The sailor is 5 feet 8 inches tall, the average height of American military personnel during World War II.

Anatomy of
a secret sub

It was top-secret, deadly and
the Imperial Navy crews were
prepared to die. America
didn't see it coming.

Ownership is unclear

---

By Burl Burlingame
bburlingame@starbulletin.com

The first picture released to the American public of the attack on Pearl Harbor was of a tiny submarine captured on a Waimanalo beach -- a top-secret weapon that caught the U.S. Navy by surprise. Derisively dubbed a "midget" submarine, this swift, powerful craft was the Stealth fighter of its day.

This week, more than 61 years after the attack on Pearl Harbor, the first casualty of the battle was found resting more than a thousand feet under the sea. Damaged in a running fight that lasted only a few minutes, the crew of the destroyer that tangled with the midget submarine didn't even report that they had sunk her -- only that they had fired at a slim shape in the water. The Americans weren't sure what they'd seen.

U.S. NAVY ARCHIVES The midget submarines were designed to be unbolted into three sections. This is the front section, showing torpedo tubes and compressed-air tanks.

Inspired by "A Sure Hit With Human Piloted Torpedoes," a 1933 article by Russo-Japanese war hero Captain Noriyoshi Yokoo, the concept of tiny submarines was adopted enthusiastically by Prince Hiroyasu Fushimi, admiral of the fleet, who allowed two prototypes to be built with the stipulation that they not be tokko (suicide) weapons.

Test runs proved the validity of the concept, and a crash construction program was instituted on the eve of war. To ensure total secrecy, the hulls and frames were made in pieces in a private yard, then taken to a small island outside Kure naval base to be constructed and fitted out. No one was allowed on the island who did not know what the submarines were.

Training was at Ourazaki, another isolated island 12 miles south of Kure, and known by the code phrase "Base P." Twenty of the tiny subs had been built by the time the Special Attack Unit sailed for Pearl, and only five of these were deemed ready for combat. All five were used.

HAWAII UNDERSEA RESEARCH LAB The bow section of the sunken midget submarine had elaborate guards to keep torpedo tubes clear of netting and other anti-submarine defenses. Here, the University of Hawaii's Pisces V submarine illuminates torpedo tubes that have lain in darkness for 61 years.

Midget submariners had to be astute judges of speed, distance and navigation. The first class of midget submariners, housed aboard the seaplane tender Chiyoda, graduated a few months before the Pearl Harbor attack.

Tactics assumed that the midget submarines would be used only in a gigantic battle on the high seas, the midgets darting in for a surprise run on the enemy's largest ships. Quietly entering a harbor and lying in wait for a battle to begin was of secondary importance, but the submariners were required to memorize the layouts of five harbors anyway - Pearl Harbor, Sydney, Singapore, Hong Kong and San Francisco.

The midget submarine skippers were confident of the superiority of their weapon -- seduced by technology, perhaps, but rightfully so. No other country had a comparable weapon.

HAWAII UNDERSEA RESEARCH LAB The "sail" of the submarine contains the conning tower and periscope for the skipper. In the center is an exit hole created by the destroyer's cannon in the starboard side of the midget submarine; the entrance hole on the port side is quite small.

HAWAII UNDERSEA RESEARCH LAB A view abaft the sail looks up the submarine toward the sail. The rudder, dive planes and propeller blades in the foreground are protected by the circular apparatus tack-welded onto the fin edges. On top of the hull is a collapsed cable to protect from nets.

U.S. NAVY ARCHIVES The interior was painted red and white. This is the aft battery compartment, with trunking for the air-purification blowers.

Tech specs Length: About 78 by 6 feet. Weapons: Two Type 97 18-inch torpedoes fired by compressed air. Each was armed with a 772-pound warhead. Once fired, the torpedo had a range of more than three miles, traveling at more than 50 mph. Crew: Two - a junior officer who steered and a petty officer who operated the ballast and trim valves. Power: 600-horsepower electric engine could run at full throttle for 50 minutes. Max. speed: 19 knots at full throttle. Range: At 2 knots it had a radius of 100 miles. Name: The midgets were named after the "mother" submarine they were assigned to. Submarine I-24's midget, for example, was I-24tou.

Launch zones

The five midget submarines were launched piggyback from mother submarines in designated zones to increase their chances of stealth and survival as they approached Pearl Harbor. None was rescued.

The nine 'hero gods' and one POW

None of the 10 crew members of the attacking midget submarines expected to return. To his shame, Ensign Kazuo Sakamaki was captured, and the remaining nine crewmen were declared "hero gods" by Japanese propagandists. From left, is the crew of midget submarine I-16tou, Masaji Yokoyama and Sadamu Uyeda; I-18tou, Shigemi Furuno and Shigenori Yokoyama; I-20tou, Akira Hiro-o and Yoshio Katayama; I-22tou, Naoji Iwasa and Naokichi Sasaki; and I-24tou, Kazuo Sakamaki and Kiyoshi Inagaki.

Mini-submarines
of World War II

The Japanese “midget” submarine of the type used at Pearl Harbor was the largest of its class, designed to fight in the open ocean rather than in protected coastal areas.