STREAM CROSSING EXPEDIENTS
(NAVMC— 3616)
1944
Published : —
For Instructional Purposes Only.
MARINE CORPS SCHOOLS
MARINE BARRACKS, QUANTICO, VIRGINIA
>
This pamphlet presents a complete course of instruction
in Stream Crossing Expedients as conducted at the Officer
Candidates' School, Marine Corps Schools, Quantico, Virginia.
It includes the physical organization and arrangement of the
instructions, hour by hour, as well as the scope of the subject
to be taught in each period, the text references, locale, equip-
ment required and the actual lectures or instruction given.
B. T. FAY,
Colonel, USMC,
Commanding.
APPROVED:
W. T. CLEMENT,
Colonel, USMC,
Commandant, Marine Corps Schools.
STREAM CROSSING EXPEDIENTS
MARINE CORPS SCHOOLS
MARINE BARRACKS, QUANTICO, VIRGINIA
SECTION 1
1. Outline. —
TYPE OF INSTRUCTION
PLACE :
MAP:
LENGTH OF PERIOD:
UNIT:
EQUIPMENT:
PURPOSE:
CONDUCT OF EXERCISE
Field Exercise.
Engineer Demonstration Area
(1331.48-1342.17).
Aerial Mosaic of USMC Reserva-
tion, Quantico, Virginia.
Four (4) hours.
Demonstration troops, ten (10)
men.
and public address
M-l w/launcher,
Microphone
system
2 Rifles, Ml
2 Carbines,
M-8
2 BAR's, M-1918A2
1 BMG w/tripod and spare parts
1 37mm Gun, AT
8 Chests, ammunition, BMG
2 Field Transport Packs, com-
plete
2 Helmets, steel
4 Truck bows, % ton
7 Canvas truck covers, % ton
2 Canvas truck covers, *4 ton
2 Canvas truck covers, VA ton
1 Canvas truck cover, 2 1 / <> ton
4 lines, % inch, 100 ft.
1 line, % inch, 50 lb. reel
1 Truck, 14 ton, (jeep)
To show the individual Marine
practical methods of floating
equipment found in an infantry
battalion.
The troops who are to see the
demonstration, form a large
semicircle around the area in
which the demonstration is to be
held (care must be taken so that
all can see the instructor and the
demonstration) .
(1) Orientation on Stream
Crossings is given by the in-
structor.
(2) The instructor calls for
two men from the demonstration
troops equipped with rifles, steel
helmets, and field transport
packs. They make up the rifle-
men's equipment shelter half
float using crossed rifles, BAR's
and sticks, demonstrating the
floats in the water as they are
made up.
(3) The same two men from
the demonstration troops make
up the riflemen's equipment
poncho float with marching
packs, using crossed rifles, car-
bines, BAR's and sticks. As the
floats are made they are dis-
played in the water.
(4) The same two men make
up the poncho float and demon-
strate its use in the water.
(5) Six men, representing a
machine-gun squad, are called
forward from the demonstration
troops. They construct the truck
bow squad raft, stow their equip-
ment and paddle across the
stream. These men are then dis-
missed.
(6) Four men from the dem-
onstration troops are called for-
ward by the instructor. They
demonstrate how to construct
and secure a bundle of brush.
This bundle, with another previ-
ously prepared one, is then prop-
erly wrapped and secured in
canvas. The four men pole or
paddle across on the brush float
demonstrating its use as a per-
sonnel float.
(7) Five men, representing a
37mm antitank squad, are then
called forward by the instructor.
They push three previously pre-
pared brush floats into the
stream and launch the 37mm
gun on the floats, securing a
holdback line and a tow line and
pull the gun across the stream.
Four men are dismissed to se-
cure the 37mm gun.
(8) Six men launch the y± ton
truck on four brush rafts, secure
the holdback and tow lines. The
other four men of the demon-
stration troops tow the truck
across.
(9) All ten men of the demon-
stration group now are used to
make the brush raft footbridge.
They push the prepared brush
floats into the stream and carry
to the stream bank the prepared
sections of the footbridge. These
men then construct the foot-
bridge across the stream. When
completed, the instructor then
has some of the observing troops
walk and double time across the
bridge.
2. General. — a. The Marine Corps Infantry Battalion is
not issued standard stream crossing equipment and must,
when necessary, devise methods to cross streams. The Engi-
neers have the equipment to set up crossings, but seldom will
they be available for small unit crossings of streams. There-
fore, an Infantry Battalion must learn how to cross personnel
and weapons using the regular equipment available to them
in the locality of the operation.
b. All the initial training of troops using expedients
for stream crossings should be conducted in streams with a
rate of flow of less than two miles per hour. Operations on
streams with a stronger current are difficult for an inexperi-
enced unit and are dangerous to both personnel and equipment.
c. The methods described in this pamphlet should not
restrict the training of the unit. Units should be encouraged
to develop other methods for stream crossings. This field is
unlimited and subject only to the ingenuity of individuals in
the training group.
