August 10th, 1942. The Bismarck Sea, 70 miles off Kavieng, New Ireland. Just after 7 in the morning, four Japanese heavy cruisers come over the horizon in column, steaming home at high speed. Aoba, Kinugasa, Furutaka, and Kako. Thirty-six hours earlier, these same ships had sunk four Allied heavy cruisers off Savo Island and killed 1,077 sailors in the worst surface defeat the United States Navy had ever suffered. Waiting for them, submerged at periscope depth, is USS S-44. She is 17 years old. She was designed during the First World War and commissioned in 1925. She has no air conditioning, no radar, no search sonar worth the name, and four torpedo tubes, all of them in the bow. Her hull is rated to 200 feet. Her torpedoes are a design from 1918. The men aboard call her a pigboat. The submariners of the modern fleet boats at Pearl Harbor call her class obsolete, and the Navy had agreed with them for a decade. At 700 yards, S-44 fires all four torpedoes at the last cruiser in the line. Three of them hit. Five minutes later, the 8,000-ton Kako is gone. It is the first Japanese heavy cruiser sunk by any American ship in the Second World War, and it was done by a submarine the Navy had written off as second-line years before the war began. This is how.

The strategic picture in August 1942 was as thin as it would ever get for the United States in the Pacific. Three days earlier, on August 7th, the First Marine Division had landed on Guadalcanal and Tulagi. It was the first American offensive of the war. The Marines were ashore, but their supplies were not. Most of the transports were still unloading in the sound between Guadalcanal and Florida Island when Vice Admiral Gunichi Mikawa brought seven cruisers and a destroyer down from Rabaul on the night of August 8th. In under an hour, Mikawa's force sank Quincy, Vincennes, Astoria, and the Australian cruiser Canberra. The Japanese lost 58 men. Then Mikawa turned for home without touching the transports. The next morning Rear Admiral Richmond Kelly Turner, with no cruiser screen left, pulled the transports out of the sound with half the Marines' supplies still aboard. The First Marine Division was on its own with a few days of ammunition and captured Japanese rice. Mikawa's cruisers, meanwhile, were racing back toward Kavieng and Rabaul with a total victory behind them and nothing in front of them. Every American carrier had already withdrawn to the south. The only thing the United States Navy had between Rabaul and the Solomons was a handful of old submarines operating out of Brisbane, and the Navy did not think much of them.

That opinion had a long history. The S-class was designed in 1917 and 1918 as the Navy's first attempt at a true ocean-going submarine. Fifty-one were built. S-44 was one of the S-42 group, laid down at the Fore River yard in Quincy, Massachusetts, launched in October 1923, and commissioned on February 16th, 1925. She displaced 906 tons on the surface and 1,126 tons submerged. She was 225 feet long, 20 feet 8 inches in the beam, and carried 38 to 42 men. Two diesels gave her 14 and a half knots on the surface. Submerged on batteries, she could make 11 knots for about an hour, or crawl for 20 hours at 5. Her armament was four 21-inch torpedo tubes in the bow, with 12 torpedoes, and a single 4-inch deck gun. Her test depth was 200 feet. By 1942, every one of those figures was a liability. The new Gato-class fleet boats coming out of Electric Boat and Portsmouth were 312 feet long, carried 24 torpedoes in ten tubes, six forward and four aft, made 21 knots on the surface, dived to 300 feet, had surface search radar and air conditioning, and could patrol for 75 days across 11,000 miles. The S-boats could manage half that, in every category. By the early 1930s the Navy rated the S-class as second-line boats. Several had been decommissioned and laid up. In 1942 the United States handed six of them to the Royal Navy because it considered them surplus. The remaining Pacific boats were sent to Manila and then, after the Philippines fell, to Brisbane, because there was nothing else to send.

Conditions aboard were the reason the crews called them pigboats. There was no air conditioning of any kind. In the tropics, the internal temperature on a submerged S-boat routinely passed 100 degrees Fahrenheit, and in the engine room it went higher. Humidity condensed on every steel surface and dripped onto the bunks, the charts, and the electrical switchboards. Men broke out in heat rash so severe that the pharmacist's mate went through the boat's supply of talcum powder. Food spoiled within days of leaving port. Fresh water was rationed to drinking only. The boats leaked at depth, the diesels were temperamental, and the batteries gave off chlorine if seawater got into the cells. An S-boat patrol was typically limited to 30 days, and the men came back thinner. Within the submarine force, the S-boats were understood as a stopgap, something to keep experienced crews at sea until enough fleet boats came off the ways to replace them.

