Two shipwrecks found during a failed search for Malaysia Airlines flight 370 were merchant vessels that sank in the 19th Century, researchers say.

A sonar image of one of the shipwrecks discovered in 2015 -- Photo: AUSTRALIAN TRANSPORT SAFETY BUREAU

The ships, discovered 2,300km (1,400 miles) off Western Australia, have been narrowed down by experts to a handful of coal-carrying British vessels.

Searchers stumbled on the wrecks during a trawl of the Indian Ocean in 2015.

Australian maritime researchers used sonar pictures and shipping records in their efforts to identify the vessels.

The location of MH370 remains unknown more than four years after it disappeared, carrying 239 people, en route from Kuala Lumpur to Beijing.

Unexpected discoveries

One of the ships, spotted in December 2015, was identified as an iron barque.

Dr Ross Anderson, curator of maritime archaeology from the Western Australian Museum, said it was likely to be one of three vessels: the West Ridge (lost in 1883), Kooringa (1894) or Lake Ontario (1897).

The West Ridge, which vanished along with its 28 crew on a trip from England to India, appeared to be the closest match, he said.

Dr Anderson said the vessel weighed between 1,000 and 1,500 tonnes and was found relatively intact and upright on the sea bed, above 4km below water level.

The other vessel, found about 36km away in May 2015, had a wooden hull.

Dr Anderson said two possibilities were the W. Gordon, which had been heading from Scotland to Australia in 1877, or the Magdala, which was lost in 1882 en route from Wales to Indonesia.

The ships most likely had crews of between 15 and 30 men, he said.

"The evidence points to the ship sinking as a result of a catastrophic event such as explosion, which was common in the transport of coal cargoes," Dr Anderson said.

He said his team could not be certain of the ships' identities due to incomplete historical records.

The shipwrecks were found during the official search for MH370 by Australia, Malaysia and China. The unsuccessful mission ended in January 2016 after 1,046 days.

A private US firm began another search for the plane earlier this year. Now in its final weeks, it has not turned up any clues.

Source: BBC