SECTION 2
PERSONNEL AND EQUIPMENT FLOATS
3. Riflemen's Equipment Shelter-half Floats — a. Two men
place their shelter-halves, one on top of the other, on the
ground. The triangular flaps are folded in from each end from
the seams of the shelter half. The packs of the men are then
placed in the center of the shelter halves with the long axis of
the packs parallel to the long axis of the shelter halves. The
packs can then be secured together by the cartridge belts of
the two men. The rifles, with the bayonet and scabbard at-
tached, are then placed on top of the packs, crossed to give
rigidity to the bundle, and secured at the point of crossing by
the web trouser belts of the men. (See Figure 1) . The diagon-
ally opposite corners of the canvas are then lashed to the
Figure 1. — Field transport packs and equipment properly stowed before
wrapping the shelter half float.
opposite ends of each rifle by use of the shelter tent ropes. (See
figure 2). The men then strip off their clothing, fold it, and
place it inside the float. (See figure 3). The float has eight to
ten inches of freeboard and may be pushed across a stream by
a swimmer. (See figure 4). This type raft can safely remain
in the water up to one hour and will carry three hundred
pounds. This float may be constructed with one shelter half as
a base, the other shelter half being tucked around the gear in
the completed float to keep it dry in case water is shipped.
Figure 2. — Completed shelter half float less clothing.
Figure 3. — Completed shelter half float with clothing stowed.
Figure 4. — Shelter half float made up with but one shelter half as a base;
the other shelter half is used to cover the gear.
b. Personnel not armed with the rifle, or personnel de-
siring to keep their rifles in readiness, can make this type raft
by using two poles each equal to the length of the rifle with
bayonet attached, in place of rifles. The BAR man can make
this float with the assistant BAR man who may be armed with
a carbine. The bipod legs of the BAR are extended horizontally
as an extension of the barrel. The assistant BAR man cuts a
stick which is equal to the length of the BAR plus bipod, and
lashes it to his carbine. The BAR is crossed with the stick tied
to the carbine to make up the float in a similar manner to the
one previously described. If two men are armed with carbines
and wish to make up a shelter half float, they should use sticks
that are rifle plus bayonet length. A raft made with poles can
be used to float a caliber .30 heavy machine gun.
c. A line may be stretched across the stream, and men
may utilize this as a safety line to support themselves. In
addition, non-swimmers have security by holding on to the
line with one hand and pushing the float with the other. This
line is a necessity in a swift moving stream.
4. Riflemen's Equipment Poncho Float. — a. Often men
will be carrying the marching pack and will not have a shelter
half with which to construct a float. We then utilize the
poncho in constructing a float. One poncho is folded double
with the neck opening at the center of the single edged fold.
(See figure 5). After securing the packs in the center of the
poncho, the rifles (without bayonets attached) are laid across
the packs, crossed, and lashed together at the point of crossing.
The men, working on opposite ends of one of the rifles, reach
down between the two butts and two muzzles, grasp the diagon-
ally opposite corners of the poncho and fold them over both
ends of one of the rifles. The corners of the poncho are folded
sufficiently enough around the ends of the rifle to insure a
secure purchase by the line or cordage used to tie them. (See
figure 6) . The two men then move to the other rifle and repeat
the above procedure, making sure the ends are brought up
taut to provide plenty of freeboard. The other poncho can be
used to cover the gear to keep it dry in case any water is
shipped. (See figure 7) .
Figure 5. — "Equipment used to make the poncho equipment float.
Figure 6. — Completed poncho equipment float with the clothing stowed.
10
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Figure 7. — Poncho equipment float being towed.
b. This type float can also be constructed using two
sticks of rifle length, two BAR's with bipod legs folded under,
one BAR and a BAR length stick with Carbine, or two Car-
bines with Grenade launchers attached.
5. a. Poncho Float. — Another type poncho float, recently
introduced in the Marine Corps, is similar in appearance to a
large paper bag and is used as a float for individual crossings.
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The poncho is laid flat and is then folded over once to form a
rectangle, with the neck opening at the center of the single
edged side. Starting at either corner that is formed by the
junction of the single and double edges, a three inch fold is
made in the double edged side and is held in place by the left
hand; another double edged fold is then folded back over the
first fold in an accordion pleat manner. Continue this folding
until all three of the double edged sides are completely folded
and are held in place by the left hand. A legging-iace or shoe
lace is then securely tied in position three inches below tne
edges of the folds. The poncho is now turned inside out by
reaching through the neck opening. The poncho is then im-
mersed in water to wet the fabric. The poncho has assumed
the shape of a bag. The neck opening is held closed by both
hands, and then is inflated orally in the same manner as one
would inflate a paper bag. The neck opening is then securely
tied with a lace and is ready for use. (See figure 8).
