/A16-3
844 19 JUL 1944
From: Commander Task Force ONE TWO TWO.
To : Commander-in-Chief, United States Fleet.
Via : Commander, U.S. Naval Forces, Europe.
Subject: Naval Combat Demolition Units; report of.
Reference: (a) CominCh ltr. FF1/98-2 serial; 001192 of
16 April, 1944.
Enclosure: (A) Lt.(Jg) H.L. BLACKWELL, Jr., D-V(G), USNR,
ltr. A16-3 of 15 July, 1944 with attached
report.
1. Enclosure (A) is forwarded in accordance with
reference (a).
A.D. STRUBLE,
Chief Of Staff.
File No.
CTF122 /A16-3
UNITED STATES FLEET
TASK FORCE ONE TWO TWO
Navy 803
Care Fleet Post Office
New York, N. Y.
15 July, 1944.
From: Lt. (jg) H.L. BLACKWELL, Jr. D-V(G) USNR.
To : Commander Task Force ONE TWO TWO.
Subject: Naval Combat Demolition units; report of.
Reference: (a) ComNavEu Orders to Lt.(jg) Blackwell
P16-3/00 of 3 Tune, 1944 and endorsements
thereto.
Enclosure: (1) Report on the work of the U.S. Naval Combat
Demolition units in operation NEPTUNE.
1. This officer has been on temporary duty with
Task Force ONE TWO TWO for the purpose of collecting information
on the work of the U.S. Naval Combat Demolition Units in
breaching beach obstacles.
2. Some of the material collected has been briefed
to make up the report which forms Enclosure (1) of this letter.
Respectfully submitted,
(signed)
H.L. BLACKWELL, JR.
Lt. (jg), USNR.
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REPORT ON
NAVAL COMBAT DEMOLITION UNITS
IN
OPERATION "NEPTUNE"
as part of
TASK FORCE 122
Submitted by:
Lt.(jg) H. L. Blackwell, Jr. D-V(G) , USNR.
Date:
5 July, 1944.
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SECTION II THE ACTUAL OPERATION A. Brief Summary of the Section. This section covers the actual assault and post-assault work of breaching the beach obstacles in operation NEPTUNE. It presents information on the Operation Plan, the methods used, the difficulties encountered and the results obtained. It is divided into two sub- sections, one devoted to each Force. B. Force OMAHA 1. The Mission of the NCDUs. (a) The. following is quoted from the Demolition Operation Order, part of Operation order No. 1-44 of Assault Force 'O' of the Western Naval Task Force, dated 31 May, 1944 (Encl. (6) hereof) 1. The Naval Combat Demolition Group is associated and working with an Army Demolition group consisting of two battalions of Combat Engineers attached to the V Corps. One NCDU together with one Army combat demolition unit forms a Gap Assault Team. NCD Sections TWO and ONE will form part Of Assault Group 0-1 and 0-2, respectively, of Force 'O' and will function under the Commanders of those Assault Groups. 2. This (Demolition) Group will: (1) Clear and mark sixteen gaps, fifty yards wide, through the seaward band of obstacles on OMAHA beaches; two on FOX GREEN, six on EASY RED, two on EASY GREEN, two on DOG RED, two on DOG WHITE, and two on DOG GREEN. (2) Widen the gaps in the seaward band of obstacles until the entire band is cleared. (3) Assist the Special Army Engineer Demolition Group in clearing gaps through other bands of obstacles and removing all obstacles from the OMAHA beaches. |
ENCLOSURE (5) METHODS -- Charges used, placement of charges, results. (a) Explosive Methods. OBSTACLE CHARGE RESULTS Element "C" 18 2-lb Hagensen packs, Obstacle placed to cut face from cleared. rear-frame, & to flatten rear-frame as well. Extra charges used when possible. Ramps one 2-lb Hagensen pack at. Legs cut off base of each leg, unless at bases, blown timbers over 18-20 inches apart at top. diam., or wood very green. Obstacle cleared. If so, 2 packs. Also one 2-lb. pack underside of apex of legs. Piling Single Hagensen pack at Obstacle base, as with ramp timbers; cleared. if extra thick, or green, 2 packs (4 lbs.) Steel hedgehogs 3 Tetrytol blocks; 2 on Obstacle cleared, one side of central gusset but much shrapnel plate, 1 on the other