The Siege of Corregidor
Though the fall of Bataan ended all organized opposition on Luzon, it did not give the Japanese the most valuable prize of all, Manila Bay. So long as Corregidor and its sister forts across the entrance to the bay remained in American hands, the use of the finest natural harbor in the Orient was denied them. And before General Homma could report to his already impatient superiors in Tokyo that he had accomplished his mission, he would also have to occupy Mindanao to the south as well as the more important islands in the Visayan group in the central Philippines.
The campaign for the Philippine Islands was not yet over. Though he had won the most decisive battle of that campaign, Homma still had to take Corregidor and the islands south of Luzon before the Japanese could integrate the archipelago into the Greater East Asia Co-Prosperity Sphere.
Since the days of the Spaniards, Corregidor had been used as an outpost for the defense of Manila. (Map 23) By a system of semaphore signals from the island the Spaniards were able to receive warning of the approach of any hostile force in time to alert the forts in and around the capital. Later, they constructed minor fortifications on the island as an outer line of defense and as a screen for the larger guns emplaced along the Cavite shore south of Manila Bay, and at Fort Santiago in Manila. By 1898, when Admiral Dewey sailed into Manila Bay, the Spaniards had on Corregidor three large cannons, each with a range of about one mile. Two of these faced Cavite; the other pointed north toward Bataan. In addition the Spaniards had twelve other coastal guns to defend the approaches to the capital city: on El Fraile and Caballo Islands, which, like Corregidor, lay across the entrance to the bay; along the southern tip of Bataan; and along the Cavite shore.
After the cession of the Philippines to the United States, a vast construction program designed to defend Manila by sealing off the entrance to Manila Bay was begun. During the years before the first World War, forts were built on Corregidor and the adjoining islands in the bay. By 1914 the task was completed. The Americans could now boast of an elaborate defense system in Manila Bay, so strong as to justify the name Gibraltar of the East. Reflecting the doctrine of the era in which they were built, the forts were designed to withstand attack from the sea by the heaviest surface vessels then known.1
The development of military aviation in
CORREGIDOR. Tip of Bataan, upper left.
the decade of the 1920's struck a sharp blow at the effectiveness of this carefully wrought and vastly expensive system of defenses. Nothing could be done to remedy the weakness of the forts, however, for by the Washington Naval Treaty of 1922 the construction of additional fortifications as well as the modernization of those already built was prohibited. Major construction after 1922, therefore, was limited to antiaircraft positions and to the tunnels dug into the solid rock of Malinta Hill on Corregidor, presumably as a storage area for supplies. When the Japanese attacked in December 1941, the defenses of Corregidor and the adjoining islands were little different from what they had been twenty-five years earlier.
Of the four fortified islands in Manila Bay, Corregidor, the site of Fort Mills, was the largest, measuring three and a half miles in length and one and a half miles at its widest point. With its bulbous head pointed toward the west and its tail stretching eastward, this tadpole-shaped island separated the bay entrance into a north and south channel. Corregidor had narrowly missed being two islands, for at the junction of the head and tail it narrowed to 600 yards and dropped to a height only slightly above sea level. This low area was known as Bottomside and contained two docks, the barrio of San Jose, shops, warehouses, a power plant, and cold-storage units. Directly to the east of Bottomside was Malinta Hill with its labyrinth of tunnels. Beyond, stretched the tail of the island, where a small airfield and a navy radio intercept station were located.
West of the narrow neck which connected the tail with the head of the tadpole was a small plateau known as Middleside. Here
MALINTA HILL, looking south. Low area, center, is Bottomside.
were located the hospital, quarters for commissioned and noncommissioned officers, a service club, and two schools for the children of the island. Beyond, lay the heavy head of the tadpole, rising 500 feet above the sea. Called Topside, this area contained the headquarters, barracks, and officers quarters, grouped around the traditional parade grounds. The ground was high almost to the beach line where it dropped precipitously to the water's edge. Cutting into the cliffs were two ravines, James and Cheney, which gave access from the beaches to the crowded area above. These ravines, together with Ramsey Ravine which led to Middleside, were the critical points in the defense of Corregidor against hostile landings.
Critical also to the defense of Corregidor and the ability of its garrison to hold out against a sustained attack was the safety of its power plant. Fresh water for the island had to be brought by barge from Mariveles or pumped from the twenty-one deep wells on the island. Perishable food could be kept in that tropical climate only by power-driven cold-storage plants. The large seacoast gun batteries, though equipped with emergency power sets, relied on the power plant, and ventilation for the vast underground tunnels depended on electrically operated blowers. Although there were sixty- five miles of roads and trails on the island, much of the heavy equipment was moved over an electric railroad with thirteen and a half miles of track which led to all important military installations. The garrison, therefore, was dependent in a very real sense on the island's power plant, and it was natural that those concerned with planning the defense should make every provision to
guard against its destruction by bombardment.
The most extensive construction on Corregidor was the tunnel system under Malinta Hill. Consisting of a main east-west passage 1,400 feet long and 30 feet wide, the tunnel had 25 laterals, each about 400 feet long, branching out at regular intervals from each side of the main passage. The underground hospital was housed in a separate system of tunnels north of the main tunnel and had 12 laterals of its own. It could be reached either through the main tunnel or by a separate outside entrance on the north side of Malinta Hill. Opposite the hospital, under the south side of Malinta, was the Navy tunnel system, connected to the main tunnel by a partially completed low passageway through the quartermaster storage lateral. Reinforced with concrete walls, floors, and overhead arches, blowers to furnish fresh air, and a double-track electric car line along the east-west passage, the Malinta Tunnel furnished bombproof shelter for the hospital, headquarters, and shops, as well as a vast labyrinthine underground storehouse.
The armament of Corregidor was formidable. Its seacoast defense alone consisted of 23 batteries, many with their own names and traditions. Altogether, Corregidor had a total of 56 coastal guns and mortars, all of World War I vintage, ranging in caliber from 3 to 12 inches. (Table 9) The longest range cannon were the two 12-inch guns of Batteries Smith and Hearn, with a horizontal range of 29,000 yards and all-around traverse. In addition, there were six 12-inch guns with a range of 17,000 yards, and ten mortars of the same caliber. Nineteen of Corregidor's guns were the 155-mm. GPF's, capable of a range of 17,000 yards. The ten 3-inchers had the shortest range. The supply of seacoast ammunition was ample but there was little of the type suitable for attacking land targets and no star shells to provide illumination for night fire. North and south of the island were extensive mine fields planted by the Army and Navy.
