Colombia’s Navy has spotted and stopped a semi-submarine vessel filled with cocaine in an operation in which hundreds of arrests have been made.

This is just one of six semi-submersibles (i.e. boats that do not fully submerge and move almost unseen) that were spotted during the operation.

The wood and fiberglass vessel is believed to have sailed from the Colombian port of Tumaco, traveling thousands of miles before stopping.

It was spotted about 2,000 kilometers southwest of Clipperton Island, an uninhabited coral atoll in the Pacific belonging to France. It was in the middle of nowhere, Colombian authorities said, about 4,800 kilometers off the country’s coast.

What is striking is that the boat had enough fuel to sail to Australia, opening a new smuggling route.

The semi-submersibles are 10-25 meters in size and can carry up to 10 tonnes of cocaine. To date, Colombian drug traffickers have carried 5-50 kilograms in shipments of fruit or other food.

Smuggling cocaine from South America to Australia is highly lucrative, the BBC reports, as a kilogram of the drug can fetch up to $240,000 there, six times more than in the US. After all, Australians are the world’s biggest cocaine users per capita, after the British, according to the OECD.

The boats were located as part of the multinational naval operation Orion in which security forces from 62 nations seized a total of 225 tonnes of cocaine over six weeks and a total of 1,400 tonnes of drugs. Over 400 people were arrested in various countries during the operation.