Saco manufacturer Yale Cordage enlisted some vicious, bloodthirsty product testers to develop a new, ultrastrong rope for the worldwide tsunami warning system.

The rope will be made for the National Oceanic and Atmospheric Administration’s National Data Buoy Center, which operates a network of about 40 buoys that measure the height of waves and other conditions off the coast of tsunami-prone population centers across the globe, including the U.S. West Coast, Japan and the Philippines. It must be resistant to deep-sea conditions, including the bites of ocean predators, so Yale commissioned the Oklahoma Aquarium, home to the largest collection of bull sharks in captivity, to test its prototypes.

Yale President Bill Putnam said bull sharks were ideal product testers because they will bite down on just about anything.

“They have a type of shark that is aggressive toward things,” Putnam said. “They tie fish to the ropes and let the sharks attack.”

The company already has tested a number of variations on its new bite-resistant rope design, he said. Thanks to the sharks, it has narrowed the field to two potential candidates for mass production.

Many of the buoys are moored to the ocean floor with anywhere from 3,500 to 5,000 feet of rope per buoy, Putnam said, and some have been set adrift. NOAA believes the cause was fish and sharks biting through the ropes, he said, so Yale assisted with a National Data Buoy Center experiment that confirmed shark damage on mooring lines. Yale then assessed the properties of rope needed to both tether the buoys and protect them from damage at a cost within the government’s budget.


The company’s research proved that bull sharks could bite through the mooring lines of those critical warning buoys, rendering them and the data they collect useless in the event of severe weather and tsunami activity, Putnam said.

Yale was a prime candidate for the project because it already produced specialty ropes, including a product that protects power utility workers from being electrocuted when they are pulling down live power lines. In fact, the company sells a bite-resistant rope called Shark Byte. However, NOAA had its own, different specific requirements for strength, diameter, buoyancy and cost, Putnam said.

Yale plans to go into production on the new rope as soon as NOAA chooses one of the two prototype products. Yale declined to provide terms of the deal.

“The National Data Buoy Center has been very pleased with the performance of the first generation of fish-bite-resistant rope, and is looking forward to evaluating the performance of the second iteration of the product,” said Craig Kohler, the center’s chief of engineering, in a written statement.

Oklahoma Aquarium Deputy Director Kenny Alexopoulos said he was proud that his sharks helped to make the tsunami warning system more reliable.

“It is extremely gratifying to see that our unique bull shark collection can contribute to such a worthy and worldly cause,” Alexopoulos said.


Putnam said it was the first time Yale Cordage has used sharks in captivity to test product prototypes.

Development of a highly specialized rope requires choosing the right materials and construction method, according to Putnam. Yale, like many other companies that work with high-tech synthetic materials, has benefited from advancements in materials science pioneered by the automotive, aerospace, military and other industries.

The company has used strong and flexible synthetic fibers developed for seat belts, tires, and bullet-proof vests, he said.

“We look at new materials wherever they are being developed,” Putnam said.

J. Craig Anderson can be contacted at 207-791-6390 or

Twitter: @jcraiganderson 

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