Supply trucks pulled through bad spot by 302d Combat Engineers
Air delivery was also utilized at this time to bring supplies forward. The Air Delivery Section of III Amphibious Corps was responsible for all air drops on the island. The section operated from CVE's until 18 April, and thereafter from Kadena airfield. Using torpedo bombers rather than C-47's, primarily because more accurate drops could thus be made, the section delivered a total of 334 short tons of supplies in 830 plane loads. Most of the air drops were to III Amphibious Corps units, particularly the 1st Marine Division, whose front-line elements were supplied almost exclusively by air between 30 May and 9 June, when the roads in its area were impassable even to tracked vehicles. The tonnage delivered by air to XXIV Corps in the week 2-9 June was small but, because of its emergency nature, important. Supplies thus dropped consisted in the main of ammunition and rations.{480}
Maintenance and construction of supply roads were impeded by the lack of good road-building material and by rapid deterioration from rainy weather and heavy traffic. In the XXIV Corps zone the limestone coral used for road building in the early stages of the campaign proved to be unsuitable, and extensive use had to be made of rubble from destroyed buildings and stone walls. A rock crusher was not available. As the Corps drove southward, the lack of adequate sources of coral limestone became acute and the use of building rubble had to be continued. When a rock crusher was made available at the end of the first week in June, it was set up and operated in a limestone quarry and then moved to a site where the excellent stone from the razed Shuri Castle could be used. It was at this time, moreover, that the problem of road maintenance became overwhelming. A 12-inch rainfall between as May and 5 June forced the abandonment of the two main supply roads serving the Corps. One of these, Route 13 along the east coast, was not reconstructed during the battle; the engineers concentrated on keeping Route 5, down the center of the island, in operation, as well as the roads running south from Yonabaru and Minatoga, to which supplies were moved by water. In the Marine zone on the west side of the island, only the continuous labor of all engineer units and rigid traffic control kept Route 1 open. By the end of June main supply roads had been developed from Chuda to Naha on the west coast (Route 1), from Chibana to Shuri in the center (Route 5), from Kin to Yonabaru on the east coast (Route 13), and at six intermediate points across the island.
Approximately 164 miles of native roads had been reconstructed and widened for two-lane traffic, 37 miles of two-, three-, and four-lane roads had been newly constructed, and a total of 339 miles of road was under maintenance.
Providing an adequate supply of ammunition to support the sustained attacks on the Shuri defenses constituted the most critical logistical problem of the campaign. The resupply of ammunition beyond the initial five CINCPOA units of fire had been planned for a 40-day operation; the island was not officially declared secure until L plus 82 (22 June).{481} The sinking of three ammunition ships by enemy action on 6 and 27 April and damage to other ships resulted in a total loss of 21,000 short tons of ammunition. The unloading of ammunition was, moreover, never rapid enough to keep pace with expenditures, particularly by the artillery, and at the same time to build up ample reserves in the ammunition supply points. Further, it was found that the ship loads of all calibers balanced according to the CINCPOA unit of fire prescription did not fit the needs of a protracted campaign; the requirements for artillery ammunition far exceeded those for small-arms ammunition and resulted in hasty, wasteful unloading and constant shortages.
The ammunition situation first became critical when XXIV Corps developed the Naha-Shuri-Yonabaru defense line during the second week of April. The ammunition expenditures in the large-scale artillery attacks mounted rapidly. As the rate of discharge from the ships failed to keep pace, the supplies on hand dwindled. The plans for the Corps attack designed to penetrate the Japanese positions called for an expenditure of 14,800 tons of artillery ammunition plus supply maintenance of some 1,000 tons a day. To conserve supplies, command restrictions on artillery ammunition expenditures were imposed on 9 April. The Corps attack was delayed until 19 April, partly in order to accumulate sufficient stocks and reserves. This was accomplished in time by means of greater unloading efforts, making available all resupply ammunition, and diverting III Amphibious Corps' stocks to XXIV Corps.
After the attack of 19 April ammunition expenditures continued to mount. By the end of the campaign a total of 97,800 tons of ammunition had been expended. XXIV Corps alone consumed about 64,000 tons between 4 April and 21 June, and restrictions on daily expenditures were continuously in force in its zone until L plus 61 (1 June). In spite of restrictions an average of more than 800 tons of ammunition was expended daily by Corps units. (See Appendix C, Table No. 10.)
