The Battle of Rennell IslandBy Philip H. Jacobsen
     Lieutenant Commander Philip H. Jacobsen, USN (Ret.) is a veteran of 28 years'  naval service, 27 of which were with the Naval Security Group and its predecessor organizations.  He retired from the Navy in 1969.  He was Attorney General for  the Territory of Guam and is on the staff of "Cryptolog", the newsletter for the Naval Cryptologic Veterans Association.
    The interaction between Operation KE, the Japanese evacuation of Guadalcanal and the Battle of Rennell Island  begins in Tokyo on December 26, 1942 when the Imperial General Headquarters agreed on the withdrawal of all troops on Guadalcanal.  By January 9, 1943, the Combined Fleet and the 8th Area Army command completed an agreement on the KE Operation. In addition to the troop withdrawal by destroyer transport in two or three phases, all available aircraft from the Eleventh Air Fleet, Sixth Attack Air Force and the R Area Air Force were to initiate an air superiority campaign about January 28. 

    When the implementing messages began to fly, the U.S. Navy‘s radio intelligence reporting stations, FRUPAC (Hawaii), FRUMEL (Melbourne) and Station N (Washington DC), began reporting the decrypts of the messages sent in the JN-25  general operations code. While the times and dates of these future Tokyo Express type evolutions were fairly well reported, they were still considered to be the normal reinforcement operations vice an evacuation of troops.  The basic details of the evacuation were in a written plan.  The first run was to commence on January 30, 1943. 

    In response to these intelligence reports and to protect the withdrawal of the 2d Marine Division, COMSOPAC, Admiral Halsey, deployed the full array of  American naval power in the South Pacific.  Near sunset of January 29, a carrier group built around Enterprise headed for a rendezvous with the Saratoga group.  
    Task Force (TF) 67 of four cruisers and four destroyer made for an intersection with Admiral Lee’s TF 64 of three battleships and four destroyers.  In front of  these  units sailed two other groups.  TF 62.8 consisted of four transports and  four destroyers.  Rear Admiral Richard C. Giffen commanded TF18 of six cruisers,  destroyers and the “jeep” carriers Suwanee and Chenango.  To meet a 2100 rendezvous with the newly created Cactus Striking Force of four destroyers under the command of Captain Robert Briscoe, Giffen detached the slower jeep carriers and upped the speed to 24 knots. This showed Giffen’s inexperience in Pacific waters by depending mainly on his own anti-aircraft batteries.  The scheduled daylight foray up the Slot on January 30 to catch the KE destroyers emerging  from their sanctuaries in the Shortlands still could have been accomplished by a later arrival at Cape Hunter so it was not necessary to detach the jeep carriers to be ready for their ultimate operational task. 

    At the time I belonged to a very small intercept, analysis and reporting station, Station AL (locally known as Cactus Crystal Ball) on Guadalcanal. When I came on the evening watch at our small station at Lunga Point on  January 29th, the air was full of Japanese naval air reconnaissance reports of  “enemy” ships South of Guadalcanal.  Soon, reports of many Betty two-engine land bomber/torpedo planes in the air headed for the area were received.  Finally,a action report of one battleship sunk was received.  These reports were sent to our consumers through our special crypto channel, Copek.  One of these reports  made its way into the Pacific Fleet intelligence summary for January 1943,  SRH-036 p. 637. 

    To: COMSOPAC  
    Info: CINCPAC - 
    These messages were sanitized to protect the source and were passed on to the TF commanders. 
    At the same time, some of my friends from Hawaii on the Radio Intelligence Unit in Enterprise were copying many of the same messages, but their TF commander would not break radio silence to warn TF18 as they had not yet joined  up so as to have visual signal communications. 

     Giffen’s formation was designed for submarine defence but was very weak from an aircraft defence point of view.  By 1920, the Wichita radar plot resembled a “disturbed hornet’s nest” as 16 aircraft of the 705th Air Group commenced their attack. Giffen remained hell-bent on meeting the rendezvous and altered neither  course nor speed and even ceased the zigzag.  This made it easy for the  attacking Japanese aircraft, which laid rows of white flares along each side of the Task Force like footlights and dropped clusters of red and green float lights to  communicate information such as speed and composition.  The 705th Air Group’s attack failed to damage any  ships, yet 15 planes of 701st Air Group, striking next, made two torpedo hits on Chicago, seriously damaging it, while a dud hit Wichita 

  Louisville took Chicago under tow and later was relieved by the tug Navajo.  Radio intelligence and coast watchers provided Giffen with information on shadowing aircraft and the 11 Bettys of the 751st Air Group that would reach  TF18 about 1600 on January 30th.  I recall copying one Japanese sighting report that mentioned “CHICAGO” in English.  In the meantime, Halsey ordered Giffen to  make for Efate.  At 1500, TF18 divided leaving the Chicago-Navajo tow operation screened by destroyers LaVallette, Conway, Frazier, Waller, Edwards, and 

  The rest of the Task Force hauled off to the east, stripping Chicago of the shield of their formidable anti-aircraft batteries (including some with the new VT “proximity” fuse) and the force fighter direction officer in Wichita. 
    As a result, only four Wildcat fighters remained to guard Chicago.  At 1540, the Wildcats spotted the shadower who preceded the 11 Bettys and started a chase that took them 40 miles away  before they splashed the snooper.  Thus, when the Bettys sighted Chicago at 1606, she lacked aerial defenders.  Fighter directors on Enterprise vectored six Wildcats into an interception.  Only two Wildcats got in among the Bettys before they reached their release points.  Chicago suffered four torpedo hits and sank, while LaVallette was hit by one torpedo, but survived.  Only four out of 11 Bettys returned to their Shortland base. 

    This attack delayed the first run of the KE destroyer transport evacuation force until February 1st.  However, it kept TF18 and the Cactus Striking Force from their intended daylight sweep up the Slot and left it up to the Cactus  Striking Force, PT boats and Henderson Field pilots to try to stop this first KE run.  On February 2, 3, and 4 up to 15 Bettys canvassed the sea around Guadalcanal.  Weather and excessive range frustrated Japanese attempts to attack the strong American naval detachments, including carriers, in the area, but the Eleventh Air Fleet kept the U.S. ships from interfering with the KE destroyer evacuation operation. 

    While two KE destroyers were sunk and several were seriously damaged, 10-12,000 Japanese troops were successfully evacuated from Guadalcanal by  February 8, 1943.  However, because so many of these troops were seriously ill, the military consequences of the evacuation were not as significant as some reports intimated.