The Planning Phase
_Working Around the Clock--X Corps Scheme of Maneuver--Intelligence
Planning for Inchon--The Landing Force Plan--Naval Gunfire and
Rockets--Plans for Air Support_
The champion globe-trotters of the 1st Marine Division were the men of
the 3d Battalion, 7th Marines. Before returning to their homes from
Korea, these military tourists would have traveled entirely around the
world by various forms of land, water, and air transportation.
The unit was originally an element of the 6th Marines, FMFLant, serving
afloat with the Sixth Fleet in the Mediterranean. On 12 August 1950
the CP aboard the USS _Yellowstone_ at Suda Bay, Crete, received a
message from CNO ordering the battalion to the Far East. Lieutenant
Colonel Frederick R. Dowsett, deputy commander, noted that the dispatch
had bypassed such channels as CMC and the Sixth Fleet.[81] This
irregularity, he learned later, was explained by the urgency of an
order which had been framed by Admiral Sherman while General Cates was
present. It directed that the APA _Bexar_ arrive on 14 August at Suda
Bay and depart two days later with the troops.
[81] The battalion commander, Colonel Reynolds H. Hayden, had
a deputy because of the administrative set-up within the
Sixth Fleet and did not accompany the unit to the Far
East.
The rub was that these Marines were dispersed on various ships all over
the Mediterranean.
Given the rush job of picking up the scattered elements of the
battalion was the USS _Leyte_, which was due to return to Norfolk for
refitting afterwards and thence to the Far East via the Panama Canal.
Not only did the carrier complete its assignment before the deadline,
but the _Bexar_ also arrived at Suda Bay on the evening of the 14th.
Both ships had hardly dropped anchor when the LCVPs and LCMs were
shuttling troops and cargo to the transport and the AKA _Montague_,
which was to accompany it to the Far East.[82]
[82] This description is based upon: Col F. R. Dowsett
interv, 2 Nov 54.
On the 16th the two vessels departed according to schedule by way
of Port Said and the Suez Canal. Security regulations were rigidly
enforced, with only one stop being made when the vessels anchored at
Ceylon for six hours to take on fuel. Marine officers were figuratively
as well as literally at sea, since they had no idea of the specific
mission awaiting the battalion in the Far East. Unaware of plans for
the Inchon landing, they envisioned the troops being employed as the
ship-based raiding party of some American task force.
Meanwhile their future teammates of the 7th Marines were preparing to
embark from San Diego. Colonel Litzenberg and his officers had made
a good start at Camp Pendleton even before the activation date of 17
August 1950. In order to build up from cadres of former 6th Marines’
troops, this regiment received the largest proportion of combat-ready
reservists of any major unit in the 1st Marine Division--about 50
per cent, counting the augmentation personnel to bring 3/6 up to war
strength when it would be taken into the outfit in Japan.[83]
[83] Giusti, II-5.
CNO had set 3 September as the date of embarkation. But Headquarters,
FMFPac, prepared the embarkation plans while the regimental staff
solved problems of organization and equipment so effectively that
the 7th Marines sailed on the 1st, thus beating the deadline by two
days.[84]
[84] PacFlt _Interim Rpt No. 1_, XV: Zebra, 15.
Orders came to El Toro on 16 August for the overseas movement of
the remaining elements of the 1st MAW. Units affected were Wing
Headquarters Squadron 1 and MAG-12, comprising Headquarters Squadron
12, Service Squadron 12, VMF-312, VMF-212, VMF(N)-542, and the rear
echelon of VMF(N)-513.
VMF-312 and the rear echelon of VMF(N)-513 were loaded on the USS
_Sitkoh Bay_ with their aircraft and sailed on 24 August. Three days
later VMF-212 and VMF(N)-542 embarked on the USS _Cape Esperance_, and
the USNS _General Morton_ weighed anchor with the remaining components
on 1 September.[85] This completed the overseas movement of the 1st
MAW, since General Harris and his staff had departed from El Toro by
air for Japan the day before.
[85] _Ibid._, XV: Charlie Charlie, 4.
_Working Around the Clock_
The first echelon of the 1st Marine Division planning group had its
preliminary briefing on 19 August, and the tractor elements of the
Attack Force were scheduled to sail for the objective area on 9
September. This left an interval of 20 days for most of the Inchon
planning--probably the shortest period ever allotted to a major
amphibious assault.
