Synthetic opportunities

Crews ready a Samson Amsteel Blue Rope Sling for a ‘wet handshake’ operation on the Cascade Chinook Project. Photos from Samson.

Synthetic rope will never fully replace steel wire rope, but it has potential, suppliers say.

Steel wire rope has long been a mainstay of the offshore lifting business, with proven capabilities and known performance. But now there is a new kid on the block. synthetic rope, which has become established as a mooring rope, is being seen by many as a potential solution to some of the issues facing offshore lifting operators, particularly as developments move into deeper and harsher waters.

For these types of projects, the extremely long lengths and heavy weight of steel wire rope creates transport and storage issues and winches / cranes are reaching their operating limits. These are issues which synthetic rope could solve. Synthetic ropes made of high modulus polyethelene (HMPE) are typically a size-for-size replacement for steel wire rope and are 85% lighter. But is it all it’s cracked up to be? Yes, up to a point, says a Dutch supplier.

Moerdijk-based United Offshore Services (UOS) specializes in large-diameter steel wire rope (50mm – 600mm) for offshore maritime heavy lifting operations.

Earlier this year, the firm took the plunge into the fiber rope market through a joint venture agreement with US-based fiber rope specialist and manufacturer, Samson. UOS is currently ramping up their facility and capabilities. By the end of the year they will have a full rig shop and fully trained staff for making synthetic heavy lifting slings. It is a door-opener and could potentially be big business, but not the be-all and end-all, says Edwin Jefferies, commercial manager for UOS.

However, he says: “Because synthetic is at a very young stage in the offshore industry, contractors are anxious to take a step in that direction. Steel wire rope is a proven product in the field for many years and it will take some time for synthetics to be considered an industry standard.”

A pre-rigged Samson Amsteel Blue Rope Sling awaits its mission on the Cascade Chinook Project.

A perceived problem in the past has been the absence of clear inspection criteria. One example is that of jacketed rope constructions; a rope with a braided core with a woven jacket over it that cannot be opened without destroying it. Users cannot see inside to either ascertain what the rope is made of or assess its condition.

However, Samson has solved some of these problems by constructing the rope differently and using lab testing and field trials to establish reliable data-driven inspection criteria. Internal inspection criteria challenges can be overcome with single strand, or non-jacketed, rope constructions. Samson’s AmSteel-Blue, AS-78, and Quantum-12 single strand ropes, among others, have very well-established inspection criteria and can easily be inspected by trained personnel for a variety of characteristics to determine wear patterns and retirement criteria. Jefferies says. “We are able to certify and inspect rope.”

Work is also underway with the International Marine Contractors Association to produce standards for proper inspection criteria, which will bring more confidence in synthetic rope use.

“We do see a huge increase in demand for synthetic ropes because of the weight saving in these slings,” Jefferies says. “Understandably, issues like rope crushing, sand ingress, the effect of chemicals, and heat are considerations for some fiber rope applications, but there are applications, like subsea installation, where synthetic will have a critical role to play and bring tremendous value to the end user in safety and ease of handling.

For us, it is currently a small part of the business, but we think it will increase tremendously in the near future.”

UOS has a 30,000sq m site with a 5000sq m production hall at Moerdijk. UOS manufactures with a cable-laying machine capable of making cable-laid ropes of up to 400mm-diameter in piece weights up to 150-ton. The firm also has a unique cable-laid grommet machine, able to make grommets of up to 300m- circumference and weighing up to 110-ton.

UOS is planning a number of capability expansions in the near future on the area of testing and inspections. It has three test-beds at the moment, and it plans to expand their capability to accommodate synthetic rope testing. Currently, their largest test bed is able to pull 1300-tonne at short lengths. The longest machine can test 165m lengths, up to 300-tonne, and will be expanding soon to a higher pulling capacity.