Man jailed for 20 years over drug bust

A man arrested on a yacht off Western Australia's north coast has been jailed for 20 years for possessing more than 16 kilograms of pure methamphetamine.

Police intercepted the yacht in August 2015 near the Montebello Islands, then searched the home of Joshua Gaskell as well as a storage unit.

Police found $608,950 in cash and 16.6 kilograms of pure methylamphetamine worth up to $6.2 million.

Gaskell, 35, pleaded guilty in the WA District Court to possessing a prohibited drug with intent to sell or supply, two counts of possessing unlawfully obtained property, two counts of aggravated possession of firearms and two counts of unlicensed possession of ammunition.

Judge Patrick O'Neal on Friday described Gaskell as instrumental in the distribution of meth into the community.

"You were acting as an essential senior participant in a multimillion-dollar drug trafficking operation," he said.

"The 16.6 kilogram of pure methylamphetamine is a quantity so great as to cause despair at the idea of its addition to the drug problem that is already in existence."

Gaskell must serve at least 18 years behind bars before he can be eligible for parole.