A multimillion-dollar floating boom designed to corral plastic debris littering the Pacific Ocean deployed from San Francisco Bay on Saturday as part of a larger high-stakes and ambitious undertaking.

The 2,000-foot-long unmanned structure was the product of about $20 million in funding from the Ocean Cleanup, a nonprofit that aims to trap up to 150,000 pounds of plastic during the boom’s first year at sea. Within five years, with the creation of dozens more booms, the organization hopes to clean half of the Great Pacific Garbage Patch.

The patch, a gyre of trash between California and Hawaii, comprises an estimated