Antiaircraft equipment consisted of 3- inch guns with a vertical range of 27,000 and 32,000 feet (depending on the type of ammunition used), .50-caliber machine guns, and 60-inch Sperry searchlights. Defending Corregidor from air attack were 24 of these 3-inch guns, 48 machine guns and 5 searchlights. Another battery of 3-inchers was emplaced on the southern tip of Bataan to tie in with these on Corregidor. Ammunition for the antiaircraft weapons was less plentiful than that for the seacoast guns, and there was a critical shortage of mechanically fuzed 3-inch high explosive shells.
Before the war, the Corregidor garrison consisted principally of headquarters, artillery, and service troops. The combined strength of the four fortified islands in Manila Bay at that time did not exceed 6,000 men, most of whom were stationed on Corregidor. After 8 December the population of these garrisons swelled rapidly. First came the survivors of the Cavite naval base, then the headquarters and service troops from Manila. MacArthur's headquarters was established on Corregidor on 25 December and with it came the 809th Military Police Company, two ordnance companies, an engineer company, and service detachments. When Olongapo was evacuated on 26 December, the 4th Marines were also transferred to Corregidor, swelling its population by over 1,000 men. Before the first blow hit that island, it was already crowded with the men of all services and a dizzying pyramid of headquarters.
The defenses of the three other islands in the entrance to Manila Bay were hardly less formidable, proportionately, than those of Corregidor. Caballo (Fort Hughes), just south of Corregidor, was the next largest in size. Only about one quarter of a square mile in area, this island rose abruptly from the bay to a height of 380 feet on its western side. The east coast, which was lower than the rest of the island, was vulnerable to amphibious attack and a marine detachment of about 100 men was sent there to augment the garrison. Later, 200 sailors from Corregidor were added to the marine detachment and Comdr. Francis J. Bridget, who had commanded the naval battalion in the Battle of the Points, assumed command of the beach defenses. His force was almost doubled when the crews of four gunboats, about 225 men, were sent to the island. By the end of April the garrison of Fort Hughes numbered about 800 men of whom 93 were marines and 443 belonged to the Navy. The antiaircraft defenses of the island were tied in with those of Corregidor and consisted of four 3-inch guns. Seacoast artillery numbered thirteen pieces: two 14-inch guns, four 12-inch mortars, two 6-inch guns, three 155-mm. GPF's, and two 3-inchers. (Table 10)
FORT DRUM. El Fraile Island before the concrete battleship was constructed, above; and after, below.
About four miles south of Fort Hughes lay Fort Drum, the most unusual of the harbor defenses. Cutting away the entire top of El Fraile Island down to the water line and using the island as a foundation, the engineers had built a reinforced concrete battleship, 350 feet long and 144 feet wide, with exterior walls of concrete and steel 25 to 36 feet thick. The top deck of this concrete battleship was 40 feet above the low-water mark and had 20-foot-thick walls. Equipped with four 14-inch guns in armored turrets facing seaward, a secondary battery of four casemated 6-inch guns, and antiaircraft defense, the fort with its 200- man garrison was considered, even in 1941, impregnable to attack.
The southernmost of the fortified islands was Carabao, only 500 yards from the shores of Cavite Province. Except at one point along its eastern shore, the island rises precipitously from the sea in cliffs more than 100 feet high. On this uninviting island the Americans had placed Fort Frank, which late in 1941 had a military garrison of about 400 men, mostly Philippine Scouts. Its armament consisted of two 14-inch guns, eight 12-inch mortars, four 155-mm. GPF's, as well as antiaircraft and beach defense weapons.
All four forts in Manila Bay, as well as Fort Wint in Subic Bay, had been formed before the war into an organization called the Harbor Defenses of Manila and Subic Bays which, in August 1941, became a part of the Philippine Coast Artillery Command. Both were commanded by Maj. Gen. George F. Moore who also commanded the Corregidor garrison. The 5,700 men assigned to the Harbor Defenses were organized into three seacoast and one antiaircraft artillery regiments, headquarters, and service troops. The three seacoast units included the American 59th and the Philippine Scout 91st and 92d. The 60th, the antiaircraft regiment, was composed of Americans. About 600 Philippine Army soldiers in training were organized into the 1st and 2d Coast Artillery Regiments (PA), but operated under the control of the two Scout regiments.2
General Moore commanded not only the seacoast and antiaircraft artillery but the beach defenses and inshore patrol as well. To exercise tactical control over all elements of his force, he had four major commands. Seaward defense he placed under Col. Paul D. Bunker who, in turn, commanded four groups, two of which covered North Channel and two South Channel. All antiaircraft units were under Col. Theodore M. Chase, commander of the 60th Coast Artillery. In addition to the normal mission of providing defense against air attack, Chase also maintained an air warning service for the fortified islands and for vessels in the bay. Though each fort commander was responsible for local defense, General Moore had an executive for beach defense who co-ordinated the plans for each of the islands. The inshore patrol remained a naval function, but under the principle of unity of command, Capt. Kenneth M. Hoeffel, USN, was under Moore's tactical control.
By the end of 1941 all that could be done in the limited time since funds had been made available in midyear to improve the defenses of Corregidor and the adjoining
islands had been accomplished.3 But the basic weakness of the harbor defenses- their vulnerability to attack from the air and from their landward flanks-was never corrected. They accomplished their mission, the denial of Manila Bay to the enemy, without firing a single round at a hostile warship; Japanese cruisers and destroyers blockading the bay stayed well out of range of Moore's heavy guns. But when Bataan fell the flank protection of Corregidor disappeared and the fortress was left exposed to destruction by air and artillery attacks and to landings by hostile forces.
