|NAVAL ORDNANCE AND GUNNERY
VOLUME 2, FIRE CONTROL
NAVAL GUNFIRE SUPPORT
| A. General
22A1. Historical introduction
In the course of World War II, naval task forces frequently carried out bombardments of enemy installations on shore. After the ineffective results noted during the Tarawa operation in November 1943, shore bombardment techniques were gradually improved and refined through successive landings at Roi-Namur, Eniwetok, Saipan, Guam, Peleliu, the Philippines, Iwo Jima, and Okinawa. Later, the Korean conflict gave frequent opportunity for the application of the techniques learned in World War II; in particular, the use of naval gunfire to support the landing of troops on defended enemy territory.
Opposed amphibious landing is one of the most hazardous types of military operation. Until World War II, many military authorities believed that such an operation was too hazardous to be attempted. This belief was based largely on the British experience at Gallipoli, in World War I. This operation failed, largely because of the absence of organic supporting arms prior to, during, and immediately after the landing. The value of naval gunfire support rests principally on its continuous availability during these critical periods.
22A2. Mission of naval gunfire support
The mission of naval gunfire in support of landing operations is to aid the seizure of the objective by reducing or neutralizing shore installations and troops that oppose our forces prior to and during the landing, and by assisting the advance of our troops after the landing has been made. This support is vitally important in the period after the troops have landed but before adequate artillery can be brought into action. To be successful, naval gunfire support for amphibious operations must be carefully planned in advance, and must be executed with skill and dispatch. Full exploitation of support can be achieved only if ground, naval, and air personnel understand the organization, basic techniques, capabilities, and limitations of naval gunfire support, and follow the standard procedure which has been agreed upon by the joint services.
Naval gunfire is delivered from ship’s batteries not only in support of troop operations, but of related naval and air operations, such as mine warfare activities, air-sea rescue operations, reconnaissance and demolition operations, demonstrations, feints, raids, flak suppression during air strikes, and interdiction of coastal roads, railroads, airfields, and troop assembly areas. All these activities rest on the same basic principles as the naval gunfire support of amphibious operations.
The basic task of naval gunfire support units in an amphibious operation is to support the seizure of the objective by destroying or neutralizing:
1. Shore installations that oppose the approach of ships and aircraft to the objective.
2. Defenses that may oppose the landing.
3. Defenses that may oppose the post-landing advance of the troops.
These tasks are carried out in the preparation of the objective for the landing, the support of the landing, and in post-landing support.
22A3. Advantages of naval gunfire for troop support
Naval gunfire has many capabilities for troop support in landings which are not possessed by artillery. The principal ones are:
1. Availability. Gunfire support ships are continuously available before, during, and after the landing, as long as the zone of action ashore is within the range of the ship’s guns.
2. Mobility. Within the limitations of navigation, ships can move rapidly from one area to another as the situation ashore develops. At the same time, the most favorable ranges and lines of fire can be fully exploited, and enemy counterfire can be evaded.
3. High rate of fire. Power loading and mechanical ammunition supply makes it possible to deliver a large volume of fire in a short time. This characteristic is of great value in neutralization missions.
4. High muzzle velocity and flat trajectory. Naval guns, particularly those of heavy caliber, have great penetration and destructive power, especially against installations presenting vertical surfaces.
5. Small deflection pattern. The comparatively small dispersion in deflection of naval guns makes them valuable for close support of troops when the line of fire can be made parallel to the troops’ front line (enfilade fire).
6. Variety of weapons and types of ammunition. Calibers of guns range from 20-mm to 16-inch, with ammunition of many types, including armor-piercing, fragmentation, and reduced-charge. Other available weapons include rocket and guided missile launchers, with a wide variety of ammunition types for each.
22A4. Limitations of naval gunfire for troop support
The tactical employment of naval gunfire in support of troops has certain limitations, which must be taken into consideration in both planning and operational stages. The most important limitations are:
1. Necessity for observation. Naval gunfire, except for area fire on very large targets, must be observed and corrected to be effective. This requires a spotting agency, such as a ground spotter, air spotter, or shipboard spotter.
2. Navigational limitations. Ships are forced to remain in safe, navigable, mine-free waters, and therefore sometimes cannot take advantage of the positions most favorable for the attack of targets. In some cases, ships cannot fire at all on certain defiladed (located on a reverse slope) targets. Obviously, the maximum range inland is limited by the position of the ships, as well as by the characteristics of the weapons used. Further, the fact that the ship is in motion requires the continuous and accurate fixing of the ship’s position for delivery of fire on targets not visible from the ship.
3. Communications limitations. Radio and visual communications between ship and shore are not as flexible, reliable, or secure as communications by wire or telephone.
4. Limitations of pattern. By comparison with artillery, naval guns have a small deflection pattern, a large range pattern, and a flat trajectory. This is an advantage in some respects, but requires careful selection of lines of fire when engaging targets near our own troops. The difficulty of fire against defiladed targets may be overcome by using reduced-velocity charges or by increasing the range, to obtain a greater angle of fall.
5. Limited ammunition capacity. The limited capacity of the ship’s magazines, coupled with the fact that a ship must always retain a certain amount of ammunition for its own protection, restricts the ability of any one ship to maintain uninterrupted support over an extended period of time. This disadvantage may be overcome by providing adequate ammunition replenishment and by rotating ships assigned to support missions.
