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2. Mines and Similar Items:
a. Numerous enemy mines
were encountered set in place, and in magazines or dumps. The following
tykes were observed:
(1) Magnetic mines.
Found only in dumps.
(2) Shaped charges.
Made from Coca-Cola signs. Those were used by the Engineers as bulk
explosives to supplement their own stocks.
(3) Lunge type mine.
Found only in dumps. This mine appeared to be only two-thids (2/3) the
size of those previously reported. No handles were found.
(4) Small Jap Anti-boat
mines. This was the only type of mine employed tactically by the enemy.
It was encountered in dumps, on the beaches, and on trails. Sae Incl #l.
(5) Molotov Cocktail.
It is believed that no previous reports have been submitted on this
item. See Inclosure #2.
It consisted of a
bottle of approximately eight (8) ounce capacity, similar to those used
for carbonated soft drinks. This was filled with a clear viscous liquid,
believed to be a solution of rubber and benzene. Around it was a well
made rubberized sling, holding a cylindrical glass vial of black
crystals. Several of these incendiaries were tested. They worked very
well and burned for a considerable tine. A number of cases containing
this type were found, but reports indicate that none were employed
against our forces.
(6)
Small size type 3 AT-AP mines. Found only in dumps.
See Inclosure #1.
(7) Yard stick mines.
Only one mine of this type was found, and that on an isolated beach.
(8) Undoubtedly there
were other largo quantities of these mines, and perhaps of other types,
stored in underground magazines or coves that were covered up or
destroyed by our attacking forces.
b. Employment of
Mines:
(1) With the single
exception of the one (1) yard stick nine, all of the mines actually laid
or employed by the enemy against our troops were of the small size
anti-boat type. In all, approximately two hundred fifty (25O) of these
mines were located. See Inclosure #16. |
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(a) One hundred thirty
(130) were discovered on the San Jose beach, laid in the pattern as
indicated on Inclosure O. It was here that the Battalion Landing Team of
the 34th Infantry landed.
Apparently the Japs had some time previous placed
dug in boxes with covers in the beach in the desired pattern. When aware
of the imminent assault on the Island, the mines were placed in these
boxes. No attempt was made by the enemy to camouflage or to keep this
mine field from being disclosed. It is interesting to note that with few
exceptions, the whole detonator or "horn" was exposed and in addition
there were many instances where part of the base was visible.
This mine field was discovered accidentally by a
truck. The Engineers and mine platoon of the Infantry cleared paths
through the field, but in spite of these gaps, the mines accounted for:
1-Jeep, 1-2 1/2 ton truck, 1-D-6 and 1-D-7. Several other trucks hit the
mines, but merely broke off the detonators without setting off the mine.
In view of the fact some unarmed mines were found elsewhere, these
malfunctioning ones may not have been armed. It is interesting to note
that the D-6 did not hit the nine until D-3. It had been placed out of
pattern and had been covered by the debris the dozer was removing. Its
effectiveness and power were demonstrated on this D-6. One whole side
except for the driving sprocket was blown off and the tractor tipped
over on its side.
(b) A mine field on the
west side of the North Dock area was found containing some fifteen (15)
to twenty (20) mines. These were planted in the same type boxes, but
most of the mines were not armed. No pattern was discernable, the
distances between mines, however, were generally several yards. Their
location was too far from the beach for use as AB mines.
(c) Another mine field
was discovered along the beach at the mouth of the James Ravine. In this
area the mines were not placed in a definite pattern. The density of the
field was about one-half (1/2) mine per yard of front. There was also a
single barbed wire entanglement and some anti-vehicle hedge hogs made of
steel and concrete in this area.
(d) On the beach
between Artillery and Infantry Points were found approximately fifty
(50) mines. These were placed in the same type boxes found on the beach
at San Jose, but they were in no pattern. Unlike those in the North Dock
area, those were all armed.
(e)
See Inclosure #4.
On the west end of the island a mine field was located on either side of
a short steep trail leading from the road to the beach. Of note is the
fact that it was impossible to get into the mined area without going
through the barbed wire entanglement, hence the value of this field as
an obstacle was almost negligible. All of the mine horns were visible
and many mines were partially uncovered.
