New rope designed for deepest core samples

A group of oceanographers at the Woods Hole Oceanographic Institution

recently asked for proposals from rope manufacturers for a high-strength, lightweight product that could be used to perform the deepest coring samples of the ocean floor. The new “piston corer” device that would be drilling on the seafloor in excess of 20,000 feet of water, was described as weighing 25,000 lbs, four times what previous coring machines weighed.

WHOI scientists stipulated that steel wire was unacceptable because of the weight. And they said the new rope would have to be able to sustain significant loads while taking turns around sheaves aboard the research vessel.

Puget Sound Rope, based in Anacortes, Wash., won the contract and will deliver the new rope, called BOB, for Braid Optimized for Bending, later this year. The rope is a hybrid of material, including Vectran and Spectra fibers.

Two lengths of the 12-by-12 BOB rope — there are 12 strands in the rope, each strand is a braid of 12 smaller strands — will be spliced into a 6,000-meter (about 20,000-foot) Plasma line, one at the surface and one on the bottom above the coring device, according to Randy Longerich, president of Puget Sound Rope. It is in these areas that the lengths of rope need to have the ability to absorb significant loads while being bent through sheaves that function as shock absorption — or “heave compensation system.”

Longerich said the company’s spending on R&D projects is what led to the success with this product. The BOB rope is bright purple in color and will be just 2 inches in diameter.

By Ocean Navigator