First word of the Japanese attack against Pearl Harbor reached General Moore from the Navy radio intercept station on Corregidor at 0340, 8 December, about the same time that General Sutherland relayed the news to the commander in chief. The garrisons of the four fortified islands had been on the alert for eight days and all battle stations were manned. There was little Moore could do except notify his commanders and instruct the sea, antiaircraft, and beach defense commanders to double their precautions against a surprise dawn attack. At 0620 official notification that a state of war existed between the United States and Japan came from MacArthur's headquarters, and the Navy temporarily closed Manila Bay to outbound traffic. About four hours later the first air-raid alarm sounded over Corregidor.4
This first alarm and those that followed during the next three weeks proved groundless. The Japanese did not attack Corregidor on 8 December and had no plan to do so at the start of war. But they had no intention either of bypassing the island fortress. They fully appreciated its strategic significance and its importance in the scheme of defense, but their first task was to seize Manila and defeat MacArthur's army. The conquest of Corregidor would follow "as soon as possible."5
The Aerial Attacks
Hardly had news of the evacuation of Manila and the transfer of MacArthur's headquarters to Corregidor reached Homma on 28 December when he ordered the 5th Air Group to begin operations against the island. Manila would soon be his and though MacArthur's army had not yet been defeated, Homma may have believed that he could soon move against Corregidor. Homma's plans, by agreement with the Navy, provided for a joint attack in which Lt. Gen. Hideyoshi Obata's 5th Air Group (Army) would be supplemented by the planes of the 11th Air Fleet (Navy). The
Army air force would strike first, at noon of 29 December, "with its whole strength." An hour later the Navy bombers were to take over. The bombardment would continue for two and a half hours, until 1430, and would, General Obata hoped, "destroy the center of the American Far East Command."6
Almost exactly on schedule, at 1154 of the 29th, the first flight of 18 twin-engine bombers of the 14th Heavy Bombardment Regiment, covered by 19 fighters, approached Corregidor at a height of 15,000 feet and in regular V formation. The flight broke into smaller flights, of 9 and 3 planes, which passed lengthwise over the island, then back, dropping 225- and 550-pound bombs on the headquarters buildings and barracks. For the half hour they were over the target, the planes of the 14th Heavy Bombardment dropped almost fifty bombs.
At 1230, 22 bombers of the 8th Light Bombardment Regiment, accompanied by 18 dive bombers of the 16th Light Bombardment Regiment, had their turn. The light bombers followed the same pattern as the first flight, dropping their sixty-six 225- pound bombs on installations and buildings on Bottomside and Topside. The dive bombers, loaded with 35-pounders, attacked from an altitude of 3,000 feet, though to the men on the ground the planes appeared to be at treetop level.
When the dive bombers left at 1300, the Navy bombers came in. Numbering about 60 planes, the naval formation continued the attack against the island and shipping in the bay for another hour. Altogether, the Americans estimated, the Japanese used about 81 mediums and 10 dive bombers and dropped about 60 tons of bombs during these two hours. None of the few remaining American aircraft rose from the recently established fighter base on Bataan to dispute their supremacy of the air on this occasion or during any of the attacks that followed.
In this first attack the antiaircraft defenses at Fort Mills, Fort Hughes, and southern Bataan gave a good account of themselves, firing a total of 1,200 rounds of 3- inch ammunition. Score for the 3-inchers was thirteen medium bombers. It was with considerable satisfaction that Capt. Roland G. Ames, commander of Battery C (Chicago), 60th Coast Artillery (AA), wrote after the attack that his men "had performed wonderfully" in their first encounter with the enemy and had brought down at least three Japanese planes.7
The dive bombers, too, were met by strong and effective opposition. The .50- caliber machine guns of the antiaircraft command downed four of the planes in their first low-level strafing attack. Thereafter, according to American sources, the Japanese did not again attempt to dive-bomb targets on Corregidor until the end of April.
The men had paid little heed to the alarm when it first sounded, since none of the previous air warnings had been followed by attack. Some of those who had recently arrived on the island with the transfer of headquarters from Manila to Corregidor casually took up a better position to watch the large enemy formation. One officer in the concrete building on Topside which housed USAFFE headquarters mounted to the second floor for a clearer view of the proceedings. Hardly had he arrived there when he heard "an ominous, whirring whistle, which rapidly increased in crescendo." He made a wild jump for the stairway, later claiming
that "the whistle of my descent must have rivalled that of the falling bomb."8 Others were equally surprised and displayed a tendency to head for the corners of the rooms where they fancied they were safer than elsewhere. Fortunately windows and entrances had been sandbagged and broken glass caused few casualties.
The first bombs hit the vacated station hospital and many of the wooden structures on Topside and Middleside. One bomb struck the post exchange, went through the roof and three concrete floors, buried itself in eight feet of earth, and left a crater about twenty feet in diameter. Fully half the barracks and headquarters buildings were demolished and only a part of the foundation of the officers' club remained after the bombing. Many of the structures were of corrugated iron, and the danger from flying bits of metal was often as great as that from the bombs. Bottomside, after the bombing, appeared to be "one huge mass of jagged and bent sheet iron."9 Fire sprang up at many points so that to an observer on Bataan the island appeared to be enveloped "in clouds of dust and black smoke."10 Altogether about 60 percent of all wooden buildings on Corregidor were destroyed during the first bombings. Headquarters, USAFFE, promptly moved into Malinta Tunnel the next day.
Fortunately, damage to military installations, the major target of the Japanese aircraft, was comparatively slight. Two of the gun batteries suffered minor damage which was repaired within twenty-four hours. Several of the small vessels docked at Bottomside and at anchor near the island were hit, and two Philippine Army planes at Kindley Field on the tail of the tadpole were destroyed. Power, communication, and water lines were temporarily disrupted but little permanent damage was wrought. Casualties for the day were twenty killed and eighty wounded.
After the first bombings there was a marked change in the reaction of the men. Before the 29th, despite warning, they had crowded the doorways and windows to watch the planes and speculate about probable targets, safe in the knowledge that Corregidor would not be hit. "All of us," wrote Captain Ames, "were too careless of bombs and bullets at first."11 But that attitude quickly changed. "Now," noted Colonel Bunker, commander of the Seaward Defenses, "they all stampede for the nearest cover and get as far under it as possible."12 As a matter of fact, it soon became difficult to get some of the men out of their shelters, even when there were no planes overhead.
