Video: Snake-Like Ocean Cleanup System Aces Tow Test

A 120-meter section of the Ocean Cleanup’s floating cleanup system was towed out of San Francisco Bay into the Pacific in May 2018 to conduct a tow test.

Arjen Tjallema, Technology Manager at the Dutch non-profit organization, said that the entire section performed satisfactorily.

“Of the minor issues that the screen did endure, most were identified during earlier testing on the North Sea; therefore, the final design had already been adjusted according to these findings. These favorable results mean we can continue the assembly of the full system and prepare for launch in the coming months,”
he said.

The organization, set up in 2013 by Dutch inventor Boyan Slat at the age of 18, is working on a floating system which will be deployed to clean up the Great Pacific Garbage Patch later this summer.

By utilizing the ocean currents, the passive drifting systems are estimated to clean up half the Great Pacific Garbage Patch in 5 years’ time. The Great Pacific Garbage Patch, located halfway between Hawaii and California, is the largest accumulation zone for ocean plastics on Earth. It contains as much as sixteen times more plastic than previously estimated, with pollution levels increasing exponentially, a study shows.

System 001 Mission Plan

Tjallema pointed out that the latest round of tests was conducted in order to analyze the screen behavior under towing conditions and to test the durability of both the screen and the floater to better prepare for the cleanup journey.

The tests were carried out approximately 50 nautical miles from the Golden Gate Bridge. The unit, which been designed to bend and flex with the waves, in a snake-like motion, was towed in various speeds and orientations relative to the wind, current and waves. The entire test lasted about two weeks.

Tjallema added that the test unit endured a severe storm and withstood the forces of the ocean and did not show any signs of damage from this performance.

“The screen and floater confirmed the behavior we observed on our North Sea Prototypes, in scale model tests and in our numerical models. The weaknesses of the screen section (design version 1.1) on the tow test unit have already been taken into account for the design of the new screen (version 2.0) that is now in production for the full system,” he noted.

“The performance of the tow test unit left the team feeling more confident with this current design iteration and has exemplified that the system is ready for the challenge it is set to face in the Pacific.”

Back on solid ground: with the tow test successfully completed, the yard crew received the green light to continue the assembly. The test piece has now been cut in half, allowing us to put the remaining sections in between in the coming weeks.

— The Ocean Cleanup (@TheOceanCleanup) June 15, 2018

This clip we received from the assembly yard could make you think the crew lost their mind. But the reason they just cut the 120-meter tow test unit in half is to move ahead with the assembly and insert the remaining 480 meters to complete the full 600-meter system. #gopro

— The Ocean Cleanup (@TheOceanCleanup) June 13, 2018

The remaining 480 meters of the system are being assembled by both the Rotterdam team and the Alameda crew as the September deadline for the deployment nears.

With the tow test completed, the final 600-meter system will be towed approximately 240 nautical miles off the coast for a final test and rehearsal before being towed to the patch.

After the trials, System 001 will be towed out to the Great Pacific Garbage Patch, approximately 1200 nautical miles offshore, where it will be launched for the first time in operational configuration and start the cleanup.

The organization plans to reach the full fleet of 60 systems by 2020, with the help of corporate sponsoring.

Image and Video Courtesy: The Ocean Cleanup