CHAPTER Ii, SECTION 1A to the individual supports and adjusting each pipe to a predetermined grade to which a correction for curvature of the earth had been applied. Figure 2-16 notes personnel and equipment used for the vertical alignment. Horizontal alignment was accomplished by transferring the horizontal line of sight to the individual supports and applying the adjustments by horizontal measurement from the established centerline of the arrav. Figure 2-17 shows a precise level party using Zeiss jevel and Invar rods lished previous to the tests to moor successively four test barges at a location in the Bikini Lagoonoff the Dog-George area. Stations 30 and 40 occupied this location but the location of Station 90 was changed to the Charlie crater and Station 10 to the Flora crater at Eniwetok Atoil. The procedure to position Station 30 con- sisted of mooring the barge at the intersection of predetermined theodolite angles from two reef stations whose precise interrelation was known. The positioning of four anchors was accomplished first by this method, the anchor cables, were connected to the barge and the barge was brought into position with winches. Then the locations and the movement of the working point around a fixed point was checked by repetition of vvservations from the reef stations. Radio communication was used to assure simultaneous observation of angles, and these observations were repeated at intervals and on successive Gays. The results of the observation proved that it was possible to meet the require- ments of mooring and holding the working point of a harge within a two-foot radius circle. Thirty positions were observed on the working point of this barge on 11 April 1954 and 30 on 19 April. Coordinates were computed and plotted for each position and indicated that the working point was being held within a radius of one and a half feet of the assigned coordinates. The mooring of Station 90 in the Charlie crater and of Station 40 in the vicimty of Station 30 location was accomplished under unusually difficult operational conditions. lt was not possible to obtain accurate position or movement checks on these stations. The positions based on limited observations to existing ScienFigure 2-17. Precise Horizontal Alignment The alignment of the pipes was checked by the User by two methods: one was a 200 power Cassegrain telescope and light probes, and the other a gamma raysource. Survey personnel worked with the Users in making these checks, and it was determined that it was practical to meet the alignment specifications by the survey procedure established for this purpose. In future projects of this type, the alignment procedure could be simplified by combining the use of the telescope with the conventional survey methods. Figure 2-18 nutes survey personnel using a target light assembly for the alignment of pipes. Station 2220 consisted of two pipes 5,600 feet long, and Station 2230 of two pipe lines 2,843 feet long. The alignment was accomplished by modification of the procedure used for Station 1203. BARGE POSITIONING AND LOCATION. Procedures and horizontal controls were estab- Figure 2-18. Target Light Assembly Page 2-45 ee mit —_s ow ae me 4 ona v deictmtadiee .