Types of Naval Vessels
3A1. General. The ability of the United Nations to survive the initial offensives of the Axis powers was dependent upon our ability to control the seas and communications across the seas. As the United Nations assume the offensive role, our ability to inflict a final and decisive defeat on the enemy is dependent upon the astounding naval superiority which has been achieved during the period when of necessity our role was defensive one.
By far the greatest navy in the world today is the United States Navy. Since the blow delivered at Pearl Harbor, we have literally raised ourselves by the bootstraps to become the ranking naval power. In the amount of tonnage constructed, in the quality of our ships, and in the diversity of types which we have created, the record is one of unparalleled achievement. The young officer may, with pride and profit, familiarize himself with the ships of this great new Navy.
3A2. Factors in naval construction. In the construction of any ship, certain factors must be considered: (1) armament, (2) armor, (3) speed, (4) seaworthiness, (5) stability, (6) maneuverability, and (7) cruising range.
Armament is the offensive power of a ship. It includes main battery guns, secondary battery guns, antiaircraft guns, torpedoes, depth charges, and such planes as may be used for bombing or strafing. Armor is part of the defensive power of a ship which includes not only the heavy armor plate, protecting the vitals, but also the subdivision of the ship by watertight bulkheads to enable her to continue to fight after absorbing underwater damage. Speed is a function of the proportion of the weight of the ship devoted to propelling machinery. Seaworthiness is, of course, present to some extent in all ships; howeverk, certain ships, such as motor torpedo boats and coastal patrol craft, are not expected to operate in all weather in the open sea, and hence, may be relatively unseaworthy. Stability is a complicated quality involving the ability to resist a force tending to capsize a vessel, the ability to recover from a heavy roll, and the number of degrees to which the ship can roll before she capsizes. Ships with long-range guns must have a slow roll, for instance, so that they will furnish a steady gun platform, while smaller ships may have a "snap roll." Maneuverability includes the ability to change courses and speed rapidly, and the ability to turn in a small radius; it is required, for example, in vessels designed to attack submarines. Cruising range depends on the speed demanded of a ship and on the amount of fuel she can carry.
These qualities are, of course, not independent of each other. A change in speed requirements will affect considerably the cruising range. Heavy armor will reduce the proportion of weight which can be used for machinery and hence, reduce the potential speed of the ship. The designer of every ship tries to incorporate as many of these features as possible, in keeping with the general use to which the particular ship or type of ship will be put. Capital ships, cruisers, and destroyers all represent a compromise in which most of these features are present in varying degrees. Other ships, such as aircraft carriers and submarines, are far more specialized and sacrifice one or more of these qualities for some special function or quality. It is at present impossible to build a ship in which all qualities are combined in the highest degree.
3B1. The battleship (BB). The battleship is built to defeat the most powerful craft that the enemy can take to sea and is expected to combine the greatest amount of offensive and defensive power possible in a single vessel. In the past, it has been considered the principal ship of the fleet and though the aircraft carrier has to some extent challenged the preeminence of the BB, recent battle experience has tended
B. Battleships and Aircraft Carriers
Figure 3-1. A modern battleship (BB).
to show that the two types supplement rather than replace each other as the major units of the modern fleet. The primary consideration in BB design, to which all others are sacrificed in some degree, are (1) armament, and (2) armor.
Armament. These ships carry the heaviest guns afloat. In armament our BB's range from the U.S.S. Arkansas with twelve 12-inch guns to U.S.S. Iowa with nine 16-inch guns in the main battery. The secondary battery of our newer BB's ordinarily consists of twenty 5"/38's used for both surface and air targets, and the antiaircraft armament may include 70 or more guns of various sizes up to 40 mm.
Armor. The importance of armor in BB construction is indicated by the fact that in recent ships 40 percent of the total weight is devoted to armor. The heaviest armor is on the turrets and conning tower, where it reaches 18 inches in thickness. The side armor usually consists of a belt 16 inches thick and 9 feet wide, extending above and below the waterline with its mid-width at the waterline. Protection against high angle fire and aerial bombs is provided by two armored decks. The heavier deck is 6 inches to 8 inches thick, and is called the protective deck. The lighter of the two is about 4 inches thick, and is called the splinter deck. The location of these decks in relation to each other varies in different ships.
