By the sumer of 1944, joint United States Army and Navy forces had pushed westward in the Pacific to the Marianas, and plans for the next major actions in the war against Japan were taking form. The Tenth Army had been formed for the purpose of seizing the island of Formosa and a section of the China coast near Amoy; however, the decision to invade the Philippines at an early date, as well as the discovery that landing beaches on Formosa were unsuitable, led to a reconsideration of the targets. Staff planners, thereupon, directed their attention to Okinawa and the Nansei Shoto, or Ryukyu Islands.
Strategically, Okinawa offered may advantages. Its occupation would place United States forces within 350 miles of the Japanese home islands. From bases established there, our forces could attack the home islands of Japan and their sea approaches with naval and air forces; could support further operations in the region bordering on the East China Sea; could sever Japanese sea and air communications between the homeland and the mainland of Asia, Formosa, Malaya, and the Netherlands East Indies; could establish secure sea and air communications through the East China Sea to the coast of China and the Yangtze Valley; and could maintain unremitting military pressure against Japan. In view of these considerations, the Joint Chiefs of Staff directed the Commander in Chief, Pacific Ocean Area, to "occupy one or more positions in the Nansei Shoto." The target date was set for March 1, 1945, but was subsequently adjusted to April 1, 1945.
Okinawa Shima, with other islands of the Nansei Shoto, forms the boundary between the East China Sea and the Pacific Ocean. These island resemble the floats of an enormous fish net, strong between Kyushu and Formosa, with Okinawa as the central, and largest, float. The island is 67 miles long and varies in width from 2 to 15 miles. The coastline is irregular, deeply indented with bays and inlets. Wide fringing coral reefs almost completely surround the island and limit access from the sea. North of a narrow isthmus at Ishikawa, the land is rugged, with peaks rising to elevations higher than 1,500 feet; south of the isthmus the hills do not exceed 700 feet. Although broken by steep limestone scarps and terraces, there are extensive areas of gently sloping land in the southern portion of the island. Land too steep or unproductive to till is covered with a moderate growth of small pines and coarse grass. In the northern hills, vegetation is heavier and approaches the jungle type. The climate is sub-tropical, and although variations in temperature are not great, the extreme humidity makes even these small variations noticeable. Rains are frequent and often torrential, and typhoons of great intensity frequently sweep across the island.
The invasion of Okinawa began on April 1, 1945. Divisions of the Third Marine Amphibious Corps and the 24th Army Corps made simultaneous landings on the west coast, north and south of the Bisha Gawa and less than 20 miles north of the port of Naha. Meeting only light opposition, our forces rapidly advanced inland to capture Yontan and Kadena airfields and to extend the beachhead to a depth of two and a half miles by nightfall. The advance was rapid for the next few days as the Marines cleared Bolo Point and the Army drove across the width of the island to the Awase peninsula. On April 7, Marine reserves landed near the town of Nago, at the base of the Motobu Hanto, augmenting forces advancing overland, and one week later, reached the northern tip of the island.
The 24th Corps found resistance considerably stiffer in the southern part of the island. Fighting from prepared positions, the enemy was able to defend a line extending eastward across the island from Machinato. This line held until April 19, when our ground forces, supported by the fleet, succeeded in breaking through. By the end of
April, our troops had captured Machinato airfield, but were halted north of Shuri and the Yonabaru airfield.
Progress during May was slow and costly, and at the end of the month, the enemy still occupied the central Shuri salient. Early in June, our forces chased the enemy to his prepared position in the southernmost part of the island, where it was necessary to dig in and blast each enemy position, before organized enemy resistance ceased on June 21, 1945. Isolated pockets of Japanese were left for mopping-up operations; however, all sites required for construction purposes became available in the next few days.
Enemy installations of engineering importance on Okinawa consisted of limited port and harbor improvements, an extensive but narrow road system, four airports previously operational according to Japanese standards, two airfields on which construction had started, two water supply systems, and miles of stone masonry seawall. Of no use to our forces were two narrow-gauge railroads, the water supply systems, and the caves and tunnels.
