A COUPLE and their three children from Suffolk are in mourning today after their family day trip ended in the death of the woman's sister in a boating accident.

A COUPLE and their three children from Suffolk are in mourning today after their family day trip ended in the death of the woman's sister in a boating accident.

Two families from Suffolk and Middlesex – two couples, each with three children – were enjoying an afternoon on the Norfolk Broads when disaster struck as their 20ft pleasure cruiser keeled over.

The fathers and the children managed to climb off the stricken vessel and on to a passing boat, but the two mothers, who were sisters, were trapped in an air pocket for about an hour with water up to their necks.

The husband of one of the women alerted emergency services by dialling 999 and rescuers – including an RAF helicopter crewman from Suffolk who was winched down to the boat – cut a hole in its hull to get to the women and they were airlifted to hospital in Norwich.

One of the women, a 49-year-old from Suffolk, was treated for hypothermia and shock before being allowed home, but her sister, a 42-year-old woman from Middlesex, died.

An investigation has now been launched into the cause of the accident, which happened on the River Bure at Horning just before 6pm on Saturday as they made their way back to Barnes Brinkcraft's yard in Wroxham.

Norfolk police said they would not be releasing the name of the 42-year-old woman at the family's request before an inquest was opened later this week.

Flight Lieutenant Chris Marriott, 25, was one of five rescuers on the RAF search and rescue helicopter which was sent to the scene from its base at Wattisham Airfield.

He was winched down to the riverbank and waded through five feet of water before climbing on to the hull of the upturned boat, cutting a hole in the hull in a desperate attempt to pull the trapped women out.

Ft Lt Marriott had first tried to reach the women by swimming under the stricken vessel using his emergency air supply, but had been unable to open a cabin door.

"It was relatively easy wading out to the boat because the water was only five feet deep and the boat was actually resting on the bottom upside down," he said.

"The people who had got off the boat were on a pleasure cruiser moored alongside. They told me that there were two women trapped and that people had tried to dive under the boat to reach them, but had been unable to do it.

"I climbed up on to the boat and actually heard shouting from inside. One of the ladies said she was okay but her sister was unconscious.

"She had actually dived under the water to pull her sister up and was standing up supporting her sister and keeping her head above water and she was trying to resuscitate her. I tried to dive underneath, but I couldn't get to them."

He added: "An inshore rescue boat and a fire brigade crew then arrived. One of the lifeboatmen climbed up on the hull with me.

"We decided we were going to have to cut a hole through the hull, which was made of fibreglass. The firemen gave us an axe and a saw.

"We initially made a small hole with the axe then started to cut a larger hole with the saw. We kept talking to the lady inside, telling her what we were doing. At one point we had to tell her to keep back as we finished off the hole.

"It took us about 20 minutes to cut a hole about 4ft by 3ft and I was able to get my head and shoulders in and pull the ladies out and they were winched on to the helicopter and taken to hospital.

"The lady who was conscious was obviously in shock, but she was concerned first and foremost about her sister. She had been a great help to us throughout the rescue. We were at the hospital when we were told that her sister had died."

Norfolk police spokesman Mel Lacey said a full investigation was under way, in conjunction with the Marine Accident Investigation Board.

Initial reports of the accident suggested the boat could have hit the riverbank, but Mr Lacey stressed there was no evidence of alcohol playing a part in what happened.

A post-mortem examination was due to take place today at the Norfolk and Norwich University Hospital.