On the island of Corregidor at the entrance to Manila Bay, American coastal defense came to a high point in the big gun defense theory of protecting vital areas of a homeland.  Using some of the biggest guns in the American arsenal, the defenders held off the enemy for over five months.  The end came swiftly though, flaws in the system exposed terribly.  Capitulation meant the garrison force marched on to the horrors of Japanese prison camps.  With the fall of the island fortress, the theory of coastal defense would slowly re-evolve.

Corregidor was a main cog in the defensive posture of Manila Bay.  The little tadpole -shaped island served as command center and chief artillery base among several other islands across the western entrance into the heart of the Philippines.  American defensive positions established on the island defended by Spanish artillery in 1898. 

SPANISH PRELUDE

The Spaniards in defense of Manila Bay, however, fielded only seventeen guns with only eight of them not muzzle loaders from another age.  The main channel – Boca Chica – was between Corregidor and the south end of the Bataan Peninsula.  Some eight mines were set in this channel though they were inoperative at the time of Dewey’s incursion.   On Corregidor, there were three 6-inch breechloaders while on the north side of the channel there was another battery of three 6-inchers and one with three muzzleloaders.  The newer guns brought in because of a war-scare with Germany over the Caroline Islands a decade earlier.

In the larger channel south of Corregidor, the water depth precluded the use of mines here.  Caballo Island featured three more 6-inch guns with three muzzleloaders on El Fraile Rock and three more at Punta Restina. 

The Spanish maintained over 200 guns closer to Manila, though only twelve breechloaders set up to defend the town from the sea.  The Spanish batteries did not see Admiral Dewey’s fleet sail past their guns early in the morning of 1 May until they were halfway past.  Five shells were fired from El Fraile and Punta Restinga without effect and Dewey’s fleet was on course for history.

AMERICAN COAST DEFENSE

The United States underwent three distinct eras of artillery forts in the years from 1793 until the Civil War.  Masonry forts featuring multiple levels of cannons symbolized the final Third System.  Advances in artillery with higher muzzle velocities and increased accuracy developing from new rifled cannons signaled a quick end to such forts when heavy enemy artillery came to bear.  Earthen bunkers replaced the masonry forts as the war went along.  Masonry fort construction finally ended in 1867 with several of forty-two forts incomplete.

Lack of defense spending in the 1870’s led most earthen forts to be badly in need of repair by the 1880’s.  Not long after the Navy finally began to construct new vessels in 1883, President Grover Cleveland appointed a joint Service-Civilian board headed by the Secretary of Defense William C. Endicott to study the state of existing defenses along the seaboards and to recommend solutions to problems found.

endicott plan

The Board of Fortifications recommended a modernization program with breechloading guns, mortars, floating batteries and mines, all to the tune of $127 million.  Twenty-nine locations along the coasts became chosen for installation of the new defensive positions.  The positions featured disappearing guns sitting behind protected and dispersed gun emplacements.  Concrete walled batteries with further protection provided by sloped earthen works.  Minefields offshore also became an important adjunct protected by smaller gunned batteries.  Fire control towers controlled the fire of all of the guns from a fort and surrounding districts.

Drawing up plans was easier than gaining the actual funding.  But most fortifications called for in the plan did not come about until 1895 to 1905.  The war of 1898 brought about a flurry of construction at various East Coast sites in response to the possible visit of a Spanish fleet.  Only after the war, however, did construction really get busy on the Endicott Program.

coaST ARTILLERY corps

To man the new forts, the Army’s Artillery Corps split into two with a field artillery side and a new coast artillery side.  From the previous seven artillery regiments 82 existing heavy artillery batteries became new coast artillery companies with another 44 new coast artillery companies created. 

The new organization also took over responsibility for controlled mine fields.  The mines could be detonated electrically from the mine casement ashore.  Mine planting vessels run by civilian crews installed and monitored the new mine fields.  After 1918, the Army created the US Army Mine Planter Service – AMPS – using Warrant officers to command the little mine layers.

