[138] _Ibid._, VII; Cdr C. E. Allmon, USN, ltr to authors, 9 Mar 55; LCdr T. B. Clark, USN, ltr to authors, 11 Mar 55; and LCdr R. H. Schneeloch, USN, ltr to authors, 20 Mar 55. At 1645, the 18 Army LVT(A)s comprising the first wave of the 1st Marines crossed the line of departure and headed for BLUE Beach. Crawling at four knots, the armored vehicles had three quarters of an hour to cover the 5,500 yards to the target. The LCVPs, capable of twice the speed of the amphibian tractors, left the inner transport area near the _Diachenko’s_ station for the five-mile trip northward to the RED and GREEN boat lanes.[139] [139] ComPhibGru-1 _OpnO 14-50_, Annex Item:VI. The roar of the fire support ships increased in volume during the approach of the landing craft until, at 1705 (H-minus 25), Admiral Higgins signaled the LSMRs into action. At once the cruisers and destroyers fell silent. Again missiles soared from the squat rocket ships in high arcs that sent them plunging into the RED and BLUE landing areas. Upwards of 6,000 rockets detonated in the seaport during the next twenty minutes, further numbing the defenders but at the same time increasing the density and volume of the overcast.[140] [140] _Ibid._, Annex George: II; and Schneeloch ltr, 20 Mar 55. _Seizure of Cemetery Hill_ The critical moment of every amphibious assault was now at hand--the moment when intelligence and planning would be put to the test of actuality. On the bridge of the _Mount McKinley_ high-ranking Army, Navy, and Marine Corps officers gathered again about General MacArthur, seated in a swivel chair. They listened for the second time that day as the loud speaker gave a blow-by-blow account of developments reported by aerial observers. Everything that air attacks and naval gunfire could do to soften up the target had been done, yet no one could be sure just what sort of opposition the troops would encounter on RED and BLUE Beaches. It might be as fainthearted as that brushed aside by 3/5 on Wolmi-do; or it might be that another Tarawa awaited on those cramped strips of urban waterfront lying between the mud flats of the harbor and the dark, crooked streets of the Asiatic town and environs. The enemy had been given ample time in which to prepare for a defense of the mainland. Even the possibility of undetected mines or surprise NKPA air attacks at the last minute had not been overlooked. Although the Attack Force continued to exercise control from the TADC on the _Mount McKinley_ of all aircraft operating in its assigned area, an alternate control agency had been installed on the USS _George Clymer_, utilizing an emergency hookup and a control unit attached to TAC, X Corps. All nets were manned and communications set up to permit a rapid shift of control to General Cushman in case of disaster.[141] [141] 1st MAW _SAR_, basic rpt; and LtGen (Ret) T. J. Cushman interv, 26 Jul 54.