ORIGINAL: Dili
That is not true, even less for those in reverse slope. Read reports of bombardments. The most common word about naval bombardment is disappointment.
Continuing to Google, found this fascinating oral history about D-Day at Saipan, by a Seabee who went in with the Marines as an ammo unloader in an LST.
http://www.battleofsaipan.com/seabee.htm
Well worth a read.
However, he has this to say about shore fire (and other things) that day (excerpts):
"On the top deck in the moonlight, the eye could pick out an occasional flash showing silhouettes of battleships firing salvo after salvo into the coastline ahead. For two days prior to the invasion, some 2,400 16-inch shells had 'softened-up' the enemy. These salvos gave an awesome sound. Something like a boxcar swishing around overhead. Possible mining of the area limited the firing line to six miles offshore, and because of this distance, spotters had difficulty in pinpointing dug-in gun pits.
At sunrise our massive fleet became visible extending as far as the eye could see. Someone said there were 600 ships. The record would show Admiral Spruance had amassed for his vengeance 14 battleships, 25 carriers and carrier escorts, 26 cruisers, 144 destroyers and countless transports, truly a fleet that meant business.
When the Japanese officers, including Admiral Nagumo, the villain of Pearl Harbor, looked through their binoculars,they must have firmly believed American ghosts of Pearl Harbor had returned to haunt them. And they had."
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"Admiral Turner, rough tongued, astute and experienced in Marine assaults, was in charge, and he knew it. At 05:42 (Navy time) his orders came - 'Land the landing force.' Into position about 1,250 yards from the line of departure, 34 LSTs moved into line. Two huge doors on the bow of each ship opened, and dropped their ramps into the water.
Then, out of the front of these LSTs, one by one, the AMTRAKs loaded with toughened Marines clanked down the ramps and into the ocean. A massive total of 719 AMTRAKs separated into special circles at the line of departure. The American Manufacturer's Association would have been very proud of their fine products being displayed to the Japanese that day.
This line of departure was some 4,000 yards from the beach. Before the Marines moved onto the beach, 24 light gun boats made the first sweep of the beach firing 4.5 inch rockets and 40mm canon. They turned aside at the reef. For good measure, Turner had 7 fighters strafe and 12 bombers hit the area with 1,200 one-hundred pound bombs. All of this strafing and heavy shelling from naval gunfire did not silence the dug in enemy. But this action did destroy vital communication links with their commanders."
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"The Japanese were not deeply concerned with Saipan's defenses. Big 8-inch guns were on box cars awaiting emplacement and many trench works, lacked concrete covers. A captured Japanese document told part of the story. "The current freight shortage which is caused by shipping losses has deprived the area of much needed material. One ship out of three is sunk and the second damaged by enemy action." Our submarines took their pound of flesh. For additional credit they sunk two large carriers in attacks on the Japanese fleet, which took on elements of Admiral Spruance's fleet. It was truly an all American effort."
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"With, this assault came a strange irony. On the ends of the long assault line were stationed two old battleships, the California and the Tennessee. Fire power from these battleships was directed by the landing party on various trouble spots. On this assault, each ship fired 100 shells from their 14-inch guns. During the day before the invasion and on 'D' Day, they took some non-critical hits because they were so close to enemy guns. They did not mind. Admiral Nagumo's planes had destroyed these ships at Pearl Harbor. There, the California lost 98 and the Tennessee lost 5 sailors. On these ships, both the living and ghosts of the dead had come to even an old score with the admiral hiding in his bunker."
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"In the distance, only Mt Tapochau stood out in this menagerie of war. High up on this mountain were bunkers for General Saito, Japanese Army Commander, and his naval counterpart, Admiral Nagumo. They held a ringside view of the fighting. But unknown to the American side, our big naval guns had cut communications with their units to pieces. So much so that the Japanese could not mount a large scale counterattack that day. They depended upon the powerful Japanese fleet with its air power to save the island."
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"We received orders on the evening of 'D' Day from CDR Dallas, commander of 302 NCB, to launch the causeway floating piers from the LSTs. When the causeways were in the water, the Seabee crews took them through the narrow channel in the darkness to the Charan Kanoa beachhead. The pier was operational by daybreak, unloading supplies from landing craft.
Orders came the next day to launch all barges carried on 7 LSTs. These LSTs pulled off-shore. As the rigging was being released on one of the LSTs, quick as a snap shot, there were four water spouts off the bow. The enemy gunners missed. The LST moved. The launching continued."