BOSTON -- The cold, choppy surface of the Atlantic sparkled like a jeweler's display case on April 8, 1963 when the Navy's pride and joy went to sea for a series of routine test dives.
The USS Thresher, SSN-593, was the proud, $45 million lead ship of a new class of attack submarines. This fastest, quietest, best-armed and deepest-diving of ships was designed to seek and destroy enemy subs.
It was four stories high, almost as long as a football field and considered a technological marvel for its time. At Portsmouth, N.H., Naval Shipyard, it had been put through the Navy's most severe testing after its August 1961 launch.
Escorted 220 miles east of Boston from Portsmouth by the USS Skylark, a tender and rescue ship, the Thresher made several shallow test dives on April 9 with its crew of 112 sailors, plus 17 civilian technicians from the shipyard.
The next morning, beyond the continental shelf drop-off, the submarine began a deep dive to a classified test depth.
Around 9:17 a.m., the Skylark received one garbled message by underwater telephone. The message indicated the Thresher was having minor problems and would try to raise itself to shallower water to correct them.
Over the hydrophone, Lt. James D. Watson, the Skylark navigator, then heard compartments collapsing and a muted, dull thud.' It was the death rattle of the Thresher, breaking apart and falling to the ocean bottom like a crushed beer can.
Twenty-five years later, the Thresher tragedy remains the world's worst known nuclear-powered submarine accident. It was the Navy's equivalent of the Challenger space shuttle disaster.
An immediate search was ordered, even though equipment and techniques made rescue impossible. Fifteen Navy vessels were quickly dispatched to the scene from other Atlantic ports. An oil slick was spotted at 5 p.m. Searchers found bits of yellow and white plastic, some cork, and several pairs of rubber gloves.
At 10:30 a.m. the next day, Adm. George Anderson, chief of naval operations, announced: 'I conclude with great regret and sadness that this ship with 129 fine souls aboard is lost.'
Flags were lowered to half-staff at the Portsmouth Navy Yard, where a proud naval tradition dated back 175 years.
A floral replica of the Thresher was flown out to sea and dropped over the area, as a chaplain aboard a search vessel committed to the deep the bodies of its crew and civilian technicians.
This Sunday afternoon, a memorial service is scheduled at North Congregational Church in Portsmouth to honor those who died aboard the Thresher.
'Enough time has past that for some families, the hurt is gone. A tremendous sacrifice was made,' says retired Naval Shipyard engineer Russell Van Billiard, vice president of the Portsmouth Submarine Memorial Association.
'This is etched deeply into the community, and it shouldn't be forgotten,' Van Billiard said.
A Navy inquiry concluded the most likely cause was a break in a pipe in the engine room, allowing water to short-circuit the electrical system, crippling the ship, which plunged beyond its test depth.
'I think we went too far too fast,' Adm. William A. Brockett, chief of the Bureau of Ships, told a House Appropriations subcommittee. Designers hadn't realized that by doubling the depth to which subs would travel, they were more quadrupling their problems, Brockett said.
Much like the Challenger explosion in January 1986 disrupted NASA's shuttle schedule, the Thresher incident brought the Navy submarine building program to a temporary standstill.
Officials ordered a reassessment of undersea safety in this first accident in nearly 1 million miles of U.S. submarine travel since the Nautilus, the nation's first nuclear sub, was launched on Jan. 17, 1955.
Construction schedules were thrown off by 18 months during an overhaul and refitting program for more than 40 existing subs. All submarines were given immediate depth restrictions, and more than a dozen separate safety improvements were made.
Engineers perfected an ultrasonic method of testing pipe joint strength. Designers reduced the number of sea water openings that brought in water for conversion to drinking and cooking, for engine operation, ballast and other purposes.
'The legacy left by the disaster was that it ensured the safety of those who came after,' Van Billiard said.
It took more than a year, and millions of dollars, before the Thresher was found. The Trieste, a bathyscaph designed for high-pressure underwater research, found it in the summer of 1964 8,400 feet below the surface.
'We saw the hull broken in large pieces in what looked like a sand pit on the ocean floor, and around it rock fish, brittle star fish and a thresher shark,' said the Trieste skipper, retired Rear Adm. Brad Mooney.
Dim, shadowy photographs showed four shattered sections. A piece of copper pipe and one fitting were retrieved and put on display at the Naval Museum in Washington.
Raymond A. McCoole, a retired lieutenant commander, was reactor control officer aboard the Thresher. He was the only crew member who did not go on the sea trial.
Just before the submarine left Portsmouth on April 8, McCoole got word that his wife, Barbara, had been temporarily blinded when a bottle of liniment exploded in her face.
The skipper, Lt. Cmdr. Wesley Harvey, with whom McCoole had served on the Nautilus, ordered a two-day emergency leave so McCoole could stay home with his wife.
McCoole, 58, is now a real estate developer in Derry, N.H. He still thinks of his shipmates, particularly on anniversaries, and is dogged by a feeling that he might have been able to prevent the tragedy because of his extensive submarine experience.
After the accident, McCoole became a safety officer on the Thresher's sister ships. The father of six was assigned to help the families of Thresher victims. Most of the wives were very young, pregnant and-or with small children.
As casualty assistance officer, McCoole was assigned to make sure families got help in coping. Little of that assistance was financial.
'Other than six months' pay, the families received almost nothing,' McCoole said. 'At that time, the families had very little insurance.
A military program providing personnel with $10,000 of free insurance had been canceled shortly before the Thresher disaster. McCoole said few, if any, crew members bothered to replace it with private insurance.
'Insurance was reinstated after the loss of the ship with a program of semi-paid insurance,' he said.
A Thresher Memorial Fund was established to help the children through college. It paid out about $300,000 to 130 dependents.
Van Billiard said those children are now beyond college age, and the remaining money has been turned over to the Dolphin Scholarship Fund to assist the children of sailors in the Atlantic and Pacific submarine forces.