- Japanese Midget Submarine, Type A (Kou) Hyoteki
- Photo page
- One of 5 midget submarines that participated in Pearl Harbor attack
- Sub-Lieutenant Kazuo Sakamaki, commander of HA-19, became first
Japanese prisoner-of-war for America
- Participated in U.S. war bond drives during WW II; visited 41 of
the 48 states
- Most advanced WW II-era midget submarine of any nation
Location and Current Status
Admiral Nimitz National Museum of the Pacific War
P.O. Box 777, Fredericksburg, TX 78624
- Status: Open for public viewing.
Owned by U.S. Navy
On loan to Admiral Nimitz National Museum of the Pacific War
- L's Assessment
Exterior: HA-19 is viewable to the public along its entire 78 foot
length on the port side, where details such as torpedo tube guards and
rudder anti-fouling rods are readily apparent. On the starboard side,
the lower after part of the conning tower is damaged.
L speculates this may be the result of
shell fire from the destroyer Helm, which is believed
to have fired on HA-19.
Interior: The interior may be seen through view ports which were cut into
the starboard side prior to the boat being used for war bond drives.
(It is said HA-19 helped raise enough money to repair all the damage
inflicted on Pearl Harbor!)
Because much interior equipment, such as batteries,
was removed shortly after capture, the empty interior of HA-19 feels
deceptively spacious. Only in the control room, where a significant amount
of equipment remains, does the exceedingly cramped nature of this midget
sub become apparent and, then, only when one actually tries to move through
this tiny compartment. The view through the side view ports does not adequately
convey the cramped hardship endured by the 2-man crews of these boats. However,
habitability and long endurance were not requirements for their mission
to strike a quick first blow in the anticipated fight
between the Japanese and American battle fleets, a mission ironically made
obsolete by the success of the attack on Pearl Harbor in which the HA-19
was a participant.
General Condition: A faulty gyro compass and other difficulties culminated
in grounding on a coral reef, thwarting HA-19's attempts to enter Pearl
Harbor. Hence, she was in good structural condition when she washed up
on a Hawaiian beach after the attack. Due largely to the efforts of the
Admiral Nimitz Museum, she remains in good condition to this day, with a
minimum of rust and other deterioration.
L is grateful to the Admiral Nimitz
National Museum of the Pacific War for granting access to the interior of
- As Completed, 1941
- Dimensions: 23.9m (78.5') (loa) x 1.8m (6') (b) x 3m (10.2') (d)
- Displacement: 46 tons (submerged)
- Ballast: 5899 lbs (534 lead bars, 11 lbs each)
- Designed Depth: 30m (100')
- Torpedoes: two 457mm (18"), muzzle-loaded into tubes
- Motor: one electric, 600 hp at 1800 rpm
- Screws: 2, contra-rotating on single shaft
Leading prop: 1.35 m diameter, right-handed rotation
Trailing prop: 1.25 m diameter, left-handed rotation
- Batteries: 192 trays of two 2 volt cells each,
Forward battery room: 136 trays
After battery room: 56 trays
- Speed: 23 kts (surfaced), 19 kts (submerged)
- Endurance: 100 nm (2 kts), 80 nm (6 kts), 18 nm (19 kts)
- Complement: 2
World War II Service
- 1933 Aug .. Full-scale design experiments commence.
- 1940 Apr .. First prototype launched.
- 1940 Jun .. Second prototype launched.
- 1940 Nov 15 Class formally adopted and named Kou Hyoteki ("small target").
- 1940 Dec .. HA-13 to HA-26 ordered.
- 1941 Jan-Aug Initial crews trained.
- 1941 Oct .. Two Kou Hyoteki commanders (Keiu Matsuo and one other) visit
Pearl Harbor for intelligence; return to Japan on liner
- 1941 Nov .. HA-19 loaded on after deck of I-24 for
transport to Hawaii.
- 1941 Nov 28 I-24 / HA-19 depart Kame-Ga Kubi (Kure) for
- 1941 en-route One HA-19 torpedo damaged by weather and manually
- 1941 en-route HA-19 gyro compass develops problem; not repairable
- 1941 Dec 05 Nightfall. I-24 / HA-19 100 miles from
- 1941 Dec 07 0333. Sub-Lieutenant Kazuo Sakamaki and
Petty Officer Kiyoshi Inagaki enter HA-19 and release
from I-24 10.5 miles off Pearl Harbor entrance.
- 1941 Dec 07 In transit. Many 11 pound lead ballast bars manually
shifted in effort to maintain proper trim.
- 1941 Dec 07 In transit. Faulty gyro compass necessitates frequent
periscope exposure for navigation.
- 1941 Dec 07 0700+ USS Ward depth charges a contact, probably
HA-19, off Pearl Harbor entrance.