COAST ARTILLERY GUNS

The larger caliber guns placed in the Endicott Program ended up mounted on disappearing carriages.  With these carriages, guns were placed in open gun emplacements protected by concrete and earthen walls in front.  The guns dropped down for reloading.  Aim of the guns dictated by fire control towers.  Loaded and with guns lain, the gun tube would pop up above the emplacement to fire.  The recoil knocked the gun back down again into the loading position.  The main guns used on these carriages included 12-inch (305 mm), 10-inch (254 mm), 8-inch (203 mm) and some 6-inch (152 mm) versions.  12-inch mortars, some 6-inch and all 3-inch guns (76 mm) used pedestal – barbette – carriages.  The smaller gun on pedestals potentially always exposed to enemy fire.  Guns on disappearing carriages only visible by enemy ships when they fired.

The 3-inch guns protected minefields.  They defended against enemy minesweeping operations.  The mortars with a very high angle of trajectory – their target unarmored ship decks – were placed in four-gun pits a bit away from the other guns.  With time and experience, many mortar pits went to only two guns, four proving too much activity going on with too many men running around at the same time.

TAFT BOARD

Newer updates to the Endicott Program came from the Taft Board created in 1905 by President Theodore Roosevelt.  The board led by Secretary of War William Taft added electricity, searchlights and better aiming technology to the forts.  Due to increasing technology, the two artillery branches separated for good in 1907. The new Coast Artillery Corps gaining an increase to 170 companies.  Fort Monroe became home to the Coast Artillery School.

In 1907, in response to board recommendations, fortifications were built in Hawaii, Cuba and the Philippines, as well as Panama.  With battleship development undergoing huge changes, new 14-inch (356 mm) guns were installed on disappearing carriages.  Two of these big guns installed at Fort Frank on Carabao Island just off the coast on the southern approach to Manila Bay.  Two more 14-inchers went to Caballo Island at Fort Hughes.  On El Fraile Rock, the unique Fort Drum featured two twin turreted casement mounts with four 14-inchers.  During 1940-1944, in the US, harbor defenses gained the bigger 16-inch (410 mm) guns. However, went to the Far East.

FORTRESS CORREGIDOR

Corregidor was always seen as the key to defense of Manila Bay. Most of the battery emplacements underwent construction between 1904 and 1910. Headquarters for the Harbor Defenses of Manila Bay located here on the island at Topside. Along with all of the twenty-five major coast artillery guns mounted here, service facilities, barracks and other housing went up. Corregidor served in the construction of the other fortifications built on other islands, as well.

Gun in the various batteries developed atop the venerable Buffington-Crozier disappearing carriages. The gun would pop up above its protecting parapet to fire. Recoil from the gun’s discharge would send the gun back down into its pit for servicing and reloading. Most gun batteries contained two big guns, built in a two-story reinforced concrete emplacement. Below, the ammunition magazines, power generators, shell hoists lay. Above were gun pits, loading platforms, plotting and observation rooms, as well as the battery commander’s room.

The batteries lie scattered about the island with an eye to shipping lanes to dominate. Also, dispersal made it more difficult for an enemy to quiet the fort as a whole.

12-inch mortar pits contained the other main weapon of the fort. Their purpose was to bring down shells in a high arced trajectory to plunge through thin deck armor of warships. The pits featured a high concrete-reinforced parapet with the service rooms sited around the sidewalls of the pit.

beyond the guns

Command of the various batteries lie in a central command. The batteries, seemingly randomly scattered about, both interdicted shipping lanes and mutually supported each other – on the island and the other islands.

Along with the batteries, fire control stations, weather stations, telephone systems, reserve magazines, searchlights all developed leading to a strong defense against seaborne assault. They would prove less so against air and land assaults. Nor would they prove effective against artillery fire launched from the Bataan Peninsula, either.

Land defenses went up later, built between 1911 to 1920. Corregidor, Caballo and Carabao Islands all got positions for artillery to use against a potential invader – 3.5-inch and later, 75-mm guns, machine gun nests, infantry tunnels more searchlights and counter-battery gun emplacements. Surplus weapons from World War 1 came out for storage on Corregidor.

The guns of Manila Bay, already dated by 1919, got a final augmentation in 1919-1921. With stocks of 16-inch guns with higher arcs of trajectory under construction, existing 12-inch guns substituted, mounted on new “long-range” carriages. Two such single-gun batteries built here on Corregidor – Batteries Smith and Hearn. The Naval Treaty of Washington then stopped further obvious development of the Harbor defenses of Manila Bay in 1922.

