The Marianas--SAIPAN

STRATEGY OF THE ASSAULT

By the late spring of 1944, our forces had established bases and airfields in the Marshalls, Admiralties, and north central New Guinea. These positions threatened enemy bases in the Carolines, eastern Netherlands East Indies, and the southern Philippines. Because of our attacks by land and carrier based aircraft, Japanese communications to the Carolines had become insecure, and the enemy air strength in that area was deteriorating. Severe losses had been inflicted on their shipping by our submarine, air, and surface forces. The enemy, however, was rapidly strengthening his position in the Marianas, In order to continue pressure on the Japanese, and to extend our control to the westward, further amphibious operations were planned. The Southern Marianas were selected as the objective. Because of the location of these islands, 1,000 miles to the west of our most advanced base at Eniwetok, with the route to them flanked on both sides by enemy land bases, their capture presented a difficult problem. June, 15, 1944 was designated as the day on which the initial landings on the island of Saipan would take place. Following this, landings were to be made on Guam on D plus 3 and on Tinian on D plus 20. Due to the strong resistance encountered on Saipan these subsequent attacks were considerably delayed.

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MARIANAS OPERATION

MARIANAS OPERATION

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THE GEOGRAPHY OF SAIPAN

The Marianas form part of an almost continuous chain of islands, extending 1,350 miles nearly due south from Tokyo. The Marianas group itself, composed of about 15 islands, covers a distance of about 450 miles from north to south. The northern islands, with the exception of Pagan, are of little military significance. In the south, the larger islands of Saipan, Tinian, Rota, and Guam were important bases in the inner line of the Japanese island defenses and communications. They are raised coral formations with volcanic cores; and are fringed with coral reefs, behind which cliffs, 50 to 500 feet high, frequently rise sharply to tablelands above, Saipan is approximately 12½ miles long with a maximum width of 5½ miles, and covers an area of about 72 square miles. Although mountainous in character, a considerable portion of the island is arable and was under sugar cane cultivation. In 1941 the civilian population was estimated to be between 30,000 and 35,000, the greatest part being Japanese, with the remainder mostly Chamorros, Koreans, and Kanaka natives. The one important harbor was Tanapag Harbor on the west coast, with reasonable facilities and able to accommodate 12 or more ships. Magicienne Bay, on the east coast, had little practical value due to its exposed position to the prevailing winds and the depth of water close to its shores. There were three airfields on Saipan. Of these Aslito Field (since renamed Isely Field) in the south, was the largest and most important with many hangars and. repair facilities. There were two other strips, one near Charan-Kanoa, a small sugar mill town on the west coast, and the other in the north near Marpi Point. A seaplane base was located in Tanapag Harbor. Saipan has about 40 miles of coast line, the north, east, and south coasts being dominated by steep, rocky cliffs, with only occasional breaks and stretches of short sandy beaches. Few, if any, suitable landing beaches exist on these coasts. Along the western side of the island, there are sandy beaches for most of the island's length, behind which the slopes are gentle for a distance of 500 to 5,000 yards. A barrier reef lies along all the western coast, extending a distance of 3 miles in the center and forming the northern and western sides of Tanapag Harbor. Elsewhere the reef is 350 to 1,700 yards off the shore. The lagoon behind is very shallow with depths generally less than 6 feet. South of Tanapag Harbor, at Charan-Kanoa, one shallow and narrow entrance breaches the reef into the lagoon. The assault beaches selected were on the southern part of the western coast,

DEFENSES INCOMPLETE

The prepared defenses of Saipan were amazingly inadequate and incomplete. Apparently only after our campaign was under way was there much activity in constructing fortification on the island. Not a single battery position or fortification was entirely complete. In many instances casemates, emplacements, and magazines were less than half finished. Much equipment was found still loaded on railway cars or lying on the ground near partially excavated gun positions. Evidently the effectiveness of our submarine warfare had contributed much to the delay in the shipment of construction material vitally needed for fortification work. Of 89 coastal defense and dual purpose guns found on the island only 32 were

