Atlantic drama gave victim idea for LR5

The LR5, the British minisub reckoned to be the most advanced underwater rescue craft in the world, was dreamed up by a former Royal Navy submariner during three-and-a-half days trapped nearly 1,600ft below the sea's surface in a 6ft diameter diving bell.

The LR5, the British minisub reckoned to be the most advanced underwater rescue craft in the world, was dreamed up by a former Royal Navy submariner during three-and-a-half days trapped nearly 1,600ft below the sea's surface in a 6ft diameter diving bell.

From the LR5's headquarters, Roger Chapman is co-ordinating the rescue effort to free the trapped Russian submariners on the Kursk. But it was his own remarkable experience which inspired the manufacture and design of the £5m LR5, owned by the Ministry of Defence but managed and manned by Mr Chapman's company, Rumic, based in Dalton-in-Furness, Cumbria.

He will understand, perhaps better than anyone, just what the Russian sailors have been going through. For in September 1973, Mr Chapman and his colleague, Roger Mallinson, entered the record books as survivors of the deepest sea rescue of human beings, from a depth of 1,575ft. The record still stands.

They had spent the previous three-and-a-half days huddled in a dark, damp, almost freezing capsule stranded on the bed of the Atlantic ocean, 150 miles off the south-west coast of Ireland. When they were finally pulled free, there was just 12 minutes of oxygen left in the diving bell's tanks. It was during that time, that the first seed of an idea began to germinate for a mini-sub rescue craft that became the LR5.

The two men were laying a telephone cable in their diving bell when it became ensnared in the towing cable attached to the mother ship. That ruptured the back end of the diving bell, which filled with water, although the crew's capsule remained sealed.

"We sank very rapidly, falling backwards at a speed of 12 knots until we hit the sea bed at 1,600 feet, well below diving depth," recalled Mr Chapman, now 54. "We crashed on Wednesday lunchtime but they couldn't even find us on the sea bed until Friday and finally started to lift us on Saturday morning.

"It was extremely claustrophobic. The conditions were damp, dark and cold, no more than three or four degrees. We hugged each other to keep warm."

They stayed alive by rationing the air supply, "bleeding" pure oxygen from tanks into the craft every 40 to 50 minutes, which meant one of them always had to stay awake despite the fact they were operating on what Mr Chapman describes as "quarter-power" in a semi-conscious state to preserve oxygen.

"The big advantage we had [over the Russians] was communication and we were kept informed of what was going on and that keeps your morale up. My mate had three kids and that was a big stress. I had been married three years."

Eventually, the diving bell was located and by the Saturday morning lines had been attached to the submersible and the operation to lift it clear began. "The most frightening part was being lifted up. All mayhem broke lose. The weather was very bad," he said.

Back home safely, the former Royal Navy submariner (his career ended in 1971 when he became short-sighted) began his quest to build the LR5, a rescue submersible that could attach itself to a submarine and transport trapped sailors to the surface.

The craft was originally designed and built for the off-shore oil industry but the LR5 was earmarked by the Royal Navy for submarine escape and rescue duties 20 years ago. Originally built by a team, including Mr Chapman, at Vickers Oceanics, it has been owned by several organisations.

In the last two years, the LR5, which is on permanent standby at Glasgow airport, has undergone a substantial refit, which increased its carrying capacity from nine to 16 evacuees.

The LR5, crewed by a team of three, is reckoned by experts to be superior to any other submersible rescue craft, including the US navy version, which is more cumbersome and less versatile. It has never been used in a real emergency before but in practice manoeuvres earlier this year it engaged successfully with a Russian-built, Polish submarine, providing grounds for optimism that it is compatible with the Kursk.

Mr Chapman hopes the rescue mission is not too late, but in a thinly veiled criticism of the Russian government, he says: "We had no political axe to grind at all [but] we could have been there two or three days earlier. The more time you have, the more chance you have of rescuing people."