Enemy airstrips were too short and their construction too light to meet the requirements for operation of our heavier aircraft. Hardstands were small and some were surrounded by diamond-shaped revetments, open at the point. Taxiways and hardstands were elaborately camouflaged -- mock villages with potted trees were used to hide aircraft in dispersal areas at Yontan.
The road network, although extensive, was constructed to standards completely inadequate to meet our minimum requirements. Cuts and embankments were narrow, and curves sharp. Native villages, with stone walls and deep gutters pressing the roadway on both sides, gave limited clearance. The best surface consisted of a thin layer of hand-placed coral stones, which failed under our heavy traffic and could not be maintained with our power equipment. Bombardment by our air and surface craft had destroyed many of the bridges and drainage structures of the road network, and the enemy, as he withdrew, wrecked with demolition charges those that were left.
The task of base development was delegated to the Island Commander, Okinawa, under whose control were the Army and Navy construction troops available for execution of the base development plan. The Island Commander, in turn, placed all construction troops in Task Unit 99.3.5, and assigned to Commander, Construction Troops, the mission of executing the base development plan and of all engineering construction on Okinawa. Construction troops under Commander, Construction Troops, consisted of three naval construction brigades, the 8th, 10th, and 11th, and one Army Engineer construction group, the 1181st. This construction group later was designated a provisional construction brigade.
Units of the command were staged for the target from bases as close as the Marianas and as distant as Seattle and New Caledonia. Some units went ashore as combat engineers with the assault troops, and others sailed in follow-up shipping echelons, but all construction units were brought forward as soon as the shipping priorities, based on limited beach capacity at the target, would permit.
The 44th Naval Construction Regiment, with the 58th, 71st, 130th, and 145th Construction Battalions assigned, was staged and shipped to the target with Marine units to which the battalions were attached. The 58th, 71st, and 145th Battalions were landed on D-Day with the assault troops; the 44th Regiment, on April 5; the 130th Battalion was held in Tenth Army reserve with the Sixth Marine Division until April 12. In addition to these regular battalions, the 130th pontoon and the 11th Special Battalions went in with the assault.
During the combat period, construction troop units landed with the assault troops, served as combat engineers in support of ground troops -- rehabilitating and improving native roads and bridges and clearing enemy mines and demolitions. They located, developed, and operated water supply points for all units; they cleared, repaired, and extended abandoned enemy airfields for early used by our fighter planes; they installed communication facilities; they provided engineer supply for combat and garrison troops; and they began the development of the permanent facilities of the base for the support of future operations against the enemy. These activities were carried on night and day until the island was declared secured, and in spite of enemy sniper activity, artillery fire, and air attacks. Perimeter defenses of the command post of the commander of construction troops -- established soon after D-Day -- and, later, of the sector of the island containing the headquarters command post were manned by construction troops.
Unloading Across a Pontoon Causeway, Okinawa
Temporary causeway established by the 128th Seabees during the assault phase
In addition, construction units were assigned sectors and special tasks under the various area defense commanders.
Engineering reconnaissance was begun on April 2, the day after the initial landings, and continued throughout the campaign. This reconnaissance was often carried on in, and immediately behind, the front lines, in areas recently taken from the enemy and exposed to enemy bombing, sniper shelling, and mortar fire. The knowledge to be gained was considered so important to the accomplishment of the mission that the risks were accepted. Two civilian geologists, attached to the headquarters during the combat period, made extensive explorations and assisted in the location and development of quarries and water supply installations.