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MARIANAS OPERATION MAP

MARIANAS OPERATION MAP TO ILLUSTRATE ADVANCE OF UNITED STATES FORCES ASHORE ON SAIPAN, 15 JUNE-9 JULY 1944

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emplaced and ready to fire. The beachline defenses consisted of pillboxes, machine guns, anti-boat guns, fire trenches, anti-tank trenches, and other minor defenses. Heavy mobile artillery and mortar fire was used for the main defense of the beaches. Some 54 pieces of heavy artillery were located on the first high ground and on the reverse slopes of this ground, about 3,000 yards inland and back of the landing beaches. These were responsible for much of the prolonged and effective fire on the landing beaches and. their approaches.

ENEMY CARRIER AND LANSD-BASED AIR STRENGTH

A considerable part of the Japanese fleet had been based in the Singapore-Philippine area for sometime, with indications that most of these units were now based on the Tawi Tawi-Davao Gulf area and organized as a Fleet Striking Force. The Japanese had a large carrier force in the area of some 9 carriers with a total of 450 planes. All aircraft based in the Marianas and Carolines were believed to be naval aircraft and were estimated at 353 planes based in the Marianas, 99 on Palau and Yap, 66 in other Caroline Islands, 217 in the Philippines, and 550 in Japan or a total of 1,295. Late in May or June part of the Marianas air force was believed moved to the Palau-Yap area. It was not thought that army aircraft based either in the Philippines-East Indies area or Japan would be used in defense of the Marianas.

ENEMY GARRISON STRENGTH

The Japanese were believed to be rapidly strengthening their forces in the Southern Marianas and on the first of June there were estimated to be between 15,000 and 17,000 enemy troops on Saipan, from 10,000 to 11,000 on Tinian and from 10,000 to 12,000 on Guam. Actually encountered on Saipan were 4,000 naval and 20,000 army troops.

ORGANIZATION OF OUR FORCES

Due to the large number of ships and vessels required for the Marianas operation, the many complex operations which had to be coordinated, and the necessity for different organizations for various phases of the whole operation, the organization of our forces was. not simple. The Fifth Fleet (Task Force 50) was commanded by Admiral R. A. Spruance. The various Task Forces were the Joint Expeditionary Force (T.F. 51), the Northern Attack Force (T.F. 52), the Southern Attack Force (T.F. 53), the Expeditionary Troops and Landing Force (T.F. 56), the Forward area, Central Pacific (T.F. 57), the Fast Carrier Task Force (T.F. 58) and Land Based Air of Forward Area (T.F. 59). A total of 486 vessels, ranging from older type battleships to small craft such as PC, LCI(G), and YMS type was assigned to Task Force 53, and this Task Force embraced many elements of other Task Forces such as 52, 53, and 56. It was in this group that the following Coast Guard manned vessels were to be found:

Ship Type and
hull number
Task
Organization
Aquarius AKA 16 53.1, 53.3
Arthur Middleton APA 25 52.3
Callaway APA 35 52.4
Cambria APA 36 52.2, 52.3

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U.S. COAST GUARD-MANNED TRANSPORT Cambria (APA-36)

U.S. COAST GUARD-MANNED TRANSPORT Cambria (APA-36)

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Cavalier APA 37 51.1
Centaurus

AKA 17 53.2

Leonard Wood APA 12 52.4

LST 19 51.3, 52.5
LST 23 52.5

LST 70 53.1, 53.3, 53.16
LST 71 51.3

LST 166 52.5

LST 169 52.5

LST 205 51.2

LST 207 53.1, 53.3, 53.16

Altogether 67,545 troops were used in the capture of Saipan including 6,693 corps troops of the V Amphibious Corps, 22,830 troops of the 2nd Marine Division, 21,618 troops of the 4th Marine Division and 16,404 troops of the 27th Army Division.

