It was dangerous to have too many men on deck while on the surface in enemy waters. Should the submarine have to dive in a hurry, there was typically less than a minute for everyone to get belowdecks. Almost always, the only hatch open was the one from the bridge downward to the conning tower. As the ship submerged, that hatch had to be cleared and its watertight cover closed before seawater reached it. Otherwise there was the risk of flooding the ship and sinking. That meant leaving men topside if everyone did not get below quickly enough.
There was little chance of recovering anyone if that happened.
During World War II, submarines had a variety of jobs to do. They were asked to observe, look for enemy shipping, sink those ships, perform lifeguard duty, deliver men and equipment into hostile places, transport and deploy mines, and more. But primarily, they were designed and built to attack and destroy enemy ships.
Thresher
and her sisters were especially well equipped for that purpose.
In addition to torpedoes, the submarines carried various weapons on their decks as well, including machine guns and small cannon. The captain usually had the opportunity to choose during construction what type of deck guns he wanted on his boat. Despite the assumption by many that subs did their damage only with torpedoes, many enemy vessels were damaged and destroyed using the boats’ deck guns as well. As it turned out, these weapons were used quite often in furious, close-range combat, especially by aggressive warriors like “Moke” Millican.
There is often confusion about why these submarines are interchangeably called “diesel boats” and “electric boats.”
While on the surface, four big diesel engines—very similar to those that drove diesel locomotives of that era—indirectly powered the vessel. Rather than actually turning the screws at the stern of the boat, the engines provided power directly to a generator and two electric motors that were, in turn, attached to twin screws that did the heavy work of propelling them through the water. Those big diesel engines also charged huge banks of storage batteries located in two separate compartments in the submarine’s belly.
Those batteries were a key part of the propulsion system. They gave the boat electricity for the motors so she could run relatively quietly and without smoke when she was submerged. They also provided power for all the boat’s systems: lights, radios, radar, and the like.
When the submarine was below the surface, the diesel engines were off. Motors, lights, sonar, instruments—everything electrical—got power from those batteries.
That is why this type of submarine is often referred to as an “electric boat” in one breath and a “diesel boat” in the next.
When the boats were at sea, diving was done daily in order to adjust the trim of the boat—its attitude in the water—as well as to determine the salinity of the water at different depths. A wartime dive could be completed in thirty to forty-five seconds if necessary.
When a submarine starts to dive, it causes a shifting of the center of gravity and the center of buoyancy of the vessel. There is a point where the center of gravity of the boat coincides with the center of buoyancy, and the goal was to get past that point quickly. If a wave were to hit the boat from the side at that moment, the submarine could actually be flipped over.
The diesels had to be stopped when the boat went into a dive. The intakes for air and the openings that released exhaust gases and smoke were closed. The speed was usually reduced to about three knots to save the precious battery power. Though these vessels could go as much as nine or ten knots while beneath the surface, they did it only for very short periods of time or in the case of an emergency.
The amount of battery power available was one determinant of how long they could remain submerged. How much air was left for the crew to breathe was the other limiting factor. When off watch while submerged, crew members were encouraged to relax in order to cut their consumption of air. In battle, though, all hands were required to be alert and ready to go to work.
When it came time to surface the submarine, the Klaxon would sound three short blasts to alert everyone on the boat about what was happening. High-pressure air was routed to the ballast tanks to blow water from them and outside into the surrounding sea. The air took its place, making the boat more buoyant. The planesmen would manipulate the bow and stern planes so that the boat would begin to make a controlled rise to the surface.
Once it was above the water, the conning tower hatch was opened so that any excess air pressure that may have built up in the boat could escape, equalizing the pressure inside the boat with that on the surface outside.
While this was going on, the main induction valves—the vents that allowed air to be routed to the engines—were opened and the diesels were cranked off.
While the systems on
Thresher
were designed to do similar tasks to those on his former submarine, Millican was more than happy with the advances that had been made from the old boat to the new one. He was pleased with his crew, too.
Only a lieutenant commander at the time and still in his mid-thirties, he was the “old man” on his ship in more ways than one. His crew was mostly in their teens and early twenties. It was not uncommon for young men of sixteen to lie about their age and have their parents go along with the ruse, confirming that they were seventeen and eligible to enlist. The average age of a U.S. Navy submarine crew member early in World War II was twenty-two.
Millican wanted to make certain his young crew was aware of what he intended to do with his new boat. Once
Thresher
was out of sight of the green Hawaiian coast and under way on her first patrol under his command—her fourth since she arrived in the Pacific—Millican picked up the microphone for the 1-MC all-boat public-address system. He was about to give his crew some good news and make them a solemn promise.
“Men, we have been assigned to a new squadron and we will be taking
Thresher
to Fremantle in Western Australia,” he told them. “Our squadron commander is Rear Admiral Lockwood.”
One crew member, Torpedoman Billy Grieves, later reported that the crew was elated with the change of scenery their skipper promised them. U.S. aircraft had twice mistakenly attacked
Thresher
since she had been in commission and operating out of Hawaii, including the bombing by aircraft flying off the decks of
Enterprise
. She narrowly escaped getting herself sunk by friendly fire each time. Other submarines had similar close calls in waters around and west of Hawaii, either from aircraft or surface units. There would be no such problems at Fremantle-Perth, located on the remote southwest coast of Australia.
The crew figured it was better to be in waters where the greatest danger came from the Japanese than to risk getting themselves laced by friendly fire. Besides, every man had heard about the friendliness of the Australian people, and especially their beautiful young women.
“We were not sorry to leave this area of the Pacific,” Grieves wrote.
Grieves also noted that the crew immediately liked the attitude of their new skipper, especially his words on the 1-MC that day.
