 The landings were scheduled to start at 06 : 30 , " H @-@ Hour " , on a flooding tide , preceded by a 40 @-@ minute naval and 30 @-@ minute aerial bombardment of the beach defenses , with the DD tanks arriving five minutes before H @-@ Hour . The infantry were organized into specially equipped assault sections , 32 men strong , one section to a landing craft , with each section assigned specific objectives in reducing the beach defenses . Immediately behind the first landings the Special Engineer Task Force was to land with the mission of clearing and marking lanes through the beach obstacles . This would allow the larger ships of the follow @-@ up landings to get through safely at high tide . The landing of artillery support was scheduled to start at H + 90 minutes while the main buildup of vehicles was to start at H + 180 minutes . At H + 195 minutes two further Regimental Combat Teams , the 115th RCT of the 29th Infantry Division and the 18th RCT of the 1st Infantry Division were to land , with the 26th RCT of the 1st Infantry Division to be landed on the orders of the V Corps commander . 
