Patrol 1

22 Aug 1944 - 20 Oct 1944

Kimikawa Maru - damaged

San Luis Maru - damaged

徳和丸 Tokuwa Maru - shared credit for the sinking with USS Hawkbill (SS-366)

Patrol 2

15 Nov 1944 - 8 Jan 1945

Sea truck (name unknown) - small vessel (estimated at 300 tons) often not included in sinkings, sunk by deck gun; not credited to Becuna in JANAC

Taian Maru - civilian cargo ship; small vessel (239 tons) often not included in sinkings; not credited to Becuna in JANAC

Patrol 3

4 Feb 1945 - 22 Mar 1945

日翼丸 Nichiyoku Maru

Patrol 4

18 Feb 1945 - 15 Apr 1945

Patrol 5

21 Jun 1945 - 27 Jul 1945

2 ships, 3,888 tons - Credit for sinking Tokuwa Maru is shared with USS Hawkbill (SS-366). In addition, Becuna sank two small vessels, Tauan Maru (239 tons) and an unidentified sea truck, neither of which were credited to Becuna in JANAC. The 300 tons credited to Becuna for the small sea truck sunk on Patrol 2 is is only an estimate.

JANAC - one ship (Nichiyoku Maru), 1,945 tons, plus shared credit for one other ship (Tokuwa Maru), 1,943 tons. Note that the criteria JANAC used included all Japanese Naval vessels (although JANAC did not usually count warships less than 500 tons that were converted from merchant ships) and all Japanese merchant vessels of 500 or more gross tons known or believed to have been lost during the war. Differences between JANAC figures and current research are noted above.

Alden-McDonald credit Becuna with 4 ships and 4,127 tons sunk, including shared credit for the sinking of Tokuwa Maru with USS Hawkbill (SS-366). The small vessels Taian Maru and an unidentified sea truck sunk by gunfire on Becuna's second patrol are included, although the tonnage for the sea truck is not included in the total tonnage.

SORG credits Becuna with 5 ships and 18,600 tons sunk.

Japanese Naval and Merchant Ship Losses - JANAC on the NHHC website

JANAC on the Hyperwar website - https://www.ibiblio.org/hyperwar/Japan/IJN/JANAC-Losses/JANAC-Losses-6.html

SORG- http://archive.hnsa.org/doc/subreports-sorg.htm (Excel spreadsheet download)

Archives of the Pacific Fleet Submarine Museum (PFSM)

War Patrol Reports - USS Becuna

Monthly Losses of Combatant and Non-Combatant Vessels

太平洋戦争時の喪失船舶明細表（汽船主体）- Lost Vessel table during the Pacific War (merchant vessels)

Alden, John D., and McDonald, Craig R. - U.S. & Allied Sub Successes in the Pacific & Far East during WWII - Fourth Edition, 2009

Cressman, Robert - The Official Chronology of the U.S. Navy in World War II, Naval Institute Press, 2000.

Wrecksite - https://www.wrecksite.eu/wrecksite.aspx

Miramar Ship Index - https://www.miramarshipindex.nz/

Imperial Japanese Navy Page - http://www.combinedfleet.com/

Wikipedia Japan - https://ja.wikipedia.org/wiki/

Japan Center for Asian Historical Records - National Archives of Japan - https://www.jacar.go.jp/index.html

Official U.S. Navy Photos - Naval History & Heritage Command

Archives of the Pacific Fleet Submarine Museum (PFSM)

Imperial Japanese Navy Page - http://www.combinedfleet.com/

Japanese Merchant Ship photos - Wrecksite - copyright owners retain all rights. Photos used on this site will be taken down should the owner request their removal.