Protection is provided against underwater explosion in the protective layer. This layer is formed by subdividing the entire lower hull into compartments, and carrying water, oil, and air in the resulting adjacent compartments; thus the layer is from 17 feet to 25 feet thick. The skin of the ship explodes the torpedo. The air compartments are compressible, and tend to absorb the expanding gases resulting from the explosion. The oil and water compartments take up much of the shock and absorb much of the heat of the explosion, thus reducing its intensity.
Other qualities. The battleship has considerable cruising range and great overall stability to provide a level gun platform. Until recently, the greatest sacrifice has been in speed, but some of our newer BB's are probably capable of doing 35 knots.
Use. Primarily, the BB exists for the purpose of bringing her big guns into contact with the enemy. Despite the great emphasis on protection in a battleship, it is armament and not armor that makes a fighting ship. The BB is a mobile, floating, gun platform, and is built around the guns it carries. Its
protection is provided for the sole purpose of keeping those guns inaction. It is interesting to note that the value of this armament against land targets as well as floating targets has been recognized, and that BB's have participated in recent amphibious operations with great success. During major fleet actions, the BB's form the battle line in the fleet disposition, surrounded by carriers, cruisers, and destroyers. As part of a task force, they add power to hit-and-run raids on enemy positions. They may aid in escorting convoys. The mere presence of a battleship and some smaller vessels may immobilize enemy ships in that particular area. Whether actually in action or merely threatening it, a battleship represents power.
Displacement in tons 27,000-52,000 Length in feet 573-880 Beam in feet 96-108 Draft in feet 26-36 Horsepower/td> 28,000-200,000 Speed in knots 21-35 Complement 1300-2000
3B2. Aircraft carriers (CV, CVL, and CVE). Carriers are a good example of the specialized type of ship which sacrifices in its design some of the usual characteristics required, in order that it may successfully carry out the function for which it was designed. Essentially CV's are seagoing, high-speed landing fields and aircraft bases. Strategically, they are merely warships which strike their blows not through guns or torpedo tubes, but through aircraft capable of great range in comparison to the former.
Structural factors. It has been necessary to create a ship with a large unobstructed flight deck; a hangar deck for plane stowage; large and rapid hoists permitting swift movement of planes from one deck to another; extensive space for repair shops, living quarters, and operational equipment; tanks capable of carrying large quantities of gasoline; extremely powerful engines which will provide the speed necessary for her planes to take off and land. Thus the main emphasis has been on (1) speed, and (2) seaworthiness. It has been necessary to sacrifice: (1) armament (in the sense of guns), (2) armor, (3) compartmentation, and (4) maneuverability (during the period when planes are landing or taking off).
Considerable improvements have recently been made toward protection from underwater damage. It is also true that the CV's have increased their antiaircraft armament. It is still true, however, that they naturally present a large target to the enemy, and that they are burdened with a tremendous fire hazard as a result of their gasoline supplies. Ordinarily they must operate at considerable distances from the enemy, or if this is impossible, must have accompanying cruisers and destroyers for protection.
Types. We have three general classes of carriers, the largest being the CV's including the older U.S.S. Saratoga, U.S.S. Ranger, U.S.S. Enterprise, and the new Essex class. The CVL's including the ships of the Independence class, are built on a long, narrow cruiser hull and are about two-thirds the size of the CV's. The CVE's of the Sangamon andBogue classes are small carriers converted from cargo ships carrying from 20 to 30 planes. The CVE's are used principally for convoy work and have recently achieved spectacular success against enemy submarines.
Displacement in tons 20,000-33,000 Length in feet 769-888 Beam in feet 80-100 Draft in feet 20-25 Horsepower 53,000-180,000 Speed in knots 30-35 Complement 2,000-3,000 Planes 80-100 3C1. The cruiser type. In naval warfare, there must be a numerous class of vessels especially adapted for patrol. They must be fast, of long range, and armed powerfully enough to cope with detached units of the enemy fleet. It happens that vessels which possess these qualifications are also admirably adapted for service with the battle fleet in the following roles: (1) scouts, (2) protective screens against destroyer attacks, (3) leaders of destroyer flotillas, (4) leaders of destroyer attacks against the enemy, (5) antiaircraft screens, (6) aircraft carrier guards, and (7) support for amphibious operations. The vessels
Cruisers and Destroyers
Figure 3-2. An escort carrier (CVE); a fleet carrier (CV).
which fulfill these requirements are the cruisers. They are the general utility ships of the Navy, capable of operating alone or in type groups of several without additional protection, or with the battle fleet itself.
