The search for five missing seamen in a rescue operation involving The Duke of Cambridge will resume today, the Maritime and Coastguard Agency said.
Two men were airlifted to safety by a RAF helicopter co-piloted by William as a cargo vessel sank in the Irish Sea about 10 miles west of the Lleyn peninsula in north Wales after being hit by an "enormous wave" in the early hours of yesterday morning.
Another person was later recovered from the sea and pronounced dead.
William was called into action after the Swanland issued a mayday call at around 2am when its hull cracked. He was understood to have been involved in the operation for several hours.
He later returned to base at RAF Valley in Anglesey, the Ministry of Defence said.
The two surviving members of the eight-strong Russian crew of the Cook Islands-registered vessel were pulled from the water clinging to liferafts soon after the alarm was raised.
Both men were taken to hospital at nearby Bangor as a precaution and were later discharged.
The search for their colleagues was called off at 4.45pm yesterday as light faded and will resume at around 8am today, the Maritime and Coastguard Agency said.
A spokeswoman said: "They are going to be searching roughly 105 miles of shoreline from Holyhead to Aberdovey using coastguard rescue teams and the RAF search and rescue helicopter from RAF Valley."
Gale-force winds battered the Irish Sea during the early hours of yesterday and the coastguard believes this could have caused the incident.
The ship, managed by Grimsby-based Torbulk Ltd, had been transporting a cargo of limestone from Llanddulas, near Abergele, to Cowes on the Isle of Wight.
Two merchant vessels initially responded to the alarm and discovered two liferafts and some floating debris.
They were able to provide shelter from the winds before helicopters from RAF Valley and the Dublin Coastguard arrived.
The search operation also involved helicopters from RAF Chivenor and the Irish Coastguard, three coastguard rescue teams, lifeboat crews from RNLI Phwllehi, Porthdinllaen, Abersoch and Trearddur Baym and a fixed-wing aircraft from Ireland.
They combed an area of 300 square miles but the only sign of the missing seafarers were the two liferafts, a lifebuoy from the 81-metre vessel and a survival suit.
Holyhead Coastguard watch manager Ray Carson said: "The two men recovered from the water were brought here before going to the hospital. I think they are OK and are just suffering from shock.
"In broken English and through drawing a diagram, the second officer told us the ship was hit by an enormous wave. It rolled the ship and it broke its back. He said this led to a catastrophic failure of the vessel."
Last August the Swanland came close to going aground on rocks at Lizard Point, Cornwall.
The nine-man crew ship suffered engine failure in high winds as it carried a cargo of stone in the early hours of August 20.
A rescue helicopter was put on standby and a lifeboat was at the scene but Falmouth Coastguard's emergency towing vessel Anglian Princess successfully brought the ship to safety. No-one was injured.
Torbulk Ltd managing director Andy Williamson said: "Our thoughts are with the families of the missing crew and the deceased crew member.
"Swanland was a well found and properly maintained sea-going ship. She was fully and properly crewed with experienced seamen. The ship was fully certificated and classed as well as being fully and properly insured at the time of her loss.
"The UK Marine Accident Investigation Branch has commenced an inquiry into the sinking of the Swanland.
"Torbulk is providing all assistance and will work closely with the MAIB as willing participants, keen to assist in determining the facts behind this tragic incident."