HEAVY CLOUDS OVER CORREGIDOR. "With the southern tip of Bataan in their possession they could now emplace artillery on the heights of the Mariveles Mountains and along the shore near Cabcaben, only two miles across the channel from Corregidor." Arrows indicate planned Japanese landings.

For the men on Corregidor it seemed as though they were living "in the center of a bull's-eye." During the last week of March there were about sixty air-raid alarms lasting for a total of seventy-four hours. Bombings begun in the morning were usually resumed in the afternoon and again at night. Since the Japanese planes were now based on Clark Field or near Manila, they were able to remain over the target for longer periods than they had during the first bombardment in December.

The effect of so heavy a bombardment over the period of seven days might well have been disastrous had not the men profited from the earlier air attacks and built underground shelters. They had also learned how effectively sand could cushion the blow from a bomb and had made liberal use of sandbags. "It used to be hard to get the men to fill sandbags," wrote one officer. "Now it is hard to keep them from laying hands on all the sandbags available and filling them when those to whom they are allotted aren't looking." The small number of casualties is ample evidence of the thoroughness with which the Corregidor garrison had dug in since the first attack on 29 December.

Installations of all kinds and critical supplies had also been placed under bombproof protection, and these suffered little damage during the bombardment. The few remaining surface installations, however, and supplies in open storage did not fare so well. On Bottomside, the theater, post exchange, and bakery were leveled to the ground and the Navy's radio station damaged. Wainwright's house, inherited from MacArthur, was destroyed on the first day of the attack. "I picked up the light walking stick which MacArthur had left for me," wrote Wainwright, "and walked down to Malinta Tunnel to live there the rest of my time on Corregidor." Several ammunition dumps were hit, exploding the shells in storage, and a quantity of TNT blown up. But losses, on the whole, were small and were quickly repaired by crews which cleared the roads and cleaned out the debris left by exploding bombs.

The Japanese, too, seemed to have profited by their earlier experience and had "learned," Captain Ames observed, "to dodge AA fire." They came in at higher altitudes than before, between 22,000 and 28,000 feet, in formations of nine planes or less. During daylight they made their bombing runs out of the sun, changing course and altitude immediately after the moment of release. Earlier the antiaircraft gun batteries had been able to get in about ten salvos before the Japanese flew out of range, usually bringing down the lead plane of the formation. When the enemy changed his tactics, the antiaircraft guns could get in fewer salvos and could no longer count on the lead plane maintaining the same course.

The most serious limitations on the effectiveness of the 3-inch guns arose from the shortage of mechanically fuzed ammunition, which could reach to a height of 30,000 feet. There was an adequate supply of ammunition with the powder train fuze, effective to a height of about 24,000 feet, but only enough of the longer range type for one of the ten antiaircraft batteries. On 3 February a submarine had brought in 2,750 more rounds of mechanically fuzed ammunition, and it became possible to supply an additional battery. Thus, when the enemy planes came in at an altitude of more than 24,000 feet, only two batteries could reach them. The remaining batteries of the antiaircraft command, equipped with powder train fuzes, could only watch idly while the Japanese leisurely dropped their bombs. Nonetheless, the contribution of these batteries, though negative, was a valuable one. By forcing the enemy to remain at extremely high altitude, they decreased his accuracy and diminished the effectiveness of the bombardment.

From the outset it had been necessary to conserve even the powder train fuzed shells, 30 percent of which were duds. This had been accomplished by limiting each gun to six rounds for any single target on any given course. The opening weeks of the war proved the most expensive in terms of rounds fired to planes destroyed, 500 rounds being required for each plane. This inaccurate fire was due to inexperience, the irregular functioning of powder train fuzes, and variation in the muzzle velocity. Between 8 December and 11 March the 3-inch gun batteries in the harbor defenses expended over 6,000 rounds for a total of 52 aircraft knocked down, or about 120 rounds per plane. With increased experience of both fire control crews and gunners and improved fire discipline, this average was steadily bettered until, by the beginning of April, the expenditure rate went under 100 rounds per plane, an excellent score even under the most favorable conditions.