PREPARATORY OPERATIONS

Operations which took place prior to D-day included mounting of the amphibious forces, rehearsal exercises, preliminary aerial and submarine reconnaissance of the objectives, bombing of enemy bases in the strategic area, movement of various groups of vessels to the combat area, preliminary air strikes by carrier based aircraft on enemy bases in the southern Marianas, bombardment of Saipan by surface ships, minesweeping of mineable areas off Saipan and demolition of underwater obstructions and mines found there. The. land-based air forces, by their prolonged operations, destroyed or damaged enemy aircraft, aircraft facilities, and shipping to such an extent that the Japanese were unable to use effectively their extensive system of air bases in the Carolines; and thus the enemy land-based air forces in these areas were unable to interfere seriously with our amphibious operations. The photographic coverage of objectives was the most satisfactory yet obtained in the central Pacific area, but because of the high altitude from which they were taken and the continual clouded areas obscuring most of the highlands, mortars, mountain guns, and other mobile weapons were difficult to identify. At about 1300 on 11 June, while 200 miles east of the Marianas, all task groups commenced launching the initial fighter sweep, consisting of 16 from each large and 12 from each light carrier, plus 2 TBP or SB2C from each task group. The fighter sweep evidently achieved surprise and a total of 150 enemy planes was destroyed at all objectives, about 75% of which were in the air at the time of destruction. Our combat losses were

11fighter planes and 8 pilots, with one-plane as an operational loss. On 12June the scheduled bombing strikes on Guam, Rota, Tinian, Saipan, and Pagan began but only a small number of enemy planes were encountered. However, the enemy managed for sometime to keep a small number of planes available for dusk and night operations in the area. Our bombing strikes damaged aircraft facilities, cratered runways, destroyed coastal guns and anti-aircraft positions) and sunk or damaged a considerable amount of shipping, including 2 sizeable convoys encountered on 12 June in the vicinity of the Marianas.

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COAST GUARD LANDS THE MARINES AT SAIPAN

COAST GUARD LANDS THE MARINES AT SAIPAN

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APPROACH OF AMPHIBIOUS FORCES

The amphibious forces left their embarkation areas late in May and early June, the Northern Attack Force and the Joint Expeditionary Force Reserve being assembled in the Hawaiian area and the Southern Attack Force in the Solomons, They proceeded in various groups to staging bases in the Marshall Islands, Eniwetok Atoll was used as a staging base for most of the groups of the Northern Attack Force and Kwajalein Atoll for the Southern. All troops assigned to the initial assault waves were here transferred from transports to LST's. Task Force 58 was the first to approach the Marianas having sortied from Majuro on 6 June. The advance Minesweeping group was due to arrive on D minus 2 day and two bombardment groups arrived in the area, on D minus 1 day. On D-day the two transport and two tractor groups of Northern Attack Force arrived, while various groups of the Southern Attack Force and the Joint Expeditionary Force Reserve followed. The bombardment of the west coast of Saipan and Tinian took place on 13 June by Task Force 58, with minesweeping of the outer shelf of the west coast and night harassment of Saipan and Tinian by destroyers, following air strikes by T.F. 58. Numerous large fires were started, indicating that quantities of enemy munitions, fuel, and supplies had been destroyed or damaged. The bombardment ships encountered no opposition and received no damage from enemy action. Commencing on 14 June and for a number of days thereafter, fire support units operated generally in seven sectors completely embracing the islands of Saipan and Tinian. Bombardment by all units commenced shortly after 0530 on 14 June and continued throughout the day until about 1840. The bombardment and aerial strikes in general, were effective in damaging or silencing most of the enemy's shore batteries.

