Operation Storm: Japan's Top Secret Submarines and Its Plan to Change the Course of World War II (9 page)

The
M-2
carried a Parnall Peto, which was a floatplane, but landing and recovering the aircraft in anything more than a force-two wind was nearly impossible.
³⁵
Though it may sound impressive, a force-two wind is a light breeze accompanied by small waves—in other words, a nice day at the beach.

Launching a Peto from the
M-2
was an improvement over the time-consuming Martin MS-1, but not by much. Ten men had to crowd inside the tiny hangar to get the plane ready. They also had to wear waders and sea boots, because the hangar door was so close to the water, they often got soaked. The good news was that the Peto could be launched in under 12 minutes, a big improvement over the American S-1’s launch time. A Peto could also land, be recovered, disassembled, and stored with the
M-2
returning to periscope depth in less than 11 minutes. Given this capability, it’s fair to say the
M-2
was the first submarine fully capable of carrying, launching, and retrieving an airplane.
³⁶

The
M-2
possessed an unfortunate design flaw, however. After the sub dove off England one January morning in 1932, the Royal Navy had to go looking for her. She was eventually found three miles off the coast in 100 feet of water. Her hangar door was open,
as was the hatch leading from the hangar into the sub. Her entire crew of 60 had perished,
³⁷
as did Britain’s desire for further experimentation with plane-carrying subs. In the future, no submarine would have its hangar door placed so near the waterline.

Though Germany, Britain, the United States, and Italy “passed” on the plane-carrying-sub concept, France was next, and her commitment was big. Named the
Surcouf
, after Robert Surcouf, who made his career as a “licensed” buccaneer attacking British ships,
³⁸
she was the world’s largest, most powerful submarine when commissioned in 1934. At 361 feet in length, she was one of the longest subs ever built until the
I-400
class came along.

Surcouf
’s size was dictated by the need for a stable weapons platform that could both launch a plane and have range enough to reach the enemy. (This was also an issue that the
I-400
s faced.) The French wanted a commerce raider to do to Germany what the U-boats had done to France during World War I. The French weren’t ones to stint on weapons systems either. As Richard Compton-Hall notes in
Submarine Warfare: Monsters & Midgets
: “The
Surcouf
had just about everything that could be crammed into a sub of the period,”
³⁹
including a watertight turret, out of which extended twin eight-inch guns. Below the waterline, the sub boasted four bow-mounted torpedo tubes supplemented with 22 torpedoes.
^‖
And of course she carried a floatplane. In other words, this baguette really packed a punch.

Surcouf
even had restraints to imprison 40 POWs from the ships she sunk,
⁴⁰
a nice touch given Robert Surcouf’s second career transporting slaves. But the French were more interested in commerce raiding than in floatplanes and soon dispensed with her aircraft. When the
Surcouf
disappeared without a trace in February 1942, French interest went with it.

Japan’s interest in sub-borne aircraft was undeterred despite all this failure. In 1923 she purchased a Caspar-Heinkel U-1 seaplane from Germany
⁴¹
and began holding sea trials to learn the trade. Japan had good reasons for developing plane-carrying subs.
First, subs played an important scouting role in the IJN’s decisive battle strategy.
⁴²
The enemy fleet had to be located and reported on while still distant from Japanese shores, and subs were ideal for this role. But subs don’t handle scouting very well. If it’s true that a submarine has a large scouting range, it’s also true that it rides so low in the water that it has a restricted field of vision. And though a land-based aircraft has a much higher field of view, its scouting radius in the 1920s was limited to an hour or two. You could dramatically improve both the scouting area and the field of view if you built a submarine that effectively carried, launched, and retrieved an aircraft while at sea. The Japanese intended doing just that.

By 1925 Japan had developed her own prototype seaplane based on the Heinkel. Called the Yokosho 1-Go, she conducted tests using the
I-21
as her host sub.
⁴³
Trials progressed enough by the fall of 1928 that the IJN was satisfied that a plane-carrying sub could serve a useful purpose.

In July 1932 the
I-5
became the first Japanese submarine to carry an aircraft in a watertight deck hangar.
⁴⁴
When fleet maneuvers demonstrated that a sub-based reconnaissance plane could successfully find and report on the enemy, enthusiasm for the program grew. Assembling and disassembling the aircraft took too long, so the IJN continued pushing improvements.
⁴⁵
The
I-6
followed in 1935. Built as an aircraft-carrying submarine from its inception (rather than modified later), the
I-6
was followed two years later by the
I-7
and a year after that by the I-8.
⁴⁶
All of these boats had their floatplane hangar on their aft deck behind the sail, a design that changed over time to favor the forward deck for hangar and catapult placement. The I-7’s and
I-8
’s storage and catapult arrangements were an improvement because the subs were larger than their predecessors.
⁴⁷
When it came to launching planes from a sub, bigger really was better.

