NR-1 - The US Navy's First Nuclear Powered,
Deep Submergence Submarine
Chapter 2A - Impetus
The nuclear necklace that the United States had hung around the Soviet Union relied upon B-52 Stratofortresses of the Strategic Air Command, some of which were always airborne, loaded with nuclear weapons, and ready to strike at a moment’s notice.
At 10:22 A.M. on January 17, 1966, one of them collided with a tanker during a refueling operation over the southeast coast of Spain, at the edge of the Mediterranean Sea. Three of the bomber’s B28 thermonuclear weapons aboard fell into tomato fields near the farming and fishing village of Palomares. Although their nuclear warheads remained intact, the high explosive charges in two of the bombs detonated and spread a powder of plutonium dust over 650 acres of farmland. Some fourteen hundred tons of contaminated crops and soil eventually would be removed and sent to the U.S. for disposal.
B-52/KC-135 Refueling Crash
The fourth bomb and its partially deployed parachute were caught by high winds and carried out to sea, where they disappeared in deep water.
Palomares became the center of world attention as the United States rushed to deal with what was called a Broken Arrow, the code for any accident involving a missing or damaged U.S. nuclear weapon. President Johnson demanded immediate results. Teams of scientists made calculations based on everything from weather data to the shape of the weapon and the assumed drift of the parachute, but could only estimate a possible impact point within some fourteen square miles. The area was much too large for an efficient search. Only after a local fisherman claimed a parachute had landed near his boat did the analysts designate a one-square-mile target zone they called Alpha One. It was centered over an underwater ravine with steep sides that swept down more than two thousand feet.
A search was begun for the live nuclear weapon, and a small armada of thirty-eight American ships spread over the area, shadowed by Russian intelligence-gathering trawlers. Admiral William S. Guest eventually had some thirty-four hundred military and civilian personnel under his command on land and at sea, but the job of finding and recovering the bomb ultimately fell to a handful of men aboard a couple of small deep-diving submersibles. Underwater technology that was only in its infancy was to be tested as never before.
In February, the Alvin and its support vans were loaded aboard Air Force cargo planes in Massachusetts and flown to Rota, Spain, then transported to Palomares. In Miami, the new Aluminaut, which had just set its deep-diving record, was taken aboard a big navy ship for the long trip across the Atlantic. The small, privately owned Cubmarine from Perry Ocean Systems was also summoned, as was the navy’s remotely operated CURV, from its torpedo test range in California.
The submersibles that searched for the missing H-Bomb
(Courtesy of Woods Hole Oceanographic Institute & George Tyler, Science Museum of Virginia)
As the odd search team assembled, some 125 navy scuba divers and the Cubmarine examined the flat, sandy shallow fringes of the Alpha One area, but found nothing.
The Aluminaut went to work exploring the rolling, muddy plain that stretched along the coast from depths of three hundred to over one thousand feet, while Alvin searched the deep canyon whose rocky sides disappeared down into darkness.
The differences between the two high-tech submersibles began to tell immediately as they fought the strong currents. The Alvin was more maneuverable, but had only one-tenth the battery life of the Aluminaut. Every time the Alvin finished a six-hour dive, precious days elapsed while it was brought back aboard the waiting mother ship and readied for another attempt. The Aluminaut could roam farther, longer, and faster, but also eventually had to yield to battery life. Maintenance for both submersibles was hampered by the need for long periods of idleness to recharge their batteries and to wait for spare parts to be flown out from the United States.
Art Markel, a pilot on the Aluminaut, recalled Admiral Guest’s determination to conduct “an eyeball search” of the bottom, a directive that did not recognize the advantage of the Aluminaut’s three different sonar devices. The Alvin had none.
Markel said that on one dive, the Aluminaut homed in on a distant sonar contact and maneuvered close enough to see it through the view ports. It was part of the tail structure of one of the crashed aircraft. Logic dictated that if the debris was that far out from shore, the bomb dangling from its parachute probably landed out even further. He photographed the debris and showed the pictures to Admiral Guest. “Kind of pissed him off,” Markel said. The admiral, instead of choosing to make further sonar searches, demanded to know why the Aluminaut had left its assigned area.
“I told him we had searched everything there and kept going,” Markel said.
“How the hell can you do this?” Guest demanded.
“We’re using sonar, admiral,” replied the frustrated Markel, an outspoken man who, as a civilian, could allow his tone to match that of the senior officer.
The exchange apparently made no difference. The Alvin kept the lead role in the search, and on March 15, on its tenth dive in thirty days, the submersible located skid marks where the bomb had slid along the bottom before dropping into an underwater canyon. The Alvin, at the limit of its power, returned to the surface, and another week went by before the submersible found the furrow again. Almost two months had passed since the collision.
The delay demonstrated the difficulty of navigating and maintaining an exact position while working beneath the surface. When a submersible comes out of the water, it cannot return to its starting place on the bottom as if it were on an elevator. Tides and currents play havoc with pinpointing anything underwater that does not have an attached locator beacon. Keeping contact is almost impossible when erratic, strong currents shove around both a submersible and its target.
After re-establishing contact, the Alvin tracked the skid marks until it found the bomb, which was covered by its parachute and perched precariously on a small ledge of a seventy-degree slope, about 2,550 feet under the surface. Again almost at the end of its search time but unwilling to give up the contact, the Alvin wedged into a crevasse and shut down everything but essential life support systems. By the time the Aluminaut arrived to take over, the Alvin was almost out of air and electrical power. The pilot, sitting in the cold and dark, described the approaching Aluminaut as “the most beautiful thing I ever saw. A great silvery-pink monster … with great green phosphorescent eyes coming through the water.” The first underwater rendezvous of two submersibles was an unsung historic moment.
The Alvinwent topside and the Aluminaut assumed the grueling vigil. “We stayed on the bomb for twenty-four hours so it wouldn’t get lost, walk away, or slide into eternity,” said Markel.
On the surface, the navy plotted the new position as a storm whipped the fleet, and only when the seas settled was the first recovery attempt made. It depended solely on a single nylon tether that had been attached to the bomb by the Alvin, and when the hoist began, the weight snapped the line and the thermonuclear bomb rolled away down the mountain. Once again, it was lost.
Another two weeks passed before the Alvin discovered it again, and this time, the Aluminaut marked the spot with an electronic transponder. Several days were wasted trying to rig a complicated recovery device, but when that proved unsuccessful, the navy brought in the unmanned, remotely controlled CURV, which had spent weeks practicing the retrieval of a similar test object. The CURV operator attached two lines to the bomb’s parachute and while trying to hook up a third one, the CURV became snagged.
“I don’t think they did it on purpose,” recalled Markel, who watched the recovery operation. “They got it all tangled and couldn’t get free, so they just brought it all back up. At first, they thought they just had the CURV, which was all mixed up in the parachute shrouds, and there was the damned bomb, just hanging there.”
On April 7, 1966, eighty days after the accident, the H-bomb was lifted, damaged but intact, aboard a navy ship. The “Palomares Incident” was the worst accident ever involving American nuclear weapons.
The recovered H-Bomb and its parachute on the aft deck of the USS
(Courtesy of Sandia Labs)
The manned submersibles had performed well and the entire undersea program received a boost as a result. However, in the process, a number of deficiencies were identified. A much longer duration at depth was needed for long searches, and better navigation systems were required, as was an ability to retrieve heavy objects. Dedicated support ships with experienced handlers were also required, as were more independent operations for the submersible.
To Admiral Rickover, the Palomares problems sounded like a design sheet for the NR-1.