SAN FRANCISCO — It's finally in the water.

For five years now, The Ocean Cleanup, an organization founded by a 24-year-old Dutch innovator named Boyan Slat, has been trying to create a system that can clean plastic out of the world's oceans.

There's a mind-boggling amount of plastic in the oceans, and that amount grows every day. At least 8 million metric tons of plastic pour into the sea every year — a number that's considered a low estimate, since it doesn't include commonly found debris like fishing nets. As this trash breaks down into tinier and tinier bits, much of it is eventually carried into one of five massive ocean regions, where plastic can be so concentrated that areas have garnered names like the Great Pacific Garbage Patch.

On Saturday, Slat's organization began the journey out to sea with its first official 2,000-foot-long plastic cleaning array, System 001. A ship called the Maersk Launcher towed the device through the San Francisco Bay out under the Golden Gate Bridge, en route to a final testing site. If everything goes well, it'll head to the Great Pacific Garbage Patch, where the cleanup crew hopes the first system will be able to collect 50 tons of plastic in its first year.

Slat and colleagues hope The Ocean Cleanup's plastic-collecting arrays can help at least remove large debris from these swirling vortexes. They say their models show that with a full deployment of 60 arrays, they could be able to remove half of the garbage-patch region's plastic within five years.

But so far, their technology is still unproven, and no one knows for sure whether it'll work as planned.

The Ocean Cleanup's plan is an inspiration for many, an effort meant to confront what seems like an impossibly large and ugly problem.

But it's also received significant criticism from members of the scientific community who study plastics. Those researchers say the system may not be effective since it can't reach most ocean plastic that has started to break into tiny pieces and sink into the water. They fear it could have negative impacts on marine wildlife or could be broken up by harsh ocean conditions, or that it could be a distraction from stopping the overall use of plastic and the management that keeps it out of the ocean in the first place.

Slat says that stopping plastic pollution needs to be a global priority but that his organization believes cleaning up what's out there already must be done as well. Yet he knows the world and the scientific community are watching as the system begins its first real test.

"It's still not proven technology, and in the next months it has to do what it has to do," he told Business Insider. The group has run models and simulations and has tested systems in the water, but this is the first time a full-size array will be assembled and, The Ocean Cleanup hopes, functioning in the Pacific.

As he said Saturday, "models are models" — helpful but imperfect demonstrations of reality.

"It'll be an exciting six months," Slat said.

Here's what the initial deployment looked like.