LANDING ON SAIPAN

At dawn on the morning of 15 June, fire support vessels took their stations, and soon thereafter commenced firing at Saipan and Tinian. In the meantime the transport and tractor groups, carrying the troops, artillery, tanks, ammunition, supplies and other equipment, arrived off the western coast of Saipan, A heavy air strike along the landing beaches was made between 0700 and 0730, and intense pre-assault close range naval bombardment of the landing beaches commenced at 0800. A diversionary demonstration by two divisions was made in the north, while the actual landing occurred on the southern part of Saipan's west coast. H-hour was finally set at 0840. The assault was carried out without difficulty despite heavy mortar and other fire from the enemy which resulted in the loss of a number of LVT's. Some were overturned in the heavy surf but casualties, during the approach to the beaches, were light. Between 0840 and 0910 about 8,000 troops, with nearly 150 LVT(A)'s operating as light tanks in support, were landed on the shores of Saipan. A beachhead was established, but casualties soon became heavy because of the effective and concentrated enemy mortar and artillery fire. Throughout the remainder of the day, reserve troops, emergency supplies, ammunition, tanks, and artillery were landed and by 1800 nearly 20,000 troops had been landed on Saipan. In the evening most of our ships retired from the area, leaving designated fire support vessels, the majority of the LST's, the Coast Guard manned Cambria (Admiral Kill's flagship) and various small craft. About dusk a small scale enemy air attack was made on the naval forces present, but no damage was done.

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THIS IS THE DISCONCERTING SIGHT WHICH MET THE EYES OF JAPANESE DEFENDERS FO SAIPAN WHEN THEY LOOKED SEAWARD ON THAT D-DAY MORNING

Landing craft approach Saipan's beaches

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FIRST STAGE IN CONQUEST OF SAIPAN

In the 25 days which followed the landing of our troops on Saipan, the Japanese defenders of the island were defeated, and all organized resistance came to an end. The military conquest of Saipan was divided into three distinct stages; first, the establishment of a beachhead which gave control to the southern portion of the island; second, the fight for control of the central mountainous area; and third, the defeat of remnants of the enemy in the northern part of Saipan. The first stage lasted until 20 June, with the most severe fighting occurring during the first two days when the forces of the enemy were best organized and could bring to bear the bulk of his heavy artillery and armor. Once the beachhead had been seized and. adequate support could be given the landing forces, the ultimate success of the battle ashore was assured. The basic movement of this stage was across the southern part of Saipan, to the coast of Magicienne Bay. Just after noon on the 16th the 4th Marine Division "jumped off" for the capture of Aslito Field, There was a vigorous enemy counter-attack early on the 17th which forced a withdrawal, but before the day was over, the ground had been regained. A coordinate corps attack to the eastward had begun with the two Marine Divisions abreast and the 165th Infantry on the right. Elements of the 165th reached Aslito Field that day and its capture was completed next morning. Progress of the troops across the island was continuously opposed by artillery fire and enemy counter-attacks. After the coast of Magicienne Bay was reached on the 19th, the control of the southern part of the island was completed on the 20th, except for a pocket of enemy troops on Nafutan point. Our losses in this stage were 673 killed, 4,415 wounded and 1,120 missing.

SECOND STAGE IN CENTRAL SECTION

The second stage involved the seizure of the central section of the island, an area of rough terrain around Mount Tapotchau, the highest point on Saipan. It was the longest and most difficult stage for the troops and was the most critical for the enemy. It was conducted over cane fields and into the cliffs and caves which were admirably adapted to the guerrilla-type delaying action fought by the enemy. They resisted mainly with machine guns, small arms, and light mortars in the daytime from well concealed and almost inaccessible positions, reserving their remaining artillery for use at night. On the 25th elements of the 8th Marines, 2nd Marine Division, reached the crest of Mount Tapotchau, while the 4th Marine Division occupied Kagman Peninsula and. by the 30th this stage was completed. During this stage the Army and Marines lost 988 killed and 3,591 wounded.

