The U. S. Navy represents a vital American investment in the security of our nation and the Free World. Within the Navy, America possesses her least vulnerable strategic deterrent system, Polaris. It is the responsibility of the Navy to guard against a large, potentially hostile submarine fleet which poses a grave threat to shipping lifelines; it is also her responsibility to provide a mobile, flexible force to contain limited warfare around the world. Needless to say, in the face of a growing enemy capability, it is essential that the Navy’s ships today and tomorrow reflect the most advanced design and possess the most advanced equipment to carry out their missions successfully. The Bureau of Ships has the responsibility of designing and building these ships.
This article describes our efforts to provide the Navy with the most up-to-date ships possible and describes, in particular, the ships of the 1973 Fleet.
To appraise the Fleet of 1973 realistically, we must consider the length of time it takes to produce a ship and the duration of her useful life. These times, of course, vary with the type of ship but from four to six years from feasibility study to operational status, and a 20-year life, are realistic figures. Obviously, a large percentage of the ships of 1973 are at least on the drawing board today. Radical departures in total ship design usually involve several additional years of research and development, model testing, and perhaps even an experimental ship before feasibility studies can begin on an operational prototype. The inference is that investigations must begin today on a novel approach if a ship incorporating that approach in her design is to be operational by 1973. Exceptions could occur, especially if expedited on a crash basis as was the Polaris program, but under normal conditions, the stated timetable will be the rule.
A study of our ship programming lends itself to the following form of analysis: First, a description of the new ships coming into the Navy today, their improvements over past similar types and the trends in design which allow some extrapolation into the future. Second, an investigation of various general systematic attempts to design more effective ships. And finally, a discussion of new and fundamentally different ship forms.
Of necessity, much important work in the Bureau of Ships will not be mentioned. Our emphasis will be placed on systems and whole ship concepts, rather than on specific weapons and equipment.
New Ships in the 1963 Navy
Six ship-type categories require analysis because of their present and future significance: carriers, destroyer-types, submarines, amphibious-types, auxiliary ships, and experimental ships. Not all ship-types will be mentioned, but representative developments and type trends have been included.
Carriers
The last ten years have seen the building or authorization of nine modern attack carriers —eight of the Forrestal-class, and the nuclear- powered Enterprise. Because aircraft weight and landing speed have not increased recently, the carrier is the only combatant ship that has stayed the same size, discounting Enterprise. The external appearance of the Forrestals is deceiving, since the latest ship, CVA-67, will incorporate many features not found in the early carriers of this class. For example, the high capacity communications system (HICAP COM), the Naval Tactical Data System (NTDS), and an automatic landing system have been installed.
Two twin missile launchers will provide added antiaircraft protection, and an improved radar will greatly extend the search range over that of earlier versions. Improvements also include greater aviation ammunition and fuel capacity and an improved handling system for stores and ammunition.
Destroyer Types
The guided missile destroyer (DDG) retains the versatility of the World War II destroyer, but is about a third again as large. She has antiair, antisubmarine, and antisurface capabilities, with her twin Tartar launcher, two 5-inch, 54-caliber guns, ASROC, torpedoes, and long range sonar.
The latest frigates, in addition to the versatility of the smaller destroyers, have the size, endurance and seakeeping qualities to serve as an effective unit of a carrier strike force. The progressive growth of this type, from the 4,700-ton full-load displacement of USS Mitscher (DL-2) to the 7,950 tons of as yet unnamed DLG-26, is indicative of the increased number, size and complexity of the weapons systems and sensors which have been added over the years. In addition to missiles and conventional armament, the DLG-26 Glass carries a Drone Anti-Submarine Helicopter (DASH), HICAP COM, and NTDS. Three of the 36 frigates now authorized are to be nuclear-powered.
The latest destroyer escorts, the DE-1040 Class and DEG-1, are very nearly double the displacement of World War II DE. They are designed specifically as ASW ships and have bow-mounted sonar, DASH, ASROC, and torpedoes. Pressure-fired boilers and fin stabilization are installed.
