The Five Worst Submarines of All Time

The worst of the worst lumbering around in the briny deep.

A boat -- or group thereof -- that meets these standards warrants membership in an undersea hall of shame. Herewith, History's Worst 5 Submarines, listed from least bad to worst of the worst:

5. Thresher, Scorpion, and Kursk

Why the hodgepodge? These are boats that sank under puzzling circumstances, damaging a great-power navy's reputation for excellence at a time when reputation truly mattered. Because it's hard to say for sure what happened -- whether equipment or human failure was more blameworthy -- these disparate boats belong in a class of their own.

Thresher, the lead boat in a new class of American SSNs, suffered catastrophic flooding in April 1963 while operating near its maximum operating depth. Deep water means intense pressure. Even a small leak in a piping system can quickly outstrip damage-control teams' efforts to patch it. Speculation has it that a weld sprung a leak, shorting out electrical equipment and causing a reactor scram. Cascading failures kept the boat from surfacing. But as Admiral Hyman G. Rickover, the godfather of U.S. naval nuclear propulsion, told Congress, "the known facts" about the disaster "are so meager it is almost impossible to tell what was happening aboard Thresher."

What we do know is that the accident sent the U.S. Navy scurrying for answers -- and trying to mend the silent service's esteem -- at a critical juncture in the Cold War. The Cuban Missile Crisis was a recent memory, while Admiral Sergei Gorshkov's Soviet Navy was embarking on a crash buildup. Clausewitz portrays military competition as a "trial of moral and physical forces" -- of strength, on other words -- "through the medium of the latter." The death of Thresher worked against the idea of U.S. undersea mastery -- heartening Moscow for the zero-sum contest between East and West.

Another American boat, the Skipjack-class SSN Scorpion, went down in May 1968. Again, courts of inquiry were unable to determine for sure what had happened. The Naval History and Heritage Command, however, reports that "the most probable event was the inadvertent activation of a Mark 37 torpedo during an inspection." The fish either commenced running within its tube, or was released, circled around, and targeted Scorpion. Either way, the cataclysm applied another sharp blow to the submarine force's prestige. The balance of moral forces again tilted Moscow's way.

Built after the Cold War, Kursk, an Oscar II-class sub, became a metaphor for the economic and political woes that ailed post-Soviet Russia. Many Russians, including President Vladimir Putin, bewailed the downfall of the Soviet Union. They longed for the days when their country was a superpower. That the Russian Navy still operated a potent undersea fleet was a token of past dignity and hopes for a restoration. Those hopes took a hit in 2000, when a torpedo malfunctioned -- setting off a chain reaction of explosions that left the pride of the Northern Fleet at the bottom of the Baltic Sea.

The lesson from these sinkings and similar debacles--think last year's explosion on board the Indian diesel boat Sindhurakshak--is sobering for navies. When a ship becomes a symbol, its death has outsized political and even cultural ramifications. Failures in seamanship or everyday routine, then, can reverberate far beyond a boat's hull.

4. Type 092 Xia

You can say one good thing about the next boat on the list: it hasn't sunk. On the other hand, China's first SSBN has done little to advance its chief mission, nuclear deterrence. The lone Xia entered service in 1983. Its crew finally managed to test-fire an intermediate-range JL-1 ballistic missile in 1988, overcoming debilitating fire-control problems. Yet the boat has never made a deterrent patrol and seldom leaves the pier. Retired submarine commander William Murray describes the Xia -- and the Han SSNs from which its design derives -- as "aging, noisy, and obsolete."

American submariners joke that some foreign subs are as noisy as two skeletons making love inside a metal trash can. When a boat becomes an object of fun, its parent navy has problems. Small wonder China's naval leadership skipped on to a more modern design, the Type 094 -- leaving the Xia a ship class of one.

3. K-class submarines

When new technologies appear, navies habitually deploy them as fleet auxiliaries -- that is, to help the existing fleet do what it's already doing, except better. Undersea craft were no exception a century ago, when navies were still experimenting with them. The Royal Navy's World War I-era K-class boat was a failed experiment, as the nicknames affixed to it--Kalamity, or Katastrophe--attest.

Designed in 1913, these boats were meant to range ahead of the surface fleet, screening the fleet's battlewagons and battlecruisers against enemy torpedo craft. Or they could seize the offensive, softening up the enemy battle line before the decisive fleet encounter. A solid concept. But to keep up with surface men-of-war, such a boat would need to travel at around 21 knots on the surface, faster than any British sub yet built. Diesel engines were incapable of driving a boat through the water at such velocity. The Admiralty's speed requirement, therefore, demanded steam propulsion.

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