The 43rd Naval Construction Regiment was the first American force to land on the east coast of Okinawa. Between the 27th and the 30th of April, the 36th, 40th, and 87th Battalions landed with the 7th, 14th, and 21st Battalions of the Eighth Construction Brigade and the 79th Battalion of the 11th Brigade. It was realized early in the planning stage that shipping limitations would prevent the landing of Seabees early enough to accomplish their mission and at the same time avoid interference with the support of combat troops. Accordingly, these eight battalions were streamlined and staged at Saipan on LST's returned from the assault echelon. They were landed on the east coast of Okinawa and developed their own beaches. Construction troops landed in this manner were able to begin work on Chimu and Awase airfields at a date much earlier than would have been possible under the regular shipping schedules.
The first operation undertaken by construction troops was the rehabilitation of beach exit roads and main supply routes. Road work was carried on day and night and without interruption of the heavy flow of military traffic from the beaches to the combat fronts. Native roads were unable to handle the heavy traffic imposed upon them by
combat operations, and deteriorated rapidly under the heavy loads and continuous rains which fell during the latter part of May. The situation became so serious that on the 25th of May, the island commander issued an order restricting all traffic to the minimum essential to the provision of water, rations, and ammunition. On the 26th of May, as heavy rains continued, the commanding general of the Tenth Army placed first priority on the maintenance of main supply roads serving the combat troops. Work on other construction projects, including airfields, was temporarily suspended, and all construction troops available concentrated on road maintenance. This condition prevailed until the return of good weather in mid-June when roads again became passable.
Initial road projects were begun in the first few days of the operation by units still attached to the assault forces. Between the 2nd and the 14th of April, when the first battalions, which had landed with the Marines, reverted to control of the commander of naval construction troops, work consisted largely of providing maintenance and keeping all roads passable. Improvements were made later, as equipment and personnel became available. Enemy demolition of bridges had been widespread; however, many of the damaged structures were quickly made usable by cribbing, filling, and shoring, and those demolished beyond repair were bypassed.
Great emphasis was placed on establishing airfield facilities for our forces at the earliest possible moment. Both Yontan and Kadena airfields had been damaged by the pre-invasion bombardment and were further obstructed with mines and booby traps. Construction troops occupied these fields on
Road-Surfacing Operations by the 71st Seabees on Okinawa
Photograph taken July 16, 1945
The was a project of the 21st Seabees
April 3 and immediately began rehabilitation of the existing strips. The initial work at Kadena was accomplished by the 1901st Aviation Engineer Battalion and CBMU 624 on April 4. At Yontan, the 58th Battalion, CBMU 617, and the 802nd Army Aviation Engineer Battalion were at work on the strip by April 3. Initial efforts were concentrated on clearing runways, repairing bomb craters, and disposing of unexploded bombs and ammunition. One strip at Yontan was ready for fighter operations on April 4.
During the latter part of April, construction troops resurfaced the existing runways and constructed taxiways, hardstands, warm-up aprons, pilot housing, and gasoline storage facilities. Damage-control parties from the battalions on several occasions filled bomb craters on one end of the runway while enemy planes were strafing the other end. In spite of enemy interference, the runways were thus kept serviceable almost without a break. At the end of April, construction was started on a new bomber strip at Yontan.
Reconnaissance and surveys which began immediately after the initial landings on Okinawa revealed possibilities for an expansion of the airfield program. In addition to the sites at Yontan, Kadena, and Awase and the sites in possession of the enemy, possible sites were at Bolo Point, Nago, Majiya, Motobu Peninsula, Chimu, and Tsuken Shima. As a result of these and other considerations, it was decided to defer indefinitely the occupation of the island of Amami, north of Okinawa
All construction forces and all aircraft units originally scheduled for the Amami operation were diverted to Okinawa . This addition brought the number of Army and Navy construction troops on Okinawa to 95,000, and called for construction of airfield facilities to accommodate 4,000 aircraft. At the close of the combat period, the first new bomber strip had been completed at Yontan, the airfields at Kadena, Chimu, and Awase were well under way, and construction was in the first stage at Bolo and Yonabaru airfields.
