Fort Drum, the unsinkable concrete ‘battleship’ of Manila Bay

Anyone who pays a visit to Manila Bay will not easily forget the enchanting sight of the ruined concrete fort that looks as if it is rising out of the waters. It has four large guns that are ominously pointing towards it.

It is also very common for passengers on ships passing by to watch the fort as they pass, with a look of amazement and wonder. I’ve visited Mindanao 3 times, within the last 36 months and haven’t found anyone that can actually identify the fort.

This ruined concrete fort is Fort Drum. Formerly called Island, it is quite literally the world’s only unsinkable battleship. Certainly deserving of a rightful place in the list of tourist spots, it has a story that is worth re-telling.

When the United States annexed the Philippines in 1898, its defense automatically became their responsibility. In order to defend their latest colony against any future invaders, the US fortified four islands at the mouth of Manila Bay during the period of 1909-1913. These four islands – Corregidor, Caballo, Carabao and El Frail went on to become Fort Mills, Fort Hughes, Fort Frank, and Fort Drum, respectively.

War Plan Orange

A plan devised by the US Military, the War Plan Orange served the dual purpose of preventing warships from entering Manila Bay and providing necessary assistance in Bataan, where the American and Filipino soldiers were supposed to fight, by delaying action for six months.

While Corregidor was indeed the biggest, and therefore the most important of these forts, the El Fraile – or Fort Drum as it was now called – was the most unique. Shaped like a real battleship and complete with a forecastle, it was often called USS Drum – due to passengers of passing ocean liners often mistakenly identifying it as a majestic, but a rather strange-looking ship.

Pearl Harbor

In order to construct Fort Drum, the US Army Corps of Engineers had to cut the small, rocky island of El Fraile. Taking the rock as the foundation, they erected a concrete fortification that was in the shape of a battleship. Said ”battleship” was 240 feet long, 160 feet wide, and 40 feet above the water line, with walls 30-40 feet thick and a deck 20 feet deep. It had four levels inside that were connected by an axial tunnel that ran across the island.

The fort had an arsenal of eleven guns, which included:

  • Battery Wilson – This had a turret that rotated with two 14-inch guns with the capacity to sink any known warship within 22,500 yards
  • Battery Marshall – It had two 14-Inch guns and the rotating turret at the front
  • Battery Roberts – It had a casemated battery with four 6-inch guns that are designed for minefield defense; and
  • Three 3-inch guns, two of these were anti-aircraft guns.

In addition to all of this, Fort Drum contained a garrison of 200 men who were stationed there, armed with 8-foot searchlights to fight during nighttime. The construction of Fort Drum took 11 years (1909-1919), and once completed, it was deemed impregnable against any and all weapons and armaments known to man.

14-inch guns and turret undergoing testing at Sandy Hook Proving Ground before installation at Fort Drum

With the bombing of Pearl Harbor in December 1941, war proceeded to enter the Philippines, with Fort Drum seeing its first combat action once the Japanese air force bombed Corregidor and the other islands on 29th December 1941, and 2nd- 6th January 1942.

Corregidor, though heavily damaged in the bombings, retained its anti-aircraft guns, which did a fair amount of damage to the Japanese planes. Fort Drum, however, remained impervious to the attacks and stayed intact. As the raids were costly and did nothing to permanently damage the fighting capabilities of the fortified islands, the Japanese decided to abort the bombing operation.

When the Usaffe got destroyed in Bataan on January 25th, the Japanese began to prepare to shell the island forts. Under the leadership of Maj. Toshinori Kondo, the Japanese began shelling the islands from the 5th of Feb using two 150-mm howitzers and four 105-mm guns. Their objective to destroy Fort Drum, however, did not materialize, as it remained intact despite being hit over a hundred times.

After this incident, the Japanese began to attack the islands on a regular basis, which again intensified towards the middle of February as two extra 150 mm howitzers were added to their arsenal. While the forts tried to retaliate with their gigantic guns, they were handicapped due to the fact that they had no forward observers to update them on the location of the Japanese’s guns. Only after Maj. Jess Villamor successfully photographed the Japanese batteries aerially, did they begin to score direct hits.

