TO: Submarine Commanders / SubRon 4A

FROM: ComSubPac / ComSubRon 4A

DATE: June 1943

SUBJECT: Mission Orders (Cycle 7 September 2002)

RMKS: 1 The Japanese five-digit code has been broken, intercepted IJN transmissions have provided important information identifying a major traffic route and escort procedures. The main route is from Empire waters South to the Palau Islands, Southwest to the equator, to about longitude 150 degrees east, than South to Kavieng on New Ireland and than South to Rabaul. Convoys are known to be transiting due South from Truk to Kavieng. It has been determined that at some point along the equator line the escorts from Truk and the Palaus turn back and hand over the convoys to escorts from Kevieng or Rabaul. Windows of opportunity present themselves as the convoys experience periods of unescorted travel while they await rendezvous with IJN warships detailed to provide protection on the second leg.

RMKS: 2 In April the code breakers provide information giving the precise itinerary of and inspection trip of Bougainville and Rabaul by Admiral Yamamoto. Forewarned. Admiral Halsey sent long ranged P-38’s from Guadalcanal and on April 18 the P-38’s intercepted Yamamoto’s plane in mid-flight and shot it down, killing Admiral Yamamoto. Admiral Mineichi Koga has succeeded Yamamoto as CinCIJN.

RMKS: 3 ONI has determined that the Japanese are shuttling carriers back and forth between Empire waters and Truk, FRUPAC has intercepted communications about enemy movements in an area Southwest of Lot’s wife which is being used as a rendezvous point for the major fleet units forming up for transit South to Truk or the Palau’s.

RMKS: 4 The Potshot (Exmouth Gulf) advance base experiment has been cancelled following the Japanese air-raid on May 20. The tender Pelias has been ordered back to Fremantle, which will remain SubSoWesPac’s base. However a fueling barge will remain stationed in Exmouth Gulf for use by SobSoWesPac submarines.

RMKS: 5 A new experimental sonar device called the ‘Bathythermograph’ is scheduled to be installed in a few boats for testing to determine whether thermal layers in the deep ocean can help a submarine avoid detection by enemy ASW forces. As these units arrive you may expect to have this unit installed.

RMKS: 6 SubRons are assigned to the following areas of operation:

SubRon 1M PacFlt – Aleutian Islands

SoWesPac – Java Sea

SubRon 2M PacFlt – Empire (Southern Japan)

SoWesPac – Malaysia

SubRon 3A PacFlt – Palau Islands

SoWesPac – Phillippine Islands

 SubRon 4A~

 

                    PacFlt - Mariana's Islands

                    LCDR Cox II, USS SeaDragon - (Mariana's - NM-2 - June-Aug 43)

 

                    LCDR Gundersen, USS Pogy - (Mariana's - NM-1 - July-Aug 43)

 

                    LCDR Doyle, USS Steelhead - (Mariana's - NM-1 - June-July 43)

 

                    SoWesPac - Sulu Sea

                    CMDR Turner III, USS Jack - (Sulu Sea - SS-5+6 - June-Aug 43)

 

                    LCDR Edwards, USS Growler - (Sulu Sea - SS-1+2 - June-Aug 43)

 

                    LCDR Schow II, USS Greenling - (Sulu Sea - SS-3+4 - June-Aug 43)

 

SubRon 5A PacFlt – Empire (Northern Japan)

SoWesPac – Indochina

SubRon 6A PacFlt – Formosa

SoWesPac – Malaysia

SubRon 7A PacFlt – Caroline Islands

SoWesPac – South China Sea

SubRon 8A PacFlt – Yellow Sea

SoWesPac – Java Sea

All Commanders are to acknowledge receipt of these orders.

 Good Luck and Good Hunting

CMDR Greg Turner III

CO: SubRon 4A

Rear Admiral Charles A. Lockwood

Commanding SubPacFlt

 

// SENDS //