All the A-bombs were carrying a critical mass of uranium. A high-pressure explosive charge caused the critical mass to explode. The pressure of 16,000 feet of water could trigger the bomb, a constant worry forty years later.
The marine scientists had studied this historic data. The old codger had described a B-47 descending rapidly to low level and dropping a bomb on the Seven Stones. Was he correct? He thought the year was in the late fifties. In the years 1957 and 1958 there were forty-nine B-47 crashes. The tricky flight characteristics lent credence to the argument. The thin swept wing of the aircraft gave it a top speed of six hundred and six miles per hour, but at four hundred and eighty-nine miles per hour applying the ailerons merely twisted the wings, making a banked turn impossible. At five hundred and twenty-five miles per hour the ailerons were totally ineffective in any part of the flight envelope.
The cruise phase at five hundred miles per hour put a heavy demand on the pilots. At forty-five thousand feet the stalling speed of four hundred and ninety-five miles per hour was a mere five miles per hour less than the cruise speed. The autopilot could not cope with such a fine margin. Many B-47s stalled at high speed, spun and broke up, known to flight crews as ‘coffin corner’.
If one of six jet engines failed, the pilot had to hurriedly dive to get above the stalling speed. The flight manual instructed him to descend at six thousand feet per minute and soft drop his A-bombs at very low level into the sea. With a failed engine and A-bombs on board, the very fast two hundred and five miles per hour landing speed of the B-47 was too dangerous.
Considering all this evidence, the marine scientists decided the old codger was right. There could be A-bombs lying amongst the Seven Stones rocks.
The Torrey Canyon Threat
On the 18th March 1967, the Torrey Canyon tanker, carrying 120,000 tons of crude oil from Kuwait to the Milford Haven oil refinery, drove straight into the Seven Stones reef at its full sixteen knots speed. An estimated 31,000 gallons of oil spilled out of a hole torn in the hull, a small amount compared the 120,000 tons (33 million gallons) about to be disgorged from the hull.
The Seven Stones reef is in a dangerous position to shipping where the rough seas of the Atlantic Ocean, the Irish Sea, the English Channel and the Bristol Channel fight for the dominating position. No individual ocean force ever wins. The clash leaves a mass of corkscrewing breaking waves best avoided by any ship rounding Lands’ End. One small ship braves the fringes of this torrid mass every day, the Scillonian, the ferry from Penzance to the Isles of Scilly. Many a holiday maker’s stomach testifies to the unpredictability of the wave motion.
The magnitude of the disaster was soon apparent. Seabirds were clogged with black oil and dying a terrible death in their thousands. Beaches and shorelines, and the plants living on them, were blackened with sticky oil from Cornwall to Brittany and the Channel Islands. It was impossible to re-float the Torrey Canyon, impossible to pump out the 100,000 tons of crude oil and impossible to put a boom around it to stop the oil spreading.
The Government decision was unanimous: bomb the Torrey Canyon!
In theory, bombing the very large crude oil carrier would set fire to the open sea spillage and burn off the oil cargo in the tanker. The intense heat would destroy the ship.
The theory went very wrong. The Royal Navy and the Royal Air Force were given the easy task of hitting a very large 90,000 ton tanker at low level, impossible to miss. The first Buccaneer fighter bomber launched its high explosive bomb and missed. The oil spillage caught fire. The dense black smoke obscured the target tanker. A further forty-one bombs were launched. All missed the target tanker. The shock waves, however, assisted the tanker’s break-up. The oil spillage became a torrent.
How many unexploded bombs lay below the sea in the craggy Seven Stones rocky reef? The dangers of exploratory diving over the reef were increasing.
The second hole in the theory failed to understand that the volatile petroleum fraction of the crude oil would quickly burn off. The sticky black heavy tar-like oil would remain unburnt to be spread across the shores of the western approaches, an environmental disaster. A decade later, the tar deposits were still being cleared up.
The marine scientists posed the question: was this legacy oil contributing to the recent diamond hard glass coatings?
Falmouth Coastguard Damper
The well-kept records in the Falmouth Coastguard office put a degree of sanity on folklore hype.
There was no record of a B-47 crash off Land’s End. There was no record of a B-47 dropping a bomb in the proximity of the Seven Stones. There was no A-bomb lodged in the Seven Stones rocks.
With regard to the air attack on the Torrey Canyon, the Coastguard had been fully involved. The area was cleared of commercial shipping. The Seven Stones lightship was taken off station, the first time since 1841, except for World War II. The Coastguard were given the aircraft gun camera films proving