Less than one-fourth of the officers and men of the 1st Marine Division
staff were on the _Mount McKinley_ when planning commenced. At that
time the distribution of the staff was as follows:
---------------------------+--------+----------+--------+------
|With the|Aboard |En route|
|1st Prov|USS _Mount|by sea |Total
|Mar Brig|McKinley_ |to Japan|
|in Korea|in Tokyo | |
---------------------------+--------+----------+--------+------
| | | |
Div Cdr Section | | 2 | | 2
Asst Div Cdr Section | 2 | | | 2
Chief of Staff Section | 2 | 1 | 1 | 4
General Staff Section: | | | |
G-1 | 2 | 2 | 1 | 5
G-2 | 2 | 2 | 7 | 11
G-3 | 2 | 2 | 1 | 5
G-4 | 2 | 2 | 2 | 6
Special Staff Section: | | | |
Adjutant | | 4 | 7 | 11
Air & Air Observers | 2 | 1 | 2 | 5
Amph Trac | [a]1 | [a]1 | | 2
Anti-Tank | [b]1 | | 1 | 1
Armored Amtracs | | | [a]1 | 1
Artillery | [a]1 | [a]1 | [a]1 | 3
Chaplains | [b]1 | | 1 | 1
Chem War & Radiol Def | | | 1 | 1
Dental | [b]1 | | 1 | 1
Embarkation | [b]1 | 2 | 1 | 3
Engineer | | [a]1 | |
Food Director | | | 1 | 1
Hq Comdr | [a]1 | | [a]2 | 3
Inspector | | | 2 | 2
Legal | [b]1 | | 1 | 1
Liaison | 3 | | | 3
Medical | 2 | | 1 | 3
Mtr Trans | 1 | 1 | | 2
Nav Gunfire | | 1 | | 1
Ordnance | [b]1 | 1 | | 1
Post Ex | | | [a]1 | 1
Pub Info | [b]1 | | 1 | 1
Prov Marshal | | | [a]1 | 1
Shore Party | | [a]1 | | 1
Signal | 6 | 2 | | 8
Spec Serv | [b]1 | | 3 | 3
Sup & Disb | [b]2 | | 9 | 9
Tank | [b]1 | | [a]1 | 1
+--------+----------+--------+------
Total | 33 | 23 | 51 | 107
---------------------------+--------+----------+--------+------
[a] Carried in other Brigade, Division, or Force units.
[b] Additional duty basis; not counted in total.[86]
[86] O. P. Smith, _Notes_, 54–55.
The Marine planners aboard the _Mount McKinley_ were short on elbow
room as well as personnel, time, and equipment. Although it was an
advantage to have the planning groups of the Attack Force and Landing
Force together, the ship did not provide enough space for both without
crowding. Moreover, the already undermanned Marine contingent had to
be further reduced late in August by sending several officers to Kobe
to meet incoming units. Thus the G-2 section, to cite one example,
consisted of only two officers, one of whom was detached on this duty
for a week.
“The issuance of and adherence to a planning schedule was utterly
impossible,” commented the 1st Marine Division report. “Only by a
virtual ‘around the clock’ working day, concurrent ... planning by
Attack Force (ComPhibGru One) and Landing Force (1st MarDiv), willing
teamwork by both, and especially the amphibious ‘know-how’ of key staff
members gained by long experience, was it possible to complete and
issue ... plans and orders for a most difficult ... landing operation.
The time-space factor denied any coordinated orientation, prohibited
even the most elementary rehearsal, made it difficult to distribute
orders, and gave subordinate units very little time for formulation and
distribution of their plans.”[87]
[87] 1st MarDiv _SAR_, basic rpt.
Command relationships during the embarkation and assault phases were as
follows:
+------+
+-----------+CinCFE+-------------+
| +------+ |
+---+----+ +----+-----+
+----+ComNavFe+--------+ |CG X Corps|
| +--------+ | +----------+
| |
+------+-------+ +------+------+
|ComPhibGru One| |CG 1st MarDiv|
+--------------+ +-------------+
All the top commanders were concentrated in Tokyo with the arrival
of Admiral Struble on 25 August. This facilitated the planning and
allowed important decisions to be worked out in conferences between the
principal commanders.[88]
[88] Struble ltr, 25 Apr 55.
Planning was based mainly on studies made by ComPhibGru One as
prospective Attack Force Commander. It was conducted entirely on a
concurrent basis by the Attack Force and Landing Force groups aboard
the _Mount McKinley_. No step was taken by either without the full
knowledge and consent of the other.
_X Corps Scheme of Maneuver_
Army planning had been initiated by the Joint Strategic Plans and
Operations Group until 16 August, when the “Special Planning Staff”
was set up at GHQ to issue directives for Operation Plan CHROMITE.
Published on 12 August as CinCFE Operation Plan No. 100-B, it was based
on these assumptions:
(a) that the North Korean ground advance would be stopped in time to
permit the build-up of our forces in South Korea;
(b) that our forces in South Korea would be built up to the
capability of mounting effective offensive operations against
NKPA forces opposing them;
(c) that we retain air and naval supremacy in the area of operation;
(d) that the NKPA ground forces would not receive major
reinforcements from the USSR or Red China;
(e) that there would be no major change in the basic disposition of
the NKPA forces.[89]
[89] MarCorps Board _Study_, v. II-B, 13–17.
It was understood from the beginning that the Special Plans Staff,
headed by General Ruffner, would be the nucleus of the future X
Corps staff. In order to have the benefit of specialized amphibious
knowledge, ten Marine and two Navy officers of TTU Mobile Training Team
Able were assigned on 19 August:
Col H. A. Forney Deputy Chief of Staff
LtCol J. Tabor Asst Coordinator, FSCC
LtCol C. E. Warren Asst G-4
Maj J. N. McLaughlin Asst G-3
Maj J. F. Warner Asst G-3
Maj C. P. Weiland Air Officer, FSCC
Maj V. H. Vogel Asst G-4
Capt H. S. Coppedge Asst G-2
Capt T. A. Manion Asst Signal Officer, FSCC
Capt V. J. Robinson Target Info Officer
Lt L. N. Lay, USN Asst Surgeon
Lt W. A. Sheltren, USN Asst NGF Officer, FSCC[90]
[90] MarCorps Board _Study_, v. II, app. 67.
