Longer, stronger ropes extend deepwater capabilities

International rope manufacturer Bridon is expanding the capabilities of offshore heavy-lifting systems. The historical challenge in deepwater operations has been to deploy 300 tonnes in 3,000 m (9,843 ft) of water. Now, as operators seek to reach greater depths, industry is increasingly demanding lifting systems that can deploy weights of 400 tonnes at depths up to 4,000 m (13,123 ft). Such systems require multistrand ropes that are long, strong and engineered to handle massive breaking loads, with optimized bend-fatigue performance, effective lubrication, and minimized rotation under load.

To accommodate, Bridon is expanding its manufacturing capabilities. The company is constructing a £30-million (US$48.1-million) factory that by the end of 2012 will produce multi-strand ropes in lengths greater than 7,000 m (22,966 ft) and in gross package weights up to 650 tonnes—making them by far the largest, most complex in the world. These ropes will significantly expand the scope of operations in deeper waters and more challenging environments.

Key to the site’s unrivalled capacity is its unique closer machine, which is used to draw together thousands of wire strands into a single rope. Bridon’s closer is the first of its kind capable of making a 600-tonne rope in a single pass, enabling the production of longer, higher-capacity ropes in a single piece and avoiding the need for multiple passes. Bridon Neptune Quay’s closer also boasts 24 bobbins (15- and 38-tonne capacity), giving it the ability to make far more complex ropes than had ever been possible with such weights. Up until now, closers capable of producing very large ropes have typically had no more than eight bobbins. 

A montage of rope cross-section designs from Bridon.

Bridon has many years of experience producing and handling large-specification ropes, and the new facility builds on the company’s understanding of the complexities and challenges involved in manufacturing such highly engineered products. The UK site’s deepwater, portside location on Newcastle’s Tyneside will allow Bridon to use innovative loading solutions to reduce delivery timescales and order lead times, allowing it to ship ropes to customers swiftly.

Bridon’s technical team is pioneering the use of special polymers as components in their wire ropes to optimize offshore performance. The company has developed and patented a manufacturing process that applies a plastic jacket around the core of a steel wire rope in an exact profile to support and follow the helix of the rope’s strands. This cushion supports the geometry of the wire rope and limits the impact of interwire contact to enhance the work life of the rope. New materials are undergoing trials to extend this technology to even more critical applications in deep waters, under high pressures, and in heat-sensitive applications, such as heave compensation.

As one of the only companies offering both steel and synthetic ropes, Bridon is also developing synthetic fiber solutions suitable for challenging offshore operations. Synthetic ropes can offer the highest strength-to-weight ratio for subsea handling, extending the depth range of existing equipment without negatively affecting static load capacity. Tailoring extension characteristics of synthetic products can also eliminate the need for additional load displacement compensation. Bridon has completed extensive studies that demonstrate these products’ performance in extension.