There was a marked change, too, in the attitude toward the weather after the first attack from the air. Bright moonlight, "by which we had wooed our sweethearts and wives," carried the threat of night attack. It gave away the position of vessels and made the large searchlights of the harbor defenses nearly useless. The beautiful sunrise and sunset of the tropics lost their attractiveness when enemy planes chose that time for attack. In the muted light of dawn and dusk it was difficult to pick out the attacking aircraft. Clouds, unless they were high and solid, were considered "a curse" by the antiaircraft gunners, and cloud formations through which enemy aircraft could drop for a bombing run were a "pet hate." The feared typhoons, on the other hand, were eagerly awaited. "We prayed for them
. . .," wrote Captain Ames, "to break up and destroy Jap planes and ships."13
For the next eight days, until 6 January, the Japanese continued to bomb Corregidor intermittently, with less and less effect and at greater cost to themselves. There were no enemy aircraft over the island on the 30th, when President Quezon was inaugurated for the second time, or on the 31st. There is some indication of air action on the first day of the New Year, but it was on the 2d, the date Manila was occupied, that the Japanese came back in force.
The day was overcast, with a low ceiling of shifting clouds. Shortly after the noon hour the first enemy bombers burst through a hole in the low-hanging clouds, released their bombs, then flew up into the safety of the clouds. Altogether fifty-four enemy aircraft participated in the attack that day. They left behind, in Colonel Bunkers words, "a scene of destruction." On a tour of inspection, he saw huge sections of corrugated iron "scattered in painfully distorted shapes" all over the parade ground, and "gaping, square, empty openings" in the barracks.14
The bombardment of the 2d was the beginning of a five-day assault during which hardly a yard of the island did not feel the effects of the enemy bombs. Except for the attacks on the 2d and the 5th, the sole enemy target was Corregidor. On the 2d, Fort Drum, and on the 5th, Fort Frank came in for their share of the bombs but were never the primary targets.
The pattern of the daily Japanese attacks was usually the same. During the morning a lone photo reconnaissance plane, whose pilot the Americans referred to familiarly as Photo Joe or The Lone Ranger, would circle Corregidor and the other fortified islands for a time and then return to base. About 1230 the bombers would come in, flying at an altitude well above 20,000 feet and at a speed of about 160 miles an hour, bomb the island for about two hours, then fly off. Until the last day, they approached the target from the same direction in a large V formation, then broke up into smaller formations for the run over the island. Only at the end did the Japanese abandon this regular formation and approach the target from different directions in scattered formations and at varying altitudes.
Total damages for the six days' bombing were extensive. On the 2d and 3d the buildings on Topside and Middleside were hit again and two of the island's precious water tanks destroyed. On the 4th the principal target was the wharves, shops, and warehouses on Bottomside. The next day a barge was bombed and set afire. It drifted into shore and set fire to a diesel oil dump near the power plant. On the 6th there was a tragic accident when thirty-four men took cover in an incomplete bomb shelter. A large bomb fell near the structure, which collapsed and killed thirty-one of the men. By the 7th practically all unprotected surface installations had disappeared or were in ruins. Bomb craters were uniformly scattered over the island and one could hardly walk more than twenty-five yards in any direction without stumbling into one.
The worst destruction was caused by fire. Barely adequate during peacetime, the Fort Mills fire department proved unable to cope with the conditions created by the hail of
GUN EMPLACEMENTS ON CORREGIDOR. Coastal defense gun at Cheney Battery, above; below, 3-inch
bombs. Much material, such as lumber, hardware, mattresses, and medical and chemical warfare supplies, which had been stored on the surface in wooden buildings, was burned. Concrete structures suffered less from the bombings and from fire, and the supplies stored in them were salvaged.
After the first attack no effort was made to keep the electric railroad line on the island in operation. It had been hit in so many places and was so exposed that it was fruitless to attempt its repair. Almost daily the main telephone cables were cut by bombs. Crews worked at night to repair them, but the next day the lines would be cut again. The maintenance of communications was a never-ending task, and there was never time to bury the cables deep enough to place them out of reach of the bombs.
The armament of the island suffered comparatively slight damage. The coastal batteries with their magazines and power plants had been bomb-proofed before the war and escaped almost unscathed. The more exposed antiaircraft units suffered more from the bombings than the seacoast batteries, but such damage as was caused was repaired quickly, usually within twelve hours. There were some casualties among the gun crews, but they were not serious enough to interfere with operations. The largest number of casualties came to those who failed to take shelter or were careless. There is no record of the total casualties for the period from 29 December to 7 January, but at least 36 men were killed and another 140 wounded during the first, second, and last days of the attack alone.
The air attacks against Corregidor ended on 6 January, the day the Bataan campaign opened. They had proved costly to the Japanese and had produced no decisive military results. But even if they had and if Homma had wished to continue to bomb the island after 6 January, he would have been unable to do so. By that time the 5th Air Group was preparing to move to Thailand, and Homma was left with only a small air force which he could ill spare for attacks against Corregidor. Except for sporadic raids by three or four planes and occasional dive bombing and strafing, the first aerial bombardment was over.
The Artillery Bombardment
Events thus far had not worked out as the Japanese had planned. The occupation of Manila had not given them the use of its fine harbor or the large military stores they had expected to find there. MacArthur had refused battle on the plains of Manila, and drawn his forces back into the Bataan peninsula intact. The occupation of Corregidor, which was next on the Japanese timetable, now had to be deferred for the lengthy and expensive campaign on Bataan. If the first air attacks against the island fortress had been intended as the prelude for a landing, they had been wasted.
To have attempted the investment of the Gibraltar of the East while the Bataan peninsula was in American hands would have been disastrous and foolhardy. The heights of the Mariveles Mountains dominated the small island only two miles offshore and were vital to its control. Even before the war the Japanese had recognized the intimate relationship between Bataan and Corregidor and in their prewar estimates had noted the flank protection Bataan offered to the island. "Mt. Mariveles in southern Bataan forms the left wall of the bay entrance," one Japanese estimate concluded, "and because
it is covered with dense forests, use of siege guns and heavy equipment to attack this fortress is impossible."15
The southern shore of Manila Bay offered only partial protection to the islands lying at the bay entrance. Here the ground was less mountainous and overgrown than on Bataan, and in the vicinity of Ternate, opposite the tip of Bataan, there were few obstacles to military movement. Into this area could be brought heavy equipment and siege guns. Once emplaced, these guns could bring the southernmost of the islands, Forts Frank and Drum, under assault. It was from here that the next attack against the harbor defenses came.
Toward the end of January reports began to reach Corregidor of the movement of Japanese artillery into Cavite Province. By the 25th, according to observers on the mainland, the Japanese had emplaced their guns in defiladed positions near Ternate, only about six air miles from Fort Drum on El Fraile Island and eight miles from the neighboring Fort Frank on Carabao Island.