About the middle of April a critical shortage of 155-mm. ammunition developed, and on 17 April Tenth Army had to call up four LST's loaded only with ammunition for 155-mm. guns and howitzers from the reserves in the Marianas. Subsequently, additional emergency requisitions on the reserves were necessary. CINCPOA was also requested to divert ammunition resupply shipments from canceled operations, as well as some originally intended for the European Theater of Operations, to Okinawa in order to alleviate the shortages. On 21 May Tenth Army had to request an emergency air shipment of 50,000 rounds of 81-mm. mortar ammunition, of which more than 26,000 rounds were received between 28 May and 9 June.
However, the expenditure of large-caliber ammunition (75-mm. and larger) on the average was within 1 percent of the over-all requirements estimated in the planning phase. Of the total of 2,116,691 rounds expended (including 350,339 rounds lost to the enemy), the greatest expenditure was in 105-mm. howitzer ammunition, with 1,104,630 rounds fired and an additional 225,507 rounds lost to the enemy. (See Appendix C, Table No. 8 and Chart No. 4.) Although this exceeded the total estimated requirements for 105-mm. howitzer ammunition by nearly 8 percent, the expenditure was well within the limits of available supply for the period.
Shortages of 4.2-inch chemical mortar ammunition, resulting in large part from an unusual percentage of defective fuses, were overcome by the use of surplus Navy stocks and by air shipments of replacement fuzes.
The supply of aviation gas on the island always bordered on the critical. Although no air missions had to be canceled, generally the two airfields barely had enough gas to carry out all scheduled missions. The relative scarcity of aviation gas was due principally to slow unloading and the lack of bulk storage facilities ashore. Gas tanks were not completed until the end of April; until then gas had to be brought ashore in drums and cans—a slow, laborious process. The use of DUKW's to take gas directly from the ships to the fields materially expedited unloading. Reserves on hand, however, were never plentiful, and, when a tanker failed to arrive on schedule at the end of April, Tenth Army had to call on the Navy to supply the gas for land-based aircraft from fleet tankers.{482}
The loss of light and medium tanks during the campaign, much heavier than had been expected, caused another critical shortage and replacements could not be secured in time. Tenth Army reported the complete loss of 147 medium tanks and 9 light tanks by 30 June; replacements were requested from Oahu on 28 April but these had not arrived by the end of the campaign. As an emergency measure, all the medium tanks of the 193d Tank Battalion, attached to the 27th Division, were distributed to the other tank battalions on the island. XXIV Corps tank units received fifty of these tanks which contributed materially to combat effectiveness. The 193d, however, could not be reequipped and returned to combat.
Hospitalization and evacuation facilities for battle casualties on Okinawa were also strained by the fierce and costly battle against the Japanese defenses, resulting in higher battle casualties than had been expected. (See Appendix C, Table No. 3.) The non-battle casualties, however, were much lower than anticipated, and the low incidence of disease, with the corresponding reduction of the use of facilities for these long-term cases, provided welcome hospital and surgical facilities for the large number of wounded.{483}
In the normal course of events on Okinawa, a man hit on the battlefield was delivered by a collecting company, in a jeep ambulance, weasel, or weapons carrier, to a battalion aid station located from two to four hundred yards behind the lines. After treatment he was carried by standard or jeep ambulance to a collecting station, the first installation equipped to give whole-blood transfusions. The next stop was the division clearing station, to which portable surgical hospitals were attached. Finally, the patient would reach a field hospital, from four to six thousand yards behind the front. Evacuation to the field hospitals functioned satisfactorily on Okinawa until the end of May, when the heavy rains made the roads impassable. Evacuations from the divisions south of Naha-Yonabaru ceased. It became necessary to evacuate casualties by LST from Yonabaru on the east coast on a June and from Machinato on the west coast on 31 May. By 10 June water evacuation from XXIV Corps zone had been extended south to Minatoga. In the III Amphibious Corps sector at Itoman water evacuation was not feasible because of the reef and enemy fire. As a result, evacuation by L-5 artillery liaison planes was instituted. The planes landed on a stretch of concrete highway just north of Itoman and delivered the patients to Chatan. On 15 June air evacuation of XXIV Corps casualties from Minatoga was begun. By the end of June, 1,232 casualties had been evacuated by cub planes to the field hospitals
