Follow-Up: "Kaiten" Subs and "Balloon" Bombs

The I-401 aircraft submarine was 400 ft. long, 39 ft. high, could dive to 330 ft., with a crew of 144, a range of 37,000 mi., and carried 3 bombers with foldup wings. The I-400 and I-401 sailed for the U. S. West Coast in 1945 in Operation PX to deliver bacteriological bombs, but both were captured at sea before launching any planes. Both were scuttled in 1946.

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.

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

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

Kaiten suicide midget submarine, 45 ft. long, 1.55 ton explosive charge on its front, operational after 11/10/44, sank 2 American ships with 162 killed, at loss of 106 kaiten pilots.

Japan sent five Type A midget submarines to Pearl Harbor Dec. 7, 1941, and were launched by larger subs. The USS Ward sank one midget sub, and another was never found.
Three were salvaged, including the Ha-19 immediately after the Dec. 7 attack.

Kamikaze planes attacked the U.S. fleet starting Oct. 1944 in the Battle of Leyte Gulf.
The USS St. Lo was sunk Oct. 25.

Japan launched 9000+ balloon bombs after 11/3/44; 1000 reached the U.S. and 285 were sighted; 6 hikers were killed 5/5/45 in Oregon

Out of some 9000 launched only about 1,000 actually made it to the US and Canada, and of those there was one case of six people being killed by the bomb carried by the balloon. For a weapon, that's a pathetic rate of success. The forest fires they hoped to start never appeared, largely because the bombs were being designed or in hiatus during the dry season in the US. If lots of fires had started then lots of people would have been needed to fight them, perhaps reducing the war effort, or at least that's what the Japanese hoped.

”The concept of balloon bombs might have changed the course of the war in favor of the Japanese had it been pursued with more vigor and tenacity. ... Had this balloon weapon been further exploited by using germ or gas bombs, the results could have been disastrous to the American people.”

The program could have caused major forest fires if they had been launched during the west's dry season. Any biological weapon descending over a city could have caused mass panic and damaged US morale. Those are could-have-beens, of course. Alternative history type of thinking.

It wasn't just an easy matter of inflating and letting the balloon go.
The weather had to be just right, the wind currents just right, and even then the wind at the surface could catch the partially-inflated balloon and cause problems for its handlers.

A balloon suspended in mid-flight, and a balloon bomb launch site (See above).

Newspaper articles gathered from:

1) Nevada State Journal, June 13, 1945,
2) The Lethbridge Herald (Canada) June 22, 1945, and

3) The Lethbridge Herald (Canada) Oct. 15, 1948

...on the function and aesthetics of the balloon bomb.



























The balloons were made often by schoolchildren.

”In numbers, school children were the greatest labor force on this project. During wartime, school hours were short in order that the remainder of their day could be devoted to the war effort. Thousands of Japanese had a part in making these balloons, but officially they were never told of their purpose. Even when word about their intended use would filter down, no one believed it.

”Two years of experimentation and some 9,000,000 yen (more than 2,000,000 prewar dollars) were spent on the manufacture of balloons.”

Cost per balloon was about $2,300 at the start of the project but went down as production increased.

This was where the balloons were launched from.

Number of balloons launched:

November 1944: 700
December 1944: 1,200
January 1945: 2,000
February 1945: 2,500
March 1945: 2,500
April 1945: 400
Total: 9,300

Joe.