A US Air Force parajumper died off St. David's after his inflatable raft capsized after he had successfully treated a medical emergency onboard a tanker during a sea rescue operation.

Air Force Sgt. Doug Eccleston, 35, was one of three parajumpers deployed on Friday to a Malaysian tanker that had a crew member needing immediate medical help for internal bleeding.

The rescuers, based at Patrick Air Force Base near Cocoa Beach, Florida, were flown to the ship some 200 miles southeast of Bermuda Friday morning. They jumped into the sea and assembled a raft to approach the ship.

After boarding the tanker, they stabilised the patient, a 49-year-old Philippine, and accompanied the Amal Belia back to Bermuda.

When the ship was close to two miles off the island, the sick crew member was transferred to a smaller vessel and taken to land.

Eccleston fell into the sea at around 9.20 on Friday night, as the rescuers' inflatable Zodiac raft was being lowered back into the sea so they could go ashore.

Air Force spokesman Lt. Col. Ken Warren said: “Apparently the Zodiac capsized, or turned over, or flipped over and put them into the water,” Warren said. There were only two airmen on the raft.

While the other rescuer was quickly pulled from the water, Eccleston couldn't be found.

Five boats hunted for Sgt. Eccleston for more than three hours and his body was recovered at 12.30 Saturday morning. A Harbour Radio spokesman said: “Their inflatable was swamped as it was being lowered into the water from the tanker and the two crew members were washed overboard.

“A major search operation was undertaken to locate the other crewman, involving five surface units and the USAF C130.”

Offshore weather conditions were normal Friday night during the rescue with winds of four to six knots and waves between four and six feet high.

Lt. Col. Warren said he did not know whether Sgt. Eccleston was wearing a life jacket.

He said: “The whole thing is under investigation. That is a very important part of this investigation.”

The crewman is now in a stable condition at King Edward VII Memorial Hospital after being treated for a perforated ulcer, said Police spokesman Wayne Caines.

The ship remained anchored off Bermuda, while Police, Marine and Ports and US Air Force investigators probed the incident on Saturday, before setting sail to Gibraltar that evening.

Police Media spokesman Dwayne Caines said yesterday that the investigation would continue. Authorities have yet to say how Eccleston died.