A Canadian man has been charged after nearly 200 gallons (757 litres) of liquid meth were allegedly found on the sailboat he was piloting off the coast of Oregon earlier this week, according to U.S. prosecutors.

A statement said John Phillip Stirling, 65, displayed signs of an overdose when U.S. Coast Guard personnel boarded his boat about 415 kilometres off Newport, Ore., on Tuesday.

While Stirling was being questioned, "his speech began to deteriorate," the statement read.

Stirling was evacuated by helicopter for medical treatment. The statement said coast guard personnel searched his boat, the U.S.-registered Mandalay, and found 28 seven-gallon (26.5-litre) jugs with liquid methamphetamine inside.

The U.S. District Attorney's office in Oregon said Stirling was charged on Thursday with possession with intent to distribute methamphetamine.

He made an initial appearance in federal court in Portland, Ore., on Friday before U.S. Magistrate Judge Stacie F. Beckerman and was ordered detained, pending trial.