The Japanese are showing an increasing tendency to use motor landing barges instead of
ships for transportation within range of United Nations aircraft in the Southwest
Pacific. This change of policy is probably due to heavy Japanese losses in transports
and destroyers as a result of air attacks.
The substitution of motor landing barges for transports would complicate Japanese shipping
problems, but it would lessen the dangers from air attacks, because: the barges are
comparatively small, they can be concealed during the day beneath overhanging trees or
even camouflaged on an open beach, and they can operate at night in shallow, reef-infested
waters where they are comparatively safe from destroyers and PT boats.
The 4,000-ton (gross) Japanese transport, commonly used for amphibious operations, can load
4,500 long tons, transport it 300 miles, and unload it in about 4 days.
In contrast, the large-type Japanese landing barge (daihatsu) can load a maximum
of 15 long tons, transport it 300 miles, and unload it in 5 days.
Therefore, for a distance of 300 miles, 375 large landing barges would be required to do the
work of a 4,000-ton transport.1 These figures, derived from a
mathematical formula, should not be applied at shorter or longer distances because the
relative capacity of motor landing barges decreases with distance.
The Japanese are known to have experimented extensively with the use of small boats (mostly
landing barges) for the transportation of personnel and matériel, both during and
after landing operations. A Japanese experiment with both large and small types of landing
barges was conducted comparatively recently in tropical waters of the Southwest Pacific. Their
conclusions regarding such matters as boat capacities, use of various types of weapons on
the boats, methods of unloading, and the provision of food and water are contained in
documents, which are paraphrased below.
2. BOAT CAPACITIES
Japanese conclusions with regard to the capacity and efficiency of landing barges for
transporting various types of troop units and equipment across large bodies of water
are summarized below. The conclusions are based on experiments conducted over a distance of
approximately 50 nautical miles. Using both their large- and small-type
landing craft, the Japanese made the trip in 7 hours.
a. For Large Landing Barge (Daihatsu)
|Rifle Co||50 ||None.|
|MG Co||40 ||3 HvMG.|
|Inf Bn gun unit||40 ||2 70-mm How (1 in
bow ready for firing; 1 dismantled in stern).|
|Inf Regt Arty unit||35 ||1 75-mm gun.|
|Mt Arty unit||35 ||1 75-mm gun.|
|Rapid-fire gun unit ||28 ||2 37-mm guns.|
|L Armd-c unit||15 ||1 L Armd-c.|
[Comment: In the loadings shown above, consideration was given to the comfort of
occupants, facilities for cooking, and defensive use of weapons. For landing
operations where distances are fairly short, these barges could carry considerably
more tonnage—probably twice as much in the case of rifle and machine-gun companies. When
the large barge is used as a command boat, the Japanese recommend that 25 to 30 men make
up the load.]
b. For Small Landing Barge (Shohatsu)
|Rifle Co ||25 ||None.|
|Rifle Co ||20 ||1 HvMG.|
[Comment: Capacities for units equipped with heavy weapons are not given, indicating
that the small barge is not considered suitable for carrying troops and heavy
equipment on a run of a full day.
For landing from troop transports, the above capacity figures for the small landing barge
probably should be about doubled.]
3. CONVENIENCES FOR PERSONNEL
a. Except in the case of tank and armored-car units, benches for the men to sit on are absolutely
necessary on long voyages. They must be thrown overboard before landing because it would be
inconvenient to unload them.
b. Rifles should be placed in an arms rack. The best positions for the racks are in the
stern or in both sides of the boat.
c. Lowering of the floor boards when there are no waves will provide better ventilation and
d. The bow operator gets tired quicker than others because he has no shelter; therefore, it is
advisable to relieve him often.
e. Personnel in the small barges should stand up for 10- to 15-minute intervals from time to time.
f. Tents are absolutely necessary. Shelter tents are thin and very hot.
g. If possible, provide a utensil in each boat for boiling water.
h. A half canteen of water [per day] is necessary for drinking, in addition to the amount
consumed with meals.
i. Coconut milk is very good for drinking.
j. The best method for carrying and preserving rice is to put it in a rice basket and
add 3 or 4 pickled plums. [The plums are preserved by a salt solution.] Rice kept
in this manner will not spoil for 17 hours or more. If it is carried in a rice
box, without pickles, it is liable to spoil after 11 hours. In any case, rice must
be cooked hard and its container must be dried thoroughly.
Rice carried in a mess kit, without pickles, will keep for 13 hours.
4. ARRANGEMENT OF WEAPONS
The rifle should be rested on sandbags, which are to be prepared and placed on the sides of the
boat for this purpose.
b. Light Machine Gun
Rather than have it handled by two men, the light machine gun should be rested on the sides of the
boat for firing. It occupies too much space when handled by two persons, and the firing
of rifles is interrupted.
c. Machine Guns
When using a rest for antiaircraft fire, the firing will be the same as under ordinary
circumstances. In circumstances under which the rest is not used for antiaircraft firing, arrange
the weapons as follows:
(1) When the left (or right) side of the boat and sandbags are used, remove the cotter pin of the
cog and lower the cog sufficiently. Remove the barrel cover pin, swing the barrel in the opposite
direction, and replace the pin. Essentials for aiming correspond to those for the light machine gun.