INTERWAR YEARS

The Treaty of Washington made defense of Manila Bay and all of the other American outposts in the western Pacific much more difficult. Planned for naval bases in Guam and Subic Bay became scrapped by the treaty. Reductions in military spending throughout the 1920’s led to large reductions in manpower as forts went to sleep maintained by caretaker staffs.

One important addition to the island’s defense was Malinta Tunnel. While not technically allowed by the treaty, the tunnel system came about to improve the transportation system of the island. To obfuscate matters more, no direct funding was allowed. In place, funding came from the annual maintenance budget. The main purpose of the tunnels being to provide protection from air assaults.

WAR COMES TO CORREGIDOR

preparation for war

American war planners wrestled with the problems of defending possessions in the western Pacific since 1909. They came up with various versions of what was War Plan Orange. For Corregidor, the idea was to hold out until the Fleet could storm across the Pacific to relieve them. In the early versions, Japan was seen as the only enemy. War Plan Orange evolved in Rainbow Five at the beginning of the war. Here, with Germany added to the list of enemies, American attentions turned first to Europe. Only then would Japan come under the gun. Plus, instead of original plans to steam across the Pacific in one swoop to match up with the Japanese fleet, the Navy invested in a slower island-by-island approach. This new approach guaranteed the fall of all American posts in the western Pacific.

With Japanese revocation of the Naval Treaty in 1937, twenty-four 155-mm tractor-pulled guns and eight 8-inch railway guns transferred to the islands without their crews. These plans to use these guns still were underway at the time of the war, however. Several made it out to the harbor island while others provided the only mobile heavy artillery defending units on Bataan.

defending forces

The federal draft began in 1940 and a tear later, President Franklin Roosevelt federalized the Philippine Commonwealth Army – an embryonic organization. Douglas MacArthur gained command of all American forces in the western Pacific – USAFFE (US Armed Forces Far East). Mines were deployed in the minefields. Batteries of 155-mm and 75-mm also became deployed for purposes of beach defenses on all of the islands of Manila Bay.

The forts in the bay complex were organized into a Harbor Defense system commanded in 1941 by Brigadier General George F. Moore, commander of the Philippine Coast Artillery at Fort Mills on Corregidor.  Available were about 5,700 men to man the forts.  There were two Coast Artillery Regiments from the Regular Army – 59^th and 60^th.  

The 59^th manned most of the batteries on Corregidor (Hearn, Crockett, Wheeler, Cheney, Smith, Geary and James) as well as one battery on Fort Drum and two on Caballo Island at Fort Hughes – one being an anti-aircraft battery.  The 60^th was responsible for air defense over the bay and the southern part of Bataan using 3-inch, 37 mm and .50 caliber guns along with 60-inch searchlights.  They also manned searchlights and a battery at Fort Wint in Subic Bay.

philippine units

Two other Regular Army Coast Artillery Regiments drew from the unique Philippine Scouts.  The Scouts enlisted local Filipinos with Regular Army officers supervising.  Filipinos also had opportunities to become officers within the Regular Army including several who graduated from West Point or Annapolis. 

The 91^st Coast Artillery manned several batteries on Corregidor – Rock Point, Morrison/Grubbs, Sunset and Ramsey – as well as Battery Crofton on Caballo and Ermita, Caballo’s anti-aircraft battery.  The 92^nd Coast Artillery served 155mm tractor-drawn guns manning batteries on Corregidor, Fort Wint and Fort Frank on Carabao Island. For beach defense, there was the 4th Marine Regiment.

Two regiments came from the Philippine Army – the 1^st and 2^nd Coast Artillery.  Philippine units suffered from both lack of training and lack of equipment.  These units received some training at Fort Wint at Subic Bay and on Corregidor.  There were about 600 soldiers from these two units on Corregidor operating under the command of the Philippine Scouts.

