CONFIDENTIAL PHIB-11 AMPHIBIOUS OPERATIONS NAVAL GUNFIRE SUPPORT (NAVMC-4029) 1945   No. 11 in a Series of Amphibious Operations   Published-- For Instructional Purposes Only.   MARINE CORPS SCHOOLS MARINE BARRACKS, QUANTICO, VIRGINIA

 

MARINE CORPS SCHOOLS
MARINE BARRACKS, QUANTICO, VIRGINIA

October 1945.

"Amphibious Operations--Naval Gunfire Support" is approved and published for instructional purposes in the Marine Corps Schools.

OLIVER P. SMITH,
Brigadier General, U.S. Marine Corps,
Commandant.

Preface

This publication on naval gunfire support is meant to be general to the extent that it be both interesting and instructional to junior troop leaders and those unfamiliar with the history, capabilities, limitations, and procurement of naval gunfire support; and special in that certain sections are of technical value to staff officers directly concerned with the planning phase of an amphibious operation.

AMPHIBIOUS OPERATIONS--NAVAL GUNFIRE SUPPORT

TABLE OF CONTENTS

Section 1 HISTORICAL INTRODUCTION
	Paragraph			Page
Early Evolution		1			1
Transition		2			1-2
World War I and the Peace Years		3			2-3
World War II		4			3-4
Section 2 CAPABILITIES AND LIMITATIONS OF NAVAL GUNFIRE
	Paragraph			Page
Introduction		5			5
Observation and Methods of Fire Control		6			5-6
Muzzle Velocity and Trajectory		7			6-7
Pattern Size		8			7
Rate of Fire		9			7
Mobility		10			7-8
Effective Range		11			8
Weapons and Ammunition		12			8-12
Ammunition Supply		13			12-13
Resolving the Fire Problem		14			13-14
Hydrographic and Terrain Problems		15			14
Shift to Air Target or Naval Attack		16			14
Section 3 CLASSIFICATION OF NAVAL FIRES
	Paragraph			Page
Introduction		17			19
Neutralization Fire		18			19
Fire for Destruction		19			19-20
Prearranged Fires		20			20
Targets of Opportunity		21			20
Call Fires		22			20
Supporting Fires		23			20
Harassing Fire		24			21
Interdiction Fire		25			21
Counterbattery Fires		26			21
Direct Fires		27			21
Indirect Fires		28			21
Section 4 THE SHORE FIRE CONTROL PARTY
	Paragraph			Page
Mission		29			23
Distribution within Division		30			23-24
Duties		31			24-27
Section 5 NAVAL GUNFIRE COMMUNICATION
	Paragraph			Page
Need for Training		32			29
Equipment		33			29-30
The Shore Fire Control Spotting Net		34			31
The Naval Gunfire Control Net		35			32
The Naval Gunfire Overload Net		36			32
The Division Naval Gunfire Net		37			33
The Gunboat Control Net		38			34
Wire Nets		39			35
Procedure		40			35
Authentication		41			36
Cipher Code		42			36
Waterproofing		43			36
Section 6 NAVAL GUNFIRE PLANNING
	Paragraph			Page
Mission of Naval Gunfire Support		44			37
Naval Attack Force Responsibility		45			37
Landing Force Responsibility		46			37
Landing Force Request		47			38
The Decision		48			38
Intelligence		49			38-39
Joint Planning		50			39
The Naval Gunfire Support Plan		51			39-43
The Landing Force Naval Gunfire Annex		52			43-45
Section 7 THE FIRE SUPPORT SHIP
	Paragraph			Page
Modern Fire Control Systems		53			47-52
Armament of Shore Bombardment Ships		54			52-58
Maximum Ordinate and Angle of Fall Tables		55			58-72
Clearance Tables		56			72
LIST OF ILLUSTRATIONS
	Figure			Page
Reference data for ships' batteries		1			15
Reference data for naval guns and artillery		2			16
Reference data for rockets		3			17
Naval gunfire spotting net		4			31
Naval gunfire control net		5			32
Division naval gunfire net		6			33
Gunboat control net		7			34
Wire nets		8			35
Fire-control system on a 2,100-ton destroyer		9			48
Combat information center		10			49
Typical destroyer CIC		11			50
Maximum ordinate-angle of fall tables		12-26			58-72
Clearance tables		27-33			74-80

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Section 1
HISTORICAL INTRODUCTION

1. Early Evolution.--Employment of the weapons of naval vessels to assist troops in forcing hostile shores has been a factor in amphibious operations since ancient times. Caesar's Roman legions, assaulting the beaches of Britain in 55 B.C., were severely pressed until ships of the fleet moved close inshore to engage the defenders with "slings, arrows, and engines." However, throughout antiquity, and in fact long after the 14th century discovery of gunpowder, naval forces in amphibious warfare were primarily concerned with transportation and the protection of supply lines. Militarists knew that surprise and overwhelming numerical superiority were the mainstays of beachhead success. The technique has survived into modern warfare, which affords numerous examples of landings made under cover of darkness, utilizing intelligence and reconnaissance to select an undefined beach.

2. Transition.--But the development of interisland and intercontinental warfare between state armies, with its accompanying improvement in coast defense tactics, has gradually minimized the reliance which amphibious commanders can place on surprise. The wider deployment of larger forces, together with the mobility of reinforcements, has decreased and often eliminated the possibility of landing without opposition. As long as the foothold could be secured by stealth, the engagement could be postponed until sufficient troops and supporting arms could be placed ashore. Deprived of this stratagem, the commander was obliged to consider the beachhead the same as any other land objective, to be wrested from the enemy by force. The action had to be joined at the shoreline. A supporting weapon was essential, and naval artillery furnished it.

The first laboratory test of naval gunfire as an auxiliary arm in the modern sense was provided by Charles XII of Sweden in his landing at Zealand in 1700. It is recorded by the Swedish General Staff as follows:

"Stuart (Military tutor to Charles) laid principal weight on the artillery fire. While the boats neared the land, the level guns were to keep the enemy from the heights of the shore and the howitzers were to be directed against the enemy reserves hidden behind the foliage. Only after this preparation had made the enemy positions ripe for the attack, was the actual activity to begin. The landing point was so selected that the artillery could carry on its work. Even after the troops came on land, the firing was continued by firing over their heads into the more elevated lines of the enemy. This was done to afford the troops protection at the moment of going on land. So far as is known, this was the first time that

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such tactics were employed outside the pure trench and siege warfare. The Swedish landing at Zealand in July 1700 stands as a pattern for all ages."

The stature of naval gunfire in this supporting role gained in the American Civil War, when it was acknowledged as the decisive factor in the struggle for Fort Fisher. This formidable work at the mouth of the Cape Fear River in North Carolina guarded the last remaining gateway between the Confederate States and the Outside world. To seize the fort, the Union, in December-January 1864-65, dispatched a strong joint force for an amphibious assault, supported by a huge fleet of 600 guns. After a sustained bombardment by the fleet for 3 days, the fort was overwhelmed. Colonel William Lamb, commander of the Confederate garrison at Fort Fisher, gives direct testimony to the part played by naval gunfire.

"Had there been no fleet to assist the army at Fort Fisher," Colonel Lamb's report on the action concludes, "the Federal infantry could not have dared assault it until its land defenses had been destroyed by gradual approaches. For the first time in the history of sieges the land defenses of the work were destroyed, not by an act of the besieging army, but by the concentrated fire, direct and enfilading, of an immense fleet poured upon them without intermission, until torpedo wires were cut, palisades breached so that they actually afforded cover for the assailants, and the slopes of the work were rendered practicable for the assault."

Thus it was demonstrated that naval ships could stand up to land fortifications, mass superior fires against them, and render them vulnerable to attack by foot troops.

3. World War I and the Peace Years.--Naval gunnery was little used in World War I as a supporting agent for ground forces. But the ill-fated Gallipoli campaign illuminated many features of amphibious warfare and supporting naval gunfire. It confirmed at least partially the conclusion of Fort Fisher: that, given favorable conditions of approach and maneuver room, ships could gain the advantage over land fortifications. By Turkish admission, every gun in the four forts guarding the western entrance to the Dardanelles was put out of commission by the British bombardment, and the magazines were destroyed. In the later land operations the coordination of ships' gunfire with the efforts of troops ashore was steadily improved. However, the lack of adequate fire control and liaison methods was apparent throughout, and this condition gave rise to subsequent exhaustive studies of the problem.

After the war, the initiative in these investigations among all the nations of the world was taken by the United States Marine Corps and the Navy. The Marines particularly, with their understanding of naval gunnery on the one hand, and the requirements of the ground forces on the other, were

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in position to contribute valuable material. Their incentive lay in their unshakable faith in the value of naval artillery for amphibious operations. As early as 1924, they practiced with the Navy the techniques of supporting fires in landing operations conducted by the two services. Each year these training procedures were expanded and improved. Using land-based artillery as a common denominator, the Marine Corps studied the effectiveness of naval bombardment, the volume of fire necessary to accomplish a given mission, the types of ammunition required, rates of fire, methods of control, and the tremendous problem of adequate coordination with the ground forces and their commanders. As communication equipment and methods were improved, the Corps constructed an operating procedure for liaison and communication between the elements concerned. They weighed, analyzed, tested, and corrected; and finally, in 1934, the Marine Corps published the Tentative Landing Manual, first adequate treatise of amphibious operations in military literature.

The Tentative Landing Manual was a long step toward the perfection of naval gunfire preparation and support. Its procedures were again taken into the field for exhaustive laboratory tests and analysis by Marine Corps and Navy experts. Four more years of labor and experiment followed. Finally, in 1938, the Navy published the findings in FTP-167, the current standard operating doctrine for amphibious warfare.

4. World War II.--When Pearl Harbor touched off the greatest amphibious war in all history, the United States, by virtue of its peacetime studies, was at least partially prepared. The procedures were clearly established, although the equipment and trained personnel were lacking. The national emergency growing out of the war in Europe had brought some improvements, however, and by the time American forces were ready to take the offensive at Guadalcanal, the Navy was prepared to give gunfire support. As the Pacific campaign progressed from one bitterly contested island to another, the role of naval artillery gained in prominence, and techniques were improved proportionately. The perfection of fire control radar, installation of modern computers in all major combat vessels, development of illuminating, smoke, and special bombardment ammunition, and many other refinements brought the American Navy to a high peak of gunnery efficiency. Progressive studies by the Navy and Marine Corps tuned up the whole complicated machinery to the point where naval gunfire became an indispensable agent in a landing operation, not only to assist the troops in gaining the shore, but in seizing subsequent objectives after the initial beachhead. The advent of rocket and mortar bombardment ammunition and weapons further enhanced the value of naval artillery.

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Its effectiveness is undeniable. Naval gunfire, through its ability to neutralize a landing beach by leisurely saturation bombardment, permitted the Allies to invade beaches of their own choice with greatly reduced losses. It enabled them to put troops ashore on islands and in areas far more heavily defended than ever before in all history.

