U.S. Marine Corps - Small Wars Manual (1940 Edition)

Chapter X. RIVER OPERATIONS.

SECTION II
TYPES AND CHARACTERISTICS OF BOATS

					Par.	
General					10-3
Coaatwise communications		10-4
Nature of the river			10-5
Lower river boats			10-6
Middle river boats			10-7
Upper river boats			10-8
Types of boats available		1O-9
Method of propulsion			10-10
influence of tactical principles	10-11

10-3. General.-The types and characteristics of boats which are to be used in a particular river operation depend upon several factors, of which the more important are:

(1) Coastwise communication required.
(2) Nature of the river.
(3) Desirable boat characteristics for lower, middle, and upper river use.
(4) Types of boats available.
(5) Method of propulsion.
(6) Influence of tactical principles.

10-4. Coastwise communications.-Navy vessels, motor launches, and local coastal schooners, normally will be used for maintaining coastwise communications. Unless a main supply base is located at the mouth of the river on which the operations are being conducted, coastal shipping will be used for the, transportation of personnel and replacements, and primarily for the shipment of supplies.

10-5. Nature of the river.-The nature of the river, more than any other factor, determines the types of boats which will be used in river operation. The depth of the lower, middle, and upper rivers; the swiftness of the current; the distances between obstacles in the river; the number and length of the portages required; the season of the year; and the probability of securing native boatmen; each of these will have some effect on the decision. Ordinarily, at least three types of boats will be required because of the limitations as to draft in the various river levels. lf the lower river is more than 300 miles long, or has a limiting depth of over 8 feet, boats of the coastwise type will be used in addition to the usual river types. On the other hand, if the length of the middle river is quite short, it may be more economical to use only two types of boats, those for the lower and upper rivers only.

10-6. Lower river boats.-Boats to be used on the lower river normally should be motor propelled, of 4 feet draft or less, and with a maximum speed of 15 miles or more per hour. Their propellers should be protected to prevent damage from submerged rocks or logs. If they are procured outside of the theater of operations, they should be of such size and weight as to permit them to be transported by Navy transports. They should be provided with .30 or .50 caliber machine guns mounted on swivel mounts at the bow, and light armor provided to protect the gunner, helmsman, and fuel tank.

10-7. Middle river boats.-Boats for use on the middle river should be of sufficient size to carry at least one squad and its equipment in addition to the boat crew. Normally these boats should have a draft of 2 1/2 feet or less. The power plant may be an outboard motor or an inboard motor with the propeller protected against damage from rocks and other obstacles. A maximum speed of 20 miles per hour is desirable. These boats should be strongly but lightly built, to facilitate their passage through rapids and through stretches of water, or their portage around such areas. The .30 caliber machine gun may be mounted forward, either on its regular tripod mount, or on a swivel mount if one has been provided.

10-8. Upper river boats.-For the upper rivers, the most suitable boats are those obtained locally from the natives. If these cannot be procured in sufficient quantity, substitutes should be of the light, shallow-draft, canoe-type boat, with fairly wide, flat bottoms and built as strongly as possible commensurate with their light weight. Provision should be made for the attachment of outboard motors, although the normal method of propulsion will be by hand in most situations. They will vary in size from small canoes capable of carrying one half of a squad plus the crew, to cargo canoes capable of carrying 8 to 10 thousand pounds of supplies in addition to the necessary crew. The average upper river boat should be of sufficient size to carry a complete squad with its equipment, in addition to the crew.

10-9. Types of boats available.-a. Local Boats.-Local boats obtained in the theater of operations have been used in the past with a fair degree of success. Unless the operation is planned a considerable length of time before its initiation, local boats will probably be the only ones available. These boats should be purchased outright if they are to be used for combat purposes. If the owners will not agree to sell them, as is sometimes the case, it may be necessary to requisition them. Receipts must be given for such boats. A record should be made of the owmer's name, if it can be ascertained, the date and place at which the boat was acquired, its condition, and the estimated value. This information should be forwarded to the area commander or other appropriate commander so that proper adjustment can be made of the owner's claim when it is submitted. If combat boats are rented on a per diem basis, the eventual cost for rent, plus the expense of repairs or replacements if the boats are damaged or lost, will be exorbitant. On the other hand, it is usually more economical to rent local boats which are to be used solely for the transportation of supplies after the river has been pacified. Local boats will be nondescript in character. This complicates the repair and upkeep of motor-propelled craft. They have one decided advantage, however, all of them will have been built for use on the river on which the operations are to take place and in that respect, they probably will be superior to boats imported for the operation.

b. Regular Navy boats will seldom be available in sufficient numbers to meet the needs of the expedition. They may be used for coastwise communications and on the lower river, depending on the depth of the water and the presence of rapids or falls in that section of the river. They are too heavy, draw too much water, and are too slow to answer the helm for use in the middle river.

