CHAPTER |, SECTION 1 its population. Planning and engineering heretofore described had been modified and extended by the character of the developing test program, and construction in place had reflected its then known requirements. Holmes & Narver Management, delegating most facilities design to Field Engineering forces, had devoted its Home Office Engineering staff to close scientific liaison and priority design of structures as quickly as criteria became firm. The early concept of OPERATION CASTLE as it affected the scientific structures program was that it would consist of two ground shots with zero stations and related photographic and recording stations of the general magnitude of the Mike shot in OPERATION IVY. In addition, the decision was made to try a detonation using a barge anchored in the lagoon for the zero point. This concept was later expanded to include three ground zero detona- tions and three barge shots, and in the fall of 1953 another barge shot was added, making a total test program of seven shots. Early in OPERATION CASTLE the H&N Engineering Division reviewed many of the major structures used in OPERATION IVY and, based on this review, prepared advance estimates of materials required for similar structures anticipated for OPERATION CASTLE. Procurement of standard materials from these advance estimates madeit possible to start a flow of materials to the Atolls prior to completion of design. This technique often made it possible for the Field forces to start construction immediately upon receipt of approved design drawings. The new design criteria developed at Los Alamos were transmitted by J-6 Division, and H&N worked closely at UCRL with their Project Engineers in development of criteria for the Laboratory’s construction requirements. Experience gained during OPERATION IVY with the 9000-foot plywood tunnel con- taining a controlled atmosphere envelope for observations taken on the Mike shot led to a decision to use pipe arrays in OPERATION CASTLE between the zero point and recording stations to accomplish the same general purpose. The information gained from a UCRLbuilt test section of this pipe served as the basis for the design of pipe arrays used in each CASTLE ground shot. The pipe technique imposed rather tight alignment and vacuum retention specifications. Pipe was designed and fabricated early in the program and subsequent construction and alignment problems were successfully solved. The proposal to use a barge as a zero point introduced a problem of maintaining stability but it was eventually determined that a zero point of this type would be feasible. Page 1-6 In order to outfit the 500-ton barges it was necessary to design a barge slip at Elmer with a traveling gantry crane which could be used for construction of the barge superstructure as well as for final installation of equipment by the Users. In addition, it was necessary to design an assembly area at Elmer wherecritical components might be stored and eventually assembled and moved onto the barges. This area incorporated facilities provided in previous operations by the USS Curtiss. Organizing the test structures construction phase of OPERATION CASTLE required a considerable amount of logistical planning because of the large area over which the construction activities were conducted. In order to use as few men as possible on Bikini Atoll and to avoid duplication of facilities, it was decided that all materials would be shipped through the Elmer central warehousing and accounting facilities, and that only a limited warehousing activity would be set up at Tare to handle construction in that area and to act as a redistribution point for materials destined to other sites in the Bikini Lagoon. It was planned that the only exception to this would be those items, such as H-beam steel piling, structural steel, and equipment, which were of such size and of such an easily identifiable nature that logically they should be discharged at Tare. The assignment of an LST by TG 7.3 as the primary means of transporting materials and equipment between the two Atolls made it necessary to carefully evaluate in advance the needs for construction equipment in order that infrequent trips of a landing ship dock (floating drydock) might be used to transport equipment such as cranes which cannot be carried on an LST without dismantling. One of the main construction problems involved in a program of this magnitude and compressed time tables was that of scheduling materials to avoid delays in the program. The normal procurement and shipping time on materials, and particularly on fabricated equipment and structures, was three to four months. Real- izing that this had to be shortened for those Stations which were designed late in the program, it was necessary to take unusual action in all phases of the supply process. For example, in order to expedite fabrication for Zero Stations designed late in the program, it was necessary to obtain a line drawing from Engineering prior to actual design, and from this drawing the Procurement Department canvassed suppliers to determine where material was available, and time-and-material-type contracts were awarded based upon these forecasts. This succeeded in placing a hold on the material and allocating time in vendors’ plants. As designs were firmed up, the vendors were allowed to proceed with fabrication, and by expediting movement of