These officers did not begin their new assignment in time to contribute
to the preliminary X Corps over-all scheme of maneuver. The main
provisions, as communicated to General Smith at General Ruffner’s
briefing conference of 23 August, were as follows:
(1) The 1st Marine Division, as the landing force, was to seize
the urban area of Inchon (line A-A); to capture a beachhead
(line B-B); to advance as rapidly as possible and seize Kimpo
Airfield (line C-C); to clear out the south bank of the Han
River (line D-D); to cross the river, seize Seoul and secure
the commanding ground to the north (E-E); and, finally, to
fortify and occupy this line with reduced forces until relieved
(apparently by the 3d Infantry Division, still in the United
States), whereupon the Division was to recross the Han and
seize a line (F-F) about 25 miles southeast of Seoul.
(2) The 7th Infantry Division was to land behind the Marines
and advance on their right flank to seize the commanding ground
south of Seoul and the south bank of the river (line D-D); to
continue the advance to phase line (E-E); and to conduct a
reconnaissance in force to the south (line F-F). There, on the
line from Suwon to Kyongan-ni, the 7th Infantry Division and
1st Marine Division would form the strategic anvil as Eighth
Army forces advanced from the Pusan Perimeter in the role of
hammer.
(3) The 1st Marine Aircraft Wing was to furnish air support,
air direction, and air warning for the Corps with units
operating from Kimpo Airfield. It was also to be prepared to
operate a control center ashore on order.[91]
[91] _Ibid._, v. I, III-B-8, and v. II, app. 16; O. P. Smith,
_Notes_, 48–49.
The Special Plans Staff gave General Smith a study explaining the
purposes of these maneuvers. “The B-B line in this study appeared
to be a suitable beachhead line,” he commented, “and we decided to
concentrate our efforts on plans for its seizure. Subsequent operations
would be reserved for later consideration.”[92]
[92] O. P. Smith, _Notes_, 50.
_Intelligence Planning for Inchon_
Good planning, of course, depended on accurate intelligence. All
possible information about the objective area had been gathered by the
staff of PhibGru One before the arrival of the 1st Marine Division
planners. Air Force planes had taken hundreds of photographs at every
stage of the tide. Hydrographic reports and navigation charts had been
studied. Army and Navy men familiar with Inchon during the American
occupation after World War II were interrogated as well as NKPA
prisoners captured by the Eighth Army.
Although a great deal of useful data was compiled, some disturbing
questions remained. How high were the sea walls of Inchon? Were the
mud flats suitable for landing either troops or vehicles at low tide?
Approximately how many NKPA guns were hidden on Wolmi-do?... These were
some of the intelligence gaps which must be filled before an effective
plan could be drawn up for an assault landing.
PhibGru One made its material available to the G-2 Section of the
1st Marine Division, and the two staffs worked together on the
_Mount McKinley_ in close cooperation. Attached were the 163d
Military Intelligence Service Detachment (MISD) and the 441st Counter
Intelligence Corps (CIC) Team. Both of these units had been furnished
by FECOM and consisted of Army commissioned and enlisted personnel
as well as native Koreans serving in liaison, interpretation, and
translation capacities.
Even when a question could not be answered conclusively, it was up
to the G-2 sections of the Attack Force and Landing Force to arrive
at a conclusion for planning purposes. For instance, it was never
satisfactorily determined from available sources--JANIS publications,
strategic engineering studies, Naval Attaché reports, and photographic
interpretation reports--whether LVTs would be able to traverse the mud
flats of the Inchon harbor area. And since there remained some doubt,
planning proceeded on the assumption that the answer was negative.
This proved to be the correct as well as the prudent decision, later
developments revealed.
Another G-2 planning problem concerned the effect that the height
of the sea walls would have upon the landing. Photographs at hourly
stages of the tide made it appear that the masonry was too high for
the dropping of ramps at any time. As a solution, G-2 officers hit
upon a device reminiscent of the storming of castles during the Middle
Ages. Scaling ladders were recommended with the suggestion that they be
built of aluminum with hooks at one end to be attached to the masonry.
Construction was started at Kobe, but the order could be only partially
filled before D-day, and wooden ladders were built as substitutes.
It is hardly necessary to point out the importance of estimates as
to the numbers and defensive capabilities of the enemy. Yet the G-2
sections on the _Mount McKinley_ were up against a peculiar situation
cited in the 1st Marine Division report:
“Our accumulated knowledge of the enemy’s military tactics, prior
to our landing at Inchon on 15 September 1950, consisted almost in
its entirety of knowledge about the enemy’s offense.... With but
few exceptions, UN forces were forced to take a defensive stand and
denied the opportunity to study large scale enemy defensive tactics
from actual combat. Thus it was that our assault landing was made
with relatively little prior knowledge regarding the enemy’s probable
reaction to a large-scale offensive of this nature, particularly when
it involved the penetration into the very heart of his newly acquired
domain.”[93]
[93] This account of G-2 planning for Inchon is based upon
1st MarDiv _SAR_, Annex Baker.
