Spelter sockets and mooring sockets have long been used to provide an effective attachment point to the end of wire rope. When load is applied to the wire rope, the conical shape of the inside of these type fittings allows for compression and strength that exceeds the actual breaking strength of the rope – in other words, 100% termination efficiency.
For many years, the sockets were fitted over the ends of the wire rope and hot molten zinc was poured into the socket “bowl” and around the wires which had been untwisted or “broomed.” The molten zinc eventually cooled and hardened around the wires. The end result was a hard cone inside the socket bowl that could not come out. Though this method was effective, it was a dangerous and hazardous process for those preparing these assemblies and industry sought an alternative solution.
In the early 1970’s, a major wire rope manufacturer and Philadelphia Resins (now ITW Polymer Technologies), worked together to develop a safer and easier to use product for securing sockets to the wire rope ends. The result of their efforts was a 2‐part polyester resin/hardener kit that polymerized and hardened when mixed together. The material was safe to use and provided enough strength that when procedures were properly followed, would produce a wire rope termination that exceeded the breaking strength of the wire rope.
Since the early 1970’s, wire ropes and in particular, offshore mooring ropes, have increased in strength as drilling has moved to greater depths. In 2009, Sea‐Fit, Inc., a manufacturer of a new generation of mooring sockets and inventor of the Super Shackle, teamed up with ITW Polymer Technologies, maker of Chockfast Orange, to begin the process to redevelop the product named Socket Lock.
The objectives were to provide a product strong and tough enough to withstand the rigors of securing a semi‐submersible drilling rig in challenging sea conditions, to make the product safe and easy to use and finally to improve the packaging to ensure the freshness of the product. The process started in the lab where the chemists developed a formula that was tougher and had greater chemical stability. Once the formula was finalized, the new material was extensively tested in a series of static, dynamic and shock load assessments.
The focus then turned towards packaging and application issues. It was decided that the resin and hardener would each be placed in environmentally sealed foil pouches and rust‐free plastic pails. To make the product easier to use, the color of the resin was changed to a bright green and the hardener to a white soft paste. Since thoroughly mixing the product is necessary for it to work properly, the contrast between green and white make it clear when it has been mixed completely as the white streaks will disappear. To eliminate spillage, a unique disposable pouring funnel is provided with each kit. The end result was a product that uses modern chemistry, is stable in storage, is both easy and safe to use and can meet the demands of 21st century socketing.
To see a 3.5 inch high strength mooring rope being broken with the sockets affixed to the rope ends with Socket Lock resin, go to www.Socket‐Lock.com. Socket Lock has been Type Approved by the ABS and DNV standards organizations.