The reports were correct. A Japanese artillery unit called the Kondo Detachment was indeed moving into position along the southern shore of Manila Bay. Formed by 14th Army on 24 January, this unit was under the command of Maj. Toshinori Kondo and consisted initially of four 105- mm. guns and two 150-mm. cannons. Kondo's orders were "to secretly deploy" near Ternate and "prepare for fire missions" against Corregidor, El Fraile, and Carabao Islands and against shipping in Manila Bay.16 By the first week of February, despite interdiction fire from Fort Frank, Kondo had completed his preparations and was awaiting further orders.
He did not have long to wait. On 5 February, his orders arrived and next morning at 0800 the Kondo Detachment opened fire against the fortified islands. Fort Drum was the principal target that day and the Japanese guns hit it almost one hundred times during the three-hour attack. By accident or design, the choice of the early morning hours for the attack placed the sun behind the Japanese and made observation by the Americans difficult. They replied as best they could with their 14- and 6-inch guns, and Fort Frank assisted with its 12-inch mortars, but scored no hits. Thus began an artillery duel that was to continue intermittently for almost two months.
Until the middle of February the daily attacks followed much the same pattern. Major Kondo's 105's and 150's usually opened fire in the morning, to be answered by counterbattery fire from the large guns of the harbor defenses. Later the Japanese fired at odd intervals during the day. Forts Frank and Drum, closest to Ternate, received the heaviest weight of shells and the greatest damage but their guns were never put out of commission and their effectiveness never seriously impaired. Damage to Corregidor was limited to occasional hits on buildings and vehicles.
During the course of the bombardment the Japanese hit upon a scheme to strike a vital blow at Fort Frank without firing a single shot. Learning from the natives that the fort received its supply of fresh water from a dam near Calumpan on the Cavite shore, they dispatched a demolition squad to locate and destroy the pipeline. On 16 February, the Japanese found the line and pulled up the section just below the dam.
Fort Frank, fortunately, had its own distillation plant and Colonel Boudreau, who had assumed command of the fort after the
evacuation of Fort Wint in December, directed that it be placed in operation at once. But its use required valuable fuel and Boudreau was understandably reluctant to expend the gasoline he needed for his guns to distill sea water. On the 19th, therefore, he made an effort to repair the pipeline and sent a group of fifteen volunteers to the mainland for that purpose. Before the men could restore the line they were attacked by a Japanese patrol of about thirty men. In the fight that followed, the Americans and Filipinos, with the support of 75-mm. guns from Fort Frank, destroyed the entire patrol, suffering only one casualty.17 The fifteen men then returned to Fort Frank safely but without having accomplished their mission. That night the Japanese retaliated by burning the barrio of Calumpan. It was not until 9 March that Colonel Boudreau was able to repair the broken water pipe.
The intensity of the Japanese attacks increased after the middle of February, when Major Kondo received two additional 150- mm. howitzers. With these reinforcements came instructions from Homma "to demoralize the enemy."18 The daily bombardments thereafter became more severe and reached their height on 20 February. Starting at 0930 that morning the guns of the reinforced Kondo Detachment fired steadily at one-minute intervals until late afternoon. The only serious damage was to the power plant on Corregidor and to several observation posts at Fort Hughes. After that date the Japanese fire diminished until, by the beginning of March, it presented no real threat to the harbor defenses. "In general," wrote the commander of the Seaward Defenses, "the Japs are resorting to nuisance firing daily and usually from a single gun."19
The slackening of enemy fire at the end of February did not mean that the attack was over. On the basis of intelligence reports, General Moore concluded that the Japanese were merely "marking time waiting for reinforcements."20 This view was confirmed when native informants reported that the Japanese were selecting new gun positions in the Pico de Loro hills southwest of Ternate and improving the trails leading into the interior. In an effort to hinder this move, General Moore ordered his seacoast batteries to place interdiction fire on roads and bridges in the vicinity of Ternate, but without observable effect. The Japanese continued to make their preparation for a fresh attack without serious interference from the coastal batteries in the bay.
The Japanese force which assembled in the Pico de Loro hills during the first two weeks of March was considerably stronger than the Kondo Detachment. To that unit had been added the 1st Heavy Artillery Regiment, the 2d Independent Heavy Artillery Battery, both equipped with 240-mm. howitzers, and the 3d Tractor Unit with prime movers for the heavy guns. The Kondo Detachment had been dissolved and a new organization, the Hayakawa Detachment, formed. Col. Masayoshi Hayakawa, commander of the 1st Heavy Artillery, led the reorganized force, and, according to the usual Japanese practice, gave it his name. By 15 March all preparations for the stepped-up artillery bombardment of the harbor defenses had been completed.
The attack opened at 0730 of the 15th with a volley from the 240-mm. howitzers
and continued throughout the day. Although all four islands came under fire, Forts Frank and Drum bore the brunt of the bombardment. Approximately 500 shells fell on Fort Frank alone; another 100 on Fort Drum. Two of Frank's batteries, one of 155-mm. guns and the other of 3-inch antiaircraft guns, were almost entirely destroyed, and two other batteries were put out of commission temporarily. Fort Drum escaped more lightly. Its only damage came when a shell penetrated the armor of the 6- inch battery on the south side and burst inside the casemate, filling the concrete battleship with flames, smoke, and fumes. Fortunately, there were no casualties. Despite every effort during the day to neutralize the enemy fire, the bombardment continued until afternoon. "It hurt me like blazes," wrote Colonel Bunker on Corregidor, "to see my friends under fire and be so powerless to help them."21
The attack continued with unabated vigor the next day and with varying intensity for five days thereafter. As on the 15th, all four forts came under fire, but the weight of the attack was again directed against the two southernmost islands. The heaviest bombardments came on the 16th and 21st. On both days the concrete battleship fairly shook under the impact of the large shells. Every time one of them hit the casemate of the 6-inch guns a flash of fire was observed, and during the height of the attack there were fire alarms as often as every five minutes. Fortunately there was no general conflagration and no serious damage.