Photographic coverage showed the Inchon harbor area to be honeycombed
with gun positions and other defensive installations. On the other
hand, daily aerial observation indicated that most of them were not
occupied.
G-2 conclusions during the planning phase often had to be based
on such conflicting evidence, even though the penalties of faulty
interpretation might be drastic. But after being viewed with due
suspicion, signs of negative enemy activity were finally accepted as
valid in estimates of light to moderate NKPA resistance.
“Sadly lacking as was information on the objective area,” commented the
Division G-2 report, “more so was that on the enemy in the area.” Early
in September, however, the Attack Force and Landing Force concurred
in the initial X Corps estimate of 1,500 to 2,500 NKPA troops in the
immediate area, consisting largely of newly raised personnel.[94]
[94] See Appendix I for the Order of Battle of the units
which opposed the 1st Marine Division throughout the
Inchon-Seoul operation, listing them in chronological
order as to area of employment, strength, and
effectiveness.
Radio reports of first-hand observations in the objective area, though
coming too late for initial planning purposes, confirmed some of the
G-2 estimates. This dangerous mission was undertaken by Lieutenant
Eugene F. Clark, a naval officer on General MacArthur’s JSPOG staff.
U. S. and British Marines provided an escort on 1 September when the
British destroyer _Charity_ brought him from Sasebo to a point along
the coast where the South Korean patrol vessel PC 703 waited to land
him at Yonghung-do, an island about 15 miles southwest of Inchon.[95]
[95] This account is based upon: Capt James B. Soper interv,
16 Aug 54; and Karig, _Korea_, 176–191.
Clark went ashore with a small arsenal of firearms, grenades and
ammunition, as well as 30 cases of C rations and 200 pounds of rice.
He quickly made allies of the 400 friendly Korean inhabitants of the
island and organized his own private little “army” of about 150 youths
from 14 to 18 years old. These “troops” were posted about Yonghung-do
for security, since the near-by island, Taebu-do, was occupied by 400
NKPA soldiers within wading distance at low tide.
The naval officer had no illusions as to what his fate might be in
the event of capture. Day and night, he kept a grenade within reach,
since he did not intend to be taken alive. When the long expected
enemy attack from Taebu-do materialized, he commandeered a “one-lung”
South Korean motor sampan and fought it out with the NKPA motor sampan
escorting boats filled with soldiers. The enemy began the strange
“naval” battle with a few badly aimed rounds from a 37mm tank gun.
Clark and his crew of three friendly Koreans finished it with a long
burst from a .50 caliber machine gun. After sinking the NKPA motor
sampan, he destroyed another boat with 18 soldiers aboard and captured
three prisoners for questioning.
One night the intrepid lieutenant rowed a dinghy to the Inchon sea
wall. When the tide went out, he tested the mire by wading in it up
to his waist. This experience led to the sending of a radio report,
“Inchon not suitable for landing either troops or vehicles across the
mud.”
Korean youths, posing as fishermen, brought intelligence which Clark
included in his daily radio messages. One of these spies made an effort
to count the guns on Wolmi-do and describe the locations. Others took
measurements of the Inchon sea wall and penetrated as far inland as
Seoul to report numbers and positions of NKPA troops.
Clark declined all offers to evacuate him. As the climax of his
exploit, he managed to restore the usefulness of the lighthouse on
Palmi Island which the enemy had put out of commission. This structure,
the former entrance beacon for Inchon by way of Flying Fish channel,
served him as a refuge when he had to leave Yonghung-do hurriedly just
ahead of NKPA troops who landed in force and butchered 50 civilians of
both sexes. Clark, who received a Silver Star, stuck it out on Palmi
until midnight of 14 September, when he turned on the beacon light to
guide the amphibious task force.
_The Landing Force Plan_
The decisions behind the Landing Force Plan--1st Marine Division OpnO
2-50--obviously had to be made without benefit of Lieutenant Clark’s
reports, since the publication date was 4 September 1950.[96] It is to
the credit of these conclusions, therefore, that so few of them had to
be corrected in the light of first-hand evidence from the objective
area.
[96] See Appendix G for a chronological list of all 1st
Marine Division operation orders during the Inchon-Seoul
operation.
Although CG X Corps was the assigned Expeditionary Troops Commander,
planning on the Corps level was concerned almost entirely with the
exploitation phase following the seizure of the beachhead. All Landing
Force planning was done on the _Mount McKinley_ by the Division in
close coordination with PhibGru One.
The first consideration, as viewed by the Navy planners, was that
the tides, currents, and tortuous channels of Inchon made necessary
a four-hour daylight approach to the transport area. This meant that
1130, at low tide, was the earliest hour of arrival; and not until
about 1700 would the next high tide provide enough water for an assault
landing.
