After six weeks of testing, the nonprofit Ocean Cleanup group has decided to use a parachute anchor system to slow down its plastic pipe-and-skirt contraption designed to collect marine litter from the Great Pacific Garbage Patch.
The new plan will allow System 001/B to achieve a consistent speed to capture plastic for eventual removal and recycling, according to an Aug. 16 website update from the Delft, Netherlands-based group.
The U-shaped system, which has been likened to an ocean rake, consists of a 525-foot-long floater pipe made of high density polyethylene and a detached polyester screen that captures plastic debris to a depth of 10 feet. The parachute anchor lets the system catch plastic and concentrates it against the screen, according to the Ocean Cleanup website.
The group had tested speeding up the system using large inflatable buoys. But using a parachute anchor to slow down the system allows wind and waves to push the plastic into the system.
"In the slow-down configuration, we haven't witnessed a negative speed differential at all, with plastic always arriving through the front, but never drifting out of the opening again. Hence, this is the concept we'll be moving forward with," the update says.
However, the group is encountering another problem it calls "overtopping." Some plastic is crossing over to a space between the pipe and screen. Now this issue needs to be solved before plastic is effectively retained.
In the original cleanup system, the screen was attached to the floater pipe but a stress crack formed at a welding point and a section broke away after only two months in the harsh ocean environment. The contraption was redesigned by detaching the skirt and bringing it forward using a cork line, something like what is used to section off a swimming pool, to hold the screen in place and prevent it from going slack.