And there was one more problem, larger than any of these, that the Navy would not admit for another year. American torpedoes did not work. The Mark 14, the weapon carried by every new fleet boat, ran an average of 10 feet deeper than set. Its Mark 6 magnetic exploder either detonated the warhead prematurely, 50 yards short of the target, or failed to detonate at all. When commanders switched to the contact setting, the firing pin crushed on a square hit and the torpedo simply bounced off the hull. Throughout 1942, fleet boat captains came back from patrol reporting hits that did no damage, and the Bureau of Ordnance told them their aim was bad. It would take until late 1943, and a series of tests where torpedoes were fired into a cliff at Kahoolawe, before the Navy accepted that the weapon itself was defective. In August 1942, that argument had barely begun.

So on paper, in August 1942, the American submarine that mattered least was an S-boat. Old, slow, shallow, half-blind, and miserable to live in. The specifications missed three things.

The first was the torpedo. The S-boats could not carry the Mark 14. Their tubes and their fire control were built for the older, shorter Mark 10, a weapon designed in 1917 and 1918 by the Naval Torpedo Station at Newport. The Mark 10 was slower, at 36 knots against the Mark 14's 46. It had a shorter range, 3,500 yards. Its warhead carried 497 pounds of TNT, against 643 pounds in the Mark 14. By every specification it was the inferior weapon. But the Mark 10 had no magnetic exploder. It used a simple contact exploder, the Mark 3, a design that had been in service for two decades and had been proved in live firings the Bureau of Ordnance had never bothered to repeat for its new weapon. The Mark 10 also ran deep, by about 4 feet, but its captains knew this and set their depths shallow to compensate. The result was that in the summer of 1942, the only American submarines carrying a torpedo that reliably exploded when it struck a ship were the ones the Navy had written off. An S-boat that got close enough to hit would sink what it hit. A fleet boat often would not.

The second was the men. The S-boats out of Brisbane belonged to Submarine Squadron Five, sent out under Captain Ralph Christie. Their crews were not raw. Most of the chiefs and many of the officers had spent years in these same hulls, on the same diesels, working the same manual trim and the same hand-cranked torpedo data. They knew exactly how the boat would behave at 100 feet with a leaking gland, and they knew how long they could stay down before the air went bad. S-44's commanding officer was Lieutenant Commander John R. Moore, known through the service as Dinty. Moore was a career submariner. He had taken S-44 on her first war patrol out of Brisbane in April 1942 and sunk a Japanese salvage vessel off Guadalcanal on May 12th. On her second patrol in June, he had sunk the converted gunboat Keijo Maru on June 21st. Two patrols, two ships, in a boat the Navy did not expect to sink anything. Moore's habit was to press in close, inside 1,000 yards, where the Mark 10's short range and the boat's crude fire control did not matter, and where a spread of four torpedoes could not all miss.

The third was where the S-boats were. Brisbane's submarines were assigned the sea lanes between Rabaul, Kavieng, and the Solomons. That was exactly the water Mikawa's cruisers had to cross on the way home. Christie had positioned his boats in the approaches to the Japanese anchorages, and S-44 had been ordered to patrol off Kavieng. On the morning of August 10th, the Japanese victors of Savo Island were steaming straight toward an obsolete submarine sitting on the one stretch of ocean where obsolete did not matter.

S-44 had been on station since early August. She was on her third war patrol, running submerged by day and on the surface at night to charge batteries, in heat that had already left several of the crew with open sores. On the morning of August 10th, she was at periscope depth about 70 miles southeast of Kavieng, near the small island of Simbari. At about 7:50, the officer of the deck spotted masts. Moore took the periscope. What he saw was four heavy cruisers in column, escorted by nothing, making around 16 knots and zigzagging, headed for Kavieng harbor. He identified them, correctly, as the cruisers of Mikawa's Sixth Cruiser Division. Aoba led, then Kinugasa, then Furutaka, then Kako.

The tactical problem was simple. S-44 could not chase. Submerged, she could make 11 knots for a few minutes, not enough to close on 16-knot cruisers if they passed at any distance. Her four torpedoes would all go in a single salvo from the bow, so she had one shot and needed to be pointed at the target when she took it. And the Mark 10 was slow. At 36 knots, a torpedo run of 700 yards took about 35 seconds. At 3,000 yards, it took over two minutes, long enough for an alert cruiser to turn away. Moore's choice was to close to point-blank range and take the last ship in line, because the last ship would be the one whose lookouts were least likely to be watching ahead, and because by the time the first three cruisers passed, the geometry would be settled. He held S-44 at periscope depth, made minimal exposures, and let the column come to him.

At about 8:06, Kako came into the periscope at 700 yards, broad on the bow. Moore fired all four tubes in sequence. The spread was set shallow, to counter the Mark 10's tendency to run deep against a cruiser drawing 18 feet. Then he watched. About 35 seconds after the first torpedo left the tube, the first explosion came. Three of the four torpedoes hit Kako along her starboard side, forward, amidships, and aft. The men in S-44's control room heard the detonations through the hull. Kako's forward magazines did not explode, but the flooding was immediate and total. She heeled to starboard, went down by the bow, and rolled over. Within five minutes of the first hit, Kako was gone. Her sister ships stopped only long enough to pick up survivors, then ran for Kavieng. Aboard S-44, Moore took her deep and cleared the area. There were no escorts to counterattack, and no aircraft found her. The submarine took no damage of any kind.

