VICTORIA -- A Vancouver Island senior who was found having a possible drug overdose aboard a sailboat loaded with jugs of methamphetamine off the coast of Oregon has pleaded guilty to a federal drug charge.

Prosecutors will recommend that John Philip Stirling, 65, serve just over seven years in prison as part of a plea agreement, according to the U.S. Attorney for Oregon.

Stirling has also agreed to forfeit his sailboat after pleading guilty on Monday to one count of possession with intent to distribute methamphetamine under the U.S. Maritime Drug Law Enforcement Act.

The island man was arrested in April after a routine U.S. Coast Guard patrol picked up his boat, the Mandalay, about 415 kilometres from the Oregon coast.

When the Coast Guard tried to communicate with Stirling, he "went below deck and would only respond via VHF radio," according to the attorney's office.

Coast Guard personnel boarded the vessel and the attorney's office said Stirling refused to provide identification or vessel documentation.

"Upon further questioning, Stirling’s speech began to deteriorate and he displayed signs of a possible drug overdose," the attorney's office said in its initial court filings.

A search of the Mandalay turned up 750 litres of liquid meth.

Stirling was airlifted from the vessel by helicopter to Astoria, Ore., and later transported to hospital in Portland.

He has been held in the Multnomah County Inverness Jail in Portland ever since.

In December, Stirling's lawyer Lisa Hay argued to have the case against him thrown out, citing a lack of U.S. jurisdiction over the Canadian on the high seas.

Stirling is now scheduled to be sentenced on April 20.

The man's arrest in April came just one year after he was released after serving most of a seven-and-a-half-year sentence handed down by a Florida judge in 2013.

In that case, Stirling had taken a plea agreement on a charge of conspiracy to possess with the intent to distribute narcotics, after admitting to a Southern District of Florida court that he was the master of a vessel containing 381 kilograms of cocaine and one kilogram of heroin when it was boarded by U.S. authorities off the coast of Colombia.

With files from the Associated Press