JUNE 16, 2016 — A retrofit option for MacGregor subsea cranes replaces the original steel wire rope with high-performance synthetic fiber rope, using the same technology as MacGregor's advanced fiber-rope crane, the FibreTrac 1500, which was introduced earlier this year.
Fiber 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.
The cranes combine MacGregor offshore crane technology with the fiber-rope tensioning technology perfected by Parkburn Precision Handling Systems.
"We are proud to introduce our fiber-rope retrofit option to the market. This unique system offers a good investment to our customers to expand their operational window," says Alexander Nürnberg, Senior Vice President, Technology and R&D, MacGregor.
"MacGregor is always searching for new solutions that deliver a competitive edge for our customers," says Gaute Sjusdal, Director of Advanced Offshore Solutions, Global Lifecycle Support at MacGregor. "By employing this fiber-rope technology, a crane is able to use its full lifting capacity at maximum depths, so a smaller crane and vessel can be used for more assignments. "The fiber rope crane can lift loads at practically any depth that is required, allowing these vessels to bid on a wider range of contracts."
Effectively, a 100-tonne fiber-rope crane has the same lifting capacity as:
- a 150-tonne crane with steel wire rope, lifting at a depth of 2,000 m
- a 200-tonne crane with steel wire rope, lifting at a depth of 3,000 m
- a 250-tonne crane with steel wire rope, lifting at a depth of 3,500 m
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 fiber rope. The system also includes a low tension fiber-rope storage drum.
The fiber 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, 3,000 m 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, fiber rope does not require lubrication, eliminating a source of pollution.
MacGregor is a subsidiary of Cargotec.