Submarines
In no ship have the changes been so revolutionary as in the submarine. Submerged speed and submerged endurance have been greatly increased by the adoption of the Albacore hull form and nuclear propulsion. The attack submarine SSN is now one of our most effective ASW weapons. The external appearance of the Thresher (SSN-593) Class shows the body of the revolutionary hull, with diving planes on the conning tower fairwater, torpedo tubes moved amidships from the bow, and a single propeller. Major improvements over previous boats include significantly increased operating depth, installation of a long range sonar in the bow, and reduction of self noise. Submarine displacements also have increased from 2,360 (Skate) to 2,830 (Skipjack) to 3,750 tons (Thresher).
When the first ballistic missile submarine, George Washington (SSB N-598), departed on her first patrol in November 1960, the nation not only gained an important strategic deterrent but witnessed the culmination of an amazing achievement in ship/weapons system development. Only five years after work had begun on the original concept, an operational unit was joining the Fleet. Three classes of these ships have since been built; the latest, the Lafayette (SSBN-616) Class, with its displacement of 7,000 tons, is larger than any previous submarine. This is the same displacement as the DLG-16 Class frigate. The SSBN has many of the characteristics of the SSN including torpedo arrangement and deep diving capability. At this writing, 39 SSN and 35 SSBN submarines have been authorized.
Future improvement will be concentrated on producing better SSN and SSBN types. This means primarily more quiet operation, deeper diving and improved sonar. These categories are receiving very high priority in the Bureau of Ships Research and Development program. As a first step in designing a deeper diving combatant submarine, a small experimental submarine, USS Dolphin (AGSS- 555), is being built. The pressure hull of Dolphin is a cylinder 18 feet in diameter closed with hemispherical heads. Submarine improvements certainly would have been slower and more costly, had it not been for such experimental submarines, as Albacore. Dolphin is expected to provide a similar test vehicle for an economical, yet rapid, experimental program in the exploration of deep depth structure, tactics, components, weapons, and oceanography. Future submarines will not only be able to dive deeper and run more quietly than today’s ships, but also they will probably be bigger and faster.
Amphibious Types
The Navy’s future amphibious force is designed to consist of fast amphibious strike forces employing both vertical and over-the- beach assault techniques. The ships forming the backbone of this force are two new types, the Amphibious Assault Ship (LPH) and the Amphibious Transport, Dock (LPD). These ships will replace the Attack Transport (APA), Attack Cargo Ship (AKA), and Landing Ship, Dock (LSD) of World War II. The LPH, 592 feet in length and displacing 18,000 tons, is designed to embark, transport and land approximately 2,000 Marines and their equipment by means of helicopters. The LPD is similar to the LSD, but has a shortened and covered well whose roof serves as a flight deck. Both landing craft and helicopters can be launched when the ship is underway or stopped. Both the LPH and the LPD carry a balanced load of Marines and their equipment; hence the loss of one ship will not upset the balance of the remaining units of an amphibious strike force.
Auxiliary Ships
The trend in underway replenishment ships is toward bigger, faster, and more versatile ships equipped with automatic materials- handling systems.
The present AE-21 and AE-23 Classes are being converted for the use of the Fast Automatic Shuttle Transfer (FAST) system for faster, yet safer, handling of missiles. This system includes the kingposts, uprights, and rigging by which the missile is delivered from the transferring ship to the missile strike-down system in the receiving ship. There will also be completely mechanized handling of the missiles from stowage to transfer station.
Two new auxiliary types are designed as “one stop” underway replenishment ships, the Combat Store Ship (AFS) and the Fast Combat Support Ship (AOE). The former will replace the AF, the older AFS and Aviation Supply Ship (AVS). She will carry from one-half to two-thirds the provisions carried by the AF and the same amount of general stores and aviation stores as the AKS and AVS. The AFS displaces 17,500 tons (compared to 15,500 tons for the existing AF-48 Class) and uses conveyors, fork-lift trucks, and other mechanized handling and transfer systems to insure rapid movement of supplies internally and to ships alongside.
The AOE is the largest and most powerful auxiliary ship ever built by the Navy. Her 50,000-ton displacement exceeds that of all World War II battleships except the Iowa- class and exceeds that of the AO-143 Class by more than 25 per cent. She is intended to provide a stable replenishment platform under adverse sea conditions. Her high sustained speed allows operation with a fast carrier task force. The cargo of this ship will include more fuel than the latest fleet oilers, one-fourth the ammunition of the AE-21, plus 250 tons of both dry cargo and frozen food. Replenishment can be accomplished at high speed, in heavy weather, and at separations up to 200 feet. Both AOE’s and AFS’s carry helicopters for longer range transfer of limited quantities of stores.
