper was presented. AbstractShip-shaped vessels have seen a tremendous growth in their use as Floating Production andlor Storage vessels. Along with this growth has come a need to moor in ever deeper water depths and with more flow lines. The most efficient means of dealing with the mooring of these vessels has been the incorporation of a turret. This turret allows the vessel to weathervane while providing a geostationary hull area to bring in flow and mooring lines. It is desirable to have these turret systems weathervane passively, which requires an efficient bearing system, particularly as many turrets are retrofitted into converted vessels. Interfacing these bearing systems with the turret and vessel structure requires extensive design and analysis to assure their mutual deformations will not affect the longevity of the bearing system.A self-aligning bearing interface, incorporating the use of elastomeric supports, has been developed which eases the design of this bearing interface and reduces bearing loads. The elastomeric support system prevents the transmission of vessel deformations to the bearings thus assuring a low torque, long life, high external load capacity, bearing system.