side. projected. (Not necessarily placed for shearing effect.) Steel hedgehogs 2 Hagensen packs; 1 each Obstacle not side of gusset. always cleared. Sometimes members merely bent, leaving hazard to light craft. Concrete tetrahedra 1 Hagensen pack at Obstacle (members wired or apex each triangle. demolished. pinned together at the joints) Concrete posts 2 Hagensen packs at Obstacle (reinforced) base. demolished. Concrete posts 1 Hagensen pack at Concrete cleared (reinforced) base. but reinf. bars left. obstacle could be pushed over by hand afterwards. Tellermines 1 Hagensen pack, or Tellermine 35, 42, 43 1 Tetrytol Block, or countermined. 1 ‡-lb. block TNT Tellermines 1 Number Eight Cap Tellermine 35, 42, 43 placed in detonator detonated. (b) Non-Explosive Methods. All the above obstacles were successfully removed with caterpillars, dozers, tank dozers, or tanks, if the Tellermines had been removed first. Tellermines can be removed by hand after unscrewing detonator, if it is desired to avoid the shrapnel caused by blowing them. Hedgehogs were eliminated by undoing bolts from central gusset plates, allowing obstacle to collapse. (c) Fixed Flamethrowers. From Lt. Smith's description, these were the same as those seen by the writer at Grandcamp, a specimen of which was recovered for forwarding to the U.S.A. These flamethrowers are a simple tank, filled with a petroleum creosote mixture, which is ejected through a goose-neck nozzle by gas pressure from a burning pyrotechnic cartridge. The mixture is ignited by another similar cartridge wired and fired electrically in parallel with the first one. The flame lasts about l‡ minutes and has a range of 50-75 feet depending on the wind. It has a general terror value, and a specific value against vehicles or concentrations of men approaching the seawall within its range.
ENCLOSURE ( 6 )
Operation Order - Force 'O'.
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1. Information as in Naval Commander Western Task Force
NEPTUNE MONOGRAPH, and Commander Assault Force 'O'
Operation Order No. BB-44.
The Naval Combat Demolition Group is associated and working
with an Army demolition group consisting of two battalions
of Combat Engineers attached to the V Corps.
One NCDU together with one Army combat demolition unit forms
a Gap Assault Team.
Tankdozers embarked in LCT(')s will land at H hour and
proceed against obstacles as directed by the Army combat
demolition unit officers.
All paths cleared through minefields will be marked by
personnel of the Army demolition units with a standard
minefield gap marker, five feet high. Individual mines
which have not been removed will be marked by an eighteen
inch probing wire with a six inch by six inch piece of
rod muslin attached to the top.
NCD Sections TWO and ONE will form part of Group O-1
and O-2, respectively, of Force 'O' and will function under
the commanders of those assault groups.
2. This Group will: (1) Clear and mark sixteen gaps, fifty yards
wide, through the seaward band. of obstacles on the OMAHA Beaches;
two on FOX GREEN, six on EASY RED, two on EASY GREEN, two on
DOG RED, two on DOG WHITE and two on DOG GREEN.
(2) Widen the gaps in the seaward band of obstacles until
the entire band is cleared.
(3) Assist the special Army Engineer Demolition Group in
clearing gaps through other bands of obstacles and removing
all obstacles from the OMAHA Beaches.
3. (a) NCD Section No. ONE land as directed by Commander
Assault Group O-2, and clear eight gaps through the seaward
band of obstacles on Beaches DOG GREEN, DOG WHITE, DOG RED,
and EASY GREEN in accordance with the table set forth
below.
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I - Assault Units
__________________________________________________________________
Serial No. of Gap
& Coordinates Beach Team Craft No. NCDU
(Eastings only) No. (LCM) No.