Naval gunfire may be classified in various ways, as shown in the following paragraphs. The classifications in use are interrelated, making it necessary to employ terms from several types of classification for a full description. These classifications are made with respect to:
1. Effect sought:
a. Destruction. Deliberate and accurate fire, usually delivered at short range, for the purpose of destroying a target, usually a material object.
b. Neutralization. Rapid, fairly accurate fire delivered for the purpose of hampering, interrupting, or preventing enemy fire, movement, or action. The destruction of weapons and personnel is a secondary consideration. The effect of neutralization is comparatively temporary, and such fire may have to be repeated.
c. Maximum damage. Fire against a target which is desired to be destroyed, but which probably cannot be completely destroyed without excessive ammunition expenditure, because of its size, location, range, or lack of vulnerability to naval gunfire.
2. Tactical use:
a. Close supporting fire. Gunfire delivered on enemy targets which, because of their proximity, present an immediate and serious threat to the supported unit.
b. Deep supporting fire. Gunfire delivered on objectives not in the immediate vicinity of friendly forces, for the purpose of neutralizing or destroying enemy reserves and. weapons and interfering with enemy command, supply, communications,, and observation.
c. Harassing fire. Sporadic fire delivered during otherwise quiet periods to prevent enemy rest, recuperation, or movement, and in general to lower enemy morale and combat efficiency.
d. Interdiction fire. Fire designed to prevent or curtail the use by the enemy of an area, bridge, defile, airfield, route of communication, or the like.
e. Illuminating fire. Gunfire employing star shells to illuminate the enemy, to detect his movements, to aid our own observation, or to facilitate own troop movements.
f. Preparation fire. A heavy volume of prearranged neutralization fire, delivered just prior to a landing or a ground attack by friendly forces on enemy positions.
g. Counterbattery fire. Gunfire delivered against active enemy guns and fire control stations for the purpose of silencing the guns.
h. Screening fire. Gunfire employing smoke projectiles, delivered to obscure the enemy’s vision of friendly units and their deployment, movement, or maneuvers.
3. Degree of prearrangement:
a. Prearranged or scheduled fire. Gunfire that is formally planned and executed against targets of known location. Such fire is usually planned well in advance and is executed at a predetermined time or during a predetermined period of time.
b. Call fire. Gunfire delivered at the request of troop units ashore, or of some spotting agency. Call-fire missions must not be interrupted without permission of the unit requesting the fire, except in case of emergency.
c. Opportunity fire. Gunfire delivered without formal planning or troop request on newly discovered targets, or upon targets of a transitory nature. Targets of opportunity may present themselves to the firing ship at any time, but fire must not be delivered without due regard for the safety of friendly troops. Ships delivering fire on targets of opportunity in close proximity to own troops require the approval of the troop echelon concerned before opening fire. Ships executing deep support missions must assure themselves that the target of opportunity is within their assigned sector of responsibility.
4. Technique of delivery:
a. Direct fire. Gunfire delivered on a target by using the target itself as a point of aim for laying the guns or director.
b. Indirect fire. Gunfire delivered on a target which is not itself used as a point of aim for laying the guns or director. Direct fire is usually used on targets which can be seen (by optics or radar) from the firing ship; indirect fire is always used on targets not visible from the ship.
5. Type of fire:
a. Area fire. Gunfire delivered in a prescribed area. Area fire is generally neutralization fire.
b. Point fire. Gunfire directed at a definite material target in order to destroy that particular object.
c. Defilade fire (reverse-slope fire). Gunfire delivered on targets located behind some terrain feature, such as a hill or ridge, which masks the target.
d. Enfilade fire. Gunfire delivered on a target in such a manner that the range pattern of the fall of shot coincides with the long axis of the target.
Some other general terms used in naval gunfire support operations are:
1. Amphibious Task Force (ATF). A task organization under naval command composed of assault shipping, embarked troops, and supporting naval units and tactical air units.
2. Amphibious Troops (AT). The troop elements assigned to an Amphibious Task Force.
3. Advance Force. A task organization of ships which conducts operations such as reconnaissance, minesweeping, underwater demolition, diversionary raids, and preliminary bombardment prior to the arrival of the main body of the ATF in the objective area.
4. Attack Force. A subdivision of an ATF consisting of assault shipping which embarked troops and supporting naval and tactical air units, operating to establish a landing force on shore and support its operations thereafter. In an operation involving only one Attack Force, it is also the Amphibious Task Force.
5. Fire Support Group. A group of ships, part of the Attack Force, assigned the mission of naval gunfire support of an amphibious operation.
6. Objective Area. A defined geographical area within which is located the objective to be captured or reached by the military forces.
7. Objective. A physical area or location on the ground, usually a readily identifiable terrain feature, which a troop unit assigned to capture or occupy. Objectives may be designated as intermediate or final objectives.
8. D-Day. The day on which an amphibious landing takes place.
9. H-Hour. The actual time to the minute at which the leading wave of the landing force touches down on the beach; if the actual H-hour differs from the scheduled H-hour, the actual time of H-hour is broadcast to all ships and troop units by the Amphibious Task Force Commander.
10. Zone of Responsibility. The land in the objective area is divided into zones which are assigned to fire-support units or to individual ships which are responsible for observing, destroying, or neutralizing known enemy installations and for attacking targets of opportunity therein. A ship may fire in its own ZR without clearance from any troop unit. These zones include all land area in the vicinity of the landing forces except the Close Support Area.
11. Close Support Area. The area between friendly front lines and the near limits of Zones of Responsibility. Support ships may fire into these areas only upon call from supported troop units, or after receiving clearance from the troop unit concerned to fire on a specific target.
12. Preliminary Bombardment. Bombardment in the objective area delivered by an Advance Force prior to arrival of the main body of the ATF, with the primary purpose of destroying enemy defenses which might hinder or abort the landing.