Command set up into four sections on Corregidor:  seaward fire – the original and main purpose for all of the forts, anti-aircraft fire, beach defense and inshore patrols – the latter two responsibilities carried out by naval Captain Kenneth M. Hoeffel.  He had men from the 4^th Marine Regiment serving with him.  Fort Frank and Fort Drum both had about 200 men serving, and Fort Hughes (Caballo) had 800.

battle

Eight days of aerial bombardment began 29 December 1941. The guns suffered little damage, but most of the buildings, including barracks, housing and the trolley system sported extensive damage.

Japanese attentions centered upon the Bataan Peninsula for the next several months. MacArthur and Philippine Commonwealth President Manuel Quezon both operated out of Malinta Tunnel. They left the island on the night of 10 March, Roosevelt not wanting to lose such high-profile members to the Japanese.

The final air campaign against Bataan beginning 24 March, included Corregidor as a target, too. Several extra men reached Corregidor just before the forces on Bataan finally surrendered 9 April bringing the population on the island to nearly 15,000. On half rations – which was still significantly more than the troops on Bataan received – since the beginning of the year, food could last only six to eight weeks. The siege of Corregidor was on.

end

Japanese brought up heavy artillery on both sides of the mouth of Manila Bay – 18 batteries of 116 guns of 240-mm, 150-mm and 105-mm caliber. Direct bombardment began 12 April chipping away at the defenses each day. Battery Crockett was knocked out with both guns destroyed 24 April. Counter-battery fire was provided by 155-mm guns and some of the mortar batteries. Concentrating fire on the mortar batteries, a 240-mm shell penetrated the magazine at Battery Geary 1 May. In an explosion rocking the island, all of the mortars of the island destroyed.

In all, over 300 air raids hit the island. Over 16,000 heavy artillery shells pounded down denuding the extensive vegetation you find today.

By 5 May, only three 155-mm guns still operated on Corregidor. With beach defenses ruined the Japanese sent in two waves of invaders that night. Overcoming appalling losses, the Japanese established a beachhead on the eastern portion of the island and started pushing west. Bringing up three small tanks during the fighting the next day, General Jonathan Wainwright – USAFFE commander with MacArthur gone – surrendered. Without anti-tank guns, he feared the possibilities of tank fire into the crowded Malinta Tunnel system. 14,700 Americans and Filipinos went into captivity from the Manila Bay forts.

The only good thing for the survivors was they missed out on the Death March and much of the horrors of Camp O’Donnell. Plenty of other horrors awaited all.

RETURN

The Japanese never tried hard to restore the defenses of the islands during their three-year occupation. American forces returned to the Philippines in October 1944 with Luzon reached early in January 1945. During the battle for Manila – February-March – assault plans for Corregidor came forward.

Defended by 5,000 men on Corregidor – another 370 on Carabao, 400 on Caballo and 65 on Fort Drum – the defenders had little in the way of artillery to help defend with. The 503^rd Parachute Regiment augmented with an amphibious landing by a reinforced battalion of the 34^th Infantry Regiment launched on 12 February after a three-week aerial bombardment.

The Japanese commander died in the initial fighting and defense of the island devolved into various groups fighting on their own. Fighting went on until the end of February with the Japanese dug and American forces slowly mopping them up. The other Manila Bay islands – also without organic artillery – fell to American forces during April.

VISITING THE ISLAND TODAY

Visits today to Corregidor start from the Esplanade next to the SM Mall of Asia – Sun Cruises – note their website is down though you may be able to get in touch through their Facebook page. Their operations – they have a monopoly on cruises to Corregidor – shut down in 2020 because of Covid. At the moment, no reopening date announced, but here is what you can expect if and when they return. Presently, the Corregidor Foundation has filled some of the void with two boats possibly operating, the island tours and Corregidor hostels where you can stay overnight. The Corregidor Inn and its 31 rooms are not open at the time of the post.

From here, your boat makes the hour and fifteen-minute voyage over to the North Dock on Corregidor. Most visitors come for one day: over on the boat in the morning, two open-air bus tours past several former batteries separated by lunch at Bottomside at theCorregidor Inn; then return to Manila late afternoon.