On 15 September a maximum high tide of 31 feet could be expected at
1919. Evening twilight came at 1909. It was estimated initially that
23 feet of water would take the LCVPs and LVTs over the mud flats, but
that 29 feet were necessary for the beaching of the LSTs.
In view of these conditions, PhibGru One planners concluded that 1700
was the best time for landing the LCVPs and LVTs, and it was decided
to beach the LSTs at about 1900. Simultaneous landings of troops on
Wolmi-do and the mainland were contemplated.
This was the point of departure for Division planners. They maintained
that Wolmi-do was the key terrain feature, and that it should be
secured first in a separate landing. The logical course, according to
the Marines, would be to utilize the morning high tide for the seizure
of this island commanding the waterfront. The enemy would be given the
whole day in which to prepare for the attack on the mainland; but the
Landing Force could also utilize this period for cleaning up Wolmi-do
and moving in supporting artillery.
It was typical of the harmony prevailing between the two planning
groups on the _Mount McKinley_ that PhibGru One immediately accepted
the concept of a double-barreled attack. The rub was that a night
approach would be necessary to assault Wolmi-do at 0600 on the morning
high tide, and the Navy doubted the feasibility of a movement of the
slow-moving and unmaneuverable APAs, AKAs, and LSTs through winding,
mud-lined channels in the darkness.
At length a compromise was reached with the decision to employ DD, APD,
and LSD types primarily, which were more maneuverable in addition to
being equipped with radar navigational instruments.[97]
[97] This summary of Landing Force planning is based upon:
1st MarDiv _SAR_, basic rpt; MarCorps Board _Study_,
v. I, II-B, 13–16; O. P. Smith, _Notes_, 58–62; PacFlt
_Interim Rpt No. 1_, XV: Able Able, 6–7.
The morning landing on Wolmi-do was to be made with a single battalion
of the 5th Marines, to be designated by the Brigade. On the mainland
the remaining two battalions would land with the evening high tide on
RED Beach, just north of the causeway connecting the island with the
city, while two battalions of the 11th Marines landed in support on
Wolmi-do. Meanwhile the 1st Marines was to hit BLUE Beach, southeast
of the urban area. And after driving rapidly inland to consolidate
their positions before nightfall, the two Marine regiments were to
make a junction in the morning and seize the beachhead while the 17th
ROK Regiment (later replaced by 1st KMC Regiment) mopped up the city
streets.
Marine G-4 planners suggested one of the most daring of all the
calculated risks. This was the decision to use LCVPs for the RED Beach
landings because their comparative speed would clear the landing area
for the beaching of eight LSTs--all that could be crammed into the
narrow confines of this strip of urban waterfront. Each was to be
loaded with ammunition, rations, water, and fuel. Obviously these Navy
workhorses, nicknamed “large slow targets”, would be easy marks for
NKPA shore guns, but this was a chance that had to be taken if the
assault troops were to be adequately supplied.
There was not time, of course, to unload and retract the ships during
the period of evening high tide. They must be unloaded during the night
and taken out on the morning tide.
Since it was not considered feasible to land LSTs on BLUE Beach, that
area would not be developed beyond the needs of the immediate assault.
For this purpose, 16 preloaded LVTs were to be used as floating dumps
until the 1st Marines could link up with the other regiment.
These were the essentials of the Landing Force plan. H-hour was
ultimately determined from a study of late photographs which brought
about a slight change in estimates. Since a tide of 25 feet (two feet
higher than the initial estimate) appeared to be necessary for the
LCVPs and LVTs to reach the sea wall, H-hour was set at 1730 instead of
1700. The completed Landing Force plan provided for these steps:
(1) BLT-3 of RCT-5 to land on Beach GREEN at L-hour on D-day
and seize Wolmi-do.
(2) RCT-5 (-- BLT-3) to land on Beach RED at H-hour, seize
Objective O-A, effect a juncture with RCT-1, and prepare for
further operations to the east in coordination with RCT-1 to
seize the FBHL.
(3) RCT-1, to land on Beach BLUE, with two battalions in
assault, seize Objective O-1, and prepare for further
operations to the east in coordination with RCT-5 to seize the
FBHL.
(4) 11th Marines (-- 3d Bn) (96th F. A. Bn, USA, attached) to
land 1st and 2d Bns on Beach GREEN at H-hour, occupy positions
on Wolmi-do and support seizure of the beachhead with priority
of fires to RCT-1. Remainder of artillery to land on call.
(5) ROK Marines, initially in Division reserve, to land over
Beach RED on call and conduct operations to occupy the city of
Inchon in coordination with RCT-5.
(6) 1st Tank Bn (--) (Reinf.) to be prepared to land on order
one company in LSU on Beach GREEN, remainder of battalion on
order on beaches to be designated.
(7) 1st Engr Bn (--) to land on Beach RED or in harbor on
order, assume control of detached companies on order, and
support seizure of beachhead as directed. Priority to opening
and maintaining MSR along southern edge of the city to RCT-1
zone of action.
(8) 1st Shore Party Bn (--) to land on order on Beach RED or in
harbor and assume control of shore party activities on Beaches
RED and GREEN.
