Prince William in new rescue for missing crew

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's helicopter rescue crew carried out a fresh search for five missing Russian seafarers after Moscow's ambassador to Britain thanked the royal pilot for his efforts saving two lives.

The Swanland, an 81-metre vessel in the Irish Sea, sent out a distress signal around 2:00 am (4pm NZT) Sunday when it was hit by a huge wave which ruptured its hull, coastguard officials said.

The Russian-crewed ship sank in a storm off the northwest coast of Wales, leaving one man dead, while two were winched to safety by a Royal Air Force (RAF) Sea King helicopter co-piloted by William, who is second in line to the British throne.

The pair were found clinging to lifeboats. Five remain missing.

Alexander Yakovenko, Russia's ambassador to London, wrote to William to thank the 29-year-old Duke of Cambridge for his efforts.

"All day long we were anxiously following the rescue operation searching for Russian seamen from the sunk Swanland vessel," he said.

"We know that you took an active part in the rescue and the two seamen were saved thanks to your selfless effort under the bad weather conditions.

"Let me express to you and your colleagues my deepest gratitude for saving the lives of the Russian citizens."

Coastguards said they and an RAF helicopter carried out a further search Monday but did not find the missing five seamen.

They covered 105 miles (170 kilometres) of the northwest Wales coast and found some additional wreckage, including a life jacket and a life ring.

"Sadly we still have not been able to locate the missing seafarers. We will carry out one final search at low water," said Ray Carson, the Holyhead Coastguard watch manager.

Rescue crews on water and in the air covered 300 square miles (775 square kilometres) of the Irish Sea on Sunday.

The Swanland was transporting 3,000 tonnes of limestone around the British coast.

The ship was owned by a Britain-based company, Torbulk, and was flying the flag of the Cook Islands, according to shipping websites and media reports.