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Application-Specific HMPE Synthetic Rope
Unitrex XS Max Wear Rope Lowers RSNs Deep Into Pacific for OOI


Bill Putnam

Twenty years ago, oceanographic professor, John Delaney, now at the University of Washington (UW), walked into a bar in San Francisco, California, and complained to a friend about the difficulty of gathering data in the deep ocean. That conversation was the impetus for a game-changing project called the Ocean Observatories Initiative (OOI), according to National Public Radio.

The U.S. National Science Foundation (NSF) hired UW to oversee the development of a networked system to study the ocean and seafloor, which included the laying of 560 miles of fiber-optic cable connected to video cameras, seismic monitors and strategically placed regional scale nodes (RSNs) along the Juan de Fuca Plate off the coast of Pacific City, Oregon. RSNs are terminal points that distribute power and bandwidth (10 gigabits per second on each port) to areas where there are sensor networks.

Because some of the most advanced and expensive technology was used in this project to collect data, UW paid close attention to how the multimillion-dollar RSNs were lowered from a cable-laying ship into the ocean. The deployment of these RSNs into deep waters of the Southern Hydrate Ridge and Axial Seamount was contracted out to L-3 MariPro Inc. (Goleta, California).

The cable installation took place in 2011, and primary RSNs were installed in 2012 in water depths ranging from 25 to 600 meters. The RSNs lowered to the seafloor have created an underwater observatory that feeds information on events happening in the ocean and seafloor to land-based scientists, engineers, educators and the public in real time. Delaney describes it as an 'undersea network designed to funnel a fire hose of open-source, real-time data to the Internet, 24/7.' Researchers and the public are now able to observe underwater volcanoes, migrating fish, major earthquakes, powerful currents and blooms of microscopic life—all observations that were not possible previously.

Unitrex Rope for RSNs
L-3 MariPro had many options for the rope it chose to lower the RSNs into the deep waters of the Pacific Ocean. Ultimately, a high-modulus polyethylene (HMPE) synthetic rope called Unitrex XS Max Wear, by Yale Cordage (Saco, Maine), was chosen, the benefits of which include a light weight, superior break strength and excellent performance on single-drum winch lines. It outperformed traditional products like steel-wire rope and other synthetic alternatives.

Lightweight Synthetics' Advantages in Deeper Waters
HMPE synthetics like Unitrex tend to have fewer limitations in deep water than steel-wire rope. Deck crews can work faster during deployment and recovery on rope systems and winch lines with reduced weight. Some single-drum winches can add more than 80,000 pounds to a vessel. When the weight of a heavy drum combines with tonnage from steel-wire cable, crews are forced to use short-range vessels. Synthetics, on the other hand, greatly reduce the weight aboard a vessel, enabling crews to operate large vessels in depths of 1,000 to 3,000 meters—essential to oceanographers studying the seafloor. In the case of OOI, scientists have reached depths of 600 meters, but have the option to venture into greater depths when additional infrastructure is deployed in 2014. To continue this article please click here.

Bill Putnam joined Yale Cordage in 1984. He has served the company as a rigging shop supervisor, purchasing manager, plant manager and executive vice president. He was named president in 2012.

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