“Men, with your help, we will be aggressive in engaging the enemy at every turn,” Millican promised them. “But I also promise you that I will not be foolhardy in that pursuit. We will do as much damage to enemy shipping—naval and commercial—as we can without taking needless and unnecessary risks. We will take the battle to the Japanese but we will take
Thresher
back to Fremantle in one piece.”
That was precisely why most of those men enlisted and chose submarines. Now they had a skipper who promised them a chance to do it.
Thresher
had already seen three war patrols under her first captain. On the third run, she, like the aircraft carrier
Enterprise
, was supporting the Doolittle raid on Tokyo. Before Doolittle’s aircraft were ever launched,
Thresher
came under a hellish twelve-hour depth-charge attack. It was easily the most vicious of the war to that point. Still she stayed on station to relay intelligence and perform lifeguard duty for any of Doolittle’s downed air crewmen who might require rescue.
The events, though, were more than her skipper at the time could stand. He decided he could serve his country and the war effort better in some other capacity. When
Thresher
finally limped back to Hawaii, her captain was one of the first men off the boat. He marched directly into the office of his squadron commander and told him he did not want to skipper a submarine anymore. From there, he went back to the States to run the submarine repair facility at Mare Island near San Francisco.
It took him three patrols and a brutal depth-charge attack, but the man finally realized he was not cut out to be a submariner, that he was risking his own life and that of his crew if he continued. To his credit, he decided to serve his country in another way before the worst happened.
That unselfish decision by the submarine’s skipper was what brought “Moke” Millican to the bridge of
Thresher
.
Although he did not mention it to the crew, Millican did tell his officers how pleased he was that he was to be working for Charles Lockwood, too. They shared a similar vision for how a submarine skipper was supposed to run his boat. He looked forward to serving in his squadron, even if it was located in a remote part of the world, a long journey away from where most of the action was. Millican, after a tour in the Aleutians, was more than familiar with being out of the mainstream, but the weather in Western Australia was much, much better. And so was his submarine when compared to
S-18
.
So much for safer waters. Before they even got to Australia, they fell under two ferocious depth-charge attacks after stopping their transit to sink some enemy ships. During one incident, Millican had to take
Thresher
down in a hurry when the Japanese pressed the attack. Before the lookouts left the bridge, they were close enough to the enemy vessels so that they could hear men on the decks of the enemy ships shouting to one another.
But when
Thresher
’s decks were awash and they were only seconds from full submersion, a sudden flood of seawater poured down the hatch, drenching everyone in the conning tower. One of the men coming down from the bridge had lost his shoe in the rush to get belowdecks. It was enough to jam the hatch cover and keep it from closing tightly. They had to stop the dive, partially surface, clear the cover, and then head deep again.
That delay allowed the enemy destroyers to arrive on the scene, locate them, straddle them, and pummel them for several hours.
Then
Thresher
and her crew suffered one of the most harrowing experiences a submariner could ever endure. Some claimed to have nightmares about it for the rest of their lives.
It happened while they were still on their way to their new squadron headquarters in Australia, and even before their first full patrol under “Moke” Millican was complete. He had radar and sonar scanning for targets between Kwajalein and Wotje atolls near the Marshall Islands, determined to arrive at their new base with no torpedoes left.
Sonar and radar technology was rapidly evolving out of necessity, and while this technology was primarily developed for surface ships, its application in submarines was inevitable. Sonar employs transmitted and reflected underwater sound waves to detect and locate submerged objects or to measure distances. Its distinctive
ping! ping! ping!
is familiar to anyone who has watched a submarine movie. The sonarman spends much of his time on duty listening, not only to the emitted pings of his own sonar equipment, but also to the other noises that are conducted by seawater, sometimes from great distances. With his headphones strapped to his head, a good sonar operator can determine considerable detail about a ship contact that may be a long way from his position. Minor sound differences, such as a worn ball bearing in a propeller shaft or bubbles at the bow of a ship, allow a sonarman to identify and track multiple vessels at once. He also listens for the sounds that indicate an aggressor has launched an attack. He hears torpedo tube doors opening or torpedoes in the water, hopefully quickly enough to allow for evasive measures. Radar, on the other hand, uses radio signals to detect objects at a distance. That technology continued to evolve throughout World War II. More sophisticated radar on all fronts—including aboard submarines—and the delay of the Japanese in obtaining more advanced technology turned out to be a key factor in the Allied victory. For submarines, radar could be used only when the antenna was poked above the surface of the water. It had no use while the ship was submerged. Millican and his crew paused in a narrow pass between islands long enough to sink a torpedo tender ship,
Shinso Maru
.
Once again, thunderous explosions rocked them as they dived to hide in the shallow water. This time, though, it was not depth charges from a destroyer. It was a well-placed bomb as well as some dangerously close depth charges, and this time they came from an airplane that caught them as they submerged. Then, based on the sudden sounds of a destroyer’s screws ratcheting away above them, they could tell that the enemy once again had them dead to rights.
No doubt the airplane summoned help to finish off the American submarine. In the close quarters of the pass, odds were very much with the enemy destroyer.
Suddenly, though, the sea above and around them grew eerily quiet. The rumbling explosions stopped. So did the frenzied spinning of the destroyer’s propellers, now reduced to an almost gentle
clack
,
clack
,
clack
, as if he were simply marking time over them.
Had he given up the brawl that easily? Or was he only drawing back his fist to throw a knockout punch?
Millican and his crew in the control room looked at one another, wondering what the enemy was up to. They had
Thresher
effectively trapped in the passageway between the islands. They could go no deeper or risk getting stuck in the mud on the bottom. The aircraft soaring overhead could probably see them in the clear water and continue bombing them or tell the destroyer precisely where to drop its charges.