Fort Frank was not so fortunate. On the 16th a 240-mm. shell penetrated eighteen inches of concrete around one of its 12-inch batteries, passed under a six-foot concrete wall and exploded below the powder room. The floor of the battery was shattered and sixty cans of mortar powder overturned, but, miraculously, none exploded. It was on the morning of the 21st that Fort Frank suffered its "greatest loss" of the war when a 240-mm. shell penetrated the 18-inch concrete roof of one of its tunnels and struck in the midst of a line of men waiting for yellow fever shots. Twenty-eight of the men were killed and another forty-six wounded.22
The damage wrought by the artillery attacks between 15 and 21 March was considerably greater than any inflicted by the 105's and 150's of the Kondo Detachment. Fort Frank, the larger target and the one closest to the enemy, was the most vulnerable of the forts and "got a fearful working-over."23 All of its surface guns-four 3-inch antiaircraft and four 155-mm. GPF guns- were visible to the enemy and were badly damaged. The depressed 12-inch mortar battery and two 14-inch disappearing guns were also hit, but were quickly repaired and put back in action. Fort Drum, the concrete battleship, came under as severe a bombardment as Frank, but was better able to withstand the battering. Every square foot of the interior surface of the casemates was deeply dented and torn by fragmentation, and between eight and fifteen feet of its reinforced concrete deck was whittled away. But though its two antiaircraft guns were ruined beyond repair, the principal target of the Japanese, the 14-inch turret guns, were never put out of action.
So heavy were the attacks against Frank and Drum that the commanders of both forts, fearing a hostile landing, had doubled their beach defenses immediately. This pre-
caution was a wise one, for the Japanese did actually plan to capture both Forts Frank and Drum, and had even designated the unit which was to make the assault. General Homma canceled this plan, however, in order to strengthen the force he was assembling late in March for the final attack against Bataan. The landing craft which had been collected for the attack, about forty-five bancas, were later destroyed by 75-mm. gunfire from Fort Frank.
Throughout the long-range artillery duel the effectiveness of American counterbattery fire was limited by the difficulty of locating the Japanese guns. There was no flash during daylight, and both Kondo and Hayakawa were careful to take every precaution to avoid giving away their position. They camouflaged their guns skillfully, moved them when necessary, and even sent up false smoke rings when their batteries were in action. The American and Filipino artillerymen tried to fix the enemy's position by the use of sound waves, but this method proved too delicate and complicated. Another method, admittedly less accurate but easier to use, was to compute the enemy's position by the line of falling duds. The results could rarely be checked, but the batteries of all four forts fired daily, hopeful that they might knock out some of the Japanese guns with a lucky hit.
For a time firing data was received from a small group of volunteers on the mainland led by Capt. Richard G. Ivey of the 60th Coast Artillery (AA). Ivey had established an observation post on high ground along the south coast of the bay and, until he was driven out on 15 February, served as a spotter, sending his information by walkie-talkie radio. Even this observed fire proved of doubtful effectiveness. During one bombardment, when Ivey's reports appeared inconsistent, the fire control center asked him how he knew there was a Japanese gun in the position. "He replied," wrote Colonel Bunker, "that he couldn't see it, but judged by the sound that it was there."24 When fire was shifted to another target, the observer's instructions, which failed to distinguish between deflection and range, were just as confusing and the fire was discontinued.
Rarely was General Moore able to secure the services of the few remaining aircraft to fly reconnaissance. When he did the results were most gratifying. One such occasion came on 9 February, when Capt. Jesus A. Villamor, in an obsolete Philippine Army training plane equipped with a camera, set out to take photographs of the Ternate area. Protecting his slow and unarmed biplane were six P-40's. Villamor completed his mission, but on the way back the formation was attacked by six enemy fighters. While Villamor came in with his precious photographs, the P-40's engaged the enemy in a spectacular fight over Bataan. In the space of a few minutes the American pilots brought down four of the enemy fighters and fatally damaged the remaining two. Only one P-40 was lost.25 Meanwhile the photographs taken by Villamor were printed and rushed to Corregidor where they were collated with reports from observers on the ground. The counterbattery fire that followed proved remarkably accurate and several direct hits were scored.
The difficulties of counterbattery fire were further increased when the Japanese moved their guns to the Pico de Loro hills
where they could be reached only by high trajectory fire. Few of the coastal guns in the harbor defenses, which had been designed for use against warships, had sufficient elevation to clear the high ground before the enemy positions. Their difficulty is illustrated by the experience of the men of Battery Hearn on 21 March, who, "in a desperate effort to silence the Japs," opened fire with their 12-inch guns. "We wound up," Colonel Bunker wrote, "with our guns elevated against the elevation stops-and that wasn't any too much."26
The only weapon in the armament of the harbor defenses with the high trajectory required to deliver effective counterbattery fire under these circumstances was the 12- inch mortar. There were twenty-two of these pieces on the four islands, but their usefulness against land targets was limited by the lack of sound ranging equipment and the shortage of ammunition with instantaneous fuzes. There was an ample supply of armor-piercing, fixed, delay fuze ammunition with a small bursting charge. This type was designed for use by coast artillery against warships but was of little use in the situation the Seaward Defenses then faced. These shells buried themselves deep in the earth before exploding and caused little damage to men and installations near by. The. ideal ammunition against the targets presented by the Japanese guns on the Cavite shore was the personnel type with instantaneous point detonating fuze. There were about 1,000 such shells, of 12-inch caliber and weighing 670 pounds, but even this small amount could not be used freely, for it would be desperately needed when Bataan fell and the enemy placed his heavy guns on the slopes of the Mariveles Mountains.
A small quantity of additional instantaneous fuze ammunition was obtained as a result of experiments made by Colonel Bunker, He modified the fuze of the 1,070- pound shells used in the 12-inch guns by removing the .05-second delay pellet, thus detonating the shell more quickly. When he test-fired two such shells he got "beautiful results, up to my wildest hopes." The effect, he noted, was equal to that of a personnel shell, "both in dirt thrown up and in noise made."27 But though the modified projectile exploded on impact, it had only a small bursting charge and a limited effect. Thus, despite every effort to secure effective counterbattery fire, the Americans were never able to prevent the Japanese from firing almost at will.
The artillery duel which had begun early in February came to an end on 22 March. Though the Americans reported artillery fire from the Cavite shore until early in April, it could not have come from the Hayakawa Detachment. That force had been disbanded on the 22d and its elements ordered to rejoin their parent units for the final attack against Bataan, then about to open. Whatever guns remained behind were of smaller caliber and were intended only to annoy the defenders.