Kako was no small prize. Laid down in 1922 and commissioned in 1926, she was one of the two Furutaka-class ships, the first heavy cruisers Japan built. After her 1930s reconstruction she displaced roughly 8,700 tons standard, carried six 8-inch guns in three twin turrets, eight 24-inch torpedo tubes for the Type 93 Long Lance, and could make 33 knots. She had fought at Savo Island 36 hours earlier and had put 8-inch shells into Astoria, Quincy, and Vincennes. Her captain, Yuji Takahashi, survived. Japanese and American accounts disagree on how many of her crew did not, with figures ranging from 34 to about 70. She was the first Japanese heavy cruiser sunk by the United States Navy in the war, the largest Japanese warship sunk by an American submarine up to that date, and the only Japanese warship lost in connection with the Battle of Savo Island. The four American and Australian cruisers on the bottom of what the Marines were already calling Ironbottom Sound had no other answer that month.

Moore's patrol report was short and exact. Four torpedoes fired, three hits, target sunk, observed through the periscope. He was awarded the Navy Cross. The crew of S-44 had now sunk a ship on each of three consecutive patrols, in a boat that had been classed as second-line before most of them had enlisted.

The measurable results explain why the sinking mattered beyond the loss of one cruiser. The Japanese Sixth Cruiser Division, four ships strong on the morning of August 10th, was three ships strong by 8:15, a 25 percent reduction in the heavy cruiser force Mikawa had available for the fight over Guadalcanal. That force would be needed. Over the next three months the Japanese would commit cruisers to Cape Esperance in October, where Furutaka was sunk, and to the naval battle of Guadalcanal in November, where Kinugasa was sunk. Aoba was crippled at Cape Esperance. Of the four cruisers that passed S-44's periscope that morning, three would be on the bottom within four months, and the first of them went to a 1925 submarine firing 1918 torpedoes.

For the American submarine force, the numbers from Brisbane told a story that the Bureau of Ordnance did not want to hear. In the same period, fleet boats with Mark 14 torpedoes were reporting multiple hits with no visible damage. S-boats with Mark 10 torpedoes were reporting hits that sank ships. S-38 under Lieutenant Commander Henry Munson had sunk the transport Meiyo Maru on August 8th, carrying troops bound for Guadalcanal, with two Mark 10 torpedoes from 1,000 yards. S-44 had sunk Kako two days later with three hits out of four. Two old boats, two patrols, two ships sunk, five hits from six torpedoes, with a weapon that had been declared obsolete before the Mark 14 was designed. The submarine captains at Brisbane could read those numbers. It took the Bureau of Ordnance until 1943 to read them the same way.

S-44 did not survive the war. After Kako she completed two more patrols out of Brisbane, then went to the Aleutians in 1943 to patrol the Kurile Islands. On the night of October 7th, 1943, off Paramushiro, she attacked what her lookouts took for a small merchant ship on the surface. It was the Japanese escort Ishigaki, and the escort shot back. S-44 was hit repeatedly at close range and went down. Two men, Ernest Duva and William Whitemore, were picked up by the Japanese and survived the war as prisoners. The rest of the crew was lost. Moore was not aboard. He had been relieved after the Kako patrol and sent to command a new fleet boat, as the Navy did with captains who had proved themselves in old ones. Of the 51 S-boats built, none survives today. The last of them were scrapped in 1946.

The Navy's judgment of the S-class had been technically right on every point. They were slow. They were shallow. They were half-blind, hot, cramped, and worn. They could not have survived the kind of patrol a Gato-class boat ran off Japan in 1944. But in August 1942, none of that was the question. The question was whether the United States had anything in the water between Rabaul and Guadalcanal that could hit a Japanese cruiser and have the hit count. The fleet boats had the range, the speed, the radar, and the air conditioning, and their torpedoes bounced. The S-boats had none of those things, and their torpedoes exploded. That difference was not an accident. It was the product of a 1918 torpedo design that had been tested until it worked, a captain who had learned that his boat's only chance was inside 1,000 yards, and a squadron commander who put his old boats on the one stretch of water the enemy had to cross.

August 10th, 1942, 700 yards off the starboard bow of the heavy cruiser Kako. A 17-year-old submarine with 42 men sweating through 100-degree heat, holding a hull rated for 200 feet at periscope depth, fires four torpedoes designed the year the First World War ended. Three explode. Five minutes later, the ship that had helped sink four Allied cruisers at Savo Island is gone, and the Japanese Navy has learned that the oldest submarines in the American fleet are the ones that can kill. The submariners who called the S-boats obsolete were right about the specifications and wrong about the war. Obsolete meant slow and hot and leaky. It did not mean harmless. Kako found that out in five minutes.