Patrol 1

17 Mar 1944- 9 May 1944

No sinkings

Patrol 2

3 Jun 1944- 12 Jul 1944

日本海丸 Nihonkai Maru

Patrol 3

1 Aug 1944-4 Oct 1944

No sinkings

Patrol 4

27 Oct 1944-21 Nov 1944

U-537 (German) - not credited to Flounder in JANAC

暁山丸 Gyozan Maru - Flounder shared credit with USS Guavina (SS-362) for the distruction of this vessel in JANAC. USS Bashaw (SS-241) may have hit Gyozan Maru earlier the same day.

Patrol 5

7 Jan 1945-26 Feb 1945

No sinkings

Patrol 6

16 Mar 1945-22 Apr 1945

3 ships, 9,523 tons, including the German submarine U-537, and shared credit for Gyosan Maru with USS Guavina.

JANAC - 1 ship, 2,681 tons, plus shared credit with USS Guavina (SS-362) for the distruction of Gyosan Maru (5,698 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 Flounder with 3 ships and 9,523 tons sunk.

SORG credits Flounder with 2 ships and 4,700 tons sunk.

Wrecksite credits Flounder with 3 ships and 9,636 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 Flounder

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)

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.