Life Under Siege
Since the first air attacks at the end of December the garrisons of the four fortified islands had worked steadily to repair the damages and improve their positions. On Corregidor a tunnel, begun in 1921 but discontinued because of treaty agreements, was rapidly pushed to completion to serve as a command post for the Seaward Defenses. The island's defenses were further
strengthened by the addition of an 8-inch gun with a range of 24,000 yards and a 360-degree traverse. This gun was brought over from Bataan and mounted on a prepared concrete base near Malinta. Though it was tested and ready for use by 4 March, no crew was available and the gun never fired a shot at the enemy. At Fort Hughes, one 155-mm. gun facing the sea was dismounted, moved through the tunnel, and emplaced on the opposite side of the island, pointing toward Bataan.
Vital installations were strengthened in various ways. Around the large well at the west end of Malinta Tunnel the engineers placed a circular parapet of sandbags, and over the gasoline storage area on Morrison Hill they placed two feet of heavily reinforced concrete, which they then camouflaged. Similar protection was given the Harbor Defenses telephone exchange at Topside. Near the entrance to Malinta Tunnel and in the port area at Bottomside, the engineers constructed tank obstacles consisting of square concrete posts reinforced with steel rails. About the same time, they placed roofs over the 75-mm. guns supporting the beach defense troops to give them protection against dive bombers.
Shortcomings in the design and location of various installations had become apparent by this time and these were corrected when the intensity of the enemy fire declined. Early plans had not taken into consideration the possibility of artillery fire from the Cavite shore and some of the tunnel entrances now faced the oncoming shells. After one attack Colonel Bunker checked his firing data and concluded that the main entrance to the Seaward Defenses command post "now points exactly along the Jap trajectory."28 Where possible, other openings were constructed, but in most cases protection was provided by baffle walls.
With the technical advice of the engineers practically all the batteries began to build their own tunnels. Some dug tunnels where there was no apparent reason for one. "We have to be at our gun practically all the time," observed one battery commander, whose men were hard at work on a tunnel, "so we may not be able to spend too much time, if any at all, in a tunnel."29 Even the troops on beach defense caught the fever and, with whatever materials they could beg or borrow, dug tunnels and constructed overhead protection. "It is safe to venture a guess," wrote the engineer cautiously, "that if all the tunnels constructed on Corregidor after hostilities commenced were connected end to end the resultant summation would not be less than two miles."30
Life on the four fortified islands in Manila Bay settled into a dreary routine. When the men were not building fortifications or going about their daily chores, they had little to do. Complaints were frequent and often dealt with the subject of food. The ration had been cut in half on 5 January, at the same time it had been cut on Bataan. The more enterprising of the men found ways of their own to increase the amount and vary the monotony of the ration, but the opportunities were fewer than on Bataan. Sunken or damaged barges washed close to shore offered a profitable field for exploitation during the early days of the campaign. One unit filled its trucks with a cargo of dried fruits salvaged from one such barge and stored it
away for future use. "Now," wrote Colonel Bunker, "if they'll only drink a lot of water, they'll be fixed fine."31
Some even managed to procure liquor in this way. One of the barges sent out from Manila just before the Japanese occupation had been loaded with whiskey from the Army and Navy Club. It was sunk in shallow water and many of the men spent their off-duty hours diving in the oil-coated waters in the hope of bringing up a bottle. Before the military police took over to relieve the lucky divers of their catch as they reached the shore, a large number of soldiers had laid in a stock of the precious commodity.32 President Quezon's yacht is also said to have supplied at least one unit with a store of fine wine. When it was being unloaded one dark night, it is reported that an officer directed the dock hands to load two trucks simultaneously. When the job was finished, one of the trucks silently disappeared into the night with its valuable cargo, never to be seen again.33
Life everywhere on the islands went underground and the symbol of the new mole-like existence was Malinta Tunnel. "Everyone who doesn't need to be elsewhere," observed Captain Ames, "was in a tunnel-chiefly Malinta."34 During the bombings it was always jammed with Americans and Filipinos who huddled back against the boxes of food and ammunition stacked along the sides to a height of six feet. Crowded into the tunnel were the highest headquarters in the Philippines, the lawful government of the Commonwealth, the 1,000-bed hospital, vast quantities of supplies, power plants, machinery, and other vital installations. One lateral alone was taken over by USAFFE. Here General MacArthur had a desk, before which were lined up his staff officers' desks. To the rear were the double-decker beds where the staff slept. Malinta also housed those dignitaries who had been evacuated from Manila. The civilians followed the routine of the military garrison, but an exception was made for the women, who were assigned special facilities in an area known as the "ladies' lateral."35
For the men outside, a trip through the tunnel was an interesting experience and never failed to rouse wonder. Milling about were Philippine and American government officials, officers of all services and all ranks, nurses in white starched uniforms, war correspondents, laborers, repair and construction crews, barbers, convalescents, and frightened soldiers in search of safety. "It is a revelation to walk through these tunnels," wrote Captain Ames to his wife. "At one time you are rubbing elbows with the daughter of some P.I. [Philippine] official, dodging a lady war correspondent, talking to a naval officer, being jostled by a plumber, . . . and having your shoes mopped by some Filipino janitor."36
Outside the tunnel the men encountered unusual and sometimes strange sights. President Quezon, ill with tuberculosis and confined to a wheel chair, spent as much time as he could outside the dust-laden tunnel, as did the U.S. High Commissioner Francis B. Sayre. On 30 December a small group wit-
USAFFE HEADQUARTERS IN MALINTA TUNNEL. General MacArthur with General Sutherland,
nessed Quezon's second inauguration in an impressive ceremony at the mouth of the tunnel and listened to speeches by the President, the High Commissioner, and General MacArthur. Some saw, too, larger sums of money and more gold than they had ever imagined in their youthful dreams of pirate treasure chests. But values change in war and they watched without visible emotion the unloading of the gold, silver, and securities of the Philippine treasury on the Corregidor docks and their removal to a strong room deep in the tunnel.