(9) 1st Amph Trac Bn to transport and land elements of RCT-1 on
Beach BLUE and continue support of RCT-1 until released.
(10) 2d Engr Spl Brig, USA (Reinf.) to furnish ships platoons
and augment Division shore party as requested. After landing
and when directed, to assume operational control of Division
shore party and responsibility for control of all port
operations. To provide logistical support of 1st MarDiv.
_Availability of Brigade Troops_
The old recipe for rabbit stew began, “First, catch your rabbit.” And
while the Landing Force plan was being formulated, General Smith had no
assurance for a few days that he could count on having the whole of his
landing force available.
General Almond informed the Marine general on 23 August that the
release of the 1st Provisional Marine Brigade for participation in
the Inchon landing would depend on the military situation. He seemed
doubtful and added that the withdrawal of the Marines would be bad for
Eighth Army morale.
The Attack Force and Landing Force began their planning, however,
on the basis of Brigade availability. It had been the intention of
CinCFE to employ a full Marine division, but an embarkation date of 1
September would not permit the 7th Marines to arrive in time. This left
the 1st Marines as the only RCT of the Landing Force unless the 5th
Marines and other Brigade units could be released.
On 30 August, Smith brought up the issue again in a dispatch to X
Corps, whereupon CinCFE issued an order making the Brigade troops
available to the Division on 4 September.
This might have settled the issue if the enemy had not launched an
all-out offensive on 1 September to smash through the Pusan Perimeter.
Although the Brigade had already sent heavy equipment to Pusan for
embarkation, the Marines were rushed up to the front on 2 September as
a mobile reserve. That same day the order for their release was revoked.
There could be no doubt about the gravity of the military situation.
Thirteen NKPA divisions were making a final effort, and the Marines
were needed in the Naktong Bulge sector, where the Korean Reds were
attempting to cut the Pusan-Taegu lifeline.
On the other hand, time was also running out for the Inchon planners.
Colonel Forney, the new deputy chief of staff for X Corps, informed
Smith on 2 September that Almond planned to use the 32d Infantry of the
7th Infantry Division if the 7th Marines could not arrive in time for
the Inchon landing. Recently, the cadres of this Army division had been
brought up to strength with 8,000 South Koreans. The remaining 12,000
U. S. troops had received no adequate amphibious training, though
instructors from Training Team Able had made a start with some of the
units.
This turn of affairs resulted in a meeting in General Almond’s office.
The Navy was represented by Admirals Joy, Struble, and Doyle; the Army
by Generals Almond, Ruffner, and Wright; and the Marines by General
Smith.
Wright opened the discussion by stating that Walker needed the
Brigade troops urgently as a mobile reserve to hold the line in the
current NKPA offensive. Almond conceded that the question of Brigade
availability must be decided on a basis of Eighth Army requirements and
tactical considerations. But if the 5th Marines could not be released,
he reiterated his decision to substitute the 32d Infantry for the
Inchon operation.
Admiral Joy declared that the success of the Inchon assault depended
on the employment of Marines trained in amphibious techniques; and
he called upon Smith for his opinion. The Marine general said that
a hastily instructed unit could not be expected to take the place
of a combat-experienced regiment in the Landing Force, and that
last-minute substitutions of this sort could not be made in complicated
ship-to-shore landings without courting trouble. He added that it would
be necessary in such an event to land in column on one beach instead
of two, with the 1st Marines in advance of the 32d Infantry. These
comments had the support of Doyle, who agreed that the availability of
the 5th Marines might mean the difference between success and failure
at Inchon.
At this point Admiral Struble commented that the issue boiled down to
the need for a mobile Eighth Army reserve. He suggested as a compromise
that a regiment of the 7th Infantry Division be embarked and moved
to Pusan as a floating reserve to be landed in an emergency as a
substitute for the 5th Marines. This solution was accepted. Almond
called up Eighth Army Headquarters immediately, and within an hour
Wright telephoned to inform Smith that the Brigade would be relieved at
midnight on 5 September.[98]
[98] O. P. Smith, _Notes_, 74–80. _Chronicle_, 31 Aug-3 Sep
50; Forney _Special Rpt_, II, 4.
As it turned out, the 17th Infantry of the 7th Infantry Division was
embarked and transferred to Pusan to substitute for the 5th Marines,
with Marine officers of Training Team Able assisting in the outloading.
After the amphibious assault, the regiment landed administratively at
Inchon to rejoin its parent unit.
_Naval Gunfire and Rockets_
At a conference on 1 September called by Admiral Struble and attended
by Admirals Richard W. Ruble, John M. Higgins, and Sir William G.
Andrewes (RN)[99] in addition to Generals Ruffner and Smith, it was
tentatively agreed that the cruisers would begin the bombardment on the
morning of D-minus 1, and the destroyers that afternoon after a napalm
air strike had been conducted against Wolmi-do on D-minus 4.
[99] See Appendix E for Naval Task Organization giving
components, ships, and commanders of JTF-7.