Characteristics. Cruisers are generally ships of from 5,000 to 15,000 tons whose construction emphasises above all (1) speed, (2) long cruising range, and (3) seaworthiness. They are armed with from to to as many as 15 medium caliber guns, in addition to antiaircraft armament, and in some cases torpedo tubes. Modern American cruisers have hangars below decks which can accommodate up to 8 aircraft. The type is divided into heavy and light cruisers solely on the basis of armament, those carrying main battery guns over 6 inches in caliber being classed as heavy, and those with guns of caliber 6 inches and under being classed as light.
Figure 3-3. A heavy cruiser (CA); a light cruiser (CL).
In order to attain the high speeds necessary for the type of operation for which they were designed, cruisers are lightly armored as compared with battleships, belt armor being from 2 inches to 3 inches thick, and rarely exceeding 5 inches in thickness at the maximum point of protection.
The cruiser is particularly important in the present war, because the basic unit with which this war is being fought is the task force. These forces are composed of several cruisers and destroyers, and built around the primary force of one or more aircraft carriers or battleships. It is obvious that the cruiser's qualities make it particularly useful for work of this sort.
3C2. Battle cruisers.There are no battle cruisers in the U.S. Navy today although the type is worthy of discussion. The qualities emphasized in their construction were (1) armament and (2) speed. Their displacement was as great as, or greater than, contemporary battleships, and they carried guns equal in caliber to those of battleships. In order to gain an increase in speed, they sacrificed armor to a great extent and carried fewer guns.
Battle cruisers were originally designed to act as (1) fast scouts in advance of the battle line, or (2) long-range raiders. They were designed to be fast enough to run away from battleships, the only vessels that could harm them. This advantage has not save the battle cruiser, as with increased engineering skill, modern battleships have both armor and speed, and can overtake and overwhelm battle cruisers.
U.S.S. Lexington and U.S.S. Saratoga were originally laid down as battle cruisers, but were later converted to carriers. Nine British battle cruisers were built, including H.M.S. Hood (then the largest warship in the world), and all have been sunk. At present it seems unlikely that this class, in the strict sense of the word will be revived.
3C3. Large cruisers (CB). The large cruisers of the Alaska class are the nearest approach to battle cruisers in our Navy, although the two types should not be confused. Information regarding these ships is not available, but they are reported to displace about 26,500 tons, with a speed in excess of 30 knots and batteries of eight or nine 12-inch guns. The mission of the CB's may not be disclosed at this time.
3C4. Heavy cruisers (CA). These ships perform all the essential duties of their class. They mount nine or ten 8-inch guns and eight or more 5-inch guns in addition to considerable antiaircraft armament. The CA is a match for any enemy except a battleship, and a close range can even engage a battleship where its rapidity of fire will offset the heavier guns of its opponent. Included in the U.S. Navy are the following classes of heavy cruisers: (1) Pensacola, (2) Augusta, (3) Portland, (4) New Orleans, (5) Wichita, and (6) Baltimore.
Displacement in tons 9,000-15,000 Length in feet 585-614+ Beam in feet 61-66 Draft in feet 16-20 Horsepower 100,000-110,000+ Speed in knots 32-35+ Complement 700-1000
3C5. Light cruisers (CL). These ships carry from ten to fifteen 6-inch guns, although the Atlanta class carries sixteen 5-inch guns in the main battery. They carry an augmented antiaircraft battery, and some classes carry six or eighth 12-inch torpedo tubes. Included in this type are probably the fastest cruisers afloat in the world today. We have the following classes of light cruisers: Cleveland, Atlanta, Brooklyn, St. Louis, Omaha.
Displacement in tons 6,000-10,000 Length in feet 541-614+ Beam in feet 52-61 Draft in feet 14-20 Horsepower 75,000-1000,000+ Speed in knots 32-42+ Complement 450-1000
3C6. Destroyers (DD). These ships are designed to be swiftly moving platforms on which to place armament. Basically, they are intended to attack larger ships with torpedoes launched from tubes mounted on deck. Their primary qualities are (1) armament and (2) speed, at the sacrifice of (3) seaworthiness, and, to some extent, stability.