Reconnaissance parties had discovered that the site originally selected for the Awase airfield was unsuitable because of poor drainage and the absence of conveniently located construction material. A new site for the field was selected a mile south of the original site and on batter terrain. The 36th Battalion began work on a 5,000-foot fighter strip at Awase on April 23.
None of the five remaining airfield sites was available for construction in April because unexpectedly strong enemy resistance had halted the advance of our troops north of Shuri. New airfield sites to the north were surveyed; one on Bolo Point and one on the north shore of Chimu Wan harbor, near Kin, were found to be suitable. The 40th Battalion began work on Chimu airfield on May 6.
On June 14, the Seventh Battalion began construction of a seaplane base on Katchin Hanto. One of the ramps was available for operations by the first of July.
Pontoon structures were used more extensively at Okinawa than in any other previous Pacific operation. The 70th Seabees maned 96 barges of 3-by-12-pontoons,
Katchin Hanto Peninsula, Okinawa
View looking westward, with the advance base construction depot in the foreground
Extension to Pier at Baten Ko, Okinawa
Both pier and extension were built by the 21st Seabees
and the 128th Battalion managed 28 sets of 2-by-30-pontoon causeways allotted for the operation. The two Seabee units were placed under the commander of the amphibious forces, United States Pacific Fleet, for this operation. The men for this job were trained and embarked at Pearl Harbor. Practice landings were made at Leyte Gulf and in the Russell Islands. A severe storm was encountered en route to Okinawa, with the result that eight causeways and 13 barges were either lost at sea or so badly damaged that they could not be launched for the invasion. Launchings started on the day of the assault, and by April 8, all available barges and causeways had been launched and were in operation.
The pontoon causeways were used at Okinawa in a slightly different manner than in the Philippines, as the character of the beach differed widely. The attack took place over a wide coral reef. LST's could come up to the edge of the reef, and at low tide it was possible to drive many vehicles ashore over the reef itself. However, pontoon causeways and finger piers were constructed to make the dry-shod landing of men and vehicles possible at high tide.
Actually, 92 pontoon barges were in operation at Okinawa. These were used as lighters, as crane transfer barges, to evacuate casualties, and as "bowser" barges to refuel small boats. A number of barges were also designated as pontoon warping tugs, and were found extremely useful for pulling stranded landing craft off the reef, and for placing moorings for causeways and landing craft. Each of these tugs had a 3,000-pound anchor and a heavy winch. During the first month of operations, the Seabee-manned lighter barges hauled more than 25,000 tons of miscellaneous cargo; the crane barges transferred 40,000 tons of cargo.
The waterfront construction program began on May 5 with preparations for placing an LST pontoon-barge pier near the town of Kin on Chimu Wan. Additional pontoon piers, constructed at Katchin Hanto, Awase, and Kuba Saki, were also placed in operation during the month, although
Pontoon Pier at Katchin Hanto, Okinawa, May 12, 1945
considerable work, such as clearing channels, dredging reefs, and improving access roads, was continued for some time. At Kuba, facilities were established for the storage and issue of pontoons and piling. Pontoon piers at Machinato and Yonabaru were rushed to completion for use in the support of combat troops. During the latter part of June, when the need for moving civilian refugees became great, a pontoon pier was constructed at Ora Wan.
Construction of some permanent facilities was begun during the combat period. On May 8, work was started on a pontoon pier at the section base at Chimu Wan. This installation facilitated the repair of harbor craft, minecraft, and minecraft equipment. Later, in June, construction of a minecraft storm refuge was begun at Unten Ko on Motobu Hanto. The project consisted of the installation of timber-pile mooring dolphins, concrete anchors for mooring buoys, and a small-boat pier.
Nearly two million tons of munitions and supplies were landed during the three month campaign at Okinawa. All of this freight had to be handled from ships to lighters and from lighters to trucks on the beaches.
To support their operations, the Third Amphibious Corps had assigned to them the 11th Special Construction Battalion and two logistics support companies (the 26th and 32nd). Initial cargo-handling plans evolved around these units. The 11th Special and the two support companies were organized into 90 ship's gangs. Men of all ratings and qualifications were used; all embarked with the assault forces.