By December 1936, Japan had withdrawn from the Washington and London naval treaties and began building submarines just as fast as she was able. Under the Third Fleet Replenishment Law, three new types of subs were planned, two of which, the Type A1 and B, carried a floatplane.
⁴⁸
Twenty new
Junsen
Type B boats were
laid down in January 1938,
⁴⁹
followed by three new
Junsen
Type A1 boats laid down in January 1939.
⁵⁰
They were among the best subs in the world at the time
⁵¹
and the only ones that carried airplanes.

Japan expected results from her aircraft-bearing submarines;
⁵²
that’s why plane-carrying subs were integrated into every major theater in which Japan’s sub force operated, including the attack on Pearl Harbor. By the start of war there were 11 frontline I-boats with floatplanes,
⁵³
and more were in the pipeline. By war’s end, Japan had built 41 such subs.
^a
54
Because of this commitment, no other nation had so much experience building and operating plane-carrying subs.

But the Japanese were soon to encounter an important strategic issue related to sub-plane combat: Which weapon took precedence? A sub is intended to hunt its enemy, while a plane is intended to scout. What this meant in practice is that each one’s mission interfered with the other. For example, before launching her scout plane, a sub would forgo attacking ships. This deterred combat operations. When her scout was returning, a sub was sometimes forced to give away her position to help the plane locate her. This ran counter to the sub’s purpose as a stealth weapon.

Sub commanders weren’t always happy subordinating their combat mission to reconnaissance, and the
I-400
class only exacerbated the situation. The
I-400
’s primary job was to deliver aircraft
to a set location. Attacking ships was now a secondary consideration. On the one hand, it was the next logical step in the evolution of sub-borne airplanes; yet it turned every conventional notion about submarines on its head. Which is why it’s not surprising that the Naval General Staff took an intermediate step in July 1942 when it instigated a mission where the seaplane rather than its host sub would be the offensive weapon. The mission was the first of its kind. It would be launched before the
I-400
’s keel had even been laid, and it would proceed using an existing plane that required little modification.

But what was most surprising was that eight months into the war, the Naval General Staff wasn’t just going to stand convention on its head—it was going to launch an aerial attack against the United States to prove that the idea could work. For Japan wasn’t satisfied with just using submarines to shell the American coastline. She was going to use an airplane-carrying sub to bomb the American mainland for the first time.

W
HEN THE CAPTAIN OF THE
I-25
HANDED
WO N
OBUO
F
UJITA A
message summoning him to the Navy Ministry in Tokyo, Fujita was nervous. It was July 27, 1942,
¹
and the
I-25
had recently returned from her third war patrol. Fujita had every intention of going on the sub’s next patrol. He respected the sub’s captain, Lt. Cdr. Meiji Tagami, and enjoyed flying her two-seater floatplane. He was in the middle of a much-deserved rest when he received the message, which was all the more unwelcome for failing to explain why he was being summoned.

It had been five months since Nambu shelled the oil facility near Santa Barbara and two months since the
I-400
subs had been approved for production. Unfortunately, the IJN had suffered a huge loss at the Battle of Midway in June. Yamamoto remained set on taking the war to the American mainland though. Shelling the west coast had been a start, and the
I-400
s might well prove the finish. In the meantime, the IJN was searching for a second act.

Certainly, Fujita was more than just a proficient seaplane pilot. During the
I-25
’s second war patrol, he had completed six successful reconnaissance missions over enemy ports in Australia and New Zealand.
²
But what could the Naval General Staff possibly want with him? He was just a pilot. They, on the other hand, were more akin to gods.

By the time he received the summons, Fujita had been flying for nine years. Born in 1911
³
and drafted into the navy in 1932, he had had extensive combat experience over China. After that he’d tested experimental aircraft,
⁴
always a sign of a respected pilot. Then he’d been promoted and assigned to the
I-23
, a plane-carrying sub. By
the time the Pacific war started, Fujita had 3,500 hours of combat flight and a sterling reputation.

Fujita had the usual reserve of an experienced pilot. Calm, cool, and collected, he came across as serious, if withdrawn. He may have appeared cold to those who didn’t know him, but he was popular among sub crews, who admired his courage and modesty. A simple man from a small farming village,
⁵
he had wide-spaced eyes and a handsome nose—the very picture of a dashing Japanese pilot.

Six weeks before Pearl Harbor, Fujita had been transferred to the
I-25
, a
Junsen
Type B class sub that carried a floatplane.
⁶
For the next month or so, he practiced night launches, then searched for a mock enemy fleet to report on. It wasn’t the same as combat duty; still, Fujita understood the importance of his job. If the Yankees were to be defeated, they had to be found first.

Fujita had been aboard the
I-25
during the attack on Pearl Harbor. He’d even been in the same sentry arc as Nambu north of Oahu. Once the attack was finished, he wanted to be the first pilot to fly over the American naval base and report on the damage. But the storm-tossed crossing had so banged up his plane, it was unable to fly.
⁷