THIRD STAGE FINISHES

The last stage was characterized by isolated, sporadic, and desperate resistance by the enemy, with little semblance of CONQUEST organized opposition. The 2nd Marine Division advanced rapidly into the ruins of Garapan and reached Mutcho point on 3 July, On the 4th the 27th Infantry Division seized the seaplane base at Flores Point. The enemy's complete restriction of movement, loss of organization, and inability to offer effective opposition was indicated by his desperate final counter-attack on 7 July. This

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COAST GUARD AND NAVY-MANNED LANDING BARGES AND AMTRACS LAUNCH THE INVASION WHICH GAVE AMERICAN FORCES DOMINATION OF THE STRATEGIC MARIANAS

COAST GUARD AND NAVY-MANNED LANDING BARGES AND AMTRACS

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penetrated the left flank of the 27th Infantry Division to a depth of about 1,500 yards, but a counter-attack by the reserves of the 27th Infantry at noon succeeded in restoring the continuity of the front by nightfall. The 27th Infantry suffered heavy casualties in this move and was relieved in the area by the 2nd Marine Division on 8 July. Enemy forces which had not been destroyed during the attack were now isolated and eliminated. Our losses in this stage were 636 killed and 3,212 wounded. On 9 July the 4th Marine Division reached and secured Marpi Point airstrip at the northern tip of the island and at 1615 it was announced that all organized enemy resistance on Saipan had ceased. Our total casualties had been 3,100 killed, 13,099 wounded, and 326 missing in action or 16,525 in all. By 13 July 15,978 enemy dead had been buried and 1,010 prisoners taken, of whom 446 were Japanese and 564 Koreans. By 9 September Japanese dead had reached 25,559 and 501 Japanese had been captured.

COAST GUARD OFFICERS FIND CHANNEL TO LAGOON

It was in the Saipan operation while probing about a shallow lagoon, as bullets whizzed overhead and enemy shells spattered coral rock against the sides of their boat, that two youthful Coast Guard officers found the channel through the coral reef along the western coast of Saipan which led to the sugar refinery pier at Charan-Kanoa. Through it they brought sorely needed supplies and reinforcements at a crucial point in the battle for the beachhead. The officers were Lieutenants (j.g.) Clifford L. Benson of Maspeth, Long Island and Truman C. Hardin of Springfield, Missouri. The Japanese had made a living hell out of the pass leading into the lagoon off Garapan, 5 miles to the north. Americans died as they tried to negotiate this narrow passage. Benson and Hardin located a. narrow channel through the reef into Charan-Kanoa. The Coast Guard officers and their crews crouched on the bottom of their boat as bullets nicked it and mortar shells exploded, nearby sending up geysers of water and debris. The use of this channel saved the day for the beleagued Marines in the vicinity. One of the first boats to use it delivered 30,000 rounds of desperately needed ammunition. Another brought in blood plasma and medical supplies. Three tanks were delivered within half an hour through the channel. Troop reinforcements splashed down the ramps and crawled up the beach to the firing line. As scores of small craft began filling the lagoon, the intensity of the enemy fire and mortar bombardment increased. It was soon no longer safe to use the shattered pier and boats risked running right up to the beach to unload. At dusk the enemy began a counter-attack. Rifle and machine gun bullets flecked the water with vicious zings. Boat coxswains bent down and steered on bended knee, popping up occasionally for a quick glance at their course. But the supplies already landed gave the Americans the necessary superiority to defeat the attack and when the action ended the Marines were in possession of the refinery and the ground surrounding it.

COAST GUARD MANNED APA's AT SAIPAN

The USS Callaway (APA-35) was manned by Coast Guards men as she proceeded to Saipan with other ships of Task Group 52.4.2. She arrived at Transport Area # 2 off Saipan at 0530 on the 15th and began unloading troops. At 1930 she was retiring from the transport

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CHURNING BEACHWARD THROUGH A HAZE OF DAWN BOMBARDMENT, TROOP-JAMMED ALLIGATORS SPEARHEAD THE INVASION OF NOEMFOOR ISLAND