The complete reversal of Japanese tactics is sufficient testimony. Early in the war they adopted, wherever possible, the policy of repulsing the invasion at the water's edge. But the tremendous weight of naval gunfire, properly coordinated with aerial bombardment, defeated this stratagem at Tarawa, the Marshalls, and elsewhere. It had the effect of forcing the enemy to yield an undefended beachhead, or one defended by fire at the most. They yielded not because of surprise or stealth, but by design because the landing zone was untenable to them. Thereafter, they shifted their tactics. The battle doctrine of the 32nd Army at Okinawa instructed them to give up the beach without contest, and to pin their hopes on defeating the Americans in the subsequent engagement inland. The results are a matter of history--a history underlined by the development of naval gunfire as a supporting weapon.

The succeeding sections of this publication will take up in detail the employment and technique of naval gunfire in landing operations.

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Section 2
Capabilities and Limitations of Naval Gunfire

5. Introduction.--Naval gunfire, like all other weapons employed in modern warfare, operates within the scope of certain capabilities and certain limitations. These capabilities and limitations are discussed in this section.

The suitability of naval gunfire for supporting shore operations is influenced by the following factors:

1. Observation and methods of fire control.
2. Muzzle velocity and trajectory.
3. Pattern size.
4. Rate of fire.
5. Mobility.
6. Effective range.
7. Weapons and ammunition.
8. Ammunition supply.
9. Resolving the fire problem.
10. Hydrographic and terrain problems.
11. Shift to air target or surface attack.

6. Observation and Methods of Fire Control.--As with artillery, fire delivered by naval guns requires observation for adjustment. This required observation may be from the ship, the air, or the ground, a characteristic which limits the effective use of naval gunfire when observation is restricted by darkness, fog, haze, or heavy rain.

Positioning of the ship may also be accomplished by use of radar to determine the ship's location and range with reference to a known shoreline. The range and bearing to the target may then be measured accordingly.

1. Unobserved fire.--Ships are capable of delivering unobserved fire, provided the position of the ship can be fixed accurately, and that either registration on some point in the target area is carried out, or a ballistic (weather) correction obtained. However, continuous accurate fixing of the ship's position may be determined only by anchoring, which is a dangerous procedure due to increased vulnerability to surface and air attack.

2. Direct fire.--In direct fire, the ship lays its guns directly on the target, without spotting or other help from outside sources, and conducts its own firing and spotting procedures.

   When targets are visible from the ship, naval guns can deliver a rapid, accurate volume of fire on such targets. This characteristic is exploited in planning prearranged supporting

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fires on and in the vicinity of landing beaches prior to the landing and by selecting logistical target areas visible from seaward for call fires. Initial ranges are obtained by radar or stereoscopic rangefinders, by navigational plot, or by estimation.

3. Air bursts.--The 5"/25, 5"/38, and 5"/54 caliber batteries are capable of adjusting and delivering direct "time" fire--that is, "air bursts" to be used for antipersonnel purposes. This type of fire is now being tested for larger caliber projectiles, and has been used in actual operations, but the results are as yet inconclusive.

4. Indirect fire.--When targets are invisible from the ship, ground or air observation of the fall of shot is necessary for adjustment. Ships equipped with modern fire control equipment can deliver accurate, effective fire on "indirect fire" targets, provided the ground or air observers are sufficiently trained. Indirect fire without observation requires that larger areas be covered, and that more ammunition be expended to insure coverage of the target.

7. Muzzle Velocity and Trajectory.--The high muzzle veolicty of naval guns is effective on targets with a vertical danger area. The disadvantage of the flat trajectory against a reverse slope may be overcome by selecting a location from which naval guns may bear from a flank or rear firing position. However, certain batteries have angles of fall which compare favorably with field artillery. Plunging fire may be obtained by increasing the range, or by reducing the powder charge.

Perhaps one of the most valuable characteristics of the high muzzle velocity is its demoralizing effect on the enemy. This is attested to by all who lay under the Japanese naval bombardment at Guadalcanal. Enemy POW's of every campaign speak of the fear which they have of naval gunfire, with its shrill whistle and "crack" as it passes overhead, or its consuming flash and explosion as the charges burst without warning. Importance of the high morale of troops has been consistently emphasized by every responsible leader; conversely, the demoralization of enemy troops by naval gunfire or any other means remains a most important objective.

A 1,200-feet-per-second powder charge produces high-angle fire, and is well suited to delivery of fire on reverse slopes. It is normally fired with gun elevation in excess of 45 degrees, but it may be used below that elevation. For high-angle fire, the range band is 5,000-8,900 yards. Outside that band, drift of the projectile is too erratic for accurate fire. It must also be remembered that certain inputs to the computer must be corrected, inasmuch as the computer is designed to control the standard 2,600-feet-per-second fire.

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The increasing use of shallow-draft, easily maneuvered gunboats, equipped with mortars and rockets, introduces another medium of high-angle, plunging fire. Their fire, however, is satisfactory only for area barrages, rather than specific targets, and wide margins of safety must be observed if friendly troops are in the vicinity.

8. Pattern Size.--Pattern sizes of ship's batteries are larger than comparable calibers of field artillery. The deflection pattern is roughly 10 per cent of the range pattern figured on the basis of guns converged to pinpoint a target. The guns may have parallax cranked out to "parallel" if desired, however, which will result in an increased spread in deflection, with each salvo of fire affecting a greater area. To increase chances of systematically covering all parts of area targets, small changes in range and deflection should be made after each salvo, according to a calculated system.

The pattern size of ship's batteries is not only dependent on the normal causes of dispersion encountered in field artillery, but also on the complexity of modern naval fire control installations. Composed of electrical, mechanical, and hydraulic mechanisms, they are subject to error due to lack of alignment. In addition, lost motion develops as a result of wear, thus increasing the dispersion or pattern. Careful alignment and adjustment is a requirement for "tight" patterns. Obviously the pattern size of identical batteries may therefore be dependent upon the age of the installations and the condition of adjustment and alignment. Pattern sizes indicated in figure 1 are based on the average pattern size for the particular type naval battery.

9. Rate of Fire.---The rate of fire of naval guns is more rapid, barrel for barrel, than comparable calibers of field artillery because of fixed battery installation which permits power loading and mechanical ammunition supply.

10. Mobility.--The mobility of ships permits flexibility in the employment of naval gunfire, the advantages of which are:

1. Inshore supporting vessels can move in and engage beach defenses at short range.

2. There is wide choice in the selection of firing positions for the execution of fire missions.

3. When hydrographic conditions permit, effective range inland can be increased and enfilade fire delivered by taking firing position along the flanks of the advance of the landing force.

4. It enables the ship to attack behind armor plate and at the same time to evade enemy fire by maneuver.

A typical example of this mobility was demonstrated at Tarawa, when the destroyers Dashiell and Ringgold sailed into the lagoon and delivered point-blank fire on enemy positions. Another outstanding example was that of the destroyer

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supporting the 2d Battalion, 2d Marines, during the closing phases of the Saipan operation. The battalion was faced with the task of sweeping a coast-line cliff which was honeycombed with caves harboring Japanese. Prior to the advance, the destroyer swung in to the edge of the reef, no more than 1,200 yards off shore, and sprayed . the cliffs with 40mm fire for a half hour. When the battalion went through this area the conquest was comparatively easy, with light casualties, because the blanket of 40mm fire poured into the caves and crevices had been most effective in beating down the waiting opposition.

A disadvantage of mobility in indirect fire is the changing line of fire, causing increased difficulty in spotting.

11. Effective Range.--Effective range inland, even when reduced by the necessity of firing from offshore positions, compares favorably with comparable calibers of field artillery.

12. Weapons and Ammunition.--a. Guns.--The selection of the proper gun for a particular mission is determined by the nature and size of the target and the proximity of friendly troops to the impact area. The 5- and 6-inch guns are normally used for close supporting fire; their rapid rate of fire and relatively small pattern size qualify them for the neutralization and destruction of most targets in close support of advancing troops. Heavier caliber guns are normally reserved for enemy batteries, heavy fortifications, and installations for which destruction and penetration are desired, and for "thickening" the fire of smaller calibers in the beach preparation. Their greater ranges make them excellent deep supporting weapons.

2. Projectiles and fuzes.--(For more detailed information, see U. S. Navy Projectiles and Fuzes, U. S. Navy Bomb Disposal School, 1 April 1943; or 25 August 1944.)

   1. Types of projectiles.--The selection of the type of projectile to be used depends upon the nature of the target and the effect desired. For purposes of shore bombardment and shore fire support, six types of projectiles are used primarily. They are:

      High capacity, or HC
      Antiaircraft common, or AAC
      Armor piercing, or AP
      Common, or C
      White phosphorous, or WP
      Illuminating, or Ill.

      1. High-capacity (HC) projectiles are designed especially for use in shore bombardment. They give a relatively great explosive content at the expense of armor-piercing qualities. HC is effective either for neutralization or for destruction. It is available in 5-, 6-, 8-, 12-, 14-, and 16-inch shells.

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2. Antiaircraft common (AAC) projectiles are similar to high-capacity projectiles in explosive and penetration qualities. These shells have a large HE content and a great effective bursting radius (35 to 50 yards). They are available for 5-inch guns only.

3. Armor-piercing (AP) projectiles are designed to pierce armor plate before detonating and have a base-detonating delay-action fuze, a heavy nose, and a relatively small HE content for the weight of the shell. Their use in shore bombardment is limited to fire on fixed enemy defenses such as concrete pillboxes and fortifications. They are available for 6-, 8-, 12-, 14, and 16-inch guns.

4. Common (C) projectiles are a compromise between high-capacity and armor-piercing projectiles with respect to bursting charge and penetrative ability. Their use is similar to that of AP projectiles. They are available in 5-, 6-, and 8-inch projectiles.

5. White phosphorus (WP) projectiles were designed for screening but also have great incendiary and antipersonnel value against exposed troops. In the latter case, optimum effect is gained by employing "air bursts," whereby the burning phosphorus is rained over a considerable area.

   White phosphorus projectiles may also be used as identifying or "marker" shots to identify salvos, when various ships are firing into the same or adjacent areas at once. WP is available in 5"/38 projectiles only. By reason of the physical limitation of the time fuze, the extreme range is 15,500 yards.

6. Illuminating projectiles are used for illumination at night in order to assist in adjustment of fire of both naval guns and troop weapons, to facilitate friendly troop activities, and to render infiltration by the enemy more difficult. This type of projectile may also be used as an "identifying" or "marker" shot. It is manufactured for both 5- and 6-inch guns, but is at present available only for the 5-inch. For purposes of illumination ashore, the illuminating projectile should be fired within a range band of 7,000-15,000 yards, for optimum effect.

2. Types of fuzes.--The nature of the effect desired on the target determines the type of fuze used.

   1. Time fuzes are used mainly in AAC projectiles but may also be used in HC shells. The time fuze is a mechanical, 45-second fuze, producing accurately controlled air bursts. When a projectile is detonated in the air, fragments are propelled at a very high velocity in directions perpendicular to the surface of the shell, producing base spray, side spray, and nose spray. A majority of the fragments are large, ragged splinters from the side spray, whereas base and nose spray fragments are generally large in size and relatively few in number. This type of fuze, when set for air burst, gives great neutralization value and provides the most effective shell for use against the enemy in the open.

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2. Point-detonating (PD) fuzes are instantaneous, super-quick fuzes designed especially for HC projectiles. They are constructed to detonate on as slight an impact as that encountered with 1/16-inch plywood. The proportion of point-detonating fuzes used might be 75 per cent when covering an area or stripping camouflage, and 25 per cent for other purposes. Side spray from projectiles fitted with PD is extremely destructive, while the base and nose spray are negligible.

