IJN Submarine I-503: Tabular Record of
© 2001-2018 Bob Hackett & Sander Kingsepp
25 April 1938:
Laid down at Odero-Terni-Orlando (OTO)
Muggiano shipyard in La Spezia, Italy.
14 May 1939:
23 September 1939:
Completed and commissioned in the Regia Marina
Italiana as COMANDANTE CAPPELLINI.
10 June 1940: Italy Declares War on the Allies:
assigned to the First Group, 12th Squadron at La Spezia. Capitano di
Corvetta (CC=LtCdr) Cristiano Masi is the Commanding Officer.
At the start of Italy's war, CAPPELLINI is en route from Cagliari,
Sardinia via the Straits of Gibraltar to Madeira, a Portuguese island off the
coast of NW Africa, but she is attacked by British patrol boats and forced to
take refuge in Ceuta, Spain and then return to Spezia.
29 September 1940:
Departs La Spezia under CC Salvatore Todaro (Gold
Medal for Valor posthumously) on her second war patrol.
15 October 1940:
CC Todaro sinks the 5,186-ton Belgian armed merchant
5 November 1940:
Arrives at the Regia Marina's "Betasom" (Beta
sommergibili or B-submarine) base at Bordeaux, France newly established under
the 1939 "Pact of Steel" between Italy and Germany. After the fall of France,
the Kriegsmarine requests that Italy establish a presence in the Atlantic, S of
Lisbon, Portugal. The Italians form the XI Submarine Group at Bordeaux under
Contrammiraglio (Rear Admiral) Angelo Parona.
Atlantic. In four patrols under CC Todaro, CAPPELLINI sinks
two ships for 12,501-tons. On her sixth war patrol, under Tenente di
Vascello (TV=Lt) (later CC) Aldo Lenzi, she probably damages the 5,231-ton
British merchant MIGUEL DE LARRINGA.
Atlantic. On her seventh patrol, under TV Marco Revedin,
CAPPELLINI sinks two ships for 13,961-tons.
12 September 1942:
S Atlantic, 360 miles N of Ascension Island. At
2010, Korvettenkapitän Werner Hartenstein's U-156 torpedoes and sinks the
armed 19,695-ton British Cunard White Star passenger liner LACONIA, currently
serving as a troopship. She is carrying 2,732 people including her regular
136-strong crew, British officals, 80 British women and children, 268 British
soldiers, 160 Free Polish troops and about 1800 Italians taken as POWs in Libya.
Hartenstein takes 193 persons on board U-156 and tows four lifeboats
with about 200 survivors. Another 1,000 or more persons are in the water or in
other lifeboats. Hartenstein radios in clear language for assistance in
rescuing the survivors.
Admiral Karl Dönitz, Befehlshaber der Unterseeboote (BdU) (CINC
U-boats) requests Contrammiraglio Romolo Polacchini, CO of Betasom at
Bordeaux, to send a submarine to assist Hartenstein. Polacchini accepts and
signals Revedin's CAPPELLINI to proceed immediately to the scene.
15 September 1942:
CAPPELLINI, U-506 and U-507 arrive and tow the
lifeboats. CAPPELLINI takes aboard 42 survivors and the U-boats take aboard up
to about 100 persons each.
16 September 1942:
At 1125, a B-24 "Liberator" bomber of the USAAF
343rd Bomb Squadron arrives from Ascension. The U-156 flies a large Red Cross
flag from her bridge. The pilot assesses the rescue situation and signals his
base for instructions. He is ordered to sink the submarines.
At 1232, the B-24 begins five low level attacks. During the first attack
one of the lifeboats is hit and capsizes. In the second attack, a bomb explodes
amidships and damages U-156. The submarines cut the lifeboats' tow lines and
17 September 1942:
The Vichy light cruiser GLOIRE arrives from Dakar,
French West Africa (now Senegal) and the minesweeper ANNAMITE arrives from
Cotonou, Dahomey. At noon, after completing transfer of survivors to the
ANNAMITE, the U-506 is attacked by a large seaplane.