As far as landing of supplies was concerned, the first thirty days of the campaign passed without incident, except for enemy aircraft attacks. The total cargo handled for 373 ships during that period was 778,992 measurement tons. In May, beaches were opened on the east coast, and shore party personnel began to be replaced by organized Seabee Special Battalions and Army port personnel. During the month of May, a total of 625,140 measurement tons of supplies were handled over the beaches in lighters and small boats.
On June 1, 1945, all shore party personnel were relived and the unloading operations became the responsibility of the commandant of the naval operating base, and was, in turn, delegated to Commander, Joint Freight Handling Facilities, in operational charge of Army and Navy cargo-handling troops.
The tactical situation in June made unprecedented demands for supplies and support on a scale far beyond any previous demands.
Although ample supplies had been behind the lines of June 1, the combat troops had advanced, and the heavy rain which fell all during the month made the roads to the rear impassable. A new and complete supply system had to be quickly devised. As overland transportation was impossible, the burden of supplying troops at the south end of the island had to be shifted to the lighterage used in normal unloading operations. To meet the emergency, cargo ships were spotted at dispersed anchorages and selectively discharged. Supplies were unloaded at every possible landing beach near the troops. Lighterage, after being unloaded on the beach, was used to evacuate casualties and natives caught in the path of advancing troops. Despite the huge burden of extra supply, 613,200 tons of supplies were unloaded during the month of June.
Kadena Traffic Circle, Okinawa
This was a project of the 130th Seabees
On July 1, the demands of the tactical forces diminished. Selective discharge of ships was no longer necessary. By July 17, the unloading rate had been increased to 35,000 tons per day. This was an increase of 15,000 tons a day over June. During July, 1,015,374 tons of freight were discharged and 206,000 tons loaded out. All of this freight was handled twice, from ships to lighters and from lighters to trucks on the beaches. In contrast, the original base development plan called for the handling of 550,000 tons per month over completed ship piers and permanent installations.
Seabee units comprising Joint Freight Handling Facilities consisted of the 3rd, 4th, 11th, 12th, 23rd, 27th, and 36th Special Battalions, the 81st, 28th, and 148th (Pontoon) Battalions, and the 137thy and 139th (Trucking) Battalions. On July 31, both Army and Navy resumed responsibility for its own unloading, and Joint Freight Handling Facilities ceased to exist as of that date. Naval personnel were reorganized to form the 12th Naval Construction Brigade.
Automotive Construction Equipment Overhaul and Repair Depot, Okinawa
Open storage area prepared by the 146th Seabees
The first major shipment of construction materials -- 15,900 measurement tons -- arrived on Okinawa on May 21. Until the arrival of these materials, construction projects were limited to those which could be accomplished through the use of native materials or of the small supplies of general construction material brought to Okinawa as a part of battalion allowances.
Major construction projects completed by the Seabees during the combat period included three airstrips at Yontan field, the Third Amphibious Corps evacuation hospital at Yontan, Special Augmented Hospital 6, a traffic circle near Kadena Field, and pontoon piers at Kuba Saki, Machinato, Awase, and Bisha Gawa. Major construction projects begun by Seabees during that same period included airstrips at Bolo, Awase, and Chimu, a seaplane base at Katchin Hanto, six highways, Special
Augmented Hospital 7 and 8, a fuel pier and a pontoon pier at Katchin Hanto, a breakwater at Tengan, an ammunition depot at Chimu Wan, a section base at Katchin Hanto, a minecraft storm refuge at Unten Ko, a receiving station at Kuba Saki, boat pool facilities at Bisha Gawa, a degaussing station at Tsuken Shima, and a joint communications center.