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(f) Between Malinta
Hill and the Landing Field, an enemy mine field consisting of some
fifteen (15) to 20 mines was discovered. The mines were generally
staggered along the shoulders of the road. However, there was ample room
for a vehicle to pass down the road without hitting the nines.
(g) The fact that this
type of AB mine is grate sensitive was brought out clearly by an
infantryman. This man, although a member of a mine laying platoon,
apparently intentionally kicked the horn of one in place which caused
its detonation.
c. Removal of Mines:
(1) The use of
electrical mine detectors was impracticable on the island due to the
large amount of bomb and shell fragments in the area.
(2) With few
exceptions, all the mines were readily visible. No attempt was made to
camouflage, either by natural or artificial cover.
(3) The enemy mines on
San Jose beach, in the north dock area, and those between Artillery and
Infantry Points were physically disarmed and removed. The standard
methods were used without any difficulties. The other fields were blown
in place:
(a.) The 161st
Engineers found that a one-half (1/2) pound block of TNT laid against
the horn did not work satisfactorily. Evidently the whole horn was blown
off and the acid did not flow into the battery cup. A two and a half (2
1/2) pound block of TNT laid on top proved 100% effective.
(b) However, the 113th
Engineers had no failures with a half pound (1/2) block laid against the
horn.
SECTION III - BEACH AND UNDER WATER OBSTACLE:
1. No under grater
obstacles were discovered.
2. The only beach
obstacles encountered, except mines, were those previously mentioned as
being in James Ravine.
SECTION IV - FIELD FORTIFICATIONS:
1. General:
The enemy defenses on
Corregidor were characterized by the absence of a well conceived and
coordinated plan. The island was dotted with well built emplacements,
but the vast majority of these were not mutually supporting and hence
could be destroyed one at a time.
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2. Air and Naval
Bombardment:
a. There is and will
continue to be much disagreement as to the effectiveness of Air and
Naval bombardment. On Corregidor, it was impossible to ascertain just
exactly what was destroyed by our forces in 1942, what was destroyed by
the enemy in 1942, and what was destroyed in the combined air and naval
bombardment preceding the landings. Those opinions and facts were
obtained by personal observation and from the Engineers of the task
force that recaptured the island.
b. The first impression
received of the island was that the installations of the entire fortress
were completely neutralized and destroyed, however, upon closer
inspection and detailed study of the area, it was amazing to note the
number of structures which still remained usable or in some instances,
intact.
In the area from San
Jose to North Docks, nothing remains but a mass of rubble. Large craters
pock mark the area, yet the concrete wall leading to Topside is still
intact. Also still undamaged are several lightly built concrete dugouts
and magazines, and both the north and south docks are virtually intact.
Malinta Hill received
heavy naval and air bombardment yet little damage was done to the mouths
of the tunnels, and a searchlight still remains intact on top of the
hill.
Inclosuros #5 and #6
are two (2) examples, showing the in-effectiveness of the Naval
shelling.
c. It is generally
accepted that the Naval bombardment of the west end of the island
neutralized many emplacements, not by direct hits, but by landslides
caused by the shelling. The air bombardment of Monkey Point is also
considered as having been quite affective.
d. The operations
carried out on Corregidor seem to confirm again the military axiom that
the Infantry has to make the final assault to occupy the ground and to
successfully and thoroughly defeat the enemy. The efforts and effects of
all other arms are merely to lighten their task.
3. Emplacements:
a. Types: The great
majority of the enemy emplacements were small, hand-dug tunnels or caves
facing the road. Sketches of the several different types and the methods
of placing the explosive charges to destroy then are shown in
Inclosures
#7 through #I4.
Automatic weapons were used in only five (5%) percent of
these caves and tunnels.
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b. Typical locations of
emplacements in relation to the terrain and their fields of fire are
shown in Inclosure #15. However, this area is developed to a greater
extent than is normal.
c. From the above
sketches it should be noted that weapons in these tunnels or caves (the
names are used interchangeably) covered generally only the area directly
in front of the entrance. In numerous instances the guns were emplaced
so far back in the tunnels that the field of fire along the road was
only a few feet wide. Occasionally the weapons emplaced in one tunnel
would cover the approaches to another. It has been reported that several
times the Japs set up their guns on the road in front of the caves,
thereby obtaining a good field of fire. It is the general opinion that
these were the intended tactics.
d. Demolition Tactics:
The infantry was interested in closing any caves or tunnels in which the
enemy was entrenched, or which were likely to be used by the Japs
infiltrating through our lines.
