How do you keep a pipelaying barge stationary in open water? It takes a complex mooring system, made up of a network of lines and anchors, to ensure these barges can fulfil their critical role: helping offshore engineers assemble the pipelines that bring crude oil and natural gas products to shore.

There’s a lot to think about when choosing the right material for these lines, including strength, safety, resistance to wear and abrasion, and ease
of maintenance and cleaning. No wonder that L&T Hydrocarbon Engineering – fed up with the limitations of steel wire ropes – turned to a superior solution made with Dyneema® SK78 fiber…

Time to break with traditions

It all started with an inspection aboard L&T’s LTB 300, a pipelaying barge operating in busy waters, in May 2022. The results clearly showed just how many problems the steel wire was causing. For one thing, since they rust under exposure to seawater, steel wire ropes need regular maintenance and refurbishment. In turn, the lubrication required not only poses a safety risk on deck, increasing the likelihood of crew members slipping, but also pollutes the marine environment. As well as these safety and efficiency limitations, there’s the danger of causing costly damage to existing subsea infrastructure, owing to the weight of steel lines.

About the LTB 300

Type: Pipelaying barge
Length: 111.56 meters
Anchor rope: 52 mm x 1,500 meters; 8 winches

Static holding load: 150 tonnes
Winching power: 85 tonnes
Year of Manufacturing: 2010

“Steel wire ropes have been used as a mooring solution for years,” explains Guna Shekhar, Chief
Engineer on the LTB 300. “Their mechanical properties, however, are less than ideal.” “Steel corrodes, it’s hard to clean, and it causes damage to onboard hardware,” agrees Karthik
Rajagopal, Deputy General Manager, L&T Hydrocarbon Engineering. “For example, the horsehead fairleads have experienced significant wear from prolonged contact with the lines, which would be a big problem in the long run. We wanted a solution with the same (or better) functional performance as steel wire, but without these downsides.”

And that solution was DSR’s 52 mm SuperMax® Plus rope made with Dyneema® SK78 fiber. The buoyancy enabled by their light weight (0.97 relative density in water) means the SuperMax®. Plus ropes don’t sink, which helps avoid damage to subsea installations.
Additionally, ropes made with Dyneema® are easier to handle, improving crew productivity, reducing safety risks, and preventing damage to the vessel’s hardware.

Light brings might

And that solution was DSR’s 52 mm SuperMax® Plus ropes made with Dyneema® SK78 fiber. Thanks to the lightweight strength of Dyneema®, these lines are just one-eighth of the weight of equally strong steel wire rope and extremely durable. They form a straight line when tensioned, with no catenary (buckling) effect in the middle. In addition, they don’t need a buoy when not tensioned, simply floating toward the sea surface on their own.

“The SuperMax® Plus ropes with Dyneema® SK78 fiber – known for its strength, lightness, and easy handling – has alleviated the stress on our hardware and improved the durability of our mooring system. With their low shrinkage, high cut resistance, and superior durability versus alternatives, I’m confident these mooring lines will serve us well in future pipelaying projects.”

Guna Shekhar, Chief Engineer, LTB 300

The ideal all-round solution

But there’s more. Our Dyneema® SK78 enables mooring lines and tethers with superior resistance to wear and UV and a superior fatigue life, extending their service life. In turn, this means no need for lubrication, and the associated slipperiness on deck. The SuperMax® Plus lines also resolved L&T’s cleanability challenge, requiring only 2,000 PSI water pressure for cleaning, compared to 12,000 for traditional steel.

After a successful trial, the replacement of the LTB 300’s steel wire ropes with the Dyneema®-based alternatives was completed with support of the DSR engineering team in June 2023. “Switching to the SuperMax® Plus ropes has brought all kinds of benefits and exceeded our performance expectations,” Karthik concludes. “Safety, precision, and reliability are non negotiable – and our new mooring lines have delivered on all fronts! For offshore engineers like us, ropes made with Dyneema® SK78 fiber are simply ideal.”

“We, DSR Corporation, have been supplying major operators of Pipe laying vessels over the world with DSR Dual-colored SuperMax78 D Plus rope made with 100% Dyneema® SK78 fiber from Dyneema®. We’re strongly confident that DSR SuperMax ropes offer the best experience to every safety anchoring operation through not only its premium quality, but also excellent service before/after use provided by a skilled team of experts from DSR Corporation and Dyneema®”, David Jo, DSR.