However, the Japanese did not slow down, but instead placed ten 240-mm howitzers in the Pico de Loro hills in Calumpang, Cavite, close to Fort Frank, under the command of Maj. Masayoshi Hayakawa. Starting Match 15, this new artillery began shelling the four islands afresh. Hayakawa’s howitzers, the deadliest in the Japanese arsenal, damaged most of the guns of Fort Frank and two searchlights and anti-aircraft guns, sparing only the 14-inch batteries.

Thankfully, no further damage took place due to Hayakawa’s artillery being pulled out to Bataan on the 22nd of March. Fort Drum, however, survived with all of its damage being 4 inches of chipped concrete.

Fort Drum and the Invasion of Corregidor

After the surrender of Bataan on April 9, 1942, the Japanese began to prepare for the capture of Corregidor and its sister islands. From April 11 onwards, the Japanese began shelling the four islands with not less than a hundred and ten guns, which ranged from 75-240 mm. Although the guns of Corregidor, Fort Hughes, and Fort Frank countered to the best of their ability, they could not defend themselves in what was an unmatched duel.

Not only did the Japanese have a larger arsenal, they also had assistance in the form of observers present both on the ground and in the air with the sensitive instrument for range-finding the islands’ batteries. Not to mention that at least an average of 50 Japanese bombers had already been bombing the islands since 24th March. In the face of so much, the Americans could do only so much to defend themselves. However, while the rest of the sister islands’ guns were destroyed, Fort Drum’s guns remained alive against all the odds.

On the occasion of the Japanese Emperor Hirohito’s birthday, the bombings further. Aiming to finally destroy Fort Drum’s guns, the Japanese attacked the fort by glide-bombing it – an attack that continued for the next four days. Surprisingly, however, this attack only affected a minor misalignment of Battery Marshall.

By May 5, all of Corregidor’s guns (bar the 12-inch 1898 mortar of Battery Way and a few roving 155- and 75-mm guns whose positions were never disclosed) had been silenced. On the night of May 5, the Japanese launched their 2-battallion Corregidor invasion force. Although around two-thirds this force was destroyed by the defenders, the remaining one-third successfully continued to attack them.

With the outflanked defenders brutally shelled by Japanese guns to keep them from containing the invaders, General Wainwright was left with no choice but to surrender Corregidor, which he did on May 6.

All this time, however, Fort Drum’s guns continued to blaze – up until minutes before the surrender.


Having returned on Oct. 20, 1944, the Americans began the process of liberating the Philippines. By 3rd February 1945, a flying column had reached Manila led to a month-long battle to liberate Manila from the Japanese. Despite the ongoing battle, however, the Americans started began to clear the fortified islands of Japanese to open Manila Bay for shipping, with Fort Drum being the last island to get liberated.

The Americans devised special tactics to liberate Fort Drum. On 13 April, a Landing Ship Medium (LSM) and a Landing Craft Mechanized (LCM) was sent to pull up alongside Fort Drum. The LSM had a specially built ramp on top of it, using which it discharged two platoons of soldiers: while the first platoon consisted of crack snipers to cover every opening where Japanese soldiers may appear, the second comprised engineers assigned to plant demolition charges.

Once the charges were in position, the LCM poured 3,000 gallons of oil into one of the vents and dumped explosives into the other. Both the LSM and LCM were moved to a safe distance after the fuses were lit. With the charges detonated, a series of explosions followed that finally blew Fort Drum’s manhole that was 1 ton in weight and 1 meter in diameter 50 meters up into the air. Finally gaining access to the fort on 18th April, the Americans went on to discover 65 charred bodies.

As of today, Fort Drum continues to stand as an old ruin right at the mouth of Manila Bay. Although no longer in action, it still holds its reputation as being unsinkable.

Unfortunately, though, in spite of all the history, Fort Drum, along with the nearby Fort Frank are still neglected as tourist spots.