(1) The parachute
engineers actually went on patrol with the infantry and proceeded to
seal the caves as requested of them. The infantry stated several times
that their advance was only as fast as the engineers could close caves
and tunnels to their rear. It is believed, however, that the infantry
should have given heavier local support to the engineer demolition
crews.
(2) The operations of
the 113th Engineers were conducted differently. Their demolition crews
did not go with the infantry patrols, but were contacted by the infantry
when there was a demolition job on a cave or tunnel. Then, with
excellent close-in support by the infantry, carried out their mission of
destroying enemy positions and fortifications.
(3) The location of
these caves was such that only direct fire weapons could be employed
successfully. In most cases the terrain and condition of the roads
limited these to hand carried weapons. The bazooka with WP rockets was
by far the outstanding weapon. The WP grenade was also very effective.
Fragmentation grenades were found to have little effect in the caves.
Flame throwers were not very effective and were seldom used. An
equivalent weight of about seventy (7O) pounds of TNT was found to be
more practicable from a weight, transportation and effectiveness
standpoint.
(a) Artillery fire was
not used extensively against the caves. The great majority of pieces
were 75mm howitzers, whose light shell had little demolition effect.
Mortars too were ineffective against emplacements.
1. The demolition
tactics generally followed this pattern:
a. Since the emplacements or caves were not usually mutually supporting
it was possible to approach them one at a time. |
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With riflemen or BAR�s
covering the entrance, a bazooka or grenades were fired into the cave.
This had one of two effects. It drove the enemy into the rear of the
cave and neutralized their fire or it drove them out in the open, where
they wore shot down. Then the Engineers or the Infantry demolition
parties placed the charges as shown in Inclosures #8 and
#9. Many times
these demolition parties could actually hear the Japs chattering inside
while they wore placing these charges. Surprisingly few casualties were
suffered by this method of operation. Occasionally tanks were used with
this team to furnish point blank fire into the tunnel.
b. When the 113th
Engineers landed, their dozers were used very successfully in cave
covering and tunnel blocking tactics. This equipment was used to
completely seal caves or tunnels only partially closed by explosives or
to cover the entrances to new ones. One method used was the dozer-tank
team. The tank fired point blank into the cave, while the dozer picked
up a large load with its blade. The tank stopped firing while the dozer
pushed its load in front of the entrance. This routine was repeated
until the mouth of the cave was closed. Special mention should be made
here of the courage and valor of the dozer operators, since those
operations were carried out without benefit of an armored cab. The dozer
- infantry team was also successfully employed using similar tactics.
c. There were as many
methods of blowing those caves as there were demolition crews. As a
general rule, two (2) charges of fifty (50) pounds to one hundred fifty
(150) pounds were placed inside about six (6) to ten (10) feet from the
mouth. It was found that larger charges blow the spoil completely out of
the entrance. Because of the steepness of the slope and the great depth
of over burden, very few were blown by externally placed charges.
SECTION V - SUMMARY.
1. Much of the success
of this operation is due to the splendid work of the three (3) engineer
units participating. The tactics were such that the infantry could not
hold ground unless they were protected from the rear. The best
protection was provided by the systematic destruction of the caves and
tunnels used by the Japs as shelters and hideouts.
2. The engineers, and
to a much lesser extent the infantry, closed those caves with explosives
or dozers. The engineers alone neutralized over three hundred (300).
EARL McFARLAND, Jr,
Major, C. E.
Asst Engineer
16 Incls:
Incl #1 Sketch of AB mine and non-metallic mine.
Incl #2 Sketch of Molotov cocktail.
Incl #3 Sketch of mine field, SAN JOSE BEACH.
Incl #4 Sketch of mine field and barbed wire, W end of island.
Incl #5 &
6 Effect of naval shell fire
Incl #7 to #14 inclusive Sketches of typical caves and tunnels.
Incl #8 Methods of destroying Jap Caves on
Corregidor Island
Incl #9 One Method of Destroying Japanese Beach
Caves on Corregidor
Incl #14 Tunnels for Servicing Coast Battery
Incl #15 Schematic Diagram Showing Typical
Defensive Area
Incl #16 Typical defensive area.
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