Experimental Ships
A noticeable trend is the growing number of ships whose designators start with “AG.” Some of these experimental ships gather scientific data or support scientific projects, for example, the Oceanographic Research Ship (AGOR), the Surveying Ship (AGS), the Missile Range Instrumentation Ship (AGM), and the Major Communications Relay Ship (AGMR). Others will be used to test various research and development concepts with the expectation that in this way desirable innovations can be introduced rapidly into the shipbuilding program at minimum cost. Among these ships are the Dolphin, described earlier, a Hydrofoil Research Ship (AGEH) which will be described later, and, of course, the Albacore (AGSS-569), now undergoing modification in the fourth phase of her research program. The new program for the Albacore will include an evaluation of contra-rotating propellers.
Finally, an Escort Research Ship (AGDE) will provide a laboratory for improving the ASW features of destroyer escorts, for example, integrated sonar systems, quiet propellers, and advanced propulsion plants. Many more of these valuable experimental ships can be expected in the future.
Bureau of Ships Programs
The design trends cited above have presented the Navy with a serious shipbuilding problem. New and improved equipment, especially electronic gear, has made an ever increasing demand for weight and space, and has required more power, more operating and maintenance personnel and more spare parts than ever before. As has been seen, the result is bigger ships. Hence, the price of a given type of ship is rising not only because more expensive equipment is being put aboard, but also because a larger ship is needed to carry this equipment. Most of the programs described below are designed to ameliorate this condition and at the same time to produce a more effective ship.
Design Work Study
The mushrooming weapons and electronics complex not only presents its own physical requirements, but also demands, for operation and maintenance, a larger ship’s force which, in turn, makes space and weight requirements for berthing, messing, fresh water, and consumables storage. The result is a trend toward larger ships to carry both the modern equipments and the additional men necessary to work them. The Bureau of Ships Design Work Study Program is seeking to combat this situation and to provide ships of minimum complement without reducing the fighting effectiveness of these vessels.
In this program, the various ship systems are examined on the drawing board for possible relocation, elimination, simplification, integration, or automation—the aim always being to reduce the manning level for operation and maintenance. For the first time in ship design, this searching examination for minimum manning is being carried out during the initial design process, and our designs will henceforth include among their specifications the minimum manning required.
Once the most efficient system has been devised with its reduced complement, it is still necessary to insure that, in practice, manpower is used efficiently. Surveys have shown that possibly a third of a sailor’s normal working hours are wasted due to bad management. Hence, the final task of a Design Work Study Program is to establish a Fleet work program and control system.
Co-ordinated Ship Electronic Design
The inclusion of complex electronic systems in ships of the Fleet has been cited as the prime contributor to the problem of ship growth—and indeed it is. Prior to World War II, the cost of electronics equipment and its maintenance was negligible. Today the bill for electronics may be 40 per cent of the total ship cost, and maintenance, several million dollars annually. There have been similar increases in weight, space, power, ventilation, spare parts and manning requirements.
Heretofore, the practice has been to design each piece of equipment individually and have the ship designer fit these “black boxes” into the ship. This is not an impractical method of designing installations for equipment as it existed ten or 20 years ago. At its worst this method might have resulted in ten systems having ten different power sources, ten different ventilation and cooling requirements and ten different sets of spare parts. But the inefficiency and incompatibility produced by this method would obviously be untenable today.
The situation now requires the integration of ship and electronics design, and the Bureau of Ships program of Co-ordinated Ship Electronic Design (CSED) makes this possible by bringing together the naval architect and the electronics engineer at the first stages of the ship design. Problems of electronics equipment location, antenna interference, shock and vibration; and requirements for space, weight, power, cooling and ventilation of the entire electronics complex are considered by the designers in relation to the design of the whole ship. Solutions being considered include integrated antenna arrays, centralized casualty indication, standardization, modular compartments, a central computer and other equipment integrations. For example, the integrated antenna approach embodies in a single concept a combination of stacks and masts to dispose of stack gases without nuisance, while at the same time providing suitable sites for a multiplicity of radar and radio antennas. This solution represents a true marriage in ship design of electronic and naval architectural considerations.