c. Marine Corps landing boats, especially the smaller types, probably can be used effectively in the lower and middle rivers. Their armament, uniformity of power plant and equipment, protected bottom and propeller, and the fact that trained crews may be available to handle them, are important advantages. Their weight may be a disadvantage for middle river operation if many portages are required.

d. There are numerous boats available in the United States which are suitable for small wars river operations and which can be purchased if the situation makes it necessary. They range in type from the larger shallow draft boats which can be used on the lower rivers, to canoes suitable for employment in the upper river. So far as possible they should have approximately the same characteristics as those found in the local theater of operations. Radical changes in type should be introduced with caution.

e. Rubber boats probably will be used extensively in future small wars river operations. Improvements and new developments are constantly taking place in boat clesign and boat materials. One can never expect to obtain a uniform flotilla of boats for river operations. The difficulty will always be to get enough boats of any description to meet the demands of the situation which are suitable for use in the particular river involved. It is probable that much better boats will be available in the future than have been utilized for such operations in the past.

10-10. Method of propulsion.-a. General.-Boats used in river operations will be motor propelled, rowed, paddled, poled, or towed, depending upon the type of boat being used, the nature of the river, and the tactical situation.

b. Inboard motor boats.-Inboard motor boats have the following advantages:

(1) Speed,
(2) Usually greater carrying capacity than other types of boats.
(3) Requires small crew.

They have the following disadvantages:

(1) Noise of exhaust, even though muffled, discloses the location of the patrol and gives warning of its approach.
(2) Gasoline and oil must be carried for the period between the initiation of the patrol until the arrival of the first supply boats. This decreases the carrying capacity for troops and rations, which may be offset by the increased speed of the movement.
(3) They draw too much water for use in the upper river, or in some stretches of certain middle rivers.
(4) Their power plant often fails, or propellers are fouled or broken in rapids where power is most essential.
(5) Weight of the boat increases the difficulties of portaging around obstacles in the river.

Inboard motors are especially useful for transporting the main body and supplies of a large patrol, and in the system of supply in the lower and middle rivers.

c. Outboard motors.-(1) Outboard motorboats have the same advantages and disadvantages as inboard motorboats. They are more subject to failure during heavy rains than the inboard type.

(2) Outboard motors can be used with a fair degree of success in the upper river, although the presence of sandbars, rocks, sunken trees, and other debris, and the innumerable rapids normally encountered in this section of the river increase the difficulties of operation.

(3) Outboard motorboats are especially useful for security units with a patrol operating entirely with motorboats; and for liaison and command missions.

(4) Outboard motors purchased for river operations should be of the multiple cylinder type and capable of developing at least 25 horsepower. Motors whose water intake is through the forward end of the propeller housing should not be purchased. They are prone to pick up too much sand, dirt, and other debris in the shallow waters in which they often have to operate.

d. Rowboats.-Rowboats will seldom be used in small war river operations. Disabled navy or large, sized motorboats may have to be rowed for comparatively short distances,

e. Paddes.-Paddles are normally used as the means of propulsion with upper river boats which are not equipped with outboard motors. They may be used when moving against the current in quiet stretches of the river, depending upon the strength of the current, and will always be used when going downstream or from one side of the river to the other. They are used as rudders in boats of the canoe type. Because of their reliability under all conditions, they are part of the normal equipment of every middle and upper river boat, whether they are equipped with motors or not.

f. Poles.-In swift water, poles must be used to make headway against the current, if the water is too shallow for the operation of motors or if the boat is not equipped with a. motor. In many cases, poles can be usecl to assist a motorboat when passing through rapids and bucking an unusually strong current. They are part of the normal equipment of every middle and upper river boat.

g. Towing.-Towing will have to be resorted to when passing upstream through very bad rapids. Occasionally the overhanging branches close to shore may be grasped to haul the boat along. Before towing a boat through bad stretches of water, it should be unloaded at the foot of the rapid and the load portaged around it. In some cases, such as falls or extremely bad rapids, the boat will have to be portaged also. In going downstream through dangerous rapids, towlines must be used to ease the boat and keep it under control.

10-11. Influence of tactical principles.-Tactical principles will have considerable influence on the type of boats selected for any particular river patrol. Security units should be transported in small, light, easily maneuverable boats, carrying one-half to a complete squad of men in addition to the crews. The command group requires a small, fast boat. Elements of the main body must be transported as units in order to facilitate their entry into action. Supply boats may be of an entirely different type than the combat boats. The necessity for speed will influence the composition of the flotilla. Even in the lower river, these tactical requirements may necessitate the employment of some middle and upper river craft; in the upper river sections, they will influence the size of the boats employed.