The DD's mount from eight to sixteen 21-inch torpedo tubes as their primary armament. They also carry from five to eight 5-inch guns as well as numerous antiaircraft guns and depth charges which are projected from throwers or dropped from racks.
They are the fastest ships afloat with exceptionally large power plants and no armor protections. Their only protection against larger vessels is their speed and the use of smoke. DD's usually attack at night or through smoke screens in daylight, and are most effective when a number of destroyers make simultaneous attacks from different directions. Cruising range as well as armor have been sacrificed, and the maximum range of a DD at economical speeds is about 6,000 miles.
The duties and uses of DD's are multitudinous and they have at various times included the following: (1) protective screen against enemy submarine, destroyer, or light cruiser attack, (2) striking force against heavy enemy units, (3) for laying down smoke screens, (4) as short-range scouts, (5) as antiaircraft screens, (6) as plane-guards for carriers, (7) as escort ships for convoys, (8) as support for landing operations, and (9) as support for operations conducted by land-based Army units.
Figure 3-4. A modern destroyer (DD); a destroyer escort (DE).
Displacement in tons 1,000-2,100 Length in feet 315-381 Beam in feet 30-36 Draft in feet 9-12 Horsepower 27,000-75,000 Speed in knots 30-? Complement 200-400
3C7. Destroyer escorts (DE). These ships represent the latest development in anti-submarine warfare. They are really small destroyers capable of being turned out rapidly and inexpensively. They are larger, fast, and more maneuverable than any ship previously designed specifically for use against submarines. The DE's are equipped with the most modern scientific developments in detection and ranging devices, and are armed with depth charges, ahead-throwers, 3-inch or 5-inch guns, machine guns up to 40mm., and in some cases triple torpedo tubes. Their mission is solely to escort convoys and to sink submarines.
Displacement in tons 1600 Length in feet 306 Beam in feet 34 Draft in feet 10 Speed in knots 18-? Complement 170 3D1. Submarines (SS). The submarine is a vessel of a very specialized type which has become one of the most important naval weapons in modern warfare. Its principal distinguishing feature is obviously the ability to submerge beneath the surface and disappear from sight. Its prime characteristics, then, may be said to be (1) submersibility, (2) armament (torpedoes), and (3) cruising range.
D. Specialized Combat Vessels
Generally speaking, submarines are classified either as coastal and fleet (oceangoing) submarines. The coastal submarines are vessels up to 800 tons surface displacement, and compare in size and purpose with the German U-boats (750 tons.) They usually mount one 4-inch gun on deck and have 4 or 5 torpedo tubes. While they are called coastal submarines,they are actually oceangoing vessels and can operate for extended periods far from their bases. The fleet submarines are vessels up to 2700 tons displacement and compare in size and purpose with some of the Japanese submarines. They have eight or ten 21-inch torpedo tubes, mount one or more deck guns of a caliber up to 6 inches, and carry antiaircraft guns as well.
When operating on the surface, the submarine is propelled by Diesel engines, and when submerged, by electric motors energized by storage batteries. Since the submarine's structure provides large fuel capacity, the cruising range of these ships is correspondingly great, and in some cases is well over 16,000 miles.
Essentially the purpose of a submarine is to sink enemy surface craft by means of torpedoes. However, the submarine has been found highly valuable in the following ways: (1) as a raider against enemy commerce or enemy warships; (2) as a long-range scout, operating far in advance of the battle line, or lying submerged off enemy harbors to detect activity; and (3) as a minelayer, either on the surface or submerged.
Displacement in tons 530-2700 Length in feet 186-381 Beam in feet 18-33 Draft in feet 12-16 Surface speed in knots 14-20 Submerged speed (max.) 8-11 Complement 33-100
3D2. Motor torpedo boats (PT). The PT is essentially a fighting craft whose characteristics are (1) speed, and (2) armament. It is constructed of plywood, propelled by high-power gasoline engines, and is designed to attack large vessels with torpedoes and to patrol coastal areas. The PT's cruising range at high speeds is about 700 miles. It usually attacks at night at very slow speed so that it cannot be seen
Figure 3-5. Motor torpedo boat (PT); Submarine (SS).
or heard and, after firing its torpedoes, attempts to escape by means of its speed and evasive tactics. It also uses smoke for purposes of deception. The outstanding record of this type in the Pacific and in the Mediterranean is familiar to all.