Middleside

The first stop – the roads used to feature the electric trolleys – is the ruins of the Middleside Barracks. The three-story building housed the 60^th Coast Artillery Regiment men, responsible for the air defense of the island. Also living here were soldiers of the 91^st Coast Artillery – PS.

battery way

Next, the mortar pit at Battery Way. Stateside, four 12-inch – 305-mm – mortars were found to be two too many for one pit. Usually, only two mortars were used per pit. This freed up mortars to use in extra pits. Many of the four gun to two gun modifications did not come until the end of World War 1. Because of the Naval Treaty, new pits for mortars was not allowed. A problem with money existed too. So, the mortar pits here on Corregidor featured the original idea of four mortars to a pit. Supposedly, there was more room in the mortar pits on Corregidor than pits used in the US, as well. With fourteen men to a mortar, it still remained crowded.

Look closely at the huge mortars – they could fire a 1,000 lb deck piercing shell against naval targets or a 700 lb high explosive charge 8.3 miles – 13.35 km – in any direction. Way, manned by men of the 60^th Coast Artillery Regiment who had been in action at Bataan and now were redundant.

william massello

Led by Major William Massello, the battery first went into action 17 April 1942. Found to be effective as a counter battery against the Japanese on Bataan, the battery became a primary Japanese target.

Slowly, fire from Bataan knocked the mortars out of action. The crews suffered 75% casualty rate including their commanding officer, Major Massello. Massello, West Point Class of 1932, fired mortars right out of school. The mortars at Way had been inactivated before the war due to lack of trained personnel. The major, still firing his last serviceable mortar on 5 May, almost got an arm blown off in the process. After firing 90 rounds, the mortar gave up the ghost though the mortar did fire off the last round of the big guns on Corregidor.

For Massello’s actions here, on Bataan and in captivity – another long story – he earned the Distinguished Service Cross, two Silver Stars, Legion of Merit, Bronze Star, two Presidential Unit citations, four Purple Hearts and a cluster of campaign ribbons. He survived the war dying only in 2007.

battery hearn

Battery Hearn featured a 12-inch gun mounted on a long-range carriage allowed for a flatter trajectory on a platform capable of firing 360 degrees giving a longer range – 27 km. The gun came over with another just before the Naval Treaty went into effect in 1922. The 12-inchers were stop-gaps until 16-inch guns could come forward. The flat trajectory proved not very helpful against targets on nearby Bataan.

The gun today shows some of the wear from the war, but painted up, the gun is a main tourist stope. The gun crew was Battery E of the 59^th Coast Artillery led by Captain Samuel M. McReynolds. McReynolds died in Japan in early 1945 in a POW camp. His remains lie today at Forest Lawn in Glendale, California.

The gun disabled before the island’s surrender got new life when the Japanese had American POW’s hand carry the present gun tube – a nearby spare tube – and parts brought over from Battery Smith placing the old tube on the ground nearby, still there today. The famous banzai photo of victorious Japanese soldiers on Corregidor comes from the gun here.

topside

Topside featured the Mile-long Barracks. While the barracks extends for over 1,500 feet, that is a bit less than a mile. But, if you add the distance times three for the three floors, then you come up with a distance closer to that mile. The building was “hurricane-proof” built from reinforced concrete. Bombs were another matter. Japanese bombing on 29 December effectively knocked out the building, though subsequent American bombs and shelling in 1945 did the building no favors, either.

This was the home of the 59^th Coast Artillery enlisted group. Regimental headquarters were located in the building, as well. Mess halls – one per battery – were on the bottom floor with latrines and showers.

The barracks faced the Parade Grounds with officer quarters on the other side. At the south side was a large theater standing in ruins today. A display of anti-aircraft guns and smaller artillery pieces are found across the street at the head of the Parade Grounds.

Near the cinema today is a monument to the Filipinos and Americans who fought here, as well as a small museum. Also, a small monument attests to the American recapture of Corregidor in 1945, honoring the 503^rd Parachute Regiment and other members of the “Rock Force” in particular.

lighthouse

Just off the Parade Ground sits the Spanish Lighthouse, second oldest in the islands. Authorized in 1845, but not completed for another eight years, the light has guided ships into the entrance to Manila Bay ever since. The keeper’s house sat beneath the light with the roof acting as a rain collector, storing water for the house and the island.