While many problems associated with CSED remain, the Bureau of Ships fully expects that this concept will result in simplified installation, better performance, greater reliability, and easier maintenance, and that CSED will therefore become a way of life in future ship design.
Seahawk Program
The programs described above are well underway. They are excellent attacks on the basic problems, but they are still somewhat limited in scope. A more comprehensive approach has been initiated to resolve the major challenges at the Bureau of Ships and at the Bureau of Naval Weapons. In Project Sea- hawk the goal is to design an ASW destroyer having the maximum feasible operational capabilities at the minimum practicable cost. Seahawk seeks to evolve an integrated ship/ weapons system, engineered as a system from its inception, to optimize ASW features.
Studies have shown that reduction in cost (both initial and recurring) will require a significantly lower manning level. The application here of the design work study principle is obvious. Further, much of the CSED method will be applicable. For example, a central computer is under consideration and equipment will be simplified, integrated, and automated to the extent consistent with the goals of the project. Consideration will be given not only to existing equipment, but also to the feasibility of developing new units in order to maximize the ASW potential. All components, from the smallest up to the main propulsion plant, will be so considered. Most importantly, this ship design concept will be closely integrated with an accelerated research and development program, seeking improved and cohesive ship systems with heavy reliance on prior evaluation of shore based prototypes. The Escort Research Ship, AGDE, will probably be assigned to this project as a test platform for concept development and evaluation.
Main Propulsion Plants
A combatant ship operates for only very short periods at full power. It is, therefore, wasteful of space and weight to carry heavy long life equipment which is seldom used at full capacity. The gas turbine, long recognized for its compactness and light weight, is one prime solution to this problem. Its specific weight is a tenth that of a steam or diesel plant. Unfortunately, its fuel consumption and initial cost have been higher, and periods between major overhauls have been shorter, than for conventional engines. Intense development of the gas turbine for aircraft in the last 15 years has lessened these disadvantages to the point where the gas turbine, if not already in use, is being considered for many prime mover applications.
Hydrofoil and hydroskimmer craft, being highly weight critical, are virtually compelled to employ lightweight gas turbines. In our more conventional ships, valuable weight and space can be saved by using a combined steam and gas turbine (COSAG) or a combined diesel and gas turbine (CODAG) plant. This combination takes advantage of the low fuel consumption and long life of the steam and diesel units for cruising and the compact lightweight gas turbine for infrequently used high speeds.
Further improvements will undoubtedly be made in gas turbines to adapt them to a shipboard, marine environment; and they will certainly be widely used in the ships of 1973, either alone or in COSAG/CODAG plants.
Presently under construction are two destroyer escorts (DE’s 1040 and 1041) which have a 75 per cent increase in shaft horsepower over previous ships, with no increase in the size of the machinery spaces and very slight increase in over-all machinery weight. This has been accomplished by putting the firebox under pressure through the use of a gas turbine supercharger. The great saving in volume is due primarily to the better heat transfer characteristics of the denser gas. Although these DE’s have gained additional power in equal space, it would also be possible to get equal power in considerably reduced space, thus resulting in a smaller and less expensive ship.
How about nuclear propulsion? Why isn’t a nuclear-powered surface fleet being built as rapidly as is our atomic underwater fleet? The nuclear power plant has certainly revolutionized submarine warfare. It has given the submarine a new dimension—it has made possible the true submersible by freeing the submarine from the surface, thus allowing essentially unlimited, high speed, submerged operation.
The benefits to a surface ship are less dramatic. Nevertheless, the advantages are numerous—some 50 times the endurance of conventionally powered ships, virtual freedom from refueling, elimination of stacks, and the ability to satisfy the growing auxiliary power demands for extended range sensors. There is only one serious disadvantage—cost. Over a 20 year lifetime, the nuclear ship would cost about 1.5 times her conventionally powered counterpart, and two nuclear surface ships just cannot do the work of three of the others.
The Navy will continue to build nuclear surface ships. Their numbers will be considerably higher in 1973, and the rate of this changeover will be accelerated when the cost differential is reduced substantially.
