The Genesis of Fort Drum

Recent newspaper accounts of our operations for recapture of the Philippines have included photographs of and brief references to the "concrete battleship" Fort Drum, which is located on the rock called El Fraile in the wide channel south of Corregidor.

As Fort Drum is the only harbor or coast defense fortification in which we have made use of steel turrets, it is of special interest to learn how they performed while the Japs were attacking Corregidor and the other fortified islands (Forts Hughes, Drum, and Frank) at the entrance to Manila Bay.

During our defense of Bataan and Corregidor in 1942, the enemy concentrated fire on Fort Drum and Fort Frank, starting about February 15 with 105 and 150mm shells and in April with240mm shells. It has been reported that in one day Fort Drum received over 1,000 direct hits on its deck; that its cage mast was hit several times rendering useless the depression position finder on top; that all antiaircraft guns were destroyed; and that over 15 feet of the reinforced concrete deck was whittled away.

Despite this terrific pounding Fort Drum suffered few casualties and the four 14-inch turret guns were never out olfaction and were still firing effectively 5 minutes before the surrender of Corregidor, although all other guns on the fortified islands, at one time or another, were rendered inoperative.

It may be interesting to note that the inception of Fort Drum was contained in a letter dated Corregidor Island, July 18, 1908,which I sent to Major G. P. Howell, District Engineer in Manila. The text of the letter follows:

Corregidor Island,
July 18, 1908,

Major G. P. Howell,
District Engineer in Manila.

Dear Sir,

In connection with Mr. E. B. Thomson's report relative to the construction of an artificial island just south of El Fraile, I beg to submit the following plan as an alternative, which I believe would prove vastly cheaper and no less effective.*Reprinted from the Military Engineer by permission.

PROPOSED FORTIFICATIONS
El Fraile Manila Bay

From a glance at the print entitled 'Entrance to Manila Bay, approximate distances from El Fraile' the following facts are apparent.

1st. That the channel north of Corregidor Island can be so well defended by open batteries on Corregidor as to force any attempt at entrance by a hostile fleet to be made through the wide channel to the south.

2d. That a battleship passing between Corregidor and Carabao Islands will of necessity come within effective range of one or the other, but no ship would attempt to make the entrance by daylight.

3d. That the distance between Corregidor and Carabao is too great for batteries on these islands to prevent the entrance of hostile ships at night.

We may therefore conclude that it is necessary to mount heavy guns at some intermediate point. The problem is thus reduced to one of two alternatives: to build an artificial island, or place guns upon El Fraile.

I strongly recommend the latter course and submit herewith three copies of a print entitled 'Proposed Fortifications, El Fraile Island, Manila Bay, P. I.’

The plans and sections are drawn to a very small scale and no attempt is made to show details. It is merely desired to set forth something in tangible form, subject to such modifications as further study and investigation may indicate desirable. The features contemplated are briefly as follows:

Armament:

Four 12-inch guns on Navy carriages in two two-gun mushroom turrets of cast nickel-steel from 21 to 24 inches thick on the sides and tapering to a thickness of 8 to 10 inches on top; these two turrets to be mounted on a concrete structure containing rooms for personnel, ammunition power, etc.

Protection of ammunition, etc.:

Horizontal, 30 feet of concrete.

Vertical, 10 feet of concrete.

Ammunition storage:

200 rounds per gun.

Power:

The power to be supplied by gasoline driven generators of total capacity about 350 K.W. sufficient for lighting, including searchlights and for driving the motors for traversing the turrets, elevating the guns, running ammunition hoists (Navy type), operating the telescopic rammers, air compressors, ventilating fans, pumps, and cooking stoves.

Interior Economy:

The structure is divided into two stories and each story into several rooms and passages by reinforced concrete floors and partitions."The first floor contains the magazines, power rooms, machine shop, storage battery and storage rooms for water and gasoline. To protect against accidents from gasoline fumes the magazines are completely cut off from the power rooms by a concrete wall. The magazines are accessible by ladder through the turret wells, the other rooms through the machinery well; ammunition is brought into the magazines by means of a chain hoist in the ammunition well.

The second floor contains the plotting rooms, office, guardroom, storerooms, lavatories, officer’s quarters, and quarters, mess room, and kitchen for a complement of 120enlisted men. There is access to the turrets and to the lower floor by means of ladders and to the top of the fort by two stairways.

During the times of peace the garrison would live on Corregidor and go to El Fraile only for drills, a guard being maintained at all times and living in a shack on top of the Fort. During war the island should be regularly garrisoned, the troops living in tents on top of the fort except during action or storm, when they should be quartered below.

Water Supply:

The main water storage is on the lower floor and from here water is pumped as needed into a small tank on top. It is probable that an artesian well could be drilled giving an ample supply for all needs. A small distilling plant should be provided.

Ammunition Service:

Projectiles are carried to the handling room beneath the turret by overhead trolley. The cartridges arc shoved through a small trap door to prevent any explosion in the turret or handling room from entering the cartridge rooms. From the handling room the charge is raised to the breech of the gun bemeans of the standard type of Navy ammunition hoists, and is rammed by the Navy telescopic rammer.

Range Finding and Fire Control:

An observing station of cast nickel steel is placed between the turrets with the observing slot at sufficient elevation to see over both turrets. The top or roof of the station is supported by steel plates radial to the axis of the observing instrument. This station should be made as small as possible so as to minimize the effect of the blast. This station might be made oblong in plan so as to accommodate two depression instruments and cover both channels at once.

To prevent the gun captains from losing their targets it would be advisable to furnish them with both range and azimuth from the B. C. Station.

Note: The present plan for torpedo defense may be carried out by placing observing stations on top between the B. C. Station and the turrets and the casemate apparatus located on the 1st and2d floors. This is in part shown.

Cost:

It is not possible without further data to make even an approximate estimate of the total cost. The concrete would amount to about 1,000 cu. yds. more per gun than in our open batteries or in all about 26,000 cu. yds. which at cost of $12 per yard would amount to $312,000.

The armor being cast nickel steel because economy of weight is not necessary would be much less expensive than the same protection on shipboard when steel forgings must be used.

Roughly we might estimate the total cost at $1,000,000 or$250,000 per gun in all respects complete.

Note: I deem it not only desirable but imperative that whatever plan be adopted it should contemplate both all around fire and protection.

Very respectfully,

JOHN J. KINGMAN,
1st Lieut.,
Corps of Engineers/'

The final design provided for 14 inch guns and armor plate in lieu of cast steel turrets. The turrets were placed at different elevations to permit the east turret guns to fire over the west turret. A cage mast was used for observation and fire control instead of steel cupolas between the turrets. While the basic conception remained unchanged, even to the caretakers’ shack on top of the fort, the final design included numerous other improvements over my original sketch plans referred to in the above quoted letter and reproduced with this article.

One important and fortunate change was the increase from 10 feet to20 feet in the thickness of the reinforced concrete roof, as this enabled Fort Drum to weather the concentrated and long continued pounding it received from Japs from about February 15 to May 6,1942.

Although the cost of Fort Drum did materially exceed my too modest estimate of $1,000,000, still, as compared to the cost of the previously contemplated artificial island, the "concrete battleship" did assuredly "prove vastly cheaper and no less effective." In fact open batteries on an artificial island, located as had been proposed, would probably not have long remained in action under such shelling.