3. Base-detonating (BD) fuzes are designed to allow delay in detonation, permitting penetration before the projectile bursts. The length of delay is determined by the amount of penetration desired and the effect sought with the particular type of projectile. BD-fuzed projectiles used in shore bombardment produce great destructive and some neutralizing effect. Nearly all projectiles used in shore bombardments are fitted with BD fuzes, either as primary or secondary means of detonation.

4. Proximity fuzes, Mark 32, are designed for antiaircraft firing, to set off the explosive charge when the shell is close to the air craft. These fuzes are highly specialized and have not yet been used in shore bombardment. Experiments with this fuze for shore bombardment have been conducted with satisfaction, but no conclusive results are as yet available. The employment of the Mark 32 fuze is similar to that of the field artillery VT fuze.

5. In 6-inch and larger projectiles, the steel nose-plug and base-detonating fuze are employed where a penetration and slightly delayed explosion are desired. Generally speaking, the percentage of delayed-action fuzes will be 75 when firing for penetration and destruction, and 25 for all other purposes.

3. Specialized lire support craft.--(1) A variety of specialized fire support craft has been developed to effect the employment of rockets, mortars, and machine guns. These craft are employed at close range from seaward, both in support of the assault against enemy-held beaches and in the continuation of the attack. Because these weapons are fired from relatively small amounts and produce little or no recoil when fired, they can be mounted on small craft of many types. The LSM is the basic type for the LM(R)(1) and LSM(R)(2). The LCI produced the LCI(G) (Gunboat), the LCI(M) (Mortarboat), and LCI(R) (Rocketboat). The LCVP and LCM(3) are also sometimes employed, although no standardized type has yet evolved from their use. The LSM(R)(1), LSM(R)(2), LCS(L) (3) are much more adequately equipped for direct fire than are other special fire support craft in that they carry directors. The LSM(R)(1) and LCS(L)(3) can control their 40mm fire with a director; the LSM(R)(2), can control both 40mm and rocket fire with a director.

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2. A list of armament of these vessels as currently installed is found in section 7. It is to be borne in mind, however, that frequent changes are being made as tests and operational employment continue, so that no list remains accurate long after the date of issue.

3. The employment of special fire support craft divides into two phases:

   1. During the assault, rocket and mortar vessels close the beach ahead and abreast of the landing waves. Rocket boats fire ranging salvos as the approach is made and, when the range is correct, fire their salvos. Because mortars do not have the fixed range of rocket launchers, they can fire at any time within maximum and minimum ranges of the target. As the first wave hits the beach, rocket and mortar boats may execute column right and left and continue to fire along the coasts flanking the beaches, or they may lie to in the boat lanes.

   2. After the landing has been made, gunboats and mortarboats are normally available in the area for fire support missions as requested by various units of the landing force. These craft are suitable for harassing and area neutralization missions at 1,500 to 2,000 yards from friendly troops, depending upon whether the 4.5-inch barrage rocket, the 5-inch aircraft rocket, or the 4.2-inch chemical mortar is employed. Mortarboats have been particularly useful in knocking out targets in ravines or draws running parallel to, and behind, the coast.

      (Refer to figure 3 for data on certain rockets now in experimentation or production.)

4. Comparison with field artillery.--It is not proposed here to enter a detailed comparison of naval batteries with those of field artillery. A rough statement of their comparative initial velocity, range, rate of fire, and pattern size, however, is useful to the naval gunfire officer in explaining the nature of naval gunfire to officers already familiar with the uses of artillery and what it will accomplish. The following table is furnished for that purpose:

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Weapon	IV (F/S)	Maximum Effective Range	Rate of Fire Rds Per Min. 5 Min. pr.	Average Pattern Size (Range)
16"/45/50*	1,900-2,000	22,500	1.5	500 yards
14"/50*	2,000	21,500	1.5	500 yards
8"/55*	2,160-2,300	21,500	2.0	400 yards
6"/47 HC	2,590-2,800	23,500	5.0	150-200 yards
5"/54 A AC	2,600	23,300	**5.0	150-200 yards
5"/51 HC	3,100	20,300	5.0	100-200 yards
5"/38 AAC	1,200	8,400	5.0	75-195 yards
5"/38 AAC	2,600	16,000	10.0	75-125 yards
5"/25 AAC	2,200	12,000	10.0	75-125 yards
75mm How	700-1,250	8,500	6.0	150 yards
105mm How	650-1,550	11,000	4.0	150 yards
155mm How	680-1,850	15,000	3.0	225 yards
155mm Gun	2,100-2,800	26,000	1.0	250 yards
8-inch How	1,950	18,500	1.0	250 yards

*These figures are compiled for ammunition using special reduced charges normally used in shore bombardment. Armor-piercing and common ammunition have relatively greater initial velocities and maximum ranges.

**This figure is approximate, and not fully determined at the present time.

(Reference should be made to figures 1 and 2 for ammunition performances and comparisons.)

13. Ammunition Supply.--a. The supply of any given vessel is of course limited by the magazine capacity of the vessel. Before an operation, each fire support ship is loaded with a proportion of each type of projectile it is expected to require. Below is a sample ammunition allowance for such ships. It is furnished only as a rough guide; considerable variation may exist in actual allowances in view of ammunition supplies on hand.

Caliber	Type	Bombardment Allow per Gun		Total Magazine Allowance
5"/38	AAC	BB: OBB: CA: CL: DD (2,100 T): DD (2,200 T)	350 200 250 150	10,000 7,040 4,400 5,400 1,900 1,760
5"/38	Ill	BB: OBB: CA: CL: DD (2,100 T): DD (2,200 T):	50	800 800 600 600 200 100
5"/38	Com.	OBB:		960

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Caliber	Type	Bombardment Allow per Gun		Total Magazine Allowance
		DDs:		200-240
5"/38	WP	DDs:	10	Up to 100
5"/51	Misc. Chg	OBB:		1,906
5"/51	Com.	do:		300
5"/51	HC	do:		1,200
5"/51	Ill.	do:		300
5"/51	AAC	do:		3,450
(Only a very few 5"/51 guns are in the Fleet.)
6"/47	AP or C do	CL: Hull #144 (Fast Firing)	10	1,800 1,200
6"/47	HC	CL:	180	1,200
6"/47	Ill	Hull #144 Class (Fast Firing)		3,600 300
8"/55	AP	CA:	10	540
8"/55	HC	CA:	90-100	810
14", 16"	AP	OBB, BB	5	360
14", 16"	HC	do	80	720

2. Supply of ammunition at a given scene of operation is also limited. In addition to that carried by the fire support ships themselves, ammunition is normally carried to the target area in ammunition ships (AE), cargo transports (AK), LSTs, or other vessels. The danger entailed in the transfer of ammunition at the target area due to enemy air and surface activity is, however, readily apparent.

   Care should be exercised not to request large expenditures of ammunition on relatively useless targets. Extensive deep support bombardment of areas about which little or nothing is known, for example, does not constitute wise employment of available fire support.

14. Resolving the Fire Problem.--When a new target is to be taken under fire by a ship, it is necessary that a new problem be set up and a new solution obtained. This is true unless the shift to the new target is so small that a correction will not materially affect the solution currently being furnished by the plotting room.

When a ship must reverse course while on the firing run, it is also necessary to make adjustment to bring the guns properly to bear before firing is resumed. The ship cannot adjust on a base point and check points, as in the case of artillery, but must, with each target, derive a new solution, since the ship will have moved since firing.

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15. Hydrographic and Terrain Problems.--This consideration has been indirectly commented upon in the discussions on muzzle velocity and trajectory, and on mobility of ships, in paragraphs 7 and 8, supra. It is apparent of course, that hydrographic conditions off shore, including reefs, small islands, channels, etc., figure importantly in positioning a firing run. The terrain ashore resolves itself into masks, elevation contours, and the lie of ridges and canyons, all of which combine with the problem of positioning the ship off shore to determine whether naval gunfire can be brought to bear on a particular target.

16. Shift to Air Target or Naval Attack.--Naval gunfire on shore installations suffers from necessity of the ship having to cease fire on shore when it becomes a target for enemy air or naval attack. This shift in target became increasingly necessary in the Pacific toward the close of World War II, as the result of Japanese Kamikaze attacks and sporadic "suicide boat" tactics.

As the object of attack, it became immediately necessary for the ship to concentrate on defending itself and to forego further shore bombardment until the attack had been repelled. This was especially true in the case of destroyers, where the 5"/38 DP guns are used as antiaircraft weapons.

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Battery	5'725 Caliber	5"/38 Caliber	6"/47 Caliber	8'755 Caliber
Ships on Which Installed	OBB's CA's 10,000-ton CL's	DD's DM's, DMS's CA's 10,000- or 6,000-ton CL's NBB's	10,000-ton CL's	CA's
Use in Shore Bombardment (in Order of Suitability)	CSF, DSF, CB	CSF, DSF, CB	DSF, CB, CSF	DSF, CB
Effective Ranges (Max. Less 10%)	12,000 yards (HC proj.)	16,000 yards (HC proj) 16,000 yards (Com proj)	20,500 yards (HC proj) 23,500 yards (AP proj)	21,500 yards (HC proj) 27,500 yards (AP proj)
Muzzle Velocity	2,200 f/s	1,200 f/s 2,600 f/s	2590-2800 f/s	2,160-2,300 f/s
Rate of Fire Per Minute for 5 minutes	10	10	5	2
* Average Pattern (Range)	About 175 yards	About 175 yards	About 250 yards	About 400 yards
No. of Guns Firing in Salvo	4-5	4-12	3-15	3-10
Type of Projectiles	AAC, C, Ill., WP	AAC, C, Ill., WP	HC, C, AP, Ill.	HC, C, AP.
Fuze	Base, Point 45 Sec. Time	Base, Point 45 Sec. Time	Base, Point 45 Sec. Time	Base, Point 45 sec. Time
Effective Bursting Radius	About 50 yards (AAC)	About 50 yards (AAC)	About 120 yards (HC)	About 240 yards (HC)
Safety Requirements (Initial Salvo)	400 yards	400 yards	600 yards	800 yards

Deflection pattern about 10% range pattern. Pattern sizes are determined by: (1) Adjustment of the fire control installation; (2) state of training of operating personnel. As a result pattern size of identical batteries will vary from ship to ship.

Figure 1.--Reference data for ships' batteries.

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SHELL	WEIGHT		ROUNDS Delivered in one minute	ROUNDS Delivered in one minute		NUMBER OF TARGETS PER HOUR	STANDARD TARGET AREA ROUNDS TO NEUTRALIZE
	METAL	HE		METAL	HE
5-inch A AC   (4 Guns)	46	7	40	1,840	280	6	200×200 80 Rounds
105mm How   (12 Guns)	26	5	48	1,248	240	---	As Desired
6-inch HC   (6 Guns)	92	13	30	2,760	390	6	300×300 60 Rounds
155mm HE   (12 Guns)	77	16	36	2,772	576	---	As Desired
8-inch HC   (9 Guns)	239	21	18	4,302	378	6	400×400 54 Rounds
8-inch HE   (6 Guns)	170	30	12	2,040	360	---	As Desired
14-inch	HC 1275 AP 1,500	104.2 22. 5
16-inch	HC 1,900 AP 2,600	153.6 40. 6
No Comparable FA Weapons

Figure 2.--Reference data for naval guns and artillery.

