British Royal Air Force helicopter pilot Prince William joined a desperate search and rescue mission Sunday for the Russian crew of a cargo ship that sank in a fierce storm in the Irish Sea.

Two rescued crew members were found clinging to a lifeboat after daybreak and hoisted to the safety of a helicopter co-piloted by William. Five other crew remain missing and another has been confirmed as dead.

Coast Guard officials said the 81-meter, Cook Island-flagged Swanland sent out a distress signal after the vessel was smashed by a huge wave that ruptured the ship's hull off the coast of north Wales.

Authorities said the vessel was carrying thousands of tons of limestone from Wales to the Isle of Wight.