MacGregor's new fibre-rope retrofit option extends subsea crane capabilities
MacGregor, part of Cargotec, has launched a fibre-rope retrofit option for its subsea cranes, the company said in its press release. The modular upgrade replaces the crane's original steel wire rope with high-performance synthetic fibre rope, using the same technology as MacGregor's advanced fibre-rope crane, the FibreTrac 1500, which was introduced earlier this year.
These game-changing cranes combine MacGregor's proven offshore crane technology with the fibre-rope tensioning technology perfected by Parkburn Precision Handling Systems.
Fibre rope's great advantage when used in this context is that it weighs virtually nothing in water, so regardless of the length of rope paid out; it does not add anything to the load experienced by the crane. This is in complete contrast to wire rope, where the increasing weight of wire paid out progressively and seriously limits the load permissible in relation to depth.
Effectively, a 100-tonne fibre-rope crane has the same lifting capacity as:
- a 150-tonne crane with steel wire rope, lifting at a depth of 2,000m
- a 200-tonne crane with steel wire rope, lifting at a depth of 3,000m
- a 250-tonne crane with steel wire rope, lifting at a depth of 3,500m
The retrofit system is designed in modules for rapid installation. It includes a deep water capstan traction device, delivered in partnership with Parkburn Precision Handling Systems, which replaces the crane's original main winch and overcomes the problems traditionally associated with handling fibre rope. The system also includes a low tension fibre-rope storage drum.
The fibre rope can be inspected for wear, internally and externally. The ability to splice in new sections adds great flexibility to the system. "While the entire rope can be replaced if necessary, damaged sections can easily be replaced and the length can be increased as required," says Mr Sjusdal. "Transportation is simple and requires no special equipment. In contrast, 3,000m of steel wire rope poses some significant challenges and has special transportation, handling and spooling requirements. With its low weight, a synthetic fibre rope can be shipped in a normal container; there is no need for a drum. Also unlike wire rope, fibre rope does not require lubrication, eliminating a source of pollution.