- 1941 Dec 07 HA-19 runs aground on coral reef off harbor entrance,
damaging one or both torpedoes.
- 1941 Dec 07 0818. HA-19 fired on by USS Helm while aground.
- 1941 Dec 07 Manually shifting lead ballast bars aft of batteries
while running full power astern helps slip HA-19 off
- 1941 Dec 07 Iron ballast manually shifted forward again to maintain
- 1941 Dec 07 Wet battery acid exudes chlorine gas, puts crew into
- 1941 Dec 07 Afternoon. HA-19 drifts out to sea.
- 1941 Dec 07 Nightfall. Crew revives from coma. HA-19 drifts
aground off Kaneohe Naval Air Station with batteries
- 1941 Dec 07 Scuttling charges set; HA-19 abandoned.
- 1941 Dec 07 Scuttling charges fail to explode.
- 1941 Dec 07 Petty Officer Inagaki swept out to sea and drowned.
- 1941 Dec 07 Sub-Lieutenant Sakamaki reaches shore and collapses.
- 1941 Dec 08 Morning. Sub-Lieutenant Sakamaki captured by Corporal
David Akui, a Japanese-American.
- 1941 Dec 08 HA-19 attacked by aircraft and jarred off reef.
- 1941 Dec 08 HA-19 washes up on beach and is captured.
- 1941 Dec 26 Initial intelligence report on HA-19 produced.
Memorial Ship Service
- 1942 Jan .. HA-19 shipped to continental US.
- 1942-1945 HA-19 tours country on war bond drives, with last
stop in Chicago, IL.
- 1947 Jan 20 Arrives at Submarine Base, Key West, FL by barge from
Navy Pier, Chicago, IL; serves as outdoor exhibit.
- 1964 Dec 02 Placed on indefinite loan from Submarine Base to Key West
Art and Historical Association; moved to Key West Lighthouse
Museum for outdoor display.
- 1987 ... .. Association agrees to relinquish HA-19 to US
National Park Service USS Arizona Memorial for
display at Pearl Harbor.
- 1988 Apr .. Marine survey finds HA-19 in "fair" condition with
loss of less than 10% of hull plate thickness.
- 1988 ... .. US National Park Service balks at cost of displaying
HA-19 at Pearl Harbor; Admiral Nimitz Museum of
Fredericksburg TX takes interest in HA-19.
- 1990 Dec .. NPS and Admiral Nimitz Museum agree to have HA-19
moved temporarily to Fredericksburg, TX.
- 1997 Dec 17 Admiral Nimitz Museum notified of executive decision to
allow HA-19 to remain in Fredericksburg on indefinite loan
from US Navy.
Sister Ships (62 units)
- Units Built
- 2 unnumbered prototypes
- HA-1 to HA-44
- HA-46 to HA-61
- Combat Successes
- Battleship H.M.S. Ramillies damaged at Diego Suarez, Madagascar, 1942 May 30
- Tanker British Loyalty sunk at Diego Suarez, Madagascar, 1942 May 30
- Barracks Ship (ex-ferry) HMAS Kuttabul sunk in Sydney Harbor, 1942 May 31
- Cargo ship Majaba torpedoed and beached off Lunga Point, Guadalcanal, 1942 Nov 07.
- Cargo ship (AK) USS Alchiba torpedoed by HA-10 and beached off Lunga Point, Guadalcanal, 1942 Nov 28.
- Combat Losses (44+)
- 5 at Pearl Harbor, 1941 Dec 07 (including HA-19)
- 2 at Diego Suarez, 1942 May 30
- 3 at Sydney Harbor, 1942 May 31
- 8 during Guadalcanal campaign, 1942 Aug 07 to 1943 Feb 07
- 3 during Aleutians campaign, 1942 Jun 07 to 1943 Jul 28
- 5 during Saipan invasion, 1944 Jun 15 to 1944 Jun 21
- 8 during Philippines invasion, 1944 Oct 20 to 1944 Dec 24
- 10+ during Okinawa invasion, 1945 Apr 01 to 1945 Jul 02
- Other Surviving Units
- Maritime Self-Defense Service School, Eta Jima, Japan -- Kou Hyoteki raised from Keehi Lagoon, Hawaii, 1960 July 14 (sunk 1941 Dec 07)
- Australian War Memorial, Canberra -- joined parts of 2 Kou Hyoteki raised from Sydney Harbor, Australia, 1942 Jun 04 (sunk 1942 May 31)
- Later Models
The original Type A (Kou) was followed by three additional models:
- Otsu (Type B) Hyoteki: 1943, 3 man crew (prototype)
- Hei (Type C) Hyoteki: 1943-1944, 3 man crew, 36 built
- Tei (Type D) Hyoteki or "Same Ryuh" (Shark Dragon): 1945, 115 built
of 500+ ordered
Copyright (C) 1998 LDJ Trust