IJN Submarine I-504: Tabular Record of
© 2001-2018 Bob Hackett & Sander KingseppRevision 3
15 February 1939:
Laid down at Odero-Terni-Orlando (OTO)
Muggiano shipyard in La Spezia, Italy.
6 January 1940:
15 May 1940:
Completed and commissioned in the Regia Marina
Italiana as LUIGI TORELLI.
Capitano di Fregata (CF) (later Capitano di Vascello (CV) Aldo
Cocchia is the Commanding Officer. 
10 June 1940: Italy Declares War on the Allies:
TORELLI is stationed
at La Spezia for training.
5 October 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.
7 October 1940:
CF Primo Longobardo (Gold Medal for Valor,
posthumously) assumes command.  CF Cocchia becomes Chief of Staff of
N Atlantic. TORELLI, under CF Longobardo, sinks four
ships for 17,489-tons.
21 July 1941:
N Atlantic. TORELLI, under Capitano di Corvetta (CC)
Antonio de Giacomo, sinks the 8,913-ton Norwegian tanker IDA KNUDSEN,
independently en route from Trinidad to Gibraltar with 13,000-tons of fuel oil.
21 September 1941:
Atlantic. TORELLI, while attempting to attack the
25-ship convoy HG 73 en route from Gibraltar to Liverpool, is damaged by depth
charges from destroyer HMS VIMY. Seven ships in the convoy are sunk by a
German wolf pack.
After German commerce raider ATLANTIS and supply ship
PYTHON are sunk by British cruisers HMS DEVONSHIRE and DORSETSHIRE respectively,
TORELLI and Italian submarines ENRICO TAZZOLI, GIUSEPPE FINZI and PIETRO CALVI
participate in the rescue of the German survivors. The submarines return 254 men
to Saint-Nazaire, France where they are welcomed by Konteradmiral Eugen
Lindau, Marinebefehlshaber Nordfrankreich.
TORELLI sinks two more ships of 16,469-tons for a total
of 42,871-tons sunk. Upon return to Bordeaux, CC de Giacomo and the COs of the
three other Italian submarines are decorated for the rescue with the Iron Cross,
First Class by Vizeadmiral Karl Dönitz, Befehlshaber der Unterseeboote (BdU)
3-4 June 1942:
Departs Bordeaux for the West Indies under Tenente di
Vascello (TV) Augusto Migliorini. TORELLI is attacked that night by a
Vickers-Armstrong "Wellington" bomber of RAF No. 172 Squadron, piloted by
Squadron Leader J. H. Greswell. This marks the first use of a 24-in airborne
"Leigh Light" searchlight fitted into a retractable lower gun turret. Greswell
straddles TORELLI with four 250-lb depth charges that damage the submarine's
steering gear and compass. TORELLI is towed by Spanish tugs to Aviles, Spain
where she is grounded.
6 June 1942:
TORELLI is refloated and departs Aviles for Bordeaux. She
is spotted limping back through the Bay of Biscay by two "Sunderlands" of RAAF
No. 10 Squadron. They strafe and then depth-charge the submarine. TV Migliorini
and another officer on the bridge are wounded and one man is killed. The
submarine's return fire damages one of the Australian flying boats. TORELLI is
later beached at Santander, Spain with a large hole amidships.
8 June-15 July 1942:
During the next month TORELLI's crew carries out
emergency repairs at Santander, but she exceeds the maximum stay allowed in the
territorial waters of a neutral country. TORELLI is scheduled to be interned by
the Spanish authorities, but on 14 July she slips quietly away and arrives at
Bordeaux the next evening.
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 replacements.
Bordeaux. TORELLI is reconfigured to carry 150-tons
of cargo. Her 100-mm deck gun is removed and her torpedo tubes and ammunition
storage magazines are converted into fuel storage tanks. Some of her batteries
are removed to make room for cargo. TORELLI's only armament is her Breda 13.2-mm
machine guns. For the duration of the voyage the to Far East TORELLI is
code-named AQUILA VI.
14 June 1943:
Departs Bordeaux for the Far East under TV Enrico
Groppello. She carries a cargo of mercury, steel, 800 Mauser MG 151/20 aircraft
cannons, a 500-kg SG 500 bomb and spare torpedoes. Her passengers include
Colonel Satake Kinjo, a telecommunications officer returning to Japan after
extensive training in Germany, radar engineer Heinrich Foders of Telefunken who
has a set of Würzburg AA radar blueprints and two civilian mechanics. Two
complete sets of Würzburg radars are also carried for delivery to the IJA and
IJN.  AQUILA VI also carries three German engineers from the U-boat builder
Deshimag AG Weser at Bremen on a technical mission to Japan.
12 August 1943:
Indian Ocean. AQUILA VI is about to run out of fuel.
She manages to rendezvous successfully with Fregattenkapitän (FK=Cdr)
Wilhelm Dommes' U-178 that transfers diesel oil to her. Thereafter, they head
eastward together. 
25 August 1943:
Arrives at Sabang, Sumatra.
27 August 1943:
Departs Sabang for Singapore in company of ERITREA.
1 September 1943:
AQUILA VI arrives at Keppel Harbour, Singapore.
Commences repairs. Most of the crew is transferred to Pasir Panjang village to
recuperate; only a skeleton crew remains aboard.