__________________________________________________________________
1. (6522 - 6526) DOG GREEN 1 1 11
2. (6545 - 6549) DOG GREEN 2 2 24
3. (6568 - 6572) DOG WHITE 3 3 27
4. (6588 - 6592) DOG WHITE 4 4 41
5. (6615 - 6619) DOG RED 5 5 42
6. (6635 - 6639) DOG RED 6 6 43
7. (6655 - 6659) EASY GREEN 7 7 140
8. (6675 - 6679) EASY GREEN 8 8 137
II - Support Units
DOG GREEN A 17 133
DOG WHITE B 18 130
DOG RED C 19 Army
EASY GREEN D 20 128
III - Reserve Craft
DOG GREEN 28
DOG WHITE 29
DOG RED 30
EASY GREEN 31
__________________________________________________________________
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I - Assault Units
__________________________________________________________________
Serial No. of Gap
& Coordinates Beach Team Craft No. NCDU
(Easting only) No. (LCM) No.
__________________________________________________________________
9. (6740 - 6743) EASY RED 9 9 44
10. (6760 - 6764) EASY RED 10 10 45
11. (6790 - 6794) EASY RED 11 11 46
12. (6811 - 6815) EASY RED 12 12 22
13. (6830 - 6835) EASY RED 13 13 23
14. (6851 - 6856) EASY RED 14 14 141
15. (6872 - 6876) FOX GREEN 15 15 138
16. (6893 - 6898) FOX GREEN 16 16 142
II - Support Units
EASY RED E 21 Army
EASY RED F 22 131
EASY RED G 23 Army
FOX GREEN H 24 129
III - Reserve Craft
EASY RED 32
EASY RED 33
EASY RED 34
FOX GREEN 35
FOX GREEN 36
__________________________________________________________________
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DISTRIBUTION |
NCDG/A4-3 WESTERN NAVAL TASK FORCE
Serial: 001 ASSAULT FORCE "O"
(TASK FORCE ONE TWO FOUR)
TOP SECRET -- NEPTUNE NAVAL COMBAT DEMOLITION GROUP
PORTLAND DORSET
OPERATION ORDER 31 May 1944: 1200
No. 1-44
ANNEX A
MOVEMENT, APPROACH, DEPLOYMENT, & LANDING PLAN
TASK ORGANIZATION
(a) Assault and Command Craft - Lt(jg) Orr, USNR. (LCM 27).
LCMs 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 19 LCMs
16, 25, 26, 27.
(b) Support Craft - Ens. Williams, USNR. (LCM 17).
LCMs 17, 18, 19, 20, 21, 22, 23, 24. 8 LCMs
(c) Reserve Craft - Ens. Edelfelt, USNR. (LCM 30).
LCMs 28, 29, 30, 31, 32, 33, 34, 35, 36. 9 LCMs
1. (a) This plan provides for orderly departure of the LCMs of the
Naval Combat Demolition Group from assembly ports, for their
movement to the Assault Area; their approach, deployment, and landing,
and for replacement of LCMs which become casualties during the
movement.
(b) Detailed information concerning the convoy in which the LCMs
proceed, is to be found in Annex C to Commander Assault Force 'O'
Operation Order No. BB-44.
(c) Appendix 3 to this Annex shows the location of the Transport
Area and the vessels therein relative to the landing beaches and
the courses and destinations thereto.
2. LCMs proceed in Convoy Group TWO, arriving off the OMAHA
Beaches in time to perform the tasks assigned in the Operation
Order and in the Field Order of Army Engineer Demolition Group
3. (a) Assault and Command Craft - LCMs 1 - 16, and 25 - 27 inclusive,
proceed from PORTLAND or POOLE as appropriate to the Assault Area
in tow of LCT(A)s and LCT(HE)s in Convoy Group TWO as set forth in
Appendix 1 to this Annex.
When towing craft lie to about 1,000 yards inshore from Point KING
LCMs go alongside the LCTs and embark Demolition teams.
Then Demolition Teams are loaded, LCM's of each section assemble on
the section commander and proceed to line of departure via the
route prescribed by the Commanders, Assault Groups O-1 and O-2
respectively. Upon arrival at the line of departure, deploy as
indicated in Appendix 2 to this Annex. Leave line of departure
when despatched by control vessels, about H - 10 minutes, and land
on assigned beaches at H + 3 minutes. After arrival at the line of
departure, LCMs 25 and 26 proceed as directed by NCD Section
commanders.
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ENCLOSURE ( 7 )
Operation Order - Force 'U'.
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| Source: Task Force One Two Two Report, Serial 844 of 19 July 1944, US Navy World War II Action Reports, Modern Military Branch, National Archives and Records Administration, College Park, MD 20749-6001 |