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	5-in. Surface Rocket (Common SS)	5-in. Surface Rocket (Gen. Purpose SS)	5-in. Surface Rocket (High Cap. SS)	5-in. Surface Rocket (High Cap. SS)	5-in. Surface Rocket (High Cap. SS)	4.5-inch Surface Rocket (Bombardment)	7. 2-inch Surface Rocket "Mousetrap"
Total Wt. of Rd. (As fired)	150.8 lb.	49.1 lb.	50.2 lb.	---	---	---	---
Velocity	1,600 f.s.	1,530 f.s.	850 f.s.	Under Development		---	---
Max. Range at 45° Elevation	11,000 yds.	11,000 yds.	5,250 yds.	2,500 yds.	1,250 yds.	11,100 yds.	300 yds.
Use	From PT boats against small targets within range	From PT boats against small targets within range	From landing craft to lay barrage at 3,000-5,000 yds.	From landing craft to lay barrages at 2,500 yds.	From landing craft to lay barrages at 1,250 yds.	From landing craft to lay barrages at 800-1,100 yds.	Primarily from LVT's and Woofus craft, for underwater demolition
Present Status	In production	Not in production	In production	Accelerated experimental work	Accelerated experimental work	In production	In production

This chart gives data on five types of spin-stabilized 5-inch rockets, the 4.5-inch rocket, and the 7. 2-inch rocket. With regard to the 5-inch rockets, experimental work has ceased on three, two of which are in production The third is not yet in production. The other two types are still in the experimental stage, and are under development as short-range barrage rockets. The data on all rockets herein listed is not complete, and that which is listed may be revised as development work progresses.

Figure 3.--Reference data for rockets.

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[BLANK PAGE]

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Section 3
Classification of Naval Fires

17. Introduction.--Naval gunfire on shore targets is classified as to:

1. Effect:

   1. Neutralization.
   2. Destruction.

2. Prearrangement:

   1. Prearranged fires.
   2. Fires on targets of opportunity.
   3. Call fires.

3. Tactical purpose:

   1. Supporting fires.
      Close.
      Deep.
   2. Counterbattery.
   3. Harassing fire.
   4. Interdiction fire.

4. Method of fire control:

   1. Direct.
   2. Indirect.

18. Neutralization Fire.--Neutralization fire is used for the purpose of causing some losses, hampering or interrupting movement or action, and in general reducing or destroying combat efficiency of enemy personnel. Neutralization is normally only temporary and the target becomes active soon after neutralization ceases.

Based on experience, it is believed that an area 200 by 200 yards square, lightly fortified, may be neutralized by 30 rounds of 5-inch fire, plus 10 rounds for adjustment, delivered in a 2-minute period. Since the 5-inch naval projectile is approximately equal to the 105mm shell in capabilities, this compares favorably with field artillery doctrines of neutralization fire. The status of enemy morale, training, supplies, and fortifications provides psychological and physical factors which will vary the effectiveness of neutralization fires.

(For other neutralization equivalents and capabilities, as well as rates of fire, refer to section 2, figures 1 and 2.)

19. Fire for Destruction.--Fire for destruction by naval guns requires considerable time, a heavy expenditure of ammunition, and continuous observation. In landing operations, destruction by ships' guns is generally direct fire and is limited to targets visible from seaward; however targets may be

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engaged by "indirect fire." Targets for destruction generally consist of coast or field artillery, antiaircraft batteries, and machine-gun and antiboat-gun emplacements located close to the shore.

20. Prearranged Fires.--Prearranged fires are those fires planned prior to the landing or to support an attack ashore to cover known or suspected enemy troops or installations.

21. Targets of Opportunity.--In contrast to prearranged fires, fires on targets of opportunity are those delivered on targets the location of which previously was unsuspected or unknown. These targets may be of all types, such as artillery, reserves, machine guns, tanks, antiboat guns, troops preparing or occupying positions, and counterattacks.

22. Call Fires.--Call fires are delivered by fire support ships after shore fire control parties have landed, reached a favorable spotting position, established communication with fire support ships, and have requested fire on specific targets. One or more ships may be assigned to each assault battalion for this purpose.

By virtue of use of the gridded target area maps, ships should be able to engage any target with call fire, subject to limitations of range, terrain, and navigation.

23. Supporting Fires.--Supporting fires are primarily neutralization fires. They are divided into close and deep supporting fires. Close supporting fires are those in immediate support of some particular infantry unit ashore, normally delivered by an assigned direct support ship, performing the same function as direct support artillery. Initially, fires delivered on enemy beach defenses are of this type. Subsequently, these fires are delivered inland on enemy positions which are to be assaulted.

Deep supporting fires are fires delivered with the principal objective of deepening close supporting fires by neutralizing reserves, weapons firing from rear positions, and for the purposes of interfering with the enemy command, communication, and observation systems.

Deep supporting fires are those which are generally not in immediate support of a particular unit of the landing force but are in general support of the operation as a whole. The function of these fires is analogous to that of general support artillery.

Field artillery is capable of massing the fires of direct and general support battalions of artillery on close support targets. However, it is not practicable to mass the fires of several ships on a close support target. If a greater volume of fire is required, a larger ship with more guns and batteries should be assigned the target for a close support mission.

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24. Harassing Fire.--Harassing fire is delivered during a relatively quiet period to prevent enemy rest and recuperation and to interfere with repair of installations and replenishment of food, water, and ammunition, thereby lowering enemy efficiency and morale. Harassing fire is particularly valuable at night.

25. Interdiction Fire.--Interdiction fire is directed against areas, routes of approach, and transport functions, usually at irregular time intervals, in order that the enemy may not pass through or utilize them.

26. Counterbattery Fires.--Counterbattery fires are for the purpose of neutralizing or destroying enemy batteries.

27. Direct Fires.--Direct fires are delivered on targets which can be seen from the firing ship. Spotting of the fall of shot is normally carried out from the ship.

28. Indirect Fires.--Indirect fires are delivered on targets which cannot be seen from the ship. These fires are spotted by plane spotters or shore fire control party spotters assigned for this specific purpose, or are fired without observation. In certain instances, spotting may be done by radar.

As has been previously stated, larger area coverage is necessary when no observation is possible; this results in a greater expenditure of ammunition.

It is advisable that a ship delivering indirect fire guard the radio frequency of the shore fire control party positioned nearest the fall of shot, whatever the method of control of fire, in order that a full measure of safety may be maintained.

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[BLANK PAGE]

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Section 4
The Shore Fire Control Party

29. Mission.-- The shore fire control party provides the trained personnel for the control and execution of naval gunfire support. The mission of the shore fire control party is dual:

1. The staff mission.--The staff mission is to furnish staff liaison officers for naval gunfire support with each echelon of command to include the infantry battalion. These officers advise the commander on the employment of naval gunfire support prior to and during the campaign. When the infantry commander decides that he requires a ship to provide support, it becomes the; duty of the staff liaison officer to pass the request for support to the next higher echelon.

2. The tactical mission.--The tactical mission is to furnish naval gunfire spotters to the infantry battalions for the purpose of spotting naval gunfire on designated targets.

30. Distribution within Division.--Shore fire control parties are included in the assault signal company (ASCO) of the Marine division. They are trained and equipped for the mission of control and execution of naval gunfire. There are 13 shore fire control parties in a division, which are attached to the various echelons for operational functions.

1. Each infantry battalion requires one shore fire control party consisting of:

   1. A naval gunfire; liaison team:

      1. Naval gunfire liaison officer (naval officer, officer in charge of the shore fire control party).
      2. Radio team (for communication with the naval gunfire spotter and with 1;he supporting ship).
      3. Wire team (for communication between the radio and naval gunfire liaison officer).

   2. A naval gunfire spotter team:

      1. Naval gunfire spotter (Marine artillery officer).
      2. Assistant naval gunfire spotter (artillery noncommissioned officer).
      3. Radio team (for communication with the naval gunfire officer and the supporting ship).

   4. Wire team (for communication between the radio and the naval gunfire spotter).

2. Each infantry regiment requires one naval gunfire liaison team consisting of:

   1. Regimental naval gunfire liaison officer.

   2. Radio team (for communication with the corps naval gunfire officer, division naval gunfire officer, and battalion shore fire control parties and the headquarters ship).

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3. Wire team (for communication between the radio and the naval gunfire liaison officer).
4. Radar beacon team.

3. Each infantry division requires one naval gunfire team consisting of:

   1. Division naval gunfire officer (Marine artillery officer of field grade, specially trained in naval gunfire support, not organic to ASCO^but an assistant G-3).

   2. Assistant division naval gunfire officer (naval gunfire liaison officer; officer in charge, shore fire control section, assault signal company).

   3. Radio team (for communication with the corps naval gunfire officer, regimental naval gunfire liaison officers, and the headquarters ship).

   4. Radar beacon team.

4. Each corps (Fleet Marine Force Expeditionary Troops) requires one naval gunfire team consisting of:

   1. Corps naval gunfire officer (Marine artillery officer of field grade).

   2. Assistant corps naval gunfire officer (Marine artillery officer of field grade).

   3. Assistant corps naval gunfire officers (naval gunfire liaison officers).

   4. Radio team (for communication with the division naval gunfire officers and the headquarters ship).

While the assault signal company provides the trained nucleus for the shore fire control parties, in some instances it has been found necessary to supplement the organic personnel with additional personnel, the source of this increase to be from other units in the division.

31. Duties.--The duties of the shore fire control parties are as follows:

1. Before the landing.--Each officer studies the attack orders of the landing force and the attack force to determine both the plan of fire support for the landing force and the general scheme of maneuver of the landing force, paying particular attention to the communication and naval gunfire annexes. Each prepares recommendations, based on the known enemy situation, for the employment of naval gunfire on suitable targets after the landing. It is desirable to hold conferences with the fire support ships to coordinate fire support, and gunnery and communication drills are held so that a minimum of difficulty will be experienced in the delivery of fire support. Closest liaison is maintained with the infantry operations and communication officers, and the artillery and air support officers of both higher and lower echelons. Each coordinates the activities of the shore fire control parties under his

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jurisdiction, insuring that they are properly equipped and trained for the operation, and takes an appropriate part in the planning of naval gunfire support.

2. Embarkation and ship-to-shore movement.--The entire battalion shore fire control party will be embarked on the same transport. The battalion shore fire control party is divided into two sections for the ship-to-shore movement. The spotter team should be boated not earlier than the second nor later than the third assault troop wave. The liaison team should be boated with the battalion commander. Under such conditions, it has been found desirable to employ radio-equipped landing craft as the offshore spotting station for the spotter and liaison teams in order to bridge the time lag between the landing of the spotter and liaison officer and the establishment of radio communication with the supporting ship.

   Regimental, division, and corps shore fire control parties land as directed by their appropriate commanders.