Building a Runway at Yontan Airfield, Okinawa
Men of the 87th Battalion grading on May 13, 1945
Although the initial landings on Okinawa were accomplished without great difficulty, the enemy thereafter did his utmost to harass our forces and to hinder the occupation of the island and the development of the base. The enemy's stubborn defense of the south quarter of the island prevented our occupation of airfield and naval base sites and made necessary the continued diversion of construction forces in support of ground troops, while transportation of construction material was delayed to accommodate the combat operations.
Air attacks against our installations, particularly the airfields, began during the first week of the occupation and continued until the Japanese surrender. The enemy made 261 air raids in the period from April 1 to June 30. Enemy night bombing raids were frequent, and, although the resulting damage was small, the interruption to work and necessary rest were considerable. Kamikaze attacks against shipping in the harbor damaged some construction equipment and material. In fact, the first ship to arrive with a cargo of unassembled pontoons and pontoon gear, the SS Carina, was struck by a suicide torpedo boat on the second night in the harbor of Nakagusuku, later called Buckner Bay [after General Simon Bolivar Buckner, CO Tenth Army, killed on combat on Okinawa]. The most serious menace to construction personnel during enemy air attacks was found to be falling fragments from automatic-weapons fire from ships in the harbor.
On land, the enemy employed mines and booby traps of all descriptions to destroy our equipment and delay our progress. Airfield sites at Yontan, Kadena, Machinato, Yonabaru, Futema, Ie Shima, and Tsuken Shima were heavily mined. Bomb-disposal squads of the 21st Construction Battalion removed tons of explosives from Tsugen Shima before construction could begin.
Bridges had been systematically destroyed by our own air forces in the pre-invasion attacks, and nearly all of those that were left were destroyed by the enemy before his withdrawal. In one case, an enemy patrol infiltrated our lines on May 18, demolished a bridge near the village of Iji, and ambushed the bridge repair party from the 14th Construction Battalion, when they set out to repair the damage. One repairman was killed and two were seriously wounded.
Overloaded Truck Towed Through Okinawa Mud
Direct attacks by enemy ground troops against Seabee bivouacks were neither frequent nor effective. Sniper fire was a constant annoyance, however, and resulted in the establishment of a rule that vehicles must not travel after nightfall except
in convoy. Construction troops at work near the combat lines were interrupted by enemy artillery and mortar fire, and, before the capture of Machinato, the airfields at Kadena and Yontan were often subjected to the fire of enemy long-range artillery. During May, the 14th, 20th, and 40th Battalion camps near Chimu were attacked with light mortar and small-arms fire, and attempts were made to sabotage equipment and supplies with explosive charges, but the damage was small. The most frequent enemy contacts were made by reconnaissance survey parties and by battalion outpost guards intercepting small enemy patrols and armed stragglers. Some 168 enemy troops were reported killed and 25 captured.
Upon the cessation of organized enemy resistance on Okinawa at the end of June, construction troops were able to concentrate their efforts on base development, and during the following two months, important progress was made toward the accomplishment of that mission. Much sniper action continued during July and until the final surrender. Additional construction troops arrived during July and August, and, with the completion of additional cargo-handling facilities and the reduction of combat requirements, the availability of construction materials was improved.
Several important organization and administrative changes in the task unit were accomplished during the period, without interruption of the work. Early in July, the plan for division of base development areas and the reassignment of battalions among naval construction brigades was placed in effect. Each naval construction brigade was made responsible for a type of work -- waterfront, airfield, or general construction -- in a particular area. As construction troop units were landed or were released from temporary duty with
Water Point, Okinawa
combat forces, they were assigned on this basis. Battalions arriving during July were assigned according to the work load and the needs of the brigades under the new plan.
Construction troops reached a maximum strength during August, when 80,000 officers and men were attached to or under operational control of the Commander, Construction Troops. The figure does not include the 7,000 engineer and naval construction troops under Island Commander, I Shima, over whom the Commander, Construction Troops, as engineer for Island Commander, Okinawa, exercised only general supervision. The strength of construction troops, made up of equal numbers of Army and Navy construction personnel, included the following basic units: 36 naval construction battalions, 21 Army engineer aviation battalions, 14 Army combat engineer battalions, and 7 Army engineer construction battalions.