(2) When manpower is used [to hold the gun while firing], take down the gunshield and rest the
front and rear legs of the weapon on the two sides of the boat. To fire, remove the barrel from
the legs, tie ropes around the barrel, and hang it a suitable height.
d. Antitank Gun
To operate an antitank gun from a large boat, the No. 3 and No. 4 gunners will fire from a standing
position. When adjusting the range sights, make no change in elevation, but change the direction
slightly. Contact the boat captain beforehand and have the boat proceed toward the target. Depending
upon the action of a moving target, set the sights at the bottom or top center, and pull the trigger
when the boat is at the crest of a wave.
e. Mountain Gun
In making arrangements for firing this gun from a large boat, pile three square pieces of timber
at the 10th rib to make a brace for the legs and the trail spades; put two sandbags on each of the
trail spades, one bag under each wheel, and two bags on each wheel in order to prevent the gun from
jumping up. At the same time, tie the wheels to the rings on the sides of the boat with ropes.
In operating the mountain gun from the boat, show the target clearly to the boat captain and
have the boat advance straight toward the target. In other particulars, operate according to the
essentials of direct fire. However, when the waves have a disturbing effect, fire when at the
crest of a wave.
5. NOTES ON UNLOADING
Japanese instructions dealing with the unloading of troops and matériel from ships at a
New Guinea port and on Guadalcanal are contained in enemy documents which are paraphrased below.
a. New Guinea
The order of unloading is mainly as follows:
(1) Land duty personnel [including unloading detail], and their necessary equipment;
(2) Antiaircraft guns (with ammunition), motor vehicles, heavy matériel (including
artillery), and the personnel who operate them;
(3) Supplies, including medical stores, important articles for all units, and the necessary
(4) Matériel of units and the necessary handling personnel;
(5) Personnel assigned to ship duties during the unloading.
In regard to munitions ships, fuel should be removed from them first, and as fast as
possible, in order to lessen the danger of fire.
Endeavor to keep intact the organization of small units, and progressively increase the
unloading and transport details (particularly the latter) as the troops land.
In the past, personnel in a number of instances have hurriedly disembarked from transports to
evade aerial bombing. This seriously reduced the number of duty personnel on board the
ships—in some extreme cases, no one was left on board to direct operations. The result has
been not only a serious delay in unloading but actually a failure in some cases to unload
anything. Such occurrences must be avoided in the future and every effort put forward to
unload everything down to the last articles, in spite of all difficulties.
The following paragraph on "Supplies" was included in the Japanese document:
During the unloading operations, the number of evening meals and snacks will be increased in
accordance with the progress of operations. The water supply will be on the same basis. This
will have a beneficial effect upon the progress of the work.
The order of unloading was practically the same as that given for the New Guinea port. Infantry
units were unloaded ahead of the land duty personnel.
The "commander of the Guadalcanal Island unloading unit" was responsible for regulations governing
the beach where the unloading took place.
(1) Use of Lights.—"Dangerous spots near the landing beach and dangerous reefs in the
sea will be marked ... with faint red lights just before the convoy comes in to anchor," the
document stated. Other references to use of lights were as follows:
Strict control of lights will be enforced at night. Dim lights, utilized in such a way that they
cannot be seen from the air or from the sea, may be used for the following purposes:
(a) For loading or unloading ships' holds;
(b) For the inspection or repair of engines on the boats; and
(c) For indicating danger or distress (use a red signal with a circular motion).
(2) Rescue and Medical Care.—Each company will prepare one rescue boat, and will
be responsible for rescue work between the anchorage and the shore.
During the daytime, the rescue boats will be identified by displaying a Red Cross flag.
Those requiring rescue will make circular motions with their red light at night, and will wave their
red flag horizontally in the daytime.
6. HOW TO DODGE PLANES
Of particular interest to air forces are two Japanese documents which describe evasive tactics
of their ships during air attacks. These documents are paraphrased below.
In cases where the planes are sighted at least 4 sea miles away, turn toward the oncoming enemy
immediately and increase your speed. When the planes are about to drop their bombs, change
course at a large angle (full helm). When the wind is fairly strong, change your course so
as to receive a full cross wind.
When attacking planes are sighted close at hand (less than 4 sea miles), or when attacks are
continuous, immediately carry out a large dodging movement. Subsequently, make continued
large turns individually, without maintaining a set course. Strive to gain the benefits of
cross winds as outlined above.
If you are in formation, break it and scatter according to circumstances.
1 According to a Japanese document, the large-type landing barge is 49 feet
long, 11 feet wide, and has a capacity for 10 horses, or a tank and an automobile. The
speed of the boat is about 8 knots. The crew numbers seven.