3. After the landing.--The naval gunfire spotter selects the best possible observation post, sets up his radio under cover, and establishes communication with the supporting ship and the liaison officer. After he is oriented, he fires on targets on his own initiative, reporting the results to the battalion liaison officer. The spotter is the target-getter--he locates and adjusts naval gunfire in support of the infantry battalion to which he is attached. Targets located outside the zone of action of the infantry battalion are referred to the liaison officer for appropriate action.

   The naval gunfire liaison officer takes post at the command post in close proximity to the operations, artillery, and air support officers. He advises the commander as to the employment of naval gunfire, and if no direct support ship has been assigned, he makes the request for a fire support ship. He coordinates naval gunfire, particularly illumination, with adjacent units. He keeps the spotter and the commander informed of the situation and passes targets lying out of his zone of action to the unit concerned. The regimental naval liaison officer consolidates and coordinates all requests for special fire missions, spotting aircraft, and radar beacon personnel.

   The division or corps naval gunfire officer takes post where coordination may best be accomplished--either with the artillery and air officers at the division command post or at the artillery fire direction center. He is an executive staff officer and advises the commander and staff in the planning and execution of naval gunfire support. He keeps the naval gunfire officers of higher and lower echelons informed of the situation, coordinating their requests for naval gunfire support and for illumination, and passing the requests for fire support to the appropriate commander. At all times the gunfire officer maintains closest liaison with the artillery and air officers.

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4. Radar beacon employment.--Radar beacon teams are supplied to shore fire control parties for the purpose of establishing and maintaining the gun-target line. The beacon is a directional, line-of-sight instrument which may be located by the ship, the location being employed exactly as are the base point in artillery or point Oboe in naval bombardment. Once the beacon is operating, the ship's fire control radar is trained on it, offsets applied, and firing begun. Radar beacon teams are assigned to shore fire control parties upon request.

5. Coordination of naval gunfire, artillery, and air support.--The principle of coordination of supporting weapons is dependent on a mutual understanding between the liaison officers of the various weapons as to their general capabilities with respect to the tactical problem of support of the infantry unit. Since artillery is best suited for close support missions, this capability is always exploited. Naval gunfire is well suited for deepening artillery fires, for close and deep support missions, for coastal targets, and for reverse-slope targets which can be engaged by changing the position of the firing ship. Air is best employed in large groups or for delivery of fire support on targets which cannot be reached by artillery or naval gunfire or when a larger amount of high-explosive smoke or incendiaries is desired on the target. The coordination of prearranged fires requires a discussion and general agreement by air, naval gunfire, and artillery liaison officers as to the responsibility of artillery, gunfire, and air for delivering fire on known targets. Each supporting arm must do all in its power to insure the maximum amount of coordination. In case of disagreement, the decision rests with the division and corps artillery officers acting as the direct representatives of the division or corps commanders in higher echelons.

   The coordination of all prearranged supporting fires for a division or corps preparation is the responsibility of the artillery commander as the direct representative of the division or corps commander. It is therefore necessary that the naval gunfire and air officers be located so that direct personal liaison can readily be maintained with the artillery commander. Based on targets located by all means at hand, a list of targets to be engaged is compiled. The representative of each supporting arm makes recommendations, and the detailed plan of fires is made by the artillery officer, who assigns targets as appropriate in view of the capabilities and ammunition supply of each weapon.

   The representatives of each arm carry out their assigned fire plan, making recommendation to the artillery commander for continued support. By personal liaison, each informs the other of the situation, and revisions of the fire plan are made as practicable during the attack.

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6. Air spot.--The officer controlling naval gunfire from the ground is often seriously handicapped by lack of observation, and a supplementary spotting agency becomes a necessity. Whether the plane to accomplish the air spot is carrier-based, from the fire support ships, or from landing fields, is incidental. Consideration should be given to the planning of air spot to work with an assigned shore fire control party, especially in the landing phase. Normally air spot will be available on station during all daylight hours for the purpose of adjusting naval gunfire on targets which cannot be observed by the infantry forces.

7. Illumination.--Night illumination may be considered a necessity during operations ashore. The request for illumination is made by the infantry battalion commanders, and the requests are consolidated and coordinated by regiments and division to insure that adequate illumination will be maintained with a minimum ammunition expenditure.

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[BLANK PAGE]

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Section 5
Naval Gunfire Communication

32. Need for Training.--The control and execution of naval gunfire support is largely dependent upon radio communication. In order that communication may be quickly established and fire support effectively delivered, shore fire control party personnel must be thoroughly trained in radio operation, in the conduct of fire, and in the use of voice and CW procedure, codes, and authenticators. Certain wire nets in the landing force parallel the naval gunfire radio nets, and shore fire control personnel must be familiar with and prepared to use the former, both as alternate means of communication and as a means of reducing traffic on the naval gunfire nets.

Several types of radios are now being used by shore fire control units. Some of these types of radios are shown in the following table.

Radio	Weight Lbs.	Voice Range (Miles)	CW Range (Miles)	Frequency Range	Mobility	Number Men Load
TBX-8*	117	15	30	2,000-5,800 KC	Portable	3 or 4
SCR-284*	109	7-15	30	3,800-5,800 KC	Portable or Vehicle M'td	3 or 4
SCR-694**	100	7-15	15-30	3,800-6,500 KC	Portable	3
TCS	141	25	75	1,500-12,000 KC	Vehicle M'td	---
SCR-193**	200	20	60	1,500-4,500 KC	Vehicle M'td	---
SCR-300	32	5-7	---	40.0-48.0 MC	Portable	1
SCR-536	6	1.5	---	3,500-66,000 KC	Portable	1

* Equipped with remote control unit.
** Can be equipped with remote control unit.

33. Equipment.--Shore fire control units are generally equipped as follows:

1. Shore fire control party:

   1. Naval gunfire liaison team:
      1 TBX-8, SCR-284, or SCR-694
      1 SCR-300
      2 telephones, EE-8-A
      2 reels combat wire

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2. Naval gunfire spotter team:
   1 TBX-8, SCR-284, or SCR-694
   1SCR-300
   2SCR-536's
   Telephones and wire as required

2. Regimental naval gunfire team:
   

   1 TBX-8, SCR-284, or SCR-694 1 SCR-300
   1 radar beacon
   2 telephones, EE-8-A
   2 reels combat wire

3. Division naval gunfire team:
   

   1 TCS, vehicle-mounted
   1 TBX-8 or SCR-284
   2 SCR-300's
   1 radar beacon
   2 telephones, EE-8-A
   Wire as required

4. Corps or expeditionary troops naval gunfire team:
   

   1 TCS, vehicle-mounted
   1 SCR-193, vehicle-mounted
   1TBX-8 or SCR-284
   2 telephones, EE-8-A
   Wire as requested

The shore fire control spotting nets are as described in figures 4, 5, and 6.

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Figure 4.--Naval gunfire spotting net.

34. The Shore Fire Control Spotting Net.--This net provides communication between the naval gunfire spotter, and the assigned direct support ship, and the naval gunfire liaison officer. Air spot assigned to work with a shore fire control party may also be present. This net is provided for conduct of fire and should not be used for any other purpose unless absolutely necessary. This net provides an auxiliary means of communication between the spotter and liaison officers when wire communication is not available. The spotter acts as net control.

Each assault infantry battalion is assigned a frequency to use for spotting naval gunfire.

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Figure 5.--Naval gunfire control net.

35. The Naval Gunfire Control Net.--This net is primarily used for the request of fire support and to pass information between the landing force and the attack force, and between the attack force commander and the fire support ships. Battalion landing teams normally make requests for naval gunfire support to regiment by wire or via the division naval gunfire net on the SCR-300, but in case of failure of normal communication the request is made on the naval gunfire control net. After consolidating the requests of regiments, division makes the request for fire support of the division to the corps, if present; otherwise to the commander of the naval attack force, over this net. This net is usually quite busy with normal control and administrative traffic. The commander of the naval attack force acts as net control.

36. The Naval Gunfire Control Overload Net.--This net is an auxiliary radio net guarded by the commander of the naval attack force, and is used for communication by any station that cannot transmit over the control net because of excess traffic.

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Figure 6.--Division naval gunfire net.

37. The Division Naval Gunfire Net.--The division naval gunfire net provides communication between all naval gunfire teams of a division, and is used in case of failure and as a supplement to other means of communication. The division naval gunfire officer acts as net control.

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Figure 7.--Gunboat control net.

38. The Gunboat Control Net.--The gunboat control net provides communication between the attack force commander and the commanders of gunboat, mortarboat, and rocketboat units and the gunboats. This net is provided for the control of the smaller heterogeneous fire support craft. Net control is exercised by the commander of the naval attack force.

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Figure 8.--Wire nets.

39. Wire Nets.--Because of the overload on the radio nets and for security reasons, telephone communication is to be used whenever possible in preference to radio nets for communication between naval gunfire units ashore.

The wire line from the naval liaison officer to the spotter is laid by the wire men of the naval liaison and spotter teams. Organic infantry wire lines are generally used for communication between the other NGF units of the landing force, wi;th separate locals from the switchboards concerned, except that separate wire lines will be established and maintained between each division and corps naval gunfire team whenever practicable.

40. Procedure.--Radio procedure is conducted in accordance with prescribed shore fire control code. Current fire control code is CSP 2156(C).

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41. Authentication.--The radio authenticator system to be used will be prescribed in current SOI or the communication plan. Authenticators are not generally used unless one or a combination of the following situations arises:

1. Deception by the enemy is used.
2. Doubt occurs as to station's identity.
3. It is considered for any reason to be desirable to identify a station.

42. Cipher Code.--The shackle numeral cipher is a number-equivalent code, employing the use of coded letters to represent numbers. Instructions for its use are prescribed in current SOI or the effective communication plan. The following numbers are always encoded:

1. Actual time of troop movements or activities.
2. Quantity of troops, ammunition, or equipment.
3. Map coordinates, if the coordinate system is compromised.
4. Frequencies, if code names for the frequencies are unknown.

43. Waterproofing.--It has been found necessary to waterproof communication equipment to such an extent that, if necessary, it may be floated into the beach without harmful effects.

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Section 6
Naval Gunfire Planning

44. Mission of Naval Gunfire Support.--The mission of naval gunfire support in an amphibious operation is to support the seizure of the objective by reducing or neutralizing shore installations which oppose the approach of the transports, to deny the enemy reinforcements in the landing area, to destroy or neutralize beach defenses that oppose the landing of troops, and to assist the advance of the troops after the landing has been made.

45. Naval Attack Force Responsibility.--The commander of the naval attack force (a Naval officer of flag rank), the highest command echelon present, is responsible for the control and execution of naval gunfire support.

46. Landing Force Responsibility.--The commander of the landing force is responsible for estimating the requirements of the landing force for naval gunfire support, and for presenting these requirements to the commander of the naval attack force in the form of a request.

When the landing force is composed of more than one corps, each corps will submit its requirements for naval gunfire support to the commander of the expeditionary troops, as soon as possible, in order that he may consolidate all requests for submission to the naval attack force commander.

Where the landing force is composed of more than one division, each division will submit its requirements for naval gunfire support to the corps commander.

Divisions will normally be expected to be prepared to plan scheduled naval gunfire bombardments for independent operations.

IT IS THE RESPONSIBILITY OF THE LANDING FORCE CAREFULLY TO ANALYZE ITS REQUIREMENTS FOR NAVAL GUNFIRE SUPPORT AND TO PRESENT THESE REQUIREMENTS TO THE COMMANDER OF THE NAVAL ATTACK FORCE IN THE FORM OF A REQUEST FOR NAVAL GUNFIRE SUPPORT.

