Japan’s WWII Alaskan mini-sub base
When the U.S. entered WWII, the entire garrison of tiny Kiska Island in the Aleutians consisted of a 10 man U.S. Navy radio/weather station. As a diversionary attack as part of the Battle of Midway, on 6 June 1942 the Japanese landed in force, some 550 men of an elite Naval Landing unit.
Over the next year, the Japanese build up on the remote island grew to 3,700 Navy personnel at Kiska Harbor and some 3,500 Army personnel at Gertrude Cove despite U.S. air and naval attacks. They put in fire hydrants and the beginnings of a water system, laid hundreds of foxholes, personnel trenches and barbed wire entanglements; dug underground bunkers into the hillsides; constructed a power and telephone network and erected a Shinto shrine.
In the harbor floated Kawanishi H6K ‘Mavis” flying boats, Nakajima A6M2-N ‘Rufe’ floatplane fighters and Aichi E13A ‘Jake’ floatplane bombers/reconnaissance aircraft. They also crafted a slipway and repair facilities for midget submarines (more on this later).
With a looming Canadian-U.S. force ready to invade the frozen tundra near the Bearing Strait in July 1943, the Japanese swiftly withdrew their troops and when the 34,000-man Allied force hit the beaches the next month, they found nothing but a ghost town– and three wrecked Japanese midget submarines.
The Japanese used Kiska as a base for Type A Kō-hyōteki-class submarines. The same type of boat that helped attack Pearl Harbor (where USS Ward splashed the first American kill of the Pacific War on one trying to penetrate the harbor), the 47-ton Type A was just 78-feet long and was electric-only, with a 600hp motor and 224 Type D batteries.
They were actually pretty fast– 19 knots submerged– but due to not being able to recharge their batteries, had a very short range (about a half-hour at full speed, 24-hours if barely spinning the contra-rotating propellers). The two-man crew of these boats carried a pair of 17.7-inch Type 98 (Type 97 “Special”) torps in a pair of blackpowder-fired tubes forward (each with a 772-pound warhead and a 3.4-mile range), and a 300-lb scuttling charge for when things went wrong.
The IJN completed about 105 of these vessels in four slightly different variants, of which a few were based at Kiska for coastal defense against encroaching U.S./Canadian vessels, and others lost in raids on Australia and Madagascar.
As noted by Combined Fleet.com, on 28 June the seaplane/submarine tender Chiyoda left Yokosuka with six Type A’s (HA-28, HA-29, HA-31, HA-32, HA-33 and HA-34) as well as the 150-man crew of the future midget submarine base, a detachment of the 12th Construction Battalion and 200-tons of cement.
The submarines on Kiska were launched to and from their base via a beaching railway with four sets of launch rails in the Western part of Kiska Harbor, and all the structures around the bases, when abandoned, were rigged with 155mm IEDs, sulphuric acid cans set to explode via live grenade, and other booby traps, making souvenir hunting hazardous to a GI’s health.
Arriving 5 July, the submarine force joined the 5th Guard Unit, Special Purpose Unit and was under command of Lt ( j.g.) Otozaka Shoichi. With Chiyoda leaving, the aging L-class submarine RO-61 (1,000-tons, completed 1920 to a British design) arrived in August to serve as a pier-side battery charger for the midgets, three of which were afloat in the harbor at a mooring buoy and three more retained on land.
By November 1942, with the submarine base built and the vessels operational, they begin taking regular personnel casualties in air raids from American bombers. Larger subs stopped coming as often.
Losses mount, with HA-33 sunk in a heavy storm in early April 1943 and on the 14th P-40 Warhawks from Amchitka strafe HA-29 and HA-34, leading to the cannibalization of HA-29 and HA-34 for spare parts, but as a result of continuing air attacks and storms repair cannot be completed.
This led Vice Admiral Kawase Shiro in May to order the midgets redeployed to nearby Attu but when two fleet submarines arrive to accomplish this, the news that Attu has fallen leads the midget crews to instead embark on I-31 and I-35 for the Kuriles.
On June 8, the two remaining midget submarines in the harbor are scuttled with demolition charges and one midget submarine is blown up using two Type 98 torpedo warheads, ending in watery graves. The three partially cannibalized midget submarines in the maintenance shed (including HA-32 and HA-34) are also demolished and the cache of some 20 remaining torpedoes are thrown in the harbor.
The sheds and buildings are burned with the stored fuel.
When the Americans arrived in August all they found were ruins.
Today these boats are still there to some degree
Kiska is federally owned and forms part of the Alaska Maritime National Wildlife Refuge, which is administered by the Fish and Wildlife Service, though the National Park Service and others are also stakeholders.