A BOAT which was lost off the WA coast eight months ago has been found near Madagascar.

When Stephen Knight last saw his LeisureCat, it was upside down in rough seas at an island about 40 nautical miles off the Exmouth coast, 1,270kms north of Perth.

"It was at anchor during a camping trip to the island and what happened a big storm came in," Mr Knight said.

"This was one of those super-cell storms, 40-knot winds and gusts at 60-knots, and basically it took the boat from its mooring and it took it about three miles out. We could still see it because it had it's anchor light on,"

"We watched it through the course of the whole night and we were on the phone to the authorities, but it was so severe they couldn't get up any planes."

By the time the weather had settled, the boat had flipped but conditions were still too rough to tow the boat, so Mr Knight has to be rescued and the boat left behind.

"I basically thought it would be on the bottom of the ocean somewhere, so to find it after all of this time is just unbelievable," he said.

"Obviously they float, so that's good for the manufacturers."

"Looking at the photos, the boat's virtually perfectly intact, so it floated across the Indian Ocean without anyone seeing it or spotting it."

An Australian Maritime Safety Authority spokesman said the badly damaged vessel was found near the island of Mayotte on January 2.

Mayotte is a small island to the north of Madagascar and is about 7400km west of Perth.

French authorities notified Australian officials in Canberra over the weekend of the find who have since notified WA Police.

Mr Knight said he had since got a new boat through insurance and now someone on the island is likely to claim salvage rights to the boat,