The lighthouse survived the Japanese capture, but not the American re-capture. Rebuilt in 1950 to a different design, there is a souvenir shop in the base of the light today. The light runs on solar power since the 1990’s.

battery geary

Original Endicott designs called for 12-inch mortars to be grouped together in four pits of four mortars. The so-called Abbot Quads would blast all sixteen mortars at the same time in the fashion of a shotgun blast towards the target with the hope one or two shots would fall on the target. Very few quads were built – the shock wave from one mortar is significant let alone sixteen. Fire control improved as the nineteenth century ended and mortars were seen to fire more accurately singly aimed than using a scatterbox technique.

The other mortar battery here we have seen – Battery Way. There were four mortars there. Battery Geary used two four-gun pits. 1 May 1942 showed why maybe four mortars together, especially two four-gun pits next to each other, might not have been such a good idea. A 240-mm Japanese shell penetrated the magazine blowing up 1,600 62-lb powder charges, scattering about the eight mortars, collapsing the high parapet. Some of the metal removed by the Japanese during the occupation for scrap recovery. The mortars still lie here and there, testimony to the enormous explosion that destroyed the battery.

battery crockett

One of the early batteries completed on Corregidor – 1905-1908, the battery faced south defending the Boca Grande channel of the bay entrance. Two 12-inch guns placed on disappearing carriages looked out over the waters. The design of the battery was the same as two other two-gun batteries, Cheney and Wheeler. One gun was put out of action by a Japanese 240-mm shell. Luckily, the magazine did not explode. The other gun was restored to service by the Japanese, but never used. Both disappearing gun mounts survive today with a reserve gun tube on the ground nearby.

japanese garden of peace

Set next to a battery of Japanese anti-aircraft guns, memorials to the Japanese rest in the Garden of Peace. One monument remembers the dead on all sides of 5 May 1942 while another remembers the Japanese defenders of 1945, 4,500 men who all died here on the island. The garden was built on a site of a cemetery American soldiers built for Japanese dead in the aftermath of the recapture of the island. The remains later cremated and returned to Japan.

Various individual memorials are here with a large memorial to Tetuo Akiyama and other individuals.

filipino heroes memorial

Nearby the Garden of Peace is a memorial to Filipino military adventures down through the ages from the 1500’s to the Edsa Revolution in 1986 deposing Ferdinand Marcos. There are fourteen high relief panels picking out important events in the Philippine martial history. A museum with paintings showing some of the horrors inflicted upon Americans and Filipinos by the Japanese completes the site.

malinta tunnel

The Malinta Tunnel is included for an extra fee including a light and special effect show. The main tunnel is restored, though many of the lateral tunnels were collapsed in the American recapture of the island.

This was the headquarters for MacArthur, USAFFE and the Philippine Commonwealth government. Manuel Quezon took his second oath of office as Commonwealth president in the tunnels here. Sadly, he would not live to see an independent Philippines, dying of tuberculosis in Saranac, New York in 1944.

notes on sources

For such a pivotal moment in American military history, there is not a lot of recent literature. Undefeated: America’s Heroic Fight for Bataan and Corregidor by Bill Sloan includes a chapter on Corregidor, but the book tells very few stories from the Filipino side. Half of the book is concentrated on the aftermath of the POW’s gathered up from Bataan and Corregidor.

The Battle of Bataan: A History of the 90 Day Siege and Eventual Surrender of 75,000 Filipino and United States Troops to the Japanese in World War II by Donald J. Young is much better for its history of the Bataan Campaign, though Corregidor is covered only in passing. The Osprey edition American Defenses of Corregidor and Manila Bay 1898-1945 by Terrance C. McGovern and Mark A. Berhow shows a good starting point for understanding of the Harbor Defenses of Manila Bay from development through the campaigns at the beginning and near the end of the war.

A newer edition from 2020 written by Glen M. Williford and Mark Berhow, Pacific Rampart: A History of Corregidor and the Harbor Defenses of Manila and Subic Bays is an excellent addition to the much slimmer Osprey book. Another book from 2020, Rock Force: The American Paratroopers Who Took Back Corregidor and Exacted MacArthur’s Revenge on Japan by Kevin Maurer relates the story of the island’s recapture in detail.

GHQ is a website devoted to Corregidor’s history, both informative and illuminating. These two other sites link to several websites dealing with Corregidor.