8 September 1943: The Surrender of Italy:
After receiving the news of
an armistice signed by the Italian government, Rear Admiral Enomoto Takaichiro
orders TV Groppello and his crew to be interned. Later that month they are
transferred to Sime Road PoW Camp where they join the crews of REGINALDO
GIULIANI (later UIT-23) and COMANDANTE CAPPELLINI (later UIT-24/I-503).
10 September 1943:
TORELLI is formally commissioned in the
Kriegsmarine as UIT-25.
23 September 1943:
Salò, Italy. Mussolini founds the new puppet
"Repubblica Sociale Italiana" (RSI) regime controlled by the Germans.
Later, some of AQUILA VI's crewmen decide to fight alongside the Germans as part
of the RSI.
6 December 1943:
Oberleutnant zur See (OL=LT(jg) Werner Striegler
8 February 1944:
Departs Singapore for Penang.
10 February 1944:
Arrives at Penang.
13 February 1944:
Penang. OL Striegler relinquishes command of the
UIT-25 and immediately assumes command of UIT-23 (ex-GIULIANI) whose Commanding
Officer, FK Heinrich Schäfer, died on 8 January 1944.
14 February 1944:
Striegler leaves on patrol. UIT-23 carries some
survivors from the sunken German raider (Hilfskreuzer IX, Schiff 28) MICHEL, but
UIT-23 is itself torpedoed by submarine HMS TALLY HO!
OL Striegler and 13 survivors are rescued by two German Arado Ar-196A
floatplanes (formerly of MICHEL) of the Marine Sonderfliegerkommando,
stationed at Penang. Five survivors at a time lash themselves to the planes'
floats and are returned to Penang. That same day, Striegler again assumes
command of UIT-25.
7 March 1944:
UIT-25 departs Penang for Surabaya, Java.
11 March 1944:
Arrives at Surabaya.
10 June 1944:
Departs Surabaya for Tamano, Japan.
25 June 1944:
Arrives at Tamano. Undergoes repairs at Tama Zosensho
The Allied codebreakers decipher a signal indicating that
UIT-25 probably is at Surabaya.
Transferred to Kobe.
OL Herbert Schrein assumes acting command. OL
Striegler is reassigned as the CO of U-196, lost in the Sunda Strait on 30
Incessant Allied air and submarine attacks render
Penang untenable as an operational base for submarines. German U-boats withdraw
to Batavia (Jakarta), Java and the Japanese I-boats relocate to Surabaya,
OL Alfred Meier (from U-183) assumes command of UIT-25.
That month, UIT-25 departs Batavia for Kobe, Japan probably to have her battery
cells replaced. Undoubtedly, she also carries personnel and war materials to
17 March 1945:
Kobe undergoes an American bombing raid by USAAF Boeing
B-29 "Superfortresses" of the 20th Air Force from Tinian, targeting the
Mitsubishi and Kawasaki shipyards. I-158 and several cargo ships are damaged in
the raid. One of UIT-25's German ratings is killed.
10 May 1945: The Surrender of Germany:
Kobe. UIT-25 is undergoing
overhaul at Kawasaki's shipyard. She is taken over by the IJN, commissioned as
I-504 and assigned to the Kure Naval District, but no Japanese crew is assigned
I-504 and I-503 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-504 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-504 is surrendered at Kobe.
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 the American Navy in the Kii Suido.
 Italian Naval Ranks:
Tenente di Vascello
Capitano di Corvetta (CC=LtCdr)
Capitano di Vascello (CV=Captain)
Contrammiraglio (Rear Admiral)
2] Longobardo trained in the U-99 under Otto Kretschmer, Germany's
highest scoring U-boat ace.
 Italy's highest military decoration.
 The Mauser MG 151/20 aircraft cannons were installed on the first
batch of specially modified Kawasaki Ki-61-I Hien ("Tony") fighters.
 The IJA's radar set transported by TORELLI/AQUILA VI is later fitted
on KINKA MARU at Kawasaki's Kobe shipyard. The Italian BARBARIGO/AQUILA V
departs Bordeaux accompaning TORELLI/AQUILA VI also carrying important Würzburg
radar components and data for Japan, then detaches from TORELLI and is sunk,
probably by Allied aircraft, on 19 June 1943 off the Azores.
 Dommes later becomes the Commander of "Gruppe Monsun" at Penang.
 On 29 October 1943, the Japanese allow the Italian submariners to
leave Singapore aboard German blockade-runners BURGENLAND, RIO GRANDE and
WESERLAND that are bound for France. On 3 January 1944, in the South Atlantic,
WESERLAND is sunk by USS SOMERS (DD-381) that recovers 130 survivors. The next
day, 55 miles NE of Brazil, USS OMAHA (CL-4) and JOUETT (DD- 396) intercept RIO
GRANDE that scuttles. The following day, OMAHA and JOUETT intercept BURGENLAND
that also scuttles. On 8 January, USS MARBLEHEAD (CL-12) rescues 72 survivors of
RIO GRANDE. That same day, USS WINSLOW (DD-359) rescues 35 survivors of
BURGENLAND. Later, 32 others are rescued later by a Brazilian ship and made
 Meier later returns to Germany aboard another vessel and assumes
command of U-3012 at Travemünde on 1 May 1945 until she is scuttled just two
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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