SS: Fiber Moorings, Recent Experiences and Research: Fiber Rope Tether Manufacturing - Current Best Practice and a vision for the Future

Abstract

Abstract Polyester Mooring Tethers are gaining wide acceptance in the Gulf of Mexico, Brazil and other areas of deepwater mooring operations. This paper looks at current rope manufacturing, developments in splicing technology, length accuracy measurements systems, rope manufacturing length and breaking strength limitations, and developments in synthetic polymer raw materials. Current areas of deepwater rope research and development include improvements in jacket cut resistance, improved termination designs between rope and rope or rope and chain or wire, higher integrity sand barriers and stiffer materials for next generation mooring lines at ultra-deepwater depths. These developments are necessary to allow the deployment of fiber rope moorings in harsh environments such as the Arctic, into ultra-deepwaters and conversely into shallower water applications, and to embrace alternative deepwater installation techniques, such as pre-lay on the sea bed. In recognition of the need to give naval architects and installation contractors' more options and ideas to develop alternative, cheaper and quicker methods of installing mooring systems, the future for Fiber Rope Tethers is reviewed. Of particular importance is the need for longer, stronger, lighter and more robust Fiber Rope tethers, composite rust free lightweight connectors to complement the rope's characteristics, installation using low cost anchor handling vessels and rental deployment systems, pre-laid moorings deployed on the seabed months before hook-up, and better ways of bedding in creep and use of lower pre-tensioning loads in mooring ropes. Introduction Polyester rope mooring tethers are gaining wider acceptance in deepwater mooring operations. The benefits of polyester rope moorings are compelling: lighter, easier to handle and with excellent mechanical properties to withstand the loads and elasticity demands of deepwater mooring. As mooring lines move to greater water depths, and further offshore, however, the engineering integrity of the mooring rope and its splice are critical to effective station-keeping. With improvements in anchoring systems design and chain quality, the focus is now on the mooring rope, and its connectors, to deliver the mechanical performance needed for ultra-deepwater moorings. Splicing Technology Polyester mooring ropes are a key component of deepwater and ultra-deepwater mooring systems. The mooring line is made up of one or more lengths of rope joined together by connectors. The longer the rope, the greater the number of connectors needed, including rope-to-rope, rope-to-chain and rope-to-wire connectors.