At another naval gunfire conference two days later, the napalm strike
was delayed until D-minus 3. On 8 September, when Admiral Struble held
his final meeting, PhibGru One and the 1st Marine Division agreed
on the scope and timing of naval gunfire support. It was decided,
therefore, that the bombardment would commence on D-minus 2 and be
repeated if necessary on D-minus 1.[100]
[100] O. P. Smith, _Notes_, 72–74.
During the following week, plans were worked out in detail. The
beachhead was divided into 52 target areas, including two on Wolmi-do
and one on Sowolmi-do. In the channel to the west and southwest of
the port, imaginary lines marked off three fire support areas for the
ships, numbered in order from south to north.
[Illustration: PLAN FOR INCHON ASSAULT]
[Illustration: _Call to Arms----Marine reservists fall in near railway
station in Seattle for departure to Camp Pendleton (U. S. Navy
Photo)._]
[Illustration: _The Invasion Fleet----Above, Marines board troopship in
Japan for voyage to objective; and, below, Marines eating breakfast on
transport at 3:30 on the morning of D-Day (Marine Corps Photos)._]
[Illustration: _Sunrise at Inchon----as seen from the USS Mount
McKinley_ (_U. S. Army Photo_).]
[Illustration: _Smiles of Victory----General MacArthur shows his
approval of the Wolmi-do Landing; behind him (left to right) are Vice
Admiral Struble, Brigadier General Wright, and Major General Almond
(U. S. Navy Photo)._]
[Illustration: _Action on Wolmi-do----Above, Marine using flame thrower
on enemy cave; and, below, assault troops mopping up on the island
(Marine Corps Photos)._]
[Illustration: _H-Hour----Above, the first wave of LCVPs heads for the
beaches at Inchon; and, below, grounded LSTs bring supplies to captured
Wolmi-do (U. S. Navy Photos)._]
[Illustration: _Hitting the Beaches----Above, Marines in landing craft
on way to BLUE Beach with scaling ladders; and, below, assault troops
using ladders to climb seawall at RED Beach (Marine Corps Photos)._]
[Illustration: _Ashore at Inchon----Above, an LST brings supplies to
RED Beach on heels of assault troops (Marine Corps Photo); and, below,
Marines hoisting tank over seawall, with LST 802 in background (U. S.
Navy Photo)._]
[Illustration: _Bombardment of Inchon----Above, railway station in
flames (U. S. Army Photo); and, below, burning factory buildings (U. S.
Navy Photo)._]
[Illustration: _Inchon Secured----Above, enemy gun emplacement (U. S.
Navy Photo); and, below, troops of 5th Marines advancing in streets of
Inchon (U. S. Army Photo)._]
[Illustration: _Advance to Force Beachhead Line----Above, assault
troops of 1st Marines move up in DUKWs; and, below, Marine tanks and
amtracs northeast of Inchon (U. S. Army Photos)._]
[Illustration: _Upper Command Level----Above, Generals Almond (left)
and Shepherd go ashore in launch of USS_ Mount McKinley; _and, below,
General Smith and Admiral Doyle confer on the USS_ Rochester (_U. S.
Navy Photos_).]
[Illustration: _Inchon Harbor Scenes----Above, a VMO-6 helicopter gives
a lift to a Marine officer on LCP; and, below, LST 1123 stranded at low
tide (U. S. Navy Photos)._]
[Illustration: _Interludes----Above, Hospitalman Philip A. Barome, USN,
shares his “C” rations with a Korean youngster (U. S. Navy Photo);
and, below, Private G. W. Febrey and Corporal Charles E. Burris of 1st
Marine Division, fill can at captured Yongdungpo brewery (U. S. Army
Photo)._]
[Illustration: _D-Plus 2----Above, Marine tank-infantry team searches
houses in Korean village (Marine Corps Photo); and, below, stripped
NKPA prisoners are marched past killed enemy tank (U. S. Army Photo)._]
[Illustration: _RED Beach----LSTs unloading and Marine trucks taking
supplies to advancing troops on D-plus 2 (U. S. Army Photo)._]
On D-day the four cruisers would stand in from 13,000 to 15,000 yards
offshore in Fire Support Area I, while the destroyers in FSAs II and
III manned stations 800 to 6,000 yards from the beach. The three LSMRs
would first support the Wolmi-do landing from close-in positions to
the north and west of the island. Later, for H-hour, one of the rocket
ships was to remain northward to soften up RED Beach, and the other two
would displace to the vicinity of BLUE Beach.[101]
[101] This summary of naval gunfire planning is derived from:
ComPhibGru One _OpnO_ 14-50, Annex George, app. II, III.
From L-minus 45 to L-minus 2, the cruisers and destroyers would dump
a total of 2,845 shells on Inchon and its outlying island, each ship
concentrating on specifically assigned target areas. From L-minus 15 to
L-minus 2, each of the three LSMRs would saturate Wolmi-do with 1,000
5-inch rockets. Most of the ships were to cease fire two minutes before
the landing on GREEN Beach, when Marine planes strafed possible enemy
positions for final shock effect. Four of the destroyers would continue
to pound Inchon targets with 55 shells during the short air attack.
