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USMC 1945 Anti-Aircraft Btn TO&E

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  • USMC 1945 Anti-Aircraft Btn TO&E

    What is the TO&E of the USMC late 1945 anti-aircraft battalion?

    What radars did it use for its 90mm gun battery's and it search light battery?

    What was the composition of it's 40mm and 20mm auto-weapons battery's?

  • #2
    I don't have the T/Os for the July 1945 G-Series organisation, which would would cover the late 1945 period. They wouldn't be too much use though, as the G-Series T/Os don't carry the details of transport and non-individual weapons, and I'm sure radar. The July 1945 AAA Bn (FMF) had the same structure as the April 1944 T/Os, which were organised as follows -

    HQ & Service Battery, comprised of;
    HQ Platoon (59 all ranks)
    Maintenance Platoon (51 all ranks)
    Battery HQ (32 all ranks)
    Total (260 all ranks)

    The Comms and Radar Section of HQ Platoon shows two Radio set 270-D (Navy Model) and two Radio set 270-D (Army Model). The former each had an operating trailer (SKD-2226), a power trailer (SKD-2226-1) and an antenna trailer (K-64-C). The latter each had a K-32 prime mover, a K-31-A, a K-62 and an E-54 truck, and a K-64 antenna trailer.

    Heavy AA Group, comprised of;
    Group HQ (45 all ranks)
    Four 90-mm AA Batteries, each (121 all ranks)
    Total (529 all ranks)

    Each 90-mm Battery included a HQ with two M1917 HMGs for defence, a Range Finder Section with an SCR-584 set, an MG Section with four water cooled M2 .50-cal machine guns, and four Gun Sections, each with a 90-mm. Group HQ also had two M1917s.

    Light AA Group, comprised of;
    Group HQ (37 all ranks)
    40-mm Battery (177 all ranks)
    20-mm Battery (81 all ranks)
    Total (295 all ranks)

    The 40-mm Battery had three Platoons, each of four Sections with a 40-mm gun and a .50-cal M2. The 20-mm Battery likewise had three Platoons, each with just four 20-mm guns.

    Searchlight Battery; comprised of;
    Battery HQ (26 all ranks)
    Two Searchlight Platoons, each (75 all ranks)
    Total (176 all ranks)

    Each Searchlight Platoon had six Sections, each with a AA searchlight and an M2 HMG.

    Total, AAA Battalion, 1260 all ranks

    16 x 90-mm AA guns
    12 x 40-mm AA guns
    12 x 20-mm AA guns

    16 x .50-cal water cooled MGs
    12 x .50-cal MGs
    10 x .30-cal MGs

    12 x searchlights

    I don't know how much different the July 1945 T/Os were from the April 1944 version, I would expect them to be refinements of, rather than entirely new versions. Hope that helps some anyway.



    • #3
      That's strange. There are no listing for SCR-268 searchlight radars.

      Those were standard in the US Army Search light battery's with a ratio of one radar for every two search lights.


      • #4
        Looks like there was some radar for the S/L Bty. There's nothing listed under equipment but there are radar operators shown for radar Mk XX in the Pls; a SSgt, Sgt, Cpl and Pvt per S/L Sec.


        • #5
          USMC Search Light Radar

          Google showed me the 1944 USMC amphibious staff officer book at Hyperwar dot com.

          This Mark XX radar was issued at a ratio of one radar per search light (12 ea.) and was much smaller than the SCR-268.

          Apparently the USMC had a radar adapted from Naval use replace the SCR-268 in 1943-44, which Army AA Search Light Btns were still using at Okinawa in 1945.


          • #6

            Do you have a TO&E for a later war Marine ground control intercept unit?


            • #7
              I don't have, sorry.



              • #8

                Thank you for the TO&E you did have.

                I will try and track this Mark XX radar mystery elsewhere.


                • #9
                  Glad I could help, I had a borderline obsession on tracking down USMC T/Os earlier this year as there is just so little available (and what there is is often repeated from the online official histories).

                  I did look briefly at the Air Warning Squadrons, due to their being cited in various assault operations as having detachments with the Marine Divs themselves. However, as the USA provided the same type of units for USMC formations as well, and given that radar and EW are somewhat out of my league, I didn't follow up on them.

                  There were three T/Os issued for Air Warning Squadrons in May43, Mar44 and Nov44, that might relate to the ground control/intercept unit you asked about (I don't have a ref for a unit of that name until 1949/50).

                  This was a link I found when trying to decide just what the AWS was for, and has a few sections on USMC units that might help -


                  If you think the AWS might be the unit you're looking into, drop me a PM and I'll give you the details you'll need to follow up on the T/Os.