RD4366
Figure 8. — Poncho Balloon Float.
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6. Truck Bow Squad Raft. — a. Machine-gun squads and
mortar squads must have some method of getting themselves
their weapons, ammunition, and equipment across streams. An
excellent means of doing this is by using the squad equipment
float, constructed from truck bows. To construct this float,
take four bows from a %-ton truck and lash them together in
pairs to form two squares. (Any size truck bow may be used as
long as you have the canvas cover from a truck of similar size.)
Place one of the square frames in the center of the canvas.
Use empty ammunition chests, bed rolls, packs, etc., as a
spreader and place the other frame on top of the spreader.
(See figure 9). The spreader may be secured to the frames
to give rigidity to the float. Throw the canvas loosely into
the center. Be careful not to have any sharp corners in the
canvas, since leaks occur whenever a sharp crease is made.
(See figure 10) . The canvas can be secured loosely across or
to the bows. The depth of the raft depends upon the height
of the spreaders used. The bottom of the raft may be covered
with brush to even the pressure of the load. If truck bows
are not available, but the canvas is, make two frames of
saplings similar to the truck bow squares.
Figure 9. — Truck bow square frames set on canvas. Machine gun chests
are used as spacers.
13
Figure 10. — Truck bow squad equipment float.
b. A raft of this type can support up to 1500 pounds,
and can safely be left in the water three to four hours. It can
carry a machine-gun squad, mortar squad, two to three casual-
ties, 1000 pounds of ammunition, stores, or medical supplies,
etc. This raft can be pushed across by swimmers, towed, or
paddled across. (See figure 11).
14
Figure 11. — Truck bow squad equipment float with personnel.
7. Brush Rafts. — a. Brush rafts are simple to construct
and are excellent all purpose floats. They can be used to float
37mm or 75mm weapons, % to % ton vehicles, two to three
people, 300-400 pounds of ammunition, used as floats for foot-
bridges, etc. In constructing a brush raft, spread a canvas
(usually a % ton or l 1 /? ton truck cover) on the ground with
the buckle side down. Build brush bundles of such a size that,
when they are placed on the canvas, the canvas will extend 18
to 20 inches beyond the bundles on all four sides. Several small
bundles are easier to handle than one large one, so make the
bundles the full length of the area to be filled, but only about
two feet wide and sixteen inches high. Two brush bundles in a
float make the float more stable and it is harder to roll over in
the water. (See figures 12 and 13). It takes three men about
an hour to cut brush, bind it, and to make one brush raft
float. These brush rafts are about 7 feet long and 3 feet wide
and will support up to 800 pounds.
15
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^^
R04366
Figure 12. — Two brush bundles laid in canvas cover.
Figure 13. — Brush float made up of two bundles.
16
b. To construct a brush bundle, drive stakes in the
ground to outline the size of the bundle desired. Lay pieces of
line or telephone wire four to five feet long across the area
formed so they will already be underneath when the brush
bundle is to be secured. Brush, either dry or green, is then
piled in between the stakes. Bind the brush with the line or
wire previously put in place. (See figure 14). Remove the
bundle from between the stakes and cut the ends off square
with a machete or other sharp cutting tool. Make enough
bundles to fill the desired area and place the completed bundles
in the canvas. Raise the sides of the canvas and tie them se-
curely in place with the lines on the canvas. The walls of the
canvas should be as nearly vertical as possible so there will be
less chance of shipping any water.
Figure 14. — Brush bundle, partially constructed, piled between stakes.
c. Brush rafts constructed with canvases in good con-
dition can be used continuously for five or six hours before
they become waterlogged or unsuitable for further use. The
canvas must then be dried before it is again ready for use.
17
d. Brush rafts can also be constructed using loose
brush. Spread the canvas out on the ground. Pile brush in the
center of the canvas that is to be wrapped around the brush.
Care must be taken to see that the brush is packed tightly
along the sides and across the ends of the brush bundles so
that the sidewalls of the canvas will be as nearly vertical as
possible.
e. If you have a large canvas, construct three or four
brush bundles to fit it, and construct a brush float. This type
of float will carry six to eight men across a stream.
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SECTION 3
FLOATATION OF VEHICLES AND WEAPONS
In this section, various means of floating weapons and
vehicles are described. Gently sloping banks for floatation of
heavy equipment should be selected. Log or sandbag ramps
can be used to supplement sloping banks.
