Prince William to the rescue in Irish sea sinking

In this July 4, 2011 file photo, Britain's Prince William heads toward a Sea King helicopter for a training exercise. Photo / AP

Prince William has joined a dramatic mission to save crew from a cargo ship that sunk amid treacherous conditions in the Irish sea, reports say.

The Duke of Cambridge, who is second in line to the British throne, was called into action when the 81-metre ship Swanland's hull was cracked by a huge wave overnight.

He helped pilot a helicopter that saved two of the ship's Russian crew from the stormy seas, The Guardian reported.

One of the ship's crew has been found dead and another five are missing.

A Ministry of Defence spokesman told British media Prince William, who is a flight lieutenant specialising in rescue work, was a key part of the difficult rescue.

"It was a four-man crew - captain, co-pilot, radar operator and winchman - and he was the co-pilot.

"The weather conditions were described as extremely bad, with poor visibility and strong winds," he said.

Crew from the Swanland were not expected to survive in the cold Irish Sea water beyond six hours, coastguard has told media.