Lightweight chain components tailored for deepwater stresses
The company is seeking to patent the multi-functional ball swivel.
MoorLink specializes in mooring components for the offshore sector. The company has developed a series of standard fittings, including swivel links, connections and wire clamps, and regularly responds to requests for customized components to overcome special mooring problems.
One such recent enquiry from Balmoral was for a means of adding buoyancy to the mooring chain of a drilling rig working on the Britannia Field in the North Sea. The aim was to lift the chain over the field's main gas export pipeline. A prime requirement was that the chain should not have to be cut. In eight weeks MoorLink developed and manufactured a novel chain clamp which has the same shape internally as the chain link and contains a rubber insert so that the links are not damaged. The clamp is simply bolted to the chain. Since the chain does not have to be cut, it is a relatively easy operation to move the buoyancy to any spot on the chain depending on the configuration of the mooring system.
The new device will likely find further application anywhere that buoyancy has to be added to a mooring line without the need for cutting the chain. For example, there is a common requirement, especially in deeper water, to reduce the vertical loading and to increase the horizontal stiffness of mooring systems by adding buoyancy to the lines.
MoorLink's Senior Partner, Bjorn Palmquist, takes the view that it is important to have very simple devices in today's tougher environments. "The move to deeper water puts greater demands on equipment and the people who use it. Mooring components, which are easy to handle and fit, are essential."
Multi-functional swivel
MoorLink's novel chain clamp allows buoyancy to be added to a mooring chain without the need to cut it.
A good example of this is the compact, multi-functioning ball swivel the company is developing. A one-third scale model was displayed at this year's OTC in Houston. The unit, which was designed using 3D CAD and finite element analysis, combines a wire socket, swivel and chain connector into one very simple unit. A version capable of being used with 90 mm wire and with a 700 tons breaking load would weigh roughly 500 kg, rather than the 1.2 tons for the various separate components used currently.
"The device is engineered to swivel under low load but not when under tension," Palmquist says. "It is also designed so that damage to the wire is avoided as it passes through the vessel's fairlead." The units are machined using computer control and can be tailor-made for any winch. MoorLink is working closely with a major drilling contractor to develop the component and is pursuing a patent application. The company expects this device to become one of its core business lines. ;
For more information contact Bjorn Palmquist, MoorLink. Tel: +46 31 711 1819, Fax: +46 31 708 7900, E-mail: [email protected]
