The Buzz

Japan's Long Lance Torpedo: The 'Hypersonic' Weapon of World War II?

When the Second World War began, the Japanese plan was to exercise patience to defeat a stronger foe. Under the "decisive battle" strategy, Japan would seize the Philippines, and as the U.S. Navy sailed across the Pacific to recapture Manila, it would be harried and worn down by persistent aircraft, submarines and destroyer attacks. Once the American battle fleet had been sufficiently weakened, the Japanese battle fleet would sortie out and sink it in a huge Jutland-style naval battle near the Philippines.

When U.S. Navy warships began exploding in the middle of the night, America realized it had a problem.

In the autumn of 1942, Guadalcanal, in the Solomon Islands near Australia, became the focal point of the Pacific War. For six months, U.S. and Japanese forces savagely battled on land, air, and sea to determine who would control the island and its strategic airfield.

For the U.S. Navy, which had belittled the Japanese as incompetent, Guadalcanal came as a shock. The disaster at Pearl Harbor could be explained by surprise and treachery, but the Navy left two dozen warships in "Ironbottom Sound" off Guadalcanal.

One reason was the "Long Lance," the Japanese torpedo that was the most powerful weapon of its kind in the early years of World War II. Developed in the late 1920s, the Long Lance, as Americans nicknamed it (the Japanese designation was the "Type 93"), was a remarkable device. In modern parlance, it would be an asymmetric weapon, designed to compensate for Japanese inferiority to more economically powerful Western nations. In some ways, it was the equivalent of hypersonic ship-killing missiles that China and Russia would use to counter the superior U.S. Navy.

Recommended: 8 Million People Could Die in a War with North Korea

Recommended: Why North Korea Is Destined to Test More ICBMs and Nuclear Weapons

Recommended: 5 Most Powerful Aircraft Carriers, Subs, Bombers and Fighter Aircraft Ever

When the Second World War began, the Japanese plan was to exercise patience to defeat a stronger foe. Under the "decisive battle" strategy, Japan would seize the Philippines, and as the U.S. Navy sailed across the Pacific to recapture Manila, it would be harried and worn down by persistent aircraft, submarines and destroyer attacks. Once the American battle fleet had been sufficiently weakened, the Japanese battle fleet would sortie out and sink it in a huge Jutland-style naval battle near the Philippines.

To accomplish this, the Imperial Japanese Navy relentlessly trained its surface ships in night torpedo attacks that would allow its ships to sneak up on and destroy the enemy. The Imperial Navy lacked radar, but lookouts were rigorously trained and equipped with powerful night binoculars. Yet all would be for naught without a good torpedo, and the Long Lance more than met the need.

The Long Lance was a big torpedo for its time, some two feet in diameter, almost thirty feet long and weighing almost three tons. It was armed with a 1,080-pound warhead that was 50 percent larger than most other torpedo warheads. Most important was the Long Lance's propulsion system. Most other nations fielded torpedoes propelled by steam, diesel or electric propulsion. But the Japanese opted for a pure oxygen-based system (inspired by an earlier British design) that could send the Long Lance out to twelve miles at a speed of 48 knots, or an incredible 24 miles—about the same range as a battleship's gun—at a speed of 36 knots. The Long Lance also didn't leave telltale bubbles on the surface to warn enemy ships a torpedo was approaching.

How did this compare to U.S. torpedoes? The 21-inch-diameter Mark 15, carried by U.S. destroyers, weighed less than two tons and only hefted an 825-pound warhead. Worst of all, its maximum range was only eight miles, or one-third that of the Long Lance. Not surprisingly, the Americans emphasized naval guns rather than torpedoes.

Pages