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47. The Landing Force Request.--The landing force naval gunfire request may be divided into two main parts: a recommended preliminary bombardment plan and a recommended D-day plan. Each plan should cover the following:

1. Targets, with the effect desired on each.
2. Time schedule for the engagement of these targets.
3. Amounts of ammunition to be fired on targets.
4. Target areas of responsibility.
5. Requirements for direct support ships and spotting aircraft.

48. The Decision.--Before the landing force can estimate its requirements and submit a request for naval gunfire support, the plan of landing must have been decided.

1. The estimate of the situation.--Certain aspects of naval gunfire support must be considered by the commander of the landing force in his estimate of the situation:

   1. In considering relative combat power there must be considered the amount and type of naval gunfire support (including ammunition) provided or to be requested.

   2. The hydrography of the sea areas and the effect it will have on the type and amount of fire support which can be delivered.

   3. The enemy's ability to reinforce and fortify his position prior to the landing, and the effect this will have on the fire support required.

   4. The advisability of concentrating the available gunfire support on one beach at a time and landing in echelon so that all available ships may concentrate successively on each landing.

2. The operation plan.--The plan of landing having been decided upon, it is carefully analyzed for the details of what, where, when, and how the landing force intends to land, and what the scheme of maneuver is to be once the troops are ashore. The detailed plans of each assault commander, and the naval gunfire desired to support his scheme of maneuver, are ascertained. The naval gunfire plan is based on the principle of how the plan of landing can best be supported.

49. Intelligence.--Vital to the study and planning of naval gunfire support of an amphibious operation is the intelligence of the target area. Working together, landing force staff officers of the various staff sections make detailed studies of the target. The study covers the location of all enemy defenses, the strength of the fortifications, and their capabilities insofar as they affect the landing and the campaign ashore. This data is cataloged and is a basis for future planning of naval gunfire, air, and artillery support. This has been called a target

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analysis for planning naval gunfire and air support, and is analogous to the target information center of the artillery. The following data may be included:

1. The target and its grid location.

2. The effect desired on the target by the bombardment.

   (Of vital consideration is the ammunition available for expenditure on the target. Fire for destruction usually requires a very high ammunition expenditure, and it is desirable carefully to consider whether fire for destruction on a target is worth this expenditure. Further, fire for destruction on a target should be attempted only when ideal conditions of observation may be obtained.)

3. The type of ammunition which it is believed will be necessary to achieve the effect desired.

4. The detailed description of the target, including the strength of construction.

5. Any remarks which, for future references, it may be desirable to include.

50. Joint Planning--General.--When the landing force has completed its plan for landing, and the landing force request for naval gunfire support is presented to the commander of the naval attack force, joint staffs of the landing force and the attack force meet in conference, and together make up the naval gunfire support plan. A continuous exchange of views and information is required, as well as agreements on the allocation of targets and scope of responsibility. The object of joint planning is the production of bombardment plans which are fully integrated with the plan of landing, and which use all supporting weapons to the utmost of their capabilities.

51. The Naval Gunfire Support Plan.--In planning naval gunfire support, joint staffs consider:

1. Fire support requirements.--If no gunfire support ships have been designated, or if the gunfire ships designated are considered to be inadequate, the landing force may be required to estimate its requirements for fire support. This request should specify the ships, by types and numbers, with ammunition requirements, to support the plan of the landing force. Since more gunfire support will be required at the time of the landing than at any other time, by estimating the ships required to neutralize the landing beaches and the targets which can fire on the landing beaches, a solution may be derived. Ammunition expenditure will depend upon the length of the bombardment and the contemplated rate of fire of the fire support ships.

   b. Pre-D-Day bombardment.--The landing force request for naval gunfire support will include an estimate as to the length of time required to accomplish the effect desired on

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the target This requires an accurate study of the enemy strength and installations and of the ammunition required, and generally is expressed in firing days.

Pre-D-day bombardments may also include fires for the purpose of locating targets. ^ Gunboat-destroyer teams, with the gunboats firing 40mm on possible shore targets for the purpose of stripping camouflage, and with the destroyer covering the gunboat for counterbattery and to destroy located targets, have proved valuable. \<

The pre-D-day bombardment may be general in nature to prevent, disclosing the landing beaches. Since targets for the pre-D-day bombardment usually are known targets on which destructive effect is desired, it has not been found practicable to allot any definite amount of ammunition for any target. Instead, the procedure is to assign certain targets to certain fire support ships or fire support groups, and to prescribe the damage desired on each without assigning any specific time or any amount of ammunition for the engagement of any target. In this respect, it is the effect desired which is important. For targets on which only neutralizing fire is believed necessary, the amount of ammunition to be fired on each should be prescribed, and if any coordination with this fire will be necessary, the time of firing should also be prescribed. In case the pre-D-day schedules prescribe specific amounts of ammunition and time for targets, wide latitude in the expenditure of ammunition should be given to the fire support group commander in the engagement of the targets.

3. Task organization.--The ships available for the bombardment (or the ships requested for the bombardment, if the landing force were required to make request for fire support) are grouped into fire support groups for the general bombardment and for the beach preparation. The guiding principle in the grouping of ships into fire support groups is to group those ships firing from the same naval fire support areas and firing with the same missions into the same fire support groups. This simplifies control and allows flexibility. The strength of the enemy in the landing beach areas and the missions of fire support influence strongly the grouping of fire support ships into fire support areas. Single ships or a group of ships may constitute a fire support group.

   Inasmuch as the individual ships available for naval gunfire support may change before the operation, it may be desirable not to list ships by name, but to list ships by class and assign a number. (Example--BB No. 1, CA No. 3, DD No. 23.)

   In grouping the ships into fire support groups and in dividing the sea areas into naval fire support areas, it is essential that the following be considered:

   1. The transports and the debarkation areas.

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2. The boat lanes and the movement of the assault waves to the beach, and the lifting of the preparation just before the assault waves reach the beach.

3. The scheme of maneuver of the landing force and the actual movement of the landing force once ashore.

4. Air support and the landing force artillery. Too much emphasis cannot be placed on the coordination between the naval gunfire support and the movement of the landing force, especially during that period extending from H-hour to H-plus-2 hours. Consideration should be given to the placing of liaison officers from the landing force aboard firing ships to assist in the location and coverage of targets which threaten or may fire on the assault elements of the landing force. In many instances a liaison officer thoroughly familiar with the plan and scheme of maneuver of the landing force can assist materially in the coordination of naval gunfire with the attack ashore.

   Of vital consideration is the method by which naval gunfire will be lifted from the landing beaches. Air observers' reports have been used effectively, and for large landing forces it may be desirable that plans include the lifting of fire from one beach while maintaining it on another. It has been found, however, that the lifting of naval gunfire from the landing beaches cannot properly be controlled from the command ship alone, but must be controlled by an observer who can accurately state the time that the preparation should be lifted.

4. Naval fire support areas.--By the assignment of definite sea areas to each fire support group, firing ships are allowed freedom of movement in the execution of fires and at the same time are prevented from interfering with transports, landing craft, and other fire support groups. The same principles used in the making of the task organizations are applicable in the allocating of the fire support areas or boat lanes, for the delivery of supporting fires.

   The naval fire support areas are shown in the naval gunfire support operations chart, which is appended to the naval attack force operation order.

   Hydrography is also a prime consideration in the assignment of the fire support areas.

5. Targets.--The landing force should submit to the commander of the naval attack force a list of targets, with priority, which it desires to be covered, with a statement as to the effect desired on each. This list, with the available intelligence data on the target, is the basis for the planning by the joint staffs for the schedule of fires.

6. Time schedule of fires.--The targets are listed in a time schedule for the bombardment. Included in this time schedule is the amount of ammunition to be fired on each.

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Recent trends have been to the effect that only D-day bombardments are in the form of a time schedule. Pre-D-day bombardments should be controlled by target, with the effect desired on each, the main consideration being the effect desired rather than the expenditure of an allotted amount of ammunition on each target. Particularly for the D-day bombardment, targets should be engaged by a time schedule, with specific amounts of ammunition expended on each, since the assault on the beach is to follow the preparation. Time schedules may be in any convenient form, graphical or tabular.

Here again, joint staffs planning the schedule of fires may designate ships by name, or by types and numbers.

The rate of fire prescribed in a schedule of fires will be dependent upon the number of ships, the ammunition available, and the time allowed for the bombardment. The rates of fire shown in the following tables have been found practicable for planning purposes:

1. Rapid fire for a period of approximately 5 minutes:

   	5-inch	6-inch	8-inch	14-inch	16-inch
   Rounds/Gun/Min	10	5	2-3	2	2

2. Extended periods:

   	5-inch	6-inch	8-inch	14-inch	16-inch
   Rapid Fire R/G/M	4	2	1	½	¼
   Slow Fire R/G/M	2	¾	¼	¼	¼

Target areas of responsibility.--Doctrine has indicated that a deep fire support ship would be assigned to each assault combat team and division. In some campaigns this assignment has not been necessary. Instead, targets of a deep support nature which could not be engaged by the assigned direct support ships were referred to the fire support commander. He then assigned appropriate available fire support ships to the mission.

In order that fire support be economically disposed to engage quickly any located targets, close or deep, and so that the target area will be kept under observation, the target area is divided geographically into areas which are assigned to fire support groups. Each fire support group commander is given detailed instructions as to the observation which he will maintain in his area of responsibility, and instructions as to targets located therein. For direct support ships the target area of responsibility is the zone of action of the infantry battalion being supported. For fire support groups the target area of responsibility is the target area assigned, regardless of size or location.

The target areas of responsibility are included in the naval gunfire support operations chart, an appendix to the naval attack force operation order.

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The doctrine of assignment of deep support ships to combat teams and divisions is sound, and should be scheduled if the situation so indicates. The assignment of target areas of responsibility to ships or fire support groups insures the availability of ships to fire on any located targets and injures that areas of the target are kept under surveillance.

8. Direct support ships.--Included in the landing force request for naval gunfire support is a recommended assignment of direct support ships to assault battalions and of deep support ships to combat teams and divisions. This recommendation includes the class of ship and numbers of each, and may include a recommendation as to the employment of air spot with the shore fire control party. Joint staffs consider the availability of fire support ships for these missions and assign ships to infantry units as available and practicable.

9. Air spot.--The employment of air spot, specifying the numbers and types of planes, should be included in the recommended naval gunfire support plan. Air spot, working on the frequency of the shore fire control party of an assault infantry battalion, has proved valuable in locating targets which the shore fire control party cannot observe, and should be planned if it is seen in the planning stage that the shore fire control party will not have good observation. Air spot has also proved practicable in assisting the ship in coordinating support fires with the movement of the infantry forces.

   For the landing, air spot will generally be available from the fire support ships, and from carriers. VOF (high-performance aircraft) have been profitably used as spot planes, especially for deep support targets where the target may be protected by antiaircraft. The landing force naval gunfire plan should include in detail the recommended air spot employment for all types of planes which will be available.

   In the planning stage, joint staffs allocate and coordinate the available spotting planes as believed desirable.