TROOP-JAMMED ALLIGATORS SPEARHEAD THE INVASION OF NOEMFOOR ISLAND

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area when she was alerted for an enemy air attack. No damage was suffered by the Callaway and she returned to her assigned position off Saipan again on the 16th and 17th. On the 17th the Callaway closed the beach to take casualties directly aboard and at 1800 she departed the transport area and proceeded eastward. After steaming in the general vicinity of 16° N and 147° E for a few days, she returned to Saipan on the 23rd and resumed unloading. On the 24th she departed for Eniwetok. The USS Cavalier (APA-36), also Coast Guard manned, arrived at the transport area off Saipan at 1645 on the 15th and began dispatching LCVP's to other ships of Transport Division 7 to assist in their unloading. All boats were lowered and some 23 that did not return to the ship were ordered to spend the night at the Line of Departure off Blue Beach # 1, while the Cavalier retired from the transport area to cruise for the night. On the 17th at 1907 while Saipan was under enemy air attack, considerable anti-aircraft fire was seen, but the nearest approach of enemy planes was within four miles of the retiring groups of transports. For the next several days the Cavalier was under way in the retirement area northeast of Saipan. On the 19th there was a concentration of enemy planes 30 miles west of her course. On the 25th she again anchored off Saipan to resume unloading. There had been no casualties to personnel on boats which had remained at Saipan. Taking aboard casualties the transport next day proceeded to Eniwetok. The Leonard Wood arrived on 15 June and completed discharge of all troops and cargo on the 24th when she departed for Eniwetok. 356 casualties from shore had been received, treated, and disposed of prior to departure.

COAST GUARD MANNED LST-166 AT SAIPAN

From the 9th until the 15th of June the Coast Guard manned LST-166 was en route from the Marshall Islands to Saipan. She zig-zagged during daylight and conducted tactical maneuvers but no enemy contacts were had. On the evening of the 14th the bombardment of Saipan Island was visible as the LST approached to take part on the next day's invasion. At 06:30 on the 15th the LST was 5 miles off the southwest coast of Saipan. 11 Marine officers ana 133 enlisted men were taken aboard from the USS Funston and a little later an LSVP minesweeping unit was lowered and departed. At 1608 Marine personnel in LVT's were discharged at a point 1½ miles off Green Beach, with the ship's LCVP being used to lead them. 16 LVT's had been launched within 13 minutes and an hour later they returned to load ammunition, rations, and water, and debark more troops. LVT's continued unloading during the rest of the 15th and on the 16th as well, when the LST got under way and retired for the night. This was again the operation on the 17th. From then until the 19th the LST stood off Saipan Island, undergoing an air raid in the interim. Anchored off Yellow Beach # 2 on the 19th the LST continued to unload cargo ana debark Marine personnel in LVT's and on the 20th LCT-993 was launched from her main deck and fueled, watered, and provisioned before departing. Mooring to the USS Custer on that date she loaded a palletized cargo of ammunition, rations, and water and on the 21st proceeded to beach at Yellow Beach #3 The palletized cargo was unloaded during the 22nd. Getting under way on the 23rd she proceeded in convoy to the Marshall Islands.

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COAST GUARD BRINGS TANKS TO NOEMFOOR ISLAND

COAST GUARD BRINGS TANKS TO NOEMFOOR ISLAND

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LST-207, COAST GUARD MANNED, FIRES ON PLANE

On 17 June, while in convoy, the LST-207 observed three planes and at the same instant received warning from Flagship, USS Stembel. When first sighted the planes were less than 5 miles distant. Shortly afterward they separated, two attacking forward and one the after part of the convoy. The LST opened fire on the plane which launched a torpedo. This, however, passed well forward of the vessel. Firing was continued and numerous hits were observed. A few minutes later the LST opened fire on a second plane making its torpedo run. This plane launched a torpedo when 400 yards from LCI-468, which was 600 yards distant. Upon launching its torpedo, the plane, attempting to gain altitude rapidly, stalled and momentarily presented a broad, stationary target. Numerous hits were observed and the plane burst into flames, hitting the water at a distance of 3,000 yards broad on the port beam. The torpedo the plane had launched hit the LCI-468 on the starboard bow and the resulting explosion enveloped the vessel in smoke and threw debris far into the air, one of the missiles wounding a Marine aboard LST-207, who later died.

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