The first oceangoing test vessel of the project Ocean Cleanup (Delft / The Netherlands; www.theoceancleanup.com) will head back to the “Great Pacific Garbage Patch” in June 2019 to recommence marine litter cleanup trials after a detailed analysis of the flaws that led it to be towed back to the California starting point after a short stint at sea – see Plasteurope.com of 12.04.2019. The relaunched system will contain modifications based on an analysis of the flaws detected in the first run. Improvements made include a simplification of the HDPE pipe and adjustments to allow minimal fluctuations in the wall thickness.

Among other problems, the initial run was marred by the system’s failure to maintain sufficient speed, which allowed the plastics to exit the system, along with a stress concentration that caused a fatigue fracture in the HDPE floater. As the dovetail connection between the pipe and the screen proved to be the reason for the fracture, the screen has been modified. To ease loads on the pipe, stabiliser frames will no longer be used. Other modifications to be tested in the patch include inflatable buoys and a sea anchor to determine whether increasing or lowering the speed is the best way to prevent plastics from escaping.

Project engineers also have reduced the dimensions of the system to accelerate equipment procurement and the assembly processes to allow a return to the patch more quickly. “Every day we are not yet operational, the plastic pollution problem is not getting better,” the Dutch organisers said in announcing the relaunch. If the changes lead to performance improvements or do not work as hoped, they said, the system will return to shore again to move forward with any necessary redesign.