                  • #10
                    I just found the "Mark XX" Marine searchlight radar at

                    as the "Mark 20 Naval Searchlight Radar."


                    • #11
                      Marine GCI Units for Operation Olympic

                      "There were three T/Os issued for Air Warning Squadrons in May43, Mar44 and Nov44, that might relate to the ground control/intercept unit you asked about..."

                      I am looking for the TO&E of the Marine GCI units listed as "4a", "4b", "4c" in the attached image.

                      Each was equipped with a SCR-527 and a SP-1M radar. I have a total manpower count of one of these GCI units, but I have no idea how that manpower is organized or what other equipment besides the radar they had.
                      Attached Files
                      Last edited by Dark Wing; 17 Oct 12, 10:14.


                      • #12
                        You could try this:

                        "Profanity is but a linguistic crutch for illiterate motherbleepers"


                        • #13
                          This is the best it has --

                          "The radar and fire control equipment employed by the defense battalions in turn allowed them to become an integral part of the overall air defense of a captured target area. Although dispersed throughout the beachhead, this equipment was linked primarily by telephone with a radio backup. A battalion fire control center coordinated the operations of each group of weapons and in turn was incorporated with other Allied radar nets. The effective ranges for fire control equipment was variously 20-45 miles for fire control gear and 120-200 miles for search radar."


                          • #14
                            The Fold3 government document digitization service has the war diaries of the USMC AAA battalions on Okinawa.

                            They fought Okinawa with 1/3 of their Mark 20 search light radars, all their SCR-584 gun laying radars and only one SCR-270 per battalion...and the SCR-270's were not the 270D models but older ones from the South Pacific or Hawaii. The specific gripe for the SCR-270's they were issued was the lack of PPI scopes.


                            • #15
                              I have discovered more information from on AWS radar kit.

                              This is the Radar TO&E of Hawaii Based USMC Air Warning Squadron 9 for July 1945.
                              • 1 ea. SCR-270 (EW) 3-meter
                              • 1 ea. SCR-527 (GCI) 1.5-meter
                              • 1 ea. SP-1M (GCI) 10-centimeter
                              • 3. ea TPS-1B (Assault/Gap filler EW) 10-centimeter

                              Given the good supply position of AWS-9 in Hawaii relative Okinawa, it's likely this the TO&E model for Operation Olympic. (War diaries of Marine AWS radar units training on the East Coast of the USA showed those units were replacing the SCR-270 with the SK-1M and the SCR-527 with a second SP-1M.)

                              Also, based upon the other AWS War diaries in Fold3 I have read of Okinawa AWS units, one or more of the TPS-1B could be replaced by any
                              of the following radars based on availability and mission needs:
                              • SCR-602, or
                              • So-7M/N, or
                              • So-13M/N.

                              For Operation Olympic there would be six SCR-270 upgraded with MTI circuit kits that would go to the AWS over the USMC AA battalions.

                              Just when I thought I had this puppy licked, I found this to further confuse the issue of USMC radar kit. It seems the USMC wanted to use a new NRL "Mark 33" Radar to replace both its So-7M/N and So-12M/N radars used in its AAA Battalions, AWS units and the 155mm Gun battalions (that were also spun off from the Defense Battalions with the AAA battalions).

                              This is an abstract I pulled from WWW.DTIC.MIL --
                              Title: (U) THE MARK 33 RADAR SYSTEM,
                              Accession Number: AD0494633
                              Personal Author(s): Pawley,M G
                              Corporate Author: NAVAL RESEARCH LAB WASHINGTON D C
                              Corporate Source Code: 251950
                              Report Date: 18 Jul 1945
                              "Abstract: (U) The Mark 33 radar system is a combined search and fire
                              control X-band equipment for trailer-borne Marine Corps service. The
                              equipment was designed to replace the Mark 16 radar in as short a time
                              as possible. To accomplish this without designing an entirely new
                              system, the Mark 33 was made up from
                              o Modified versions of the SG-2S antenna,
                              o Mark 3 antenna mount,
                              o SO-3 transmitter-receiver, and
                              o Two modified VF remote precision indicators and
                              o Auxiliary equipment
                              o All mounted in an SP-1M trailer.
                              This report includes a general description of the system and a more
                              detailed description of the coordination unit which was designed by
                              NRL. Plates are included showing the coordination unit circuit diagram
                              and chassis layout, and representative photographs of the indicator
                              screens. Performance data is presented. (Author)"

                              From what I have been able to discover, this "Mark 33 M/N" would have been a crackerjack surface search radar much better able to spot Japanese suicide boats at short range, pick up low flying aircraft below 100 feet, and operate close to shore with scattered land echos.


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