On August 15, joint Army-Navy command in the Ryukyus was dissolved; however, Commander, Construction Troops, maintained joint Army-Navy control of construction forces and construction work until September 1. During the interim, Commander, Construction Troops, was responsible to the Commanding General of the First Army Service Command for Army construction and to the Commandant of Naval Operating Base, Okinawa, for Navy construction. This arrangement was made to allow the expeditious completion of urgently needed Army facilities, including airfields and command posts upon which naval construction units were employed.
With the close of the combat phase, shipping arrivals at Okinawa increased daily, and unloading operations soon became a major problem. Although construction troops were assisting at the piers with additional cranes and loading crews, the piers could not be cleared with the trucks available from receiving units and those assigned to Joint Freight Handling Facilities. In order to alleviate this critical condition, the First Construction Battalion Provisional Truck Company, made up of officers, men, and equipment attached from each of the three naval construction brigades, was activated on July 2. This provisional company, under the administrative control of the 11th Brigade, was given the mission of keeping the east coast piers cleared by handling all classes of supply, from piers to dumps, until Joint Freight Handling Facilities could take over. The company began operations on July 5, and continued until August 31, when Navy Cargo Operations, reinforced by the arrival of regular trucking units, was able to relieve them.
One of the major engineering accomplishments of the Okinawa operation was the rapid construction of Awase airfield. The field was located in a rice paddy area on the east coast of the island, where drainage was poor and the sub-base was a blue clay which became unstable when wet. The nearest sources of coral for fill and surfacing were located at Gushikawa and Myazato, 3 and 5 miles distant, respectively, although a limited supply of finger coral and coral sand was available on the Awase Peninsula. The field was urgently needed as a base for fighter aircraft conducting the air defense of the island, and the desired operational date was set at July 1.
The scheme of the Commander Construction Troops, for landing naval construction units on the east coast of Okinawa became a proven success when the 36th Battalion debarked at Gushikawa and was able to begin construction of Awase on the 23rd of April, Rice paddies were drained; large drainage canals were dug; and tide gates, installed in the sea wall. A bypass for the main supply road was constructed next, and traffic diverted around the field. These preliminary steps ahd been nearly completed and work was under way on the fills when the torrential rains of late May and early June caused the Commanding General of the Tenth Army to divert all heavy earth-moving equipment to the maintenance of main supply roads.
Upon the return of dry weather in mid-June and the return of normal priority to airfields, construction troops redoubled their efforts on Awase. The 36th Naval Construction Battalion was reinforced with all available equipment and operators. Six battalions cooperated in moving coral to the field from the quarries at Gushikawa and Myazato. The Island Command provost marshal assisted in the traffic control, and a continuous line of trucks and other earth carriers moved from the quarries to the field and back again.
Work continued night and day, except when enemy aircraft interrupted. The fill material was spread, compacted, shaped, and rolled as it was placed; the strip, taxiways, and hardstands rapidly took shape. Control towers and operational buildings were constructed concurrently.
On June 30, the strip was pronounced ready for initial operation; the desired operational date had been met. The obstacles and difficulties of drainage,
material, weather, and interference by the enemy had been overcome. The first planes of Marine Air Group 33 landed on the strip that same day.
During the period from July 1 to August 31, construction troops were able to continue and complete many of the base-development projects begun during the combat period and to initiate the construction of all base-development projects which had been delayed because the enemy prevented occupation of the selected sites.
During the base development period, Seabees completed the airstrip at Bolo, Chimu, Awase, and Yontan, Special Augmented Hospitals 3 and 6, Mine Assembly Depot 8, a degaussing range at Tsuken Shima, a minecraft storm refuge at Unten Ko, and a pontoon barge and LST pier at Baten Ko. As of August 15, the Yonabaru airfield became operational, with the completion of 6,500 feet of runway.