Life on the islands had its seamier side. Not all men were brave and each garrison had its share of "tunnel rats," the taunt reserved for those who never left the safety of Malinta Tunnel. Such men were said to have "tunnelitis," a disease characterized by a furtive manner and the sallow complexion associated with those who live underground. For these men, those outside the tunnel had only contempt, tinged perhaps with envy. "We say of them," wrote one of those on the outside, "that they will lose tunnel-credit if they are seen outside the tunnel. And we josh them about the DTS medal (Distinguished Tunnel Service) ... if they gather plenty of tunnel credits. As opposed to shell-shocked, we say of confirmed 'tunneleers' that they are shelter-shocked."37
Such unfair judgments were perhaps inevitable where some men were exposed to danger and others, by reason of their assignment, enjoyed the safety-and discomfort- of Malinta Tunnel. Nerves wore thin during the enforced intimacy of the prolonged
siege, and there were few opportunities for recreation. During their idle moments men discussed the most fantastic rumors, deplored the lack of support from the United States, and commented smugly about the invariably misinformed "brass hats in Malinta Tunnel." And always the men exercised the immemorial right of the soldier to "gripe." The days passed thus with monotonous and dreary regularity, filled with work, idle conversation, and speculation about the future.
Early in January, it will be recalled, Imperial General Headquarters had transferred the bulk of the 5th Air Group out of the Philippines, leaving General Homma with only a small air force whose major mission was to support ground operations on Bataan. A month later, after 14th Army had been badly beaten in its efforts to gain a quick victory on the Orion-Bagac line, Homma had received large reinforcements, including Army and Navy air units. From Malaya had come two heavy bombardment regiments, the 60th and 62d, with a total of sixty twin-engine bombers. This single accretion alone tripled Homma's air strength. In addition, the Navy had sent two squadrons of Bettys (land-based, twin-engine bombers), one squadron of Zekes (fighters), and one squadron of carrier-based bombers to the Philippines, thus making available for the offensive of late March and early April a considerably augmented air force.38
Homma's plan for the final assault against the defenders of Bataan had provided for a heavy artillery and aerial preparation, starting on 24 March and continuing until victory was achieved. To the air forces he had assigned a threefold mission: to support the advance of ground units, bomb forward and rear installations, and cut the line of supply between Bataan and Corregidor. All aircraft were given targets on Bataan; but the 60th and 62d Heavy Bombardment Regiments and the Navy were directed to bomb Corregidor as well. Careful plans were made for the period from 24 to 28 March and an agreement was concluded between the Army and Navy which made possible a unified plan of air action and the joint bombardment of targets by the aircraft of both services. After the 28th the bulk of the heavy bombers were to concentrate on Bataan, but, "in order to demoralize the enemy and to boost the fighting spirit of our army," a small number of planes would continue to bomb Corregidor every few hours around the clock.39
The aerial attack opened on schedule simultaneously with the artillery preparation on Bataan, at dawn of the 24th, when the first of the Army's six bomber squadrons rose from Clark Field and headed toward Corregidor. At the same time two navy squadrons (twenty-four Bettys) stood by to take off from their base at Clark near Manila to join in the attack. At 0924 the air-raid alarm, the seventy-seventh of the campaign, sounded on Corregidor. One minute later, the first enemy flight of nine Army bombers came over the island to drop their 550- and 1,100-bombs. They were followed by the remaining Army squadrons which, in turn, gave way to the Navy's planes. The attack continued during the day and that night, when three more planes made a nuisance raid against the island. Alto-
gether, forty-five of the sixty twin-engine bombers of the 60th and 62d Heavy Bombardment Regiments and the two squadrons of naval land-based bombers participated in the first day's attack to drop a total of seventy-one tons of bombs.
The next day the Japanese sent only three Army squadrons, twenty-seven planes, against Corregidor; the Navy, a similar number. This pattern continued until the 29th, the Navy planes alternating with the Army bombers. In addition small groups of planes came in over Corregidor every two or three hours "to carry out the psychological warfare and destroy the strong points, without failure."40 The routine bombings continued steadily until 1 April, with at least one Army squadron attacking during the day and another at night. The Navy planes, which had no missions on Bataan, continued their bombardment of the island fortress in undiminished strength.
For the men on Corregidor it seemed as though they were living "in the center of a bull's-eye."41 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. A graphic picture of the intensity of the bombardment can be gained from General Moore's summary of the first day's action.
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."43 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."44 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."45 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.
Under ideal conditions antiaircraft guns form a ring around the defended area, or a line in front of it, from where they can strike enemy aircraft before they reach the objective. On Corregidor it was not possible, for obvious reasons, "to follow the book." The antiaircraft guns could not engage the enemy until he was almost over the island. Moreover, by being located on the target, they became "part of what is being bombed," with the result that their efficiency and freedom of fire was limited most at the moment of greatest need. "Naturally our job is to fire on the bombers," wrote Captain Ames, ". . . and if possible prevent the bombing. Fire we do, but prevent the bombing we cannot." In a letter which never reached his wife he graphically explained the difficulty which beset all the antiaircraft men.
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.
In February an effort was made to use the 12-inch mortars for antiaircraft fire in the hope that a salvo from these pieces, bursting in the midst of the enemy formation, would discourage mass bombing. The 670-pound shells were first fitted with the powder train fuze but the shell would not explode. Next, the 155-mm. shrapnel and the mechanical antiaircraft fuze were tried, but they failed also to detonate the charge. "If it can be made to work," thought Colonel Bunker, "it will sure jolt the Japs."47 But the problem was never solved, and at the end of the campaign Ordnance still did not know whether the 12-inch shell would not explode because of the low rotational velocity or the size of booster charge in the fuze.
With the second aerial bombardment of Corregidor the Japanese for the first time resorted to night bombing. During this period they made twenty-three such attacks, delivered by small groups of bombers from an altitude of 24,000 to 27,000 feet. In almost every case the searchlight batteries illuminated the planes before they reached the bomb release line. Many of the pilots seemed to be confused by the lights and turned away to approach from another direction; others jettisoned their bombs or
abandoned the attack altogether. Those that got through were apparently too nervous and too anxious to get back to bomb with any accuracy. On the whole, the night attacks proved ineffective and after 6 April were discontinued.
By the beginning of April, the aerial bombardment was virtually over. Little additional damage had been received and comparatively few casualties had been suffered by the men who had had two months to prepare. All eyes were now turned to Bataan, upon which the Japanese had concentrated their entire air and artillery strength in preparation for the final assault. For the next ten days, while the fight for Bataan ran its grim course to a bloody and tragic end, the men on Corregidor and its sister fortresses were granted a brief respite. Their turn, they knew, would come soon.
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