Displacement in tons 50 Length in feet 70-80 Beam in feet 20 Draft in feet 4 Horsepower 3600
Speed (loaded) in knots 45+ Complement 11
3D3. Anti-submarine vessels. Due to the emphasis placed on the submarine by the enemy, it has been necessary to meet this attack with a large class of vessels whose primary mission is to sink submarines. Both land-based and carrier-based aircraft are playing a role of ever-increasing importance in anti-submarine ware; however, it is our purpose in this section to discuss surface craft which have been developed for this task.
The standard anti-submarine attack by surface craft is made either with stern-dropped depth charges or ahead-thrown projectiles of a somewhat similar nature. This type of attack is carried out against submerged submarines by means of sound gear which enables the attacker to determine the position and movements of the enemy with a fair degree of accuracy. Therefore, the prime requisite is for the surface craft to have maneuverability equal or superior to the submarine. It is also necessary that these ships be sufficiently seaworthy to remain at sea in all conditions of weather while engaged in convoy operations of long duration. The two most important qualities in any vessel designed to combat submarines, then, are (1) maneuverability, and (2) seaworthiness. The destroyer escort which is playing a prominent role in this work has already been discussed.
Corvettes and gunboats (PG). This type has carried a large part of the convoy escort burden since the wear began. The corvettes are mostly Canadian-built and many of the gunboats are converted yachts. In many respects, they are ideal for this duty. Their turning circle is no greater than that of a submarine, they are adequately equipped and armed, and are seaworthy. A typical PG displaces from 1,000 to 2,000 tons, is 230 to 330 feet long, 35 to 40 feet in beam. It has a top speed of about 18 knots and a crew of 100 to 200 men. WIthin this classification there is wide variation in construction and design, and it is not practical to present statistics covering the class as a whole.
Patrol craft (PC). This type is also doing magnificent work in escorting convoys, although the small size of these ships and especially their narrow beam handicap their operations in heavy weather. The PC
Figure 3-6. PC boat.
is 173 feet long, 18 feet in beam, draft of 61/2 feet, with top speed of 17 knots, and complement of about 60 men. It displaces about 400 tons and is equipped with detection and ranging devices and the armament necessary to cope with enemy submarines.
Submarine chasers (SC). The SC is a wooden ship, and is the smallest used effectively in this type of warfare. It is used solely for coastal escort and patrol duty in the Atlantic and Pacific. This class is 110 feet long, 15 feet in beam, about 5 feet in draft, and displaces about 100 tons. Top speed is about 15 knots and the complement is about 30 men. The SC is equipped with the usual anti-submarine gear and armament, and has performed excellent service in its field.
3D4. Landing craft. The strategic positions of the enemy in Europe, in the Pacific land areas, and formerly in North Africa have necessitated that this war in the initial stages of the offensive phase be largely an amphibious operation. We have seen in North Africa, Sicily, Italy, and in the Pacific, amphibious operations on a large scale, and it is probable that we will see other landings of greater proportions and of increasing complexity. The peculiar character of this type of warfare has required the development of many different sorts of landing craft, and there are today more than 40 different types, most of which are small boats that are launched from transports and are used for short runs to the beachhead. We will confine our discussion to four types of large landing craft.
Landing ship, tank (LST). This ship is perhaps the most spectacular development in its general classification. It is really an oceangoing cargo carrier capable of discharging its cargo on any beach over a ramp which extends through closable openings in its bow, or at a dock by means of an elevator from the hold to the main deck.
Tanks, other vehicles, or general cargo are carried in a hold 200 feet long, on either side and outboard of which are compartments in which troops are quartered. It is customary to carry cargo on the main deck as well as in the hold. The armament is primarily defensive in nature and consists of 3-inch or 40 mm. dual-purpose guns and 20 mm. or other antiaircraft guns.
The LST is built not for the purpose of seizing beachheads, but for the purpose of landing its cargo on beachheads already established. In approaching a beach, an LST drops a stern anchor 100 yards or more from the beach and uses this anchor to assist her in making a straight landing, as well as to assist her in coming off the beach after she has discharged her cargo.