18 September 1942:
At 1130, CAPPELLINI meets the colonial sloop
DUMONT D'URVILLE from Conakry, French Guinea. CC Revedin transfers all the
LACONIA's survivors to the sloop except two English officials and six Italians.
Together the three Vichy French ships rescue 1,083 persons from the lifeboats
and take aboard those picked up by the four submarines, but 1,649 lives are
lost, mostly Italian PoWs.
17 October 1942:
CAPPELLINI arrives at Bordeaux.
20 February 1943:
Grossadmiral Dönitz, newly appointed as
Oberbefehlshaber der Kriegsmarine (CinC of the Navy) briefs Adolf Hitler
that German surface blockade runners plying war materials to and from the Far East
are suffering unacceptably high losses. Dönitz suggests that further such trade
could be carried out by submarine. He observes that the large, slow-diving
Italian submarines based at Bordeaux are unsuitable for war in the Atlantic and
could be converted to long-range supply submarines. Later, Dönitz flies to Rome
and secures agreement on his proposal from the Italian dictator Benito
Mussolini and Ammiraglio Arturo Ricardi, CinC of the Regia Marina,
in return for the Germans providing new Type VIIC U-boats to Italy as
CAPPELLINI is rebuilt to carry 150 tons of cargo. Some
of the modifications include removal of her deck guns, attack periscope and some
batteries. Her torpedo tubes and ammunition storage magazines are converted into
fuel storage tanks. For the duration of the voyage the to Far East CAPPELLINI is
code-named AQUILA III.
11 May 1943:
AQUILA III departs Bordeaux for the Far East under CC
(later Contrammiraglio, Marina Militare Italiana) Walter Auconi
(former CO of submarine DANDOLO). She carries 95 tons of cargo, including
spare torpedoes for the German "Gruppe Monsun", bars of aluminum and steel,
replacement parts and war material for the Japanese.
AQUILA III is damaged by heavy seas in the "Roaring
Forties" as she rounds the Cape of Good Hope, South Africa.
9 July 1943:
AQUILA III arrives at Sabang, Sumatra with almost
empty fuel tanks. She is the first Italian submarine to reach the Far East.
10 July 1943:
Departs Sabang for Singapore, escorted by Capitano
di Fregata (CF=Cdr) Mario Iannucci's colonial sloop ERITREA.
12 July 1943:
Arrives at Singapore, where her cargo is unloaded.
Undergoes repairs. Embarks 110 tons of rubber, 44 tons of tin ingots and 10
tons of other cargo including quinine, opium and spices for her return voyage
21 August 1943:
Departs Singapore for Sabang, again escorted by
9 September 1943: The Surrender of Italy:
After receiving a
coded message about an armistice signed by the Italian government from
ERITREA, CC Auconi and his crew attempt to escape from Sabang, supposedly to
conduct a training cruise. The IJN port authorities order the submarine to
stay there. Auconi next meets Vice Admiral Hiraoka Kumeichi, CO of the
9th Base Unit at Sabang, announcing that he and his crew are ready to
surrender their submarine and its cargo. When the local IJN garrison
attempts to board CAPPELLINI, the Italians threaten to blow up the sub.
Finally, a preliminary agreement is reached between both parties. CC Auconi
agrees to return to Singapore.
10 September 1943:
CAPPELLINI is formally commissioned in the
Kriegsmarine as UIT-24. Oberleutnant zur See (OL=Lt(jg) Heinrich
Pahls is appointed the CO.
13 September 1943:
Departs Sabang for Singapore.
16 September 1943:
Arrives at Singapore. Transferred to Seletar
Naval Base. CC Auconi meets Rear Admiral Enomoto Takaichiro in charge of
the local fuel depot to negotiate the terms of the interment of his crew.
The negotiations fail and later that month most of CAPPELLINI's sailors are
transferred to Sime Road PoW Camp. A SNLF squad arrives aboard to submarine
to prevent its scuttling by the four remaining Italian crewmembers.
23 September 1943:
Salò, Italy. Mussolini founds the new puppet
"Repubblica Sociale Italiana" (RSI) fascist regime controlled by the
Nazis. Most CAPPELLINI's enlisted internees except 28 decide to continue to
fight as part of the RSI. 