58th Seabees Place Mat for Seaplane Ramp, Katchin Hanto Seaplane Base
During this period, they also continued to work on the construction of communication facilities, including the erection of a joint communications center, the receiving station at Kuba Saki, naval facilities at Bisha Gawa, the repair base at Baten Ko, the fuel pier at Katchin Hanto, and the breakwater at Tengan.
An advance base construction depot was started during this period. It included a spare parts depot and an automotive construction equipment overhaul and repair depot. New construction of port facilities included an ammunition pier at Chimu Wan, a pontoon barge pier at Tsuken Shima, a general cargo pier at Katchin Hanto, and two piers for the naval supply depot at Tengan. Large base facilities were started at the supply depot, the naval bases at Buckner Bay and Chimu Wan, and the section base at Katchin Hanto. Other new projects included a naval ammunition depot, Special Augmented Hospital 4, a fleet petroleum storage facility, a tank farm, permanent water systems at Tengan and Baten Ko, a ship repair base at Baten Ko, and docking facilities for aviation repair ships at Awase.
Tide-Control Gates for Drainage of Yonabaru Airfield
This was a project of the 74th Seabees
When the Japanese government formally surrendered on September 2, the mission of developing Okinawa as an advance base for the support of fleet, air, and ground forces engaged in prosecuting further attacks against the Japanese Empire had been completed in the degree necessary to that end. Pending a definition of the post-war mission of the base, naval construction troops were directed to proceed with projects underway.
Major projects developed after the surrender of Japan included the naval operating base at Baten Ko, the Kuba Saki receiving station and staging area (for demobilization of troops), ammunition depot, Fleet Hospital 116, the Katchin Hanto section base, the aviation supply depot, Baten Ko fleet landing, and a fleet recreation area at Tsuken Shima, as well as additions to the naval supply depot at Tengan on Chimu Wan. The separation
Building the Operational Unit for the 301st Fighter Group, Ie Shima
of joint Army and Navy commands in the Ryukyus became effective for construction troops on September 1, 1945. Commander, Construction Troops, was detached from duty under the Army Service Command and reported for duty to the Commandant, Naval Operating Base, Okinawa. Upon reporting, he was designated as Commander Naval Construction Troops, with the mission of constructing all base facilities designed primarily for naval use. Thus came to an end the largest joint force of Army and Navy construction troops ever assembled under one engineer commander.
Extensive damage to installations was caused by a severe typhoon, the center of which passed over the southern portion of the island on October 9,1945. It necessitated the concentration of construction troops for the reconstruction of the fleet post office at Baten Ko, Special Augmented Hospital No. 4, and other facilities required for demobilization.
By the close of 1945, naval facilities on Okinawa covered 20,000 acres, and included 4,180 lineal feet of wharves, 712,000 square feet of general covered storage, 11,778,000 square feet of open storage, 193,000 cubic feet of cold storage, as well as storage for 8,820,000 gallons of aviation gasoline, 30,000 barrels of diesel oil, 50,000 barrels of fuel oil, 13,000 square feet for ammunition. Aviation repair shops covered 324,100 square feet and general repairs shops, 91,000 square feet. Hospital space amounted to 338,000 square feet, and quarters 4,755,000 square feet.
Ie, which was developed in conjunction with Okinawa, became a naval advance base. Its four airstrips were under Army control, but were used by Naval Air Transport Service. The naval base included 16,700 square feet of general storage and space, 7,475 cubic feet of cold storage space, and 4,500 square feet of open storage. In addition to 700 lineal feet of wharfage, there were repair shops covering 5,500 square feet; hospital, 2,400 square feet; and quarters, 67,692 square feet.
Docking Facilities at Ie Shima
Photograph, taken June 1, 1945, shows a project of the 106th Seabees in operation
Chimu Airfield, Okinawa
Photograph shows this project of the 40th Seabees as it looked on July 16th, 1945
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