Displacement in tons (medium load) 3300 Length in feet 316 Beam in feet 50 (approx.) Mean draft in feet (at sea) 121/2 Draft in feet (landing operations) 3 fwd.-91/2 aft. Speed in knots ? Troop capacity 175 Complement 111
Landing craft, infantry (LCI(L)). These ships are designed primarily to carry troops in to a beach, disembarking them over outboard ramps on both bows. Like the LST's they are oceangoing craft, and have a cruising range of over 4,000 miles. However, because of the limitations of galley, toilet and living accommodations, it is not practical to load troops more than 48 hours away from their destination.
The LCI's have stern anchors for assistance in landing and in leaving the beach. Their equipment is very limited and armament consists only of several antiaircraft machine guns.
Displacement in tons 250 (approx.) Length in feet 153 Beam in feet 23 Draft in feet (at sea) 51/2 Draft in feet (landing) 21/2 fwd.-41/2 aft. Troop capacity 192 Complement 23
Landing craft, tank (LCT). Equipped with a simple ramp bow, LCT's are designed for the transport and landing of tanks and other vehicles. Several different sizes have been developed. The 150-foo type, for instance, will transport 6 tanks, make a speed of 10 or 12 knots, and carries a complement of 28 men and 1 or 2 officers.
Figure 3-7. Landing Craft, Infantry, Large (LCI-L); Landing Ships, Tank (LST)
Figure 8. A mine layer (CM); a minesweeper (AM).
Landing ship, medium (LSM.) LSM's are a new type of landing craft about which little information is as yet available. Somewhat larger than LCT's, they combine features of both LCT's and LST's. In appearance, the bow of an LSM looks like the bow of an LST while the superstructure more closely resembles that of an LCI(L). They serve a function similar to that of the LCT, but are lorger than LCT's, faster and more seaworthy. They are, in fact, oceangoing vessels. An LSM displaces about 725 tons, is slightly over 200 feet in length, has a beam of 34 feet, a complement of more than 50 officers and men, and is defensively armed.
In addition to the four types of landing craft just discussed, there are many other specialized types. Some of the more common designations are LCA( assault), LCS (support), LCM (mechanized), LCV (vehicle), LCP (personnel), LCC (control), and LCD (dock).
3D5. Minecraft. The term minecraft includes a great variety of ships, from specially designed 6000-ton vessels to small converted fishing trawlers. Basically, they consist of two types, (1) minelayers, and (2) minesweepers. The former are used offensively to sow mine fields in waters used by enemy vessels, or defensively to mine our own harbors to prevent enemy raids. Minesweepers are in constant use in wartime to clear areas in which mines are known to be or suspected to have been planted. Though not publicized to any extent, these craft fulfill a very important mission. Along our own coastline they keep regular
channels open and safe for our own shipping and, in more distant theatres of operation, clear the way for landing craft or sweep captured enemy harbors before transports and supply ships make use of them.
Minecraft which operate with the fleet or in hazardous advanced areas must be reasonably fast, seaworthy, and capable of self-defense. Some of our minecraft are especially designed for this type of operation. Others are converted destroyers with torpedo tubes removed and mine-laying racks or sweeping gear installed. For defensive operations along our own coastlines, small wooden ships or converted tugs and fishing vessels are satisfactory.
There are several classes of minecraft in the U.S. Navy. Some of the more common are:
- CM--large ships designed for fleet mine-laying.
- CMc--coastal minelayers, usually converted from small merchant ships.
- DM--Light, fast, fleet minelayers converted from World War I destroyers.
- DMS--light, fast minesweepers converted from old destroyers.
- AM--especially designed fleet minesweepers.
- AMc--small wooden-hulled coastal minesweepers.
- YMS--small minesweepers assigned to navy yards or naval districts.
3D6. Attack Transports (APA). The attack transport is the spearhead of most amphibious operations against an enemy. The Commander of the Amphibious Force making the landings usually designates and uses one of the APA's as his flagship. The attack transport's prime characteristics may be said to be (1) ability to transport and subsist specially trained landing forces of either Army or Marine troops, (2) ability to transport and land all equipment needed by the forces making the landings, (3) large cruising radius to enable development of long-range approach tactics, (4) great overall stability to permit loading and safe transportation of heavy equipment which must be loaded in accordance with tactical and priority-of-discharge considerations rather than stability considerations, (5) ability to stow, maintain, and employ large numbers of small landing craft based on the ship on which the troop elements are transported under battle conditions to the landings on a hostile beach.