UIT-24, while at Singapore, is organizationally
assigned to Korvettenkapitän Klaus Scholtz's 12th U-boat flotilla based
at Bordeaux. The Germans install a 105-mm deck gun and mount a 20-mm
AA gun on a platform abaft the conning tower. The submarine is manned by a
mixed crew of German and Italian sailors (mostly engineering personnel).
2 February 1944:
Departs Singapore for Penang.
8 February 1944:
UIT-24 departs Penang for Bordeaux with her
original cargo of rubber, tin ingots, etc.
12 March 1944:
Indian Ocean. 1,000 miles SE of Mauritius. The
10,000-ton German oiler/supply ship BRAKE is attacked by the destroyer HMS
ROEBUCK and forced to scuttle. The loss of BRAKE causes UIT-24 to
obtain emergency refueling from U-532 that had taken on fuel from BRAKE
just before she was attacked. UIT-24 then aborts her mission.
3 April 1944:
UIT-24 returns to Penang.
5 April 1944:
Departs Penang for Singapore.
25 May 1944:
Departs Singapore for Kobe.
6 June 1944:
Arrives at Kobe. Drydocked for engine repairs.
5 September 1944:
Departs Kobe for Singapore.
20 September 1944:
Arrives at Singapore.
Late September-early October 1944:
Transferred to Penang for
another planned voyage to Europe. As a result of the loss of all available
German supply ships the idea is abandoned.
10 October 1944:
Departs Penang for Singapore.
12 October 1944:
Arrives at Singapore.
15 January 1945:
Departs Singapore for Kobe.
18 February 1945:
Arrives at Kobe. Commences repairs.
10 May 1945: The Surrender of Germany:
Kobe, Japan. UIT-24 is in
dock undergoing overhaul at Mitsubishi's Kobe Yard. She is taken over by the
IJN and commissioned as I-503.
I-503 and I-504 are the only submarines to fly all three Axis
powers' flags in World War II.
14 July 1945:
Lt Hirota Hideo (67)(former Chief Equipping Officer of
HA-112) is appointed the CO of I-503 and I-504 as additional duty.
15 July 1945:
I-503 is attached on paper to the Kure Naval
District to protect the base in case of an Allied invasion, but the actual
transfer is planned for later.
30 August 1945: The Surrender of Japan:
I-503 is surrendered at
30 October 1945:
Lt Tanaka Chiaki (69)(former navigating officer of
I-5) is appointed the CO of I-503 and I-504 as additional duty.
30 November 1945:
Removed from the Navy List.
16 April 1946:
Scuttled by American Navy in the Kii Suido.
 Italy's highest military decoration.
 After this action, Admiral Dönitz issues an order, known as the
"Laconia Order", that U-boats are not to take part in any rescue operations and
are to leave any survivors in the sea. At the 1946 Nürnberg Tribunal, Dönitz is
acquitted on a charge that this order was a war crime, but he is convicted on
other charges and serves 10 years and 20 days in Spandau prison.
 On 29 October 1943, after less than two months internment, the
Japanese allow CC Auconi and other Italian submariners to leave Singapore
aboard three German blockade-runners bound for France. 27 crewmembers of
CAPELLINI depart aboard the 7,320-ton BURGENLAND. On 5 January 1944, a Martin
PBM-3S "Mariner" of VP-203 sights and tracks BURGENLAND in the South Atlantic.
Later, she is damaged by gunfire from USS OMAHA (CL-4) and JOUETT (DD-
396), then scuttled by her crew at 07-29S, 25-37W. The survivors, including
Auconi and some of his crew, take to five lifeboats. On 15 January 1944, Auconi
and the 31 Germans and Italians in his lifeboat are picked up by a Brazilian
ship and later made PoWs.
Special thanks for help in preparing this TROM go to Dr. Higuchi
Tatsuhiro of Japan and to Alan Alsleben of the United States for assistance in
identifying IJN units.
– Bob Hackett and Sander Kingsepp.
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