Caballo was the
inspiration for the plan by which Fort Drum was reduced. On this
horse-shaped rock the entire Jap garrison had been killed within a
few days, except a band of sixty or so who had holed up in two huge
mortar pits, which resisted all efforts of infantry engineers, and
artillery to reduce them. Of reinforced concrete, eight to ten feet
thick, the walls at Caballo had originally been built by the
Americans and later improved by the Japs.
were offered and rejected.
formulated by Lt. Col. Fred C. Dyer, G-4 of the 38th which had
worked so well on Caballo, was finally accepted. An LCM was fitted
with a centrifugal pump and two tanks capable of holding more than
5,000 gallons. A special mixture of two parts diesel oil and one
part gasoline was prepared and pumped into the tanks.
General (then Colonel) Robert H. Soule, assistant division
commander, selected this plan as the one most likely to reduce Drum.
preparations for the landing were begun a week before D-Day. On
Corregidor a reinforced platoon of riflemen from Company "F," 151st
Infantry and a platoon of demolition men from Company "B," 113th
Engineers, made repeated dry runs so that each man should know what
he must do when he stepped atop Fort Drum.
On the parade ground at Corregidor
the surface of the island was simulated. Dummy gun turrets and air
vents were built. Each rifleman was assigned a specific opening in
the surface of the fort to cover. Every gun turret, every air vent,
every crack in the surface was to be covered with an M-1 or a BAR,
so that no enemy would be able to come topside. The infantrymen
practiced repeatedly so that each one was able to carry out his
appointed task without a hitch.
were trained in planting explosives at strategic intervals on the
rock, while others went through the motions of dragging a fire hose
topside from the LCM which was scheduled to pull up alongside in the
manner of the Caballo operation.
direction of Major Robert E. Hisle, S-3 of the 113th Engineers, an
especially designed wooden ramp was built from the conning tower of
the LSM, much like a drawbridge. It was located on the starboard
side and let down at right angles to the length of the ship. The
ramp was necessary since the height of the island—40 feet—prevented
the troops from landing in the usual manner.
effecting an entry through the sally ports were rejected because a
Naval reconnaissance force landing from a PT boat at these points
had received machine-gun fire from the tunnel.
April 13 — a
Friday — was selected by an unsuperstitious staff as D-Day; H-Hour
was set at 1000. At 0830 the troops loaded from Corregidor's south
dock walking over the narrow plank from the pier to the landing
were burdened with 600 pounds of explosives, while the infantry
carried rifles and bandoleers of ammunition. In the crow's nest
towering above the landing ramp a BAR man was stationed, while below
him on a precarious platform a light machine gun was set up, thus
providing adequate protection for the troops who were to land.
1000 the LSM pulled up at Fort Drum. It was a ticklish operation to
maneuver the squat bulky craft so that it snuggled tightly against
the island and held there steadily.
As the LSM moved
up on the port side, three LCVP's manned by naval personnel came up
alongside the larger ship, bows first, and with motors racing pushed
against the LSM, shoving it against the rock.
As soon as the LSM was close
enough, sailors standing in the well-deck let down the ramp by means
of a block and fall. Immediately, other sailors rushed ashore across
the ramp carrying lines which were fastened to the gun turrets or
any other available projection to make the LSM more secure.
in single file moved up the circular ladder to the conning tower.
Sailors helped them climb to the ramp and onto the rock, like so
many charging knights.
strong lines and the LCVP's, the LSM pitched and rolled and the ramp
scraped dangerously back and forth over the concrete top deck.
The LCM used in
the Caballo invasion was brought in behind the larger vessel and a
fire hose was passed up to the engineers on the LSM by means of a
line. The line was thrown up to the deck of Fort Drum where other
engineers grabbed it and brought up the hose.
The Infantry did
its job well. Every vent was covered by a rifleman. A Jap could
never have gotten his head above the surface without having it blown
off. The engineers set about their task of planting the explosives
with sureness and dexterity. Particular attention was given the
powder magazine which was below the surface on the first level, and
protected by an armor plate six inches thick under the layer of
In ten minutes
the job was finished; thirty-minute fuses were lighted; and the men
began to file back onto the ship.
Once at one
point, the hose broke and while the break was being repaired, the
first opposition developed. A Jap sniper hidden in one of the
six-inch gun turrets on the port side opened up. His aim was bad on
the first couple of shots. Although the sniper couldn't be seen,
sailors manning the LSM's 20mm guns were anxious to spray the
turret, but a redheaded ensign yelled from the bridge that oil was
leaking through an aperture in the turret and that shells would
undoubtedly ignite it, jeopardizing the success of the whole
operation. Fuming, the sailors held their fire but remained at their
positions exposed to the enemy rifleman.
The sniper opened up again with
another volley and a bullet passed through the fatigue jacket of
Sgt. Mack Thomson, the colonel's driver and radio operator. Thomson,
unaware that the sniper had been firing, was standing some distance
away toward amidship. The bullet made seven holes passing through
the jacket, baggy pocket, and sleeve. Thomson was not even
Another bullet grazed Cpl. Vincent
Glennon's left hand. At the first shot this aid man dropped behind a
ventilator for protection. But a bullet passed through the light,
thin metal of the ventilator, creasing his hand and drawing no more
blood than a pin scratch.
A sailor was less fortunate. One
shot split the fittings that connected the three air hoses to the
gyroscopic sight of a 20mm gun and several of the pieces embedded
themselves in his throat. He had been manning the gun at the time.
Army and Navy medical corpsmen teamed up to give him an immediate
blood transfusion and dress his wounds. Those were the only
casualties–a cheap price for Fort Drum.
After Colonel Lobit and his men
returned safely, the lines were cut, the LCVP's backed off and the
LSM pulled away, stopping about a thousand yards off to watch the
show. In thirty minutes there was a slight explosion. Nothing else
happened. Disappointment was written in the faces of the men. They'd
have to do it all over again now. But no.
Suddenly it seemed as though the
whole island were blown out of the sea. First there was a huge cloud
of smoke rising from the island, then seconds later, the GI's on the
LSM heard the thunderous explosion. Blast after blast ripped the
concrete battleship; debris was showered into the water, creating
hundreds of small geysers; a huge flat object, later identified as
the six-inch, 12 foot square slab of armorplate protecting the
powder magazine, was blown hundreds of feet into the air to fall
back into the sea with a large splash.
A satisfied cheer went up as the
explosions rocked the air and there were the usual salty comments in
As the LSM moved toward Corregidor
more explosions were heard and dense black smoke continued to rise
from the "impregnable" battleship.
Two days later–on a Sunday – the
drama was partially reenacted. This time the object was to gain
admittance to the lower levels. But wisps of smoke that curled up
from the ventilators indicated the (illegible) was
still burning. Major Paul R. LeMasters, commander of the 2d
Battalion, called the descent off and the disappointed troops
returned to Corregidor.
day the troops again returned. Now they were able to make their way
as far down as the second level but again smoke forced them to
withdraw. Eight Japs — dead of suffocation—were found on the first
two levels. Two days later another landing party returned and this
time was able to explore the whole island. The bodies of sixty Japs
— burned beyond recognition — were found on the third level in the
The inside, of
course, was a shambles. The walls were blackened with smoke and what
installations there were had been blown to pieces or burned.