Operation Storm: Japan's Top Secret Submarines and Its Plan to Change the Course of World War II (24 page)

NO. 5 (STARBOARD): AUXILIARY ROOM
Opposite the control room on the starboard side of the sub was a special compartment, which at least one source claims was used to overhaul
Seiran
engines. A hatch 31 inches in diameter connected the compartment to the control room.
⁷⁴
There was also an overhead access tube leading to the aircraft hangar.
^§
75
Seiran
engine maintenance was usually conducted in the hangar, which is not surprising, since it is hard to imagine how they fit an
Atsuta
engine into the auxiliary room even on a sub as large as the
I-401
.

Two of the sub’s supplementary generators were located in the auxiliary room, as was the sub’s turbo blow, which was used to
empty the main ballast tank when the sub was surfaced and (God forbid given how high she sat in the water) required more freeboard.

GALLEY
Every sub has a galley. The
I-401
’s was located adjacent to the auxiliary generators.
⁷⁶
One can imagine the difficulty in preparing three meals a day for 200 men. Somehow, the
I-400
cooks managed. Three freezer lockers below the galley deck kept food cold,
⁷⁷
and four
⁷⁸
oversize steam kettles turned out large quantities of rice to provide the crew with the much-cherished staple.
⁷⁹

Food was the best part of life aboard the
Sen-toku
subs. It was far better than anything the Imperial Japanese Army received, and there was plenty of it. Rice was served at every meal, and the galley even managed delicacies like cow tongue, boiled eel, and sweet bean paste. Staples included broiled fish, shrimp or vegetable
tempura
, beefsteak, pork cutlets, eggs, pickled horseradish, dried seaweed called
nori
, chestnuts, fresh oranges, canned peaches, pears, and pineapples, fruit juice or sodas, and
miso
soup for breakfast.
⁸⁰
Green tea was consumed in vast quantities, and coffee less so, though it was available. Evening snacks included noodles, or biscuits with milk.
⁸¹
Some Sixth Fleet subs even had ice cream, though it was usually reserved for special occasions like the last meal before a dangerous mission.
⁸²
In fact, after a few weeks at sea, one of the
I-400
cooks yearned for simpler fare, such as brown rice and pickled plum.
⁸³

An onboard nutritionist planned every meal
⁸⁴
even though fresh vegetables ran out by the tenth day at sea. After that it was canned food morning, noon, and night,
⁸⁵
with onions thrown in for variety. Tinned vegetables were especially unpopular, since they tasted like sand and ashes.
⁸⁶
There were only so many canned sweet potatoes a crew could eat before complaining set in. Bottled vitamins were available at each meal, since it wasn’t unusual on longer voyages for mild cases of beriberi to develop.
⁸⁷
The real problem with the
I-401
’s food supply though was that the sub’s size greatly reduced the number of flying fish that jumped on her deck. This
limited a much-appreciated supplement to the standard fare—yet another consequence of being big.

CONNING TOWER
Immediately above the control room was the
I-401
’s conning tower, which was used for combat operations. It was a dark, cramped space 8 feet in diameter and 20 feet long,
⁸⁸
only 2 feet longer than the
Segundo
’s conning tower. When nine men squeezed in during battle stations, the compartment became impossibly tight. Nambu could make a ship or aircraft sighting through one of two periscopes, calculate firing solutions, and launch torpedoes from the conning tower. There were also duplicative sound, radar, and helm stations, a further example of how redundancy was a central design feature in submarines.

One of the worst things a sub could face was its conning tower being flooded, either by accident or by an enemy blowing a hole in its plating. The situation was especially dangerous aboard the
I-401
, because the sail’s offset position could easily heel the sub onto her side.
⁸⁹
The sail had extra steel plating to protect against such an event,
⁹⁰
but it was still a risk.

NO. 6 COMPARTMENT: PORT AND STARBOARD ENGINE ROOMS
The
I-401
’s engines were located in two compartments aft of the control and auxiliary rooms. Unlike the
Segundo
, where the engine rooms were sequential (one forward, one aft), the
I-401
’s engine rooms flanked each other with a hatch connecting the port and starboard compartments. The sub’s four diesel engines were the only ones of their kind in the Sixth Fleet,
⁹¹
but their defining characteristic, besides their unusual size, was how temperamental they could be. Each engine was rated at 2,250 shp and was connected to one of two propeller shafts via reduction gears in the aft section of the compartment.
⁹²
With a clean bottom, the
I-401
could generate a top speed of 20 knots surfaced and up to 7 knots submerged (though not for long).
⁹³
She might have been big, but she was by no means slow.

Up to four engines could be used on the surface to power the
I-401
, though one engine was usually delegated to charging her batteries. However, her diesels couldn’t operate below periscope depth, so batteries were used to drive an electric propulsion system.

Nambu’s sub carried approximately 500,000 gallons of diesel oil, enough to fill 15 railway tank cars.
⁹⁴
Fuel was in such short supply that the Imperial Japanese Navy cut it with soybean
⁹⁵
and pine oil.
⁹⁶
This means it burned dirty and left a black exhaust cloud for enemies to follow. Unfortunately, nothing could be done about it.