Another intricate piece in the mosaic of destruction was the mission
assigned to one LSMR for the period immediately preceding and following
the landing of 3/5. The lone rocket ship would lumber parallel to
Wolmi-do’s shoreline, across the front of the advancing first wave, and
pour 40mm shells into the beach area. Clearing the route of approach
to GREEN Beach just in time for the landing craft to speed by, the
LSMR was to continue southward along the coast and direct its heavy
automatic fire at the slopes in advance of the attacking troops.
Once Wolmi-do was secured, the full fury of the support ships would
rain down on targets in the Inchon area. From H-minus 180 to H-minus
5, the cruisers and destroyers were scheduled to blast their assigned
targets with a total of 2,875 shells. Chiming in at H-minus 25 with
2,000 rockets apiece, the LSMRs would pulverize RED and BLUE Beaches
until five minutes before the landings by the two Marine regiments.
At that time, all ships must cease fire to clear the way for strafing
Corsairs and Navy Skyraiders.
The meticulous planning left nothing to chance, even with the
assumption that a foothold would be successfully established by
darkness. During the night of D-day, the cruisers would expend an
additional 250 shells on interdictory missions, and the destroyers
were authorized to fire a total of 300 5-inch rounds on call from the
infantry. To help thwart any possible enemy ambitions at dawn of D-plus
1, the cruisers would be prepared to unload 300 shells for interdiction
and call fires, while the destroyers stood poised with the same number
of high-explosive missiles plus 300 illuminating shells.
Other details of the elaborate plan dealt with the coordination of
naval gunfire, air, artillery, mortars, and rockets. At certain times,
for example, Marine and Navy gunners could fire only below a maximum
trajectory of 1100 feet, so that planes, whose minimum altitude was set
at 1500 feet, could pass safely over Inchon during strikes on adjacent
areas. During those periods when close support Corsairs were scheduled
to descend on beachhead targets, all other heavy weapons would fire
completely clear of broad circles defining strike areas for the air
missions.
More tables and instructions in the formidable appendixes of Admiral
Doyle’s operation order assigned shore fire control parties their ships
and radio frequencies, ships their battery missions and ammunition
allowances, and a host of other tasks and responsibilities.
_Air Support for Inchon_
Air support, of course, was closely related to naval gunfire planning.
After the arrival of CG 1st MAW and his staff at Tokyo on 3 September,
part of the group proceeded at once to Itami Air Force Base while
General Harris and selected staff members remained at Tokyo for
planning conferences.
Air support planning for Inchon was based on the decision that the sky
over the objective area was to be divided between the organic air units
of JTF-7 and X Corps.
JTF-7 counted on its fast carrier task force, TF-77, to gain air
supremacy and furnish deep support and interdiction strikes. Close
support for the landing was to be provided by the two squadrons of
TG-90.5, on board the CVEs _Sicily_ and _Badoeng Strait_, which had
been the main air components of MAG-33 in support of the 1st Marine
Provisional Brigade. In addition, the Attack Force commander could also
call upon the aircraft of TF-77 for close support.
Organic air support for X Corps was to be the mission of the Tactical
Air Control set up under the operational control of the corps
commander and the direct command of General Cushman. The inspiration
for this organization came from Marine officers on the staff of X
Corps. Their suggestions were accepted by General Almond, who used his
authority as FECOM chief of staff to put the idea into effect.
MAG-33 was designated by General Harris from the Forward Echelon, 1st
MAW, to serve as TAC X Corps, with VMFs 212 and 312 in addition to
VMF(N)-542 and the rear echelon of VMF(N)-513. These units were not to
be assigned, however, until X Corps assumed control of operations in
the objective area, whereupon they would be based at Kimpo Airfield.
Meanwhile, they remained under the administrative control of ComNavFE
and MAG-12, with headquarters at the Itami AFB in Japan. The two
Marine carrier-based squadrons and the forward echelon of VMF(N)-513,
having come out to Korea in August as units of MAG-33, continued to be
assigned temporarily to that group for administrative purposes.[102]
[102] 1st MAW _SAR_, basic rpt and Annex Able: PacFlt
_Interim Rpt No. 1_, XV: Charlie Charlie, 4–5.
TAC X Corps was activated on 8 September, just six days before its
components landed in Japan. 1st MAW planners designated the Air Support
Section of MTACS-2, which had controlled air support for the Brigade,
to continue in that capacity for the Landing Force and later for the
entire X Corps. Arrangements were made with the Combat Cargo Command,
FEAF, to airlift aviation fuel and ammunition from Japan to Kimpo
Airfield, after its capture, until such supplies could be transported
by sea.
Marine air units were also affected, of course, by the planning which
the 1st Marine Division air and naval gunfire representatives of the
Fire Support Coordination Center had already accomplished. Working
aboard the _Mount McKinley_ in conjunction with their opposite numbers
of PhibGru One, the FSCC group had been busy since its arrival in Japan
on 18 August. Planning was conducted with the CO 11th Marines after
the artillery regiment landed in Japan, and the resulting decisions
coordinated with air and naval gunfire plans.
The 1st MAW completed its planning on 9 September. General Cushman was
designated Tactical Air Commander, X Corps, on that date and departed
for the objective area the next day with the air elements scheduled to
proceed by ship.