The necessity for integrating the design of weapons systems, main propulsion plants, and all other systems and equipment into the hull design, and for the intensification of such systems efforts through work studies such as GSED and project Seahawk is pointing the way toward a revolution in warship design and construction. The ultimate concept will require an organization in which a whole ship —hull, machinery, weapons and sensors—is designed and constructed as a fully integrated effort by a fully integrated team. In fact, the future will bring organizational changes in the Navy Department that will enhance closer teamwork among all who are concerned with any phase of designing a modern man of war.
New Ship Types
We have considered thus far more or less conventional hull forms and attempts to improve performance within these hulls. With the stepped up pace of sea warfare, with the advent of high performance submarines, more effective sensors, missiles, high speed aircraft and nuclear devices, has come a pressing need for a high performance ship which a conventional hull design has not been able to produce.
The principal, but by no means the only, reasons for investigation of unusual hull forms are to obtain increased speed and improved seakeeping qualities. The conventional surface ship rides at the interface between water and air. As a result, her speed is sharply limited by wave resistance, and she is forced to endure the worst of the sea’s motions. It is possible to eliminate both wave resistance and the vehicle’s motion by moving her away from the interface, as in the case of the airplane and submarine. Or resistance and motion can be decreased by a lesser shift away from the surface. The Bureau of Ships has made a wide variety of investigations of many designs along these lines for possible naval application. Hydrofoil Ships
Hydrofoils and hydroskimmers represent two radical departures in hull design aimed at solving the interface problem. Though it is premature to state the role which each of these types will play, both are being examined for possible use as ASW ships, landing craft, minesweepers, and high speed patrol craft. It is entirely likely that the 1973 Navy will have both hydrofoils and hydroskimmers as operational units.
Although the hydrofoil uses “skis” to lift her hull clear of the water, while the hydroskimmer rides just above the surface on a cushion of air, the two have much in common. They have, in comparison to conventional hulls, improved speed and, it is expected, improved seakeeping qualities. On the other hand, they are weight critical, requiring lightweight power plants and structure much akin to aircraft. Both have problems in control, power transmission and propulsion which demand careful investigation.
Our hydrofoil and hydroskimmer programs began during the Fifties. A number of small hydrofoil craft were built to develop the hydrofoil principle, to determine the nature of attendant problems, and to test various hydrofoil configurations. Among the major results of this testing was a decision to concentrate on the completely submerged foil system due to its greater range of control, especially in heavy following seas in which a surface piercing system is liable to stall.
The culmination of the Navy’s early effort was the inclusion in the 1960 shipbuilding program of the PCH, a 115-foot, 110-ton hydrofoil, capable of making 45 knots. The PCH, High Point (PCH-1) was launched in August 1962 and will be delivered to the Navy shortly. She has retractable foils in a canard configuration, with the larger foil area aft, and is stabilized and controlled by an autopilot system (utilizing accelerometers, gyros and an acoustic height sensor) which activates foil flaps. It is powered, foil-borne, by two 3,100 s.h.p. Bristol-Siddeley Proteus gas turbine engines which drive, through right angled gearing, four propellers, one at each end of the two propulsion nacelles at the after strut-foil intersections. The mission of the PCH will be that of a coastal patrol craft. For her ASW work she will carry a retractable, active, low-frequency sonar, a lightweight variable-depth sonar and torpedoes. Additionally, she will be used to evaluate hull and component design and the military capabilities of hydrofoil craft.
The foils of High Point are similar to airfoils. Above a certain speed cavitation occurs, thus decreasing lift and effectively limiting maximum speed for such subcavitating foils to 60 knots in calm water and less in rough water. A new supercavitating foil has been developed which is designed to operate in the presence of the vapor cavity. Although this design results in a smaller lift to drag ratio, it does permit much greater speeds. To demonstrate the feasibility of such foils on a fairly large scale, the Navy has built the recently launched, 15- ton test hydrofoil, Fresh-1, which will be capable of making 100 knots.
The Fresh-1 has a catamaran hull to permit flexibility of foil arrangement. Airplane, tandem and canard configurations with three or four struts will be tested with various loading distributions.
Another ship, the AGEH, