First off the real credit for taking Omaha beach goes to the US Army. That said, a case can be made that a few USN "Tin Cans" provided meaningful assiatnce to those gallant and hard pressed troops at a very critical time. US Navy Destroyers (AKA Tin Cans or just Cans) at Normandy Close-in fire support for the infantry at Omaha Beach was ineffective during the crucial early hours. Why? June 6, 1944, at H-hour 0630 real trouble started. Landing craft coxswains lost their bearings in the early morning mist, deepened by smoke and dust kicked up by the naval bombardment. Many of them missed their assigned landing sectors. Of the 64 DD tanks (amphibious) 27 made it to the Dog beaches but only five got ashore on Easy beaches; the rest foundered on the way in. 0830 USS Carmick breaks the cease-fire order that had suspended supporting naval gunfire at H-hour. (Some 1 & 1/2 to 2 hrs of withering German cliff-top defensive firing w/o much, if any, U.S return fire support at all.) 1st and 29th Division assault waves - sitting ducks. USS Carmick action report: ..."Early in the morning a group of tanks were seen to be having difficulty making their way along the breakwater road toward Exit D-1 [the Vierville draw]. A silent coorporation was established wherein they fired at a target on the bluff above them and we then fired several salvos at the same spot. They then shifted fire futher along the bluff and we used their bursts again as a point of aim."... Captain Sanders, COMDESTRON 18 Commander was in the USS Frankfort, arriving off the beachead just before 0900. Concerned about increasing casualties on the beach, he ordered ALL destroyers to close on the beach as far in as possible and support the assualt troops. Close-in fire support by navy destroyers speeded up much improved conditions all along the beach at Omaha by 1000. After action report: (personal letter from Sergeant James E. Knight of the 299th Combat Engineer Battalion wrote to the crew of the USS Frankfort)..."There is no question, at least in my mind, if you had not come in as close as you did, exposing yourself to God only knows how much, that I would not have survived the night. I truly believe that in the absence of the damage you inflicted on Geman emplacements, the only way any GI was going to leave Omaha was in a matress cover or as a prisoner of war."...Sergeant Barton Davis, 299th Combat Engineer Battalion wrote to say: " How well I remember your ship coming in so close. I thought then as I do now that it was one brave thing to come in so close...Your ship not only knocked out the pillbox but the mortar positions above us...I always thought how great it would be to tell the Captain of this ship how grateful I am..." ( a personal letter to Captain James Semmes, CO of the USS Frankfort). Colonel S.B. Mason, USA, Chief of Staff of the 1st Division, wrote the following letter to Rear Admiral Hall after an inspection of the German defenses at Omaha. They should have been impregnable" "But there was one element of attack they could not parry...I am now firmly convinced that our supporting naval fire got us in; that without that gunfire we positively could not have crossed the beaches."... Almost scraping the bottom with destroyer keels off Omaha Beach were the: USS Frankfort; USS McCook; USS Doyle; USS Thompson; USS Carmick...D-Day - June 6th, 1944. Footnote: In his book, "The Longest Day", Cornelius Ryan so described German defenses of Omaha. The German 352nd Division's artillery batteries were only a part of what Ryan called "the deadly guns of Omaha Beach": There were 8 concrete bunkers with guns of 75 millimeters or larger caliber [75mm to 88mm]; 35 pillboxea with artillery pieces of various sizes/or automatic weapons; 4 batteries of artillery [presumably Pluskat's]; 18 antitank guns [37mm to 75mm]; 6 mortar pits; approximately 40 rocket-launching sites; each with four 38-millimeter rocket tubes; and NO LESS THAN 85 strategically placed machine gun nests My asumption is pre-landing bombardment was lifted as wave 1 got within 500 yds of the beach what we called in the trade (NGFS) "Danger Close." From that point on SOP is to shift to preplanned fire missions so as not to endanger our own people. The naval landing spotter teams would then, under the orders of the Army, place calls for fire on specific targets. It appears very few of these teams made it ashore or survivd long enough to set up shop. Lacking this direction SOP is not to fire danger close to our troops. Exactly how the "Tank spotting" was worked out is not clear but both the US cans and army signal corps types were trained in blinker light and signal flags.