The engine compartment also housed several vapor-compression stills. Each still (called an evaporator) turned the ocean into fresh water by boiling it. Their output was never as advertised, so there was little water for personal use and none for showers.
⁹⁷
This partly accounted for the sub’s unmistakable smell of grease, diesel fumes, hydraulic fluid, male sweat, cigarette smoke, and whatever was being cooked for lunch. After a while, nobody cared.

NO 7. COMPARTMENT: PORT AND STARBOARD MANEUVERING ROOMS
Just aft of the main engine rooms were the sub’s port and starboard maneuvering rooms. If Nambu wanted to increase speed, the information was relayed via engine annunciators from either the conning tower or the control room to an electrician’s mate in the maneuvering cubicle. There he manipulated a set of long metal levers to power the sub’s electric motors either up or down, depending upon Nambu’s order.

The
I-401
had two 1,200 shp electric motor-generators, one for each propeller shaft. The electric motors drew electricity from storage batteries used to drive the sub when submerged. If the engine room was defined by noise, the motor room was defined by heat. In fact, the electric motors generated so much heat, the men worked shirtless. The sub’s humidity also shorted out the compartment’s electrical distribution panels, making for constant problems.
⁹⁸

NO. 8: AFT COMPARTMENT
The last compartment inside the
I-401
was her largest. Located in the stern, it was the crew’s aft berthing
compartment. Here the sub’s interior hull gave way to a 61-foot-long space, the widest in the sub and second in size only to her aircraft hangar. U.S. subs usually reserved their aft compartment for a stern torpedo room, but the
I-401
’s held sleeping quarters, a head, various steering mechanisms, and an emergency signal ejector to let rescue ships know where the sub had gone down.
⁹⁹

The aft compartment was slightly more relaxed than the rest of the sub, in part because it was the area least likely to be visited by an officer. Crew members entering the compartment removed their shoes before stepping onto a raised wooden deck. So many feet rubbed the wood planking that it soon became as polished as a dance floor.
¹⁰⁰

BATTERY COMPARTMENT
Below the
I-401
’s habitable space was a second world, where the sub’s inner workings were housed. It was a dark, dank place that included the pump room, the ventilation exhaust blowers, the lubricating and freshwater tanks, the anchor chain, ammunition storage, and a considerable number of valves and piping: it was no place for a man suffering from claustrophobia.

The
I-401
’s life-giving battery cells were located here. Made of lead and containing sulfuric acid, each cell weighed more than 100 pounds. These cells were used when the sub was submerged to power the electric propulsion system. Batteries could prove a liability, however, especially if contaminated by saltwater, which produced fumes that could overwhelm a crew. There was also a chance, when the batteries were recharging, that hydrogen might build up and ignite. Not surprisingly, batteries were checked as often as a boat’s powder magazine, since an explosion in either could scuttle the sub.

U.S. subs were hardly five-star hotels, but they were downright luxurious compared to the
I-401
and a lot more reliable. For example, the
Segundo
had three showers, four heads, and more than half a dozen sinks for 70 men, while a typical I-boat would have considerably fewer bathroom facilities for more than twice the crew. A Balao-class sub not only had what a Japanese I-boat captain
would have considered an impressive number of bathroom facilities, it also had a top-notch air-conditioning plant. And if that didn’t ensure a crew’s comfort, there were an ice cream freezer, a film projector, a sunlamp in the engine room, steak on the menu, and a washing machine that used too much water. There was even an escape hatch in case the sub went down, although most submariners had little faith it would work and insisted its only purpose was to placate their mothers. These were inconceivable luxuries for a Japanese sub captain like Nambu. Sixth Fleet submarines were at war—sunlamps had nothing to do with it.

I
T WOULDN
’
T HAVE
taken long for Nambu to conclude that his sub’s huge size reduced her maneuverability. Anything that increased a sub’s dive time or diminished her operational capacity was frowned upon. So though the
I-401
was fast both above and below the surface, her dive time (not to mention her ability to stop promptly) was compromised.

Another problem was the sub’s sail. The fact that it was offset to port created an unbalanced form of drag when the sub was submerged. It was as if the front wheels of a car were permanently out of alignment. A helmsman had to steer a seven-degree starboard course at two knots submerged just to follow a straight line. Additionally, the offset tower meant the sub required a larger starboard turning radius when underwater.
¹⁰¹
Nambu would shrug off these difficulties, but they’d be constant worries for his helmsmen.

After Nambu’s inspection of his new sub, he likely drew the following conclusions: the
I-401
’s high freeboard, broad beam, and deep draft would make her a comfortable boat in a seaway; her hull shape would naturally reduce roll and pitch, and her bridge would remain dry under most weather conditions; and though her safety depth was only 328 feet (82 percent of her overall length), she was fast and well armed.
¹⁰²
Yes, size reduced dive time and maneuverability, which made her lumbering, but she could certainly defend herself.

When Nambu finally exited the
I-401
, his heart pounded with
a sense of expectation. He would soon command a sub that the Imperial Japanese Navy had staked everything on.
¹⁰³
That he would lead her on a top secret mission designed to change the course of the war only added to his pride. Though he knew his chances for success were slim, Japan’s future rested on his shoulders. He would complete the mission or die trying. There was no turning back.

A
S
1944
DREW TO A CLOSE, THE
I-401
REMAINED UNFINISHED
. Nearly two years had passed since the sub’s keel had been laid. Katayama’s timeline had proved optimistic. Although the Sasebo naval yard was working around the clock, the flagship was still behind schedule.
¹