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.

PLAN FOR INCHON ASSAULT
Call to Arms——Marine reservists fall in near railway station in Seattle for departure to Camp Pendleton (U. S. Navy Photo).
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).
Sunrise at Inchon——as seen from the USS Mount McKinley (U. S. Army Photo).
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).
Action on Wolmi-do——Above, Marine using flame thrower on enemy cave; and, below, assault troops mopping up on the island (Marine Corps Photos).
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).
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).
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).
Bombardment of Inchon——Above, railway station in flames (U. S. Army Photo); and, below, burning factory buildings (U. S. Navy Photo).
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).
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).
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).
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).
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).
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).
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.