A SURVIVOR of a boat that capsized at a notorious shipwreck spot said lives may have been lost if not for two heroic fishermen.

Marine biologist Nick Tregenza was one of four people rescued off Land's End in Cornwall after their 18ft vessel was tipped upside down by a huge tidal swell yesterday.

The stricken boat was stranded about one mile offshore at the Runnel Stone – a hazardous rocky location notorious for its sweeping tides and known as the "sailor's graveyard" – when two Newlyn fishing boats spotted their distress.

Coastguards say that without the intervention of the skippers of the Cynthia and the Boy Dylan, the boat could have drifted "out of sight".

Three men and one woman, all in their 60s, were gripping to the side of the upturned boat when they were hauled on to the Boy Dylan.

The drama concluded when they were transferred to a passing Royal Navy training ship before being brought back to dry land by the Penlee lifeboat.

Two of the crew were taken to hospital and one is described as being in a serious condition after swallowing seawater. All four were said to be "clearly in shock".

Dr Tregenza, 63, from Long Rock, near Penzance, said: "You do fear for your life when you lose your boat like that. The fishermen and the RNLI were absolutely brilliant. We are totally grateful. They did everything perfectly."

Patrick "Patch" Harvey, RNLI coxswain at Penlee, said the tide could have very quickly taken them away from the popular fishing spot.

"It was very, very fortunate that they were spotted – if they had not been, it would have been different altogether."

Dr Tregenza and his colleagues were carrying out experiments with marine acoustic equipment when an unexpected tidal swell snagged the anchor, flooding the angling boat and forcing the vessel over.

Fisherman Andrew Pascoe, who skippers the Cynthia, and Jesse Walter, who fishes on the Boy Dylan, were cruising close to Runnel Stone when they spotted the boat.

Mr Pascoe, 39, from a long-standing Cornish fishing family, said conditions were fine and calm and Dr Tregenza's boat was bobbing around cheerfully.

"The next thing I knew, it looked like it was upside down," he said. "It just happened so quickly. It was like being in a film."

The Boy Dylan, the quicker of the two, motored to the floundering boat while Mr Pascoe alerted the emergency services.

They arrived next to the boat to find all four holding on to it for dear life, and were immediately concerned that other people might have been taken away on the tide.

One man was taken down with the boat but managed to free himself after being caught underwater for about 30 seconds.

Mr Pascoe said: "One of them was looking quite poorly, looking a bit white. We just wanted to make sure we got everyone on the boat.

"It was stroke of luck that we saw them. The boat was going west, must have been about 2.5 miles an hour.

"You just don't know when they would have seen another boat. Anything could have happened to them."

The RNLI's Mr Harvey said the four had had a lucky escape: "The way the tide was going, if Andrew hadn't seen them, they could have been carried out towards Wolf Rock and they would never have been seen because it is not an area that people fish.

"It is also very hard to see people in the water if you are not looking for them."

Mr Pascoe brushed aside any suggestion of heroics. He said: "Fishing and boating is like that. It's not as if you can phone the AA out there.

"You just have to look out for each other. It's just what anyone else would have done."

The Runnel Stone has been a hazardous shipping channel for centuries.

From the fishing boat, the group of four were transferred to the Royal Navy University training ship HMS Charger.

They were brought ashore to Newlyn in the Penlee inshore lifeboat, crewed by Mr Harvey and crew volunteers Peter Buckland and Wayne Davey, a paramedic who gave immediate first aid.

The casualties were handed over to a waiting ambulance crew at the lifeboat station.