10. Coordination.--(1) The agencies to insure staff coordination of naval gunfire, air, and artillery during the operation are planned by the joint staffs.

    It has been considered that the landing force artillery officer, acting in his staff capacity as artillery officer, is an appropriate agent to effect coordination of all supporting arms for the direct support of the troops. Ships and aviation, so far as troop support is concerned, normally comply with the requests of this artillery officer.

    2. The coordination of naval gunfire with air strikes to prevent endangering friendly aircraft over the target has been solved in several ways, such as:

       1. Having aircraft carry out strikes without regard for the danger of friendly artillery and naval gunfire.

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2. Stopping all artillery and naval gunfire whose maximum ordinate exceeds a limit agreed upon.

3. Stopping all artillery and naval gunfire with, a maximum ordinate of 1,000 feet or over, within a 2,500-yard radius of the target.

52. The Landing Farce Naval Gunfire Annex.--It is the responsibility of the landing force to plan in detail what is required of naval gunfire support.

The final naval gunfire plan is made by the joint staffs of the landing force and the attack force, and is issued as an annex to the naval attack force operation order.

The naval gunfire support annex to the landing force operation order is issued to the landing force for INFORMATION and although it is signed "By Command of General X," it is not an order for execution of naval gunfire support. The information given in the landing force naval gunfire annex is taken from the attack force operation order.

A form and check list for the landing force naval gunfire support annex follows:

Annex BAKER to Operation Order 3-45, FIFTH MARINE DIVISION

NAVAL GUNFIRE SUPPORT

1975-11-3 301/044 Ser 003

FIFTH MARINE DIVISION In the Field 1200K, 1Sept45

TOP SECRET

Excerpts from Northern Attack Force Attack Order A21-45. Published for information by FIFTH MARINE DIVISION. (Where the landing force is composed of more than one division, the senior landing force commander may publish a joint annex for the entire landing force, stating that the annex is published as a joint annex for information of the corps and divisions of the landing force.)

TASK ORGANIZATION:

1. (53.2)   NORTHERN SUPPORT GROUP--Rear Admiral NSG

   (53.2.1) Fire Support Group One--Rear Admiral SGA
                 OBB 43 TENNESSEE (F)
                 OBB 44 CALIFORNIA
                 CL 62 BIRMINGHAM
                 CL 60 SANTA FE
                 CA 33 PORTLAND

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              DD 407 STERETT
              DD 360 PHELPS

              (Fire support ships as listed in the Attack Force Task Organization.
              Ships may be listed as: BB#1, BB#2, CL#1, CL#2, CA#4, DD#12, DD#13, etc.,
              instead of by name.)

1. 1. Information of Enemy Installations. (Enemy intelligence as pertinent to naval gunfire support and may include reference to intelligence annex.)

   2. Information of Friendly Forces. (May include air strikes, fleet covering strikes or bombardments, etc.)

      (Since the information in paragraph 1 is to be found in other annexes of the operation order, it may be omitted entirely.)

2. The mission of naval gunfire support, including the priority of targets, areas for the massing of fires.

3. 1. Pre-D-day bombardment.

   2. D-day bombardment (may be subdivided into pre-H-Hour and beach preparation).

   3. Direct support ship assignment (requested assignment, if appropriate).

   4. Gunboat employment plan.

   24. 1. General instructions regarding coordination of naval gunfire with the assault troops.
       2. General instructions regarding illumination.
       3. General instructions regarding smoke.
       4. General instructions regarding air spot.
       5. General instructions as to the means of lifting of naval gunfire from the landing beaches.
       6. Use of radio-equipped boats by shore fire control parties.
       7. General instructions regarding coordination of naval gunfire with artillery and air support.
       8. Restrictions on firing.
       9. Grid system and maps to be used jointly.

4. Ammunition allowances, restrictions, and replacement.

5. 1. Communication plan (may include reference to communication annex and to naval gunfire communication appendix.)

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1. Special instructions regarding visual expedients.

2. Special instructions regarding use of naval gunfire control net.

BY COMMAND OF MAJOR GENERAL X:
Colonel, U. S. Marine Corps,
Chief of Staff.

Appendices:

Appendix 1: Pre-D-day Schedule of Fires*
Appendix 2: D-Day Schedule of Fires*
Appendix 3: Shore Fire Control Communication Plan**
Appendix 4: Naval Gunfire Support Operations Charts*

Distribution:
Official:
Colonel, USMC,
ACofS, G-3.

 

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* Appendices may be joint attack force and landing force.
** Pertinent parts of the communication annex may be extracted and appended to the naval gunfire annex.

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Appendix 4 to Northern Attack Force
Order A 21-45
Operations Chart

NOTES:

1. 1. Fire support sectors are selected considering:

   1. Maneuvering room for ships.
   2. Grouping of fire support ships for bombardment.
   3. Division of target areas into areas of responsibility.

2. Inland boundaries of target responsibility areas (TRA) should follow ridge lines, terrain formations and natural boundaries which affect the delivery of fire.

3. Exact locations to be occupied by fire support ship for preparation may be shown on this chart if scale is sufficiently large, but may be designated by other means.

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Section 7
The Fire Support Ship

53. Modern Fire Control Systems.--In order that a more comprehensive understanding of the capabilities and limitations of naval gunfire may be had, it is desirable to review the component units of the modern fire control systems installed on U. S. warships, and the ways in which these units work together to produce the desired results: accurate, rapid shooting. Fire control systems vary in number, size, and arrangement, according to the ship on which employed. A destroyer is equipped with one complete system, and can take under fire by main battery but one director-controlled target at a time. Cruisers and battleships have several systems on each ship, determined by the extent and arrangement of armament, and are enabled to engage two or more targets simultaneously. While these systems vary in size and arrangement, the functions and basic mechanism contained in the units composing the systems are essentially the same. Inasmuch as the modern destroyer mounts one complete fire control system, and for the further reason that it constitutes the most-used fire support ship in landing operations, a description of the system follows:

The units comprising the fire control system of a typical destroyer are:

Director, MK 37
Combat information center (CIC)
Plotting room
5"/38 main battery

(Refer to figure 9 for locations of these units and principal component parts and functions.)

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Figure 9.--Fire control system of a 2,100-ton destroyer.

1. Director, Mk 37.--Mounted on top the ship's bridge, with practically unlimited vision through 360 degrees, this unit is the station of the control officer (normally the gunnery officer on a destroyer). The director provides radar ranges, stereoscopic rangefinder ranges, and can lay on the target in point and train. It is designed to maintain constant train (deflection) on the target, and to transmit all values, directly and/or by telephone, to the plotting room and combat information center (hereafter designated "CIC").

   In the delivery of direct fire involving counterbattery or targets of opportunity, spotting and general control of fire are conducted by this station.

   The 40mm guns, as well, can be controlled by the Mk 37 director. At close ranges this fire is excellent for the bombardment of caves in cliffs, use against enemy personnel, and wherever accurate, rapid fire is desired.

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Figure 10.--Combat information center.

2. Combat information center (CIC).--CIC is a plotting and evaluation unit located in a room in the bridge superstructure, normally two or more decks below the director. The unit includes the dead reckoning tracer (DRT), tracking table, air spot, surface and air search radar, and instruments giving ship's course and movement, such as the compass repeater, fathometer (depth of water), pitometer (ship's speed), etc. An elaborate intercommunication system is maintained in CIC, and it is through CIC that radio communication is conducted with the shore fire control party when the ship is supporting operations ashore.

   For purposes of shore bombardment and shore fire support, a map of the area involved is placed on the DRT table; on this map is plotted the course, speed, and position of the ship during the firing run. Thus it may be seen that by advance predictions of range, target angle, and target bearing, communicated and verified to the plotting room by "mark" at close intervals, the problem is generated accurately by the computer (see below), and the guns laid on the target, ready for firing.

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Corrections in range and deflection as received from shore fire control or air spot are transmitted to "plot," where they are introduced into the computer.

When a new target is to be taken under fire, another solution is set up in the same manner as just described, and fire resumed. If this new target involves only a small correction, it is possible to proceed on the same solution, in which case the ship is advised that the correction is for the purpose of taking a new target under fire. The ship is then enabled to evaluate its accuracy in firing without being confused as to location of the target currently being treated.

3. Plotting room.--More generally called "plot," this unit receives the aggregation of fire control data from the director, CIC, and other precision sources. It is then necessary for "plot" to generate a solution, using this data, which will lay the guns on the target. This is done through the medium of automatic mathematical solutions by the computer, which solutions are rendered constant by the stable element.

   In delivering fire from naval guns, movement of the firing ship introduces the necessity of continually correcting the direction and elevation of the guns to compensate for the movement of the firing ship through the water. This is accomplished automatically by a mechanical-electrical device called the COMPUTER (rangekeeper).

   After the initial direction and elevation have been established, the introduction of the course and speed of the ship, together with all other fire control data, into this device maintains the theoretical correct direction and elevation which may yet require spots to actually bring the fire on the target.

   Roll and pitch of the ship must also be eliminated, in order to position the guns on a constant horizontal reference plane, to provide stability to the solution by the computer. In naval gunnery, there are two methods for establishment of a horizontal reference plane for elevation, as follows:

   1. Use of the horizon as a horizontal reference plane.
   2. Establishment of a true horizontal reference plane by the use of a gyroscope.

   In modern indirect fire control installations, the second method is used. This gyroscope, called the STABLE ELEMENT, maintains a true horizontal angle, unaffected by ship's pitch and roll, and, by means of electric-hydraulic motors, actuates a motion of the guns in an angular direction equal and opposite to the pitch and roll. These functions of level and cross-level are introduced into the computer and are thereby entered as a constant factor into the solution-laying of the guns.

   Thus, by use of the computer and stable element, the movement of the ship on its course through the water, and the roll and pitch, have been eliminated from the fire control

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problem. The computer has combined the fire control data to reach a solution of the firing problem, and it automatically positions the turrets by means of electro-hydraulic train and elevation gun drives.

4. Guns.--When all data has been supplied by the above-described sources, and a solution reached as explained, the result is transmitted to the guns by means of electro-hydraulic train and elevation gun drives. Within the limits of mechanical and human errors, which will be corrected by subsequent spots, the guns are thereby automatically laid on the target, ready to commence fire.

In general.--From the foregoing, it will be seen that location of ship, time required for plotting in CIC, etc., combined with necessity for setting up the problem in "plot" on the computer, will cause a short delay in opening fire on a designated target. Allowance should be made for this lapse (normally under 5 minutes), and for brief delays between salvos when adjusting. Short delays in fire must also be expected in the use of 1,200-feet-per-second powder (described in section 2), as the reduced velocity of the charge necessitates conversion of certain of the inputs to the computer, which is designed to compute on the basis of 2,600-feet-per-second charges.

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Figure 11.--Typical destroyer CIC. 53

Top.--The latest plotting facilities.
Center.--Looking into the operator's corner.
Bottom.--Ready for station-keeping, navigation, fighter direction, and gunnery.

