The Ocean Cleanup towed its repaired and redesigned trash-collection system back to the Great Pacific Garbage Patch after successful testing of a parachute sea anchor on Vancouver Island in Canada.
The parachute will be used to slow down the U-shaped system, which is made up of a floating polyethylene pipe and polyester skirt designed to form a synthetic coastline for gathering marine debris for eventual recycling.
The second iteration of the ocean sweeper — called System 001/B — returned June 27 to the soupy mess of fishing nets and other plastic swirling in the garbage gyre halfway between California and Hawaii.
In a series of recent Twitter updates, Boyan Slat, founder of the Netherlands-based Ocean Cleanup nonprofit group, said of the parachute anchor: "At low speed, it performed as planned with satisfactory results. We are now green-lighted to test with the system in the patch."
This Cleanup's predecessor — System 001 — broke apart in December after two months in the harsh environment. Several changes were made to the original 2,000-foot floater pipe, which had a tapered polyester screen attached underneath to corral garbage from the water's surface to a depth of 10 feet.
The second Cleanup is about one-quarter the size of the original and more modular. The skirt was detached from the pipe and brought forward to reduce the chance of fatigue fractures. Last year the system broke when a stress crack formed at a welding point attaching the screen to pipe.
A parachute and six buoys, which are described as "inflatable bags" and "fenders," also have been incorporated into the new design to better control the speed of the Cleanup system. The original Cleanup didn't collect much plastic, and it was determined that the speed of the system needed to be more consistent and always move either faster or slower than the garbage in the patch.
To adjust the Cleanup's speed, the group will use either a 20-meter-diameter parachute to slow it down so plastic will flow into it "and concentrate against the screen," or two to six inflatable "lift bags" to propel the system forward by the force of the wind so that it catches plastic. The group will try the parachute first and then the lift bags, and if needed, a larger and heavier version of the lift bags, which are being referred to as trial fenders.
"The first tests will be conducted to attempt to slow down System 001/B, using the parachute sea anchor as the main testing component for this option," the group said in a June 27 update.
"Should the slow-down option prove ineffective, we will face the system in the other direction and speed it up ... using inflatable bags or fenders. All of the modifications we are trialing will not necessarily be the final design — they are essentially a first phase of possible alterations we are testing. If either the slow-down or the speed-up option works, we will then pursue a more permanent solution with this design feature."
The group expects to conduct about two months of tests on various configurations and speeds of the smaller system, which is 160 meters as opposed to the original 600 meters. When they have a proven concept, "the size of Systems 002-060" will be increased.
"Hopefully nature doesn't have too many surprises in store for us this time. Either way, we're set to learn a lot from this campaign," Slat tweeted.