The attack transport, in many cases a converted merchantman of design and powerplant susceptible to such conversion, has played a vital part in securing the original beachheads in Africa, Sicily, Italy, and in a great number of enemy-held islands in the Pacific. Their present development is a result of excellent Navy-Marine Corps-Army teamwork in ironing out the intricate problems of the amphibious operation.
Like the BB, this type, having a set duty or task to perform, must be effectively supported in its task by other units of the Fleet--notably CL's, CV's and DD's. They afford protection primarily against submarines and large surface units. Self-protection against air attack is largely assumed by each APA, since they are equipped with a great number of AA guns.
3E1. The train. No fleet could exist as a fighting force without the train. The train is cmposed of the invaluable auxiliary vessels which perform the multitude of tasks necessary to keep the fleet at sea. All the skill and ingenuity demanded of combat ships is required for these ships to carry out the function of keeping warships in repair; supplying them with ammunition, food, and fuel; salvaging damaged vessels; transporting troops; removing wounded from battle areas; and carrying out a multitude of similar tasks. These ships are classified according to their function and the many types may be found in the table in the succeeding paragraph. 3E2. Designating symbols. The following is a table of the symbols used to designate major U.S. naval vessels by type. It includes both combat vessels and auxiliaries.
E. Auxiliaries and Designating Symbols
SYMBOL TYPE OF SHIP AD Destroyer Tender AE Ammunition Ship AF Provision Store Ship AG Auxiliary Miscellaneous AGC Combined operations, Head Communications Ship AGP MTB Tender AGS Survey Ship AH Hospital Ship AK Cargo Ship AKA Cargo Ship, Attack
Figure 3-9. Auxiliary ships. Upper left, cargo ship (AK); upper right, oceangoing tug (AT); lower left, seaplane tender (AV); lower right, transport (AP).
SYMBOL TYPE OF SHIP AKS General Stores Issue Ship AM Minesweeper AMb Harbor Minesweeper AMc Coastal Minesweeper AN Net-laying Ship AO Oiler AOG Gasoline Tanker AP Transport APA Attack Transport APc Coastal Transport APD Destroyer Transport APH Transport for evacuation of wounded APM Mechanized Artillery Transport APR Transport Rescue Vessel APV Aircraft Transport AR Repair Ship ARB Repair Ship--Battle Damage ARD Floating Drydock ARG Repair Ship--Internal Combustion Engine ARH Repair Ship-Heavy Hull ARL Repair Ship for landing craft ARS Salvage Vessel AS Submarine Tender
SYMBOL TYPE OF SHIP ASR Submarine Rescue Vessel AT Oceangoing Tug ATR Rescue Tug AV Seaplane Tender AVD Seaplane Tender, Destroyer AVP Seaplane Tender, Small BB Battleship CA Heavy Cruiser CL Light Cruiser CM Minelayer CMc Minelayer, Coastal CV Aircraft Carrier CVL Aircraft Carrier, Small CVE Aircraft Carrier, Escort DD Destroyer DE Escort Vessel DMS Minesweeper, high speed IX Unclassified vessel LCA Landing Craft, Assault LCC Landing Craft, Control LCI(L) Landing Craft, Infantry (large) LCM Landing Craft, Mechanized LCP Landing Craft, Personnel LCS Landing Craft, Support LCT Landing Craft, Tank LCV Landing Craft, Vehicle LSD Landing Ship, Dock LSM Landing Ship, Medium LST Landing Ship, Tank PC Patrol Craft PCE Patrol Craft, Escort PCS Patrol Craft, Small PE Patrol Craft, Eagle PF Frigate PG Gunboat PT Motor Torpedo Boat PY Yacht PYc Yacht, Coastal SC Subchaser SS Submarine YAG District Auxiliary YFB Ferry Boat YHB Houseboat YMS District Minesweeper YN Net Tender YNT Net Tender Tug YO Fuel Oil Barge YP Patrol Vessel YT Harbor Tug
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