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54. Armament of Shore Bombardment Ships.--The armament of U. S. Navy vessels used in shore bombardment missions is shown in the following table:

Battleships (BB)

Tonnage	Name	Hull Number	Armament	Guns Bearing Per Side
26,000	ARKANSAS	33	12 12"/50 6   5"/51 10 3"/50	12 12"/50 3   5"/51 5   3"/50
27,000	NEW YORK	34	10 14"/45 6   5"/51 10   3"/50	10 14"/45 3   5"/51 5   3"/50
	TEXAS	35	do	do
29,000	NEVADA	36	10 14"/45 16   5"/38	10 14"/45 8   5"/38
	PENNSYLVANIA	38	12 14"/45 16   5"/38	12 14"/45 8   5"/38
33,000	NEW MEXICO	40	12 14"/50 6   5"/51 8   5"/25	12 14"/50 3   5"/51 4   5"/25
MISSISSIPPI	41	do	do
IDAHO	42	12 14'750 8   5"/25	12 14"/50 4   5"/25
32,000	TENNESSEE	43	12 14"/50 16   5"/38	12 14"/50 8   5"/38
	CALIFORNIA	44	12 14"/50 16   5"/38	12 14"/508   5"/38
31,500	COLORADO	45	8 16"/45 8   5"/51 8   5"/25	8 16"/45 4   5"/51 8   5"/25
MARYLAND	46	do	do
WEST VIRGINIA	48	8 16"/45 16   5"/38	8 16"/45 8   5"/38
35,000	NORTH CAROLINA	55	9 16"/45 16   5"/38	9 16"/45 10   5"/38
	WASHINGTON	56	do	do
	SOUTH DAKOTA	57	9 16"/45 16   5"/38	9 16"/45 8   5"/38
	INDIANA	58	9 16"/45 20   5"/38	9 16"/45 10   5"/38
	MASSACHUSETTS	59	do	do
	ALABAMA	60	do	do
45,000	IOWA	61	9 16"/50 20   5"/38	9 16"/50 10   5"/38
	NEW JERSEY	62	do	do
	MISSOURI	63	do	do
	WISCONSIN	64	do	do
	*ILLINOIS	65	do	do
	*KENTUCKY	66	do	do
	* Not commissioned.

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Heavy Cruisers (CB)

Tonnage	Name	Hull Number	Armament	Guns Bearing Per Side
27,000	ALASKA	1	9 12"/50 12 5"/38	9 12"/50 8 5"/38
	GUAM	2	do	do
	*HAWAII	3	do	do

Heavy Cruisers (CA)

Tonnage	Name	Hull Number	Armament	Guns Bearing Per Side
9,000	PENSACOLA	24	10   8"/55 8   5"/25	10   8"/55 4   5"/25
	SALT LAKE CITY	25	do	do
	CHESTER	27	9   8"/55 8   5"/25	9   8"/55 4   5"/25
	LOUISVILLE	28	do	do
	AUGUSTA	31	do	do
	NEW ORLEANS	32	do	do
9,800	PORTLAND	33	do	do
	INDIANAPOLIS	35	do	do
9,900	MINNEAPOLIS	36	do	do
	TUSCALOOSA 37	do	do
	SAN FRANCISCO	38	do	do
10,000	WICHITA		do	do
13,000	BALTIMORE	68	9   8"/55 12   5"/38	9   8"/55 8   5"/38
BOSTON	69	do	do
CANBERRA	70	do	do
QUINCY	71	do	do
PITTSBURGH	72	do	do
*ST. PAUL	73	do	do
*COLUMBUS	74	do	do
HELENA	75	do	do
13,000	OREGON CITY	122	do	do
	* ALBANY	123	do	do
	*ROCHESTER	124	do	do
	*NORTHAMPTON	125	do	do
13,000	*CAMBRIDGE	126	do	do
	BRIDGEPORT	127	do	do
	*KANSAS CITY	128	do	do
	*TULSA	129	do	do
	*BREMERTON	130	do	do
	*FALL RIVER	131	do	do
	*MACON	132	do	do
	* Not commissioned.

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Heavy Cruisers (CA)

Tonnage	Name	Hull Number	Armament	Guns Bearing Per Side
13,000	*TOLEDO	133	9   8"/55 12   5"/38	9   8"/55 8   5"/38
	*DES MOINES	134	do	do
	*LOS ANGELES	135	do	do
	*CHICAGO	136	do	do
	*NORFOLK	137	do	do
	*SCRANTON	138	do	do
	*	139	do	do
	*	140	do	do
	*	141	do	do
	*	142	do	do
	*	143	do	do
	*	148	do	do
	*	149	do	do
	* Not commissioned.

Light Cruisers (CL)

Tonnage	Name	Hull Number	Armament	Guns Bearing Per Side
10,000	BROOKLYN	40	15   6"/47 8   5"/25	15   6"/47 4   5"/25
	PHILADELPHIA	41	do	do
	SAVANNAH	42	do	do
	NASHVILLE	43	do	do
	PHOENIX	46	do	do
	BOISE	47	do	do
	HONOLULU	48	do	do
	ST. LOUIS	49	do	do
	CLEVELAND	55	12   6"/47 12   5"/38	12   5"/47 8   5"/38
	COLUMBIA	56	do	do
	MONTPELIER	57	do	do
	DENVER	58	do	do
	SANTA FE	60	do	do
	BIRMINGHAM	62	do	do
	MOBILE	63	do	do
	VINCENNES	64	do	do
	PASADENA	65	do	do
	SPRINGFIELD	66	do	do
	TOPEKA	67	do	do
	BILOXI	80	do	do
	HOUSTON	81	do	do
	*PROVIDENCE	82	do	do
	*MANCHESTER	83	do	do
	* Not commissioned.

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Light Cruisers (CL)

Tonnage	Name	Hull Number	Armament	Guns Bearing Per Side
10,000	VICKSBURG	86	do	do
	DULUTH	87	do	do
	MIAMI	89	do	do
	ASTORIA	90	do	do
	OKLAHOMA CITY	91	do	do
	*LITTLEROCK	92	do	do
	*GALVESTON	93	do	do
	*YOUNGSTOWN	94	do	do
	AMSTERDAM	101	do	do
	*PORTSMOUTH	102	do	do
11,000	WILKES-BARRE	103	do	do
	ATLANTA	104	do	do
	DAYTON	105	do	do
	*FARGO	106	do	do
	*HUNTINGTON	107	do	do
	*NEWARK	108	do	do
	*NEW HAVEN	109	do	do
	*BUFFALO	110	do	do
	*WILMINGTON	111	do	do
	*TALLAHASSEE	116	do	do
	*CHEYENNE	117	do	do
	*CHATTANOOGA	118	do	do
	*		do	do
11,000	*WORCESTER	144	12   6"/47	12   6"/47
	*ROANOKE	145	do	do
	*VALLEJO	146	do	do
	*GARY	147	do	do
6,000	SAN DIEGO	53	16   5"/38	14   5"/38
	SAN JUAN	54	do	do
	OAKLAND	95	12   5"/38	12   5"/38
	RENO	96	do	do
	FLINT	97	do	do
	TUCSON	98	do	do
	*JUNEAU	119	do	do
	*SPOKANE	120	do	do
	*FRESNO	121	do	do
	* Not commissioned.

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Destroyers (DD)

1,500 to 1,630 Tons (Farragut Class)	4	5"/38 caliber guns
1,800 Tons (Selfridge Class)	5	5"/38 caliber guns
2,100 Tons (Fletcher Class)	5	5"/38 caliber guns
2,200 Tons (Sumner Class)	6	5"/38 caliber guns     (3 twin mounts)
Destroyer Minesweepers (DMS):     Converted 1,600-ton destroyers     (Hulls Nos. 19 and 30, both incl.)	4	5"/38 caliber guns
Destroyer Minelayers (DM):     Converted 2,200-ton destroyers     (Hulls Nos. 23 to 34, both incl.)	6	5"/38 caliber guns

Gunboat, Rocketboat, and Mortarboat Armament

LSM(R)(1):

1	15"/38 DP aft
2	40mm single-mounts; Mark 51 director control
3	20mm single-mounts
330	single-rail 5-inch fin-stabilized aircraft rocket launchers
50	six-rail 5-inch fin-stabilized aircraft rocket launchers; Total rocket load: 3,000 rounds

LSM(R)(2):

1	15"/38 DP aft, Mark 52 director control; total 5"/38 ammunition: 350 rounds
2	40mm in twin mount, Mark 51 director control
4	20mm in twin mounts
4	4.2-inch mortars; total mortar load: 800 rounds
10	5-inch spin-stabilized aircraft rocket launchers; direct control;     total rocket load: 5,000 rounds

LCS(L)(3):

1	3"/50 (currently being replaced by 40mm twin-mount forward, director control)
1	40mm twin-mount aft, director control
4	20mm machine guns
10	Mark 7 rocket launchers; 4.5-inch barrage rocket;     total rocket load: 240 rounds

LCI(G), Type 1, hull numbers 350 and below:

2	40mm machine guns, single-mount
5	20mm machine guns
10	Mark 7 rocket launchers; 4.5-inch barrage rockets;     total rocket load: 240 rounds

LCI(G), Type 2, hull numbers 351 and above:

3	40mm machine guns, single-mount

--58--

4	20mm machine guns
32-42	Mk 7 rocket launchers; 4.5-inch barrage rockets;     total rocket load: 550 rounds

LCI(M):

1	40mm single-mount or 20mm machine gun forward
4	20mm machine guns
3	4. 2-inch chemical mortars;     total mortar load: 1,200 rounds WP and HE

LCI(R) with troop-carrier allowance:

1	40mm single-mount machine gun forward
4	20mm machine guns
6	5-inch aircraft rocket launchers; Mk 51 and Mk 30; 144 rounds spin-stabilized (SSR); 72 rounds fin-stabilized (FSR)

LCI(R) with gunboat allowance:

1	40mm single-mount machine gun forward
4	20mm machine guns
6	5-inch rocket launchers: MK 51 and MK 30; 1,700 rounds spin-stabilized (SSR); 1,100 rounds fin-stabilized (FSR)

LCM(3) Woof us rocket craft:

1	120 rail launchers, 7. 2-inch demolition rockets

55. Maximum Ordinate and Angle of Fall Tables.--Figures 12 to 26, which follow, are maximum ordinate and angle of fail tables. They are self-explanatory.

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Figure 12.

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Figure 13.

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Figure 14.

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Figure 15.

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Figure 16.

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Figure 17.

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Figure 18.

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Figure 19.

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Figure 20.

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Figure 21.

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Figure 22.

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Figure 23.

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Figure 24.

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Figure 25.

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Figure 26.

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56. Clearance Tables.--a. In using the tables which follow, the user must:

1. Determine the range from the firing ship to the target.

2. Determine the distance from the target to the point to be checked for trajectory clearance. (Spotter's position or any hill mark in the line of fire.)

3. Subtract 200 yards from the distance in paragraph (2) above for safety.

4. Using the clearance table for the size gun, weight of projectile, and initial velocity being used, enter the curve nearest in value to the distance computed in paragraph (3) above.

5. Read the weight of trajectory in feet on the abscissa of the graph where the range line and the distance curve intersect. Then, subtract the elevation of the point to be checked from the height of trajectory as read from the graph; the resulting value is the distance in feet the trajectory clears the point in question.

2. The curves which are included in figures 27 to 33 are self-explanatory.

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Figure 27.

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Figure 28.

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Figure 29.

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Figure 30.

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Figure 31.

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Figure 32.

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Figure 33.

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