8. Floating the 37mm Gun. — Construct three brush rafts
in the manner described in Section 1. Spot these rafts in
line at the water's edge. Back the gun into the water and
place the spades on the center raft. The weight of the trail
will hold the spades secure in the raft. Place a pole beneath
the recoil cylinder of the gun and rest it in the center of the
other two brush rafts. If you cannot secure one pole strong
enough to support the gun, two lighter poles can be used.
Nothing has to be secured, as the weight of the gun will hold
the poles in place under the recoil cylinder and on the brush
rafts. Attach a towline to the trail spades and holdback line
to the spade of the weapon. (See figure 15). The gun can be
pulled across the stream, trail first, and beached. Holdback
lines are attached to the weapon so that the raft can be kept
under control while it is towed across the stream. Any piece
of artillery (75mm or 105mm) can be floated across streams
in this manner. Larger brush rafts are necessary for larger
and heavier weapons.
19
RD43*
Figure 15. — 37mm gun floated on three brush rafts.
9. Floating the Va Ton Truck with Brush Rafts.— Build
four brush rafts, using the canvas cover of either the % ton
or the % ton truck for each raft. To prepare the truck for the
crossing, lash a pole about sixteen feet long to each bumper.
Spot two brush rafts in the water so the truck can be driven
in between them. Rest the front pole in the center of the two
brush rafts, and continue to drive the truck into the stream
until there is room to place the remaining two rafts beneath
the ends of the rear pole. Attach a towing line to the front of
the truck and a holdback line to the rear. The truck is ready
to be taken across the stream. It is not necessary to lash the
poles to the brush rafts as the weight of the vehicle will hold
them in place. (See figure 16) .
20
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Figure 16. — ^-ton truck floated on 4 brush rafts.
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SECTION 4
FOOTBRIDGES
10. General. — Footbridges are one means of crossing for
personnel who are carrying their normal tactical equipment.
This is a quick method, and a well-constructed bridge is very
reliable. Any material which will support the weight of a
Marine in the water can be converted into some type of foot-
bridge. When training troops in the preparation of bridges as
expedients, instruction should not be limited to those given
here; originality should be encouraged in an attempt to de-
vise other types of bridges.
11. Brush Raft Footbridge.— a. Construct sufficient brush
rafts of % ton truck covers so that there is one brush raft for
each 10 feet of stream to be crossed. Prepare flooring sections
by preparing poles about six inches in diameter and eleven
feet long. Nail to the poles a flooring of two foot long saplings
or any other available material, leaving an extension of six
inches at each end of the poles. Sufficient flooring should be
prepared to completely span the stream. (See figure 17).
23
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b. The bridge is held in place against the current by
a line stretched across the stream from a tree or other
anchorage to an anchorage on the other bank. Place this line
about five feet upstream from the site selected for the foot-
bridge. After the line is in place, float the brush rafts into
position just off shore below it. Tie one end of a 12 foot piece
of line to each raft. Pass this line over the cable and bring it
back to the raft. Station a man on each raft as it is placed in
position. This man adjusts the alignment of the raft by means
of the lashing. One flooring section is placed on the first raft
and it is poled across the stream to the opposite bank. This
section of flooring extends from the first raft to the far bank.
In the meantime a second raft with a flooring section aboard
is poled across the stream and this section of flooring is ex-
tended to the first raft that went across. The two sections
are then interlocked (See figure 17) and lashed together. The
rest of the brush raft footbridge is constructed in a similar
manner with succeeding brush rafts, with a flooring section,
poled across and the sections of bridge securely interlocked.
(See figure 18).
Figure 18. — Brush raft footbridge.
25
c. When the bridge has reached the far bank, use the
extra flooring section placed on the first two rafts to complete
the connection to the far bank. The man on the brush rafts
adjusts the lashings until the bridge is properly alined, and
then uses the free end of the lashing to tie the flooring sections
firmly together.
d. When used at night, this bridge will require a hand-
rail. A number of types of handrails can be improvised. One
satisfactory method is to stretch another line along the edge
of the flooring, to guide Marines across the bridge. (See fig-
ure 19).
Figure 19. — Completed brushraft footbridge in use.
e. Satisfactory floatation for footbridges can also be
obtained by using a combination of 55 gallon gas drums. Five
gallon water or gasoline cans, used in large numbers, will pro-
vide sufficient floatation for an improvised footbridge. Care
must be taken in any improvised bridge to make the flooring
as rigid as possible. Too much spring in the flooring of a foot-
bridge will make it almost impossible for soldiers to run across
the bridge.
13368 MCS QUANTICO, VA. 8-30-44--3M
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