Patrol 1

30 Jun 1942- 30 Jul 1942

Grunion lost on this patrol

第25号駆潜艇 Submarine Chaser No. 25

第27号駆潜艇 Submarine Chaser No. 27

鹿野丸 Kano Maru - damaged by Grunion, then by aircraft; total loss

3 ships, 9,492 tons, including shared credit for Kano Maru

JANAC - 2 ships, 600 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 Grunion with 3 ships and 9,492 tons, including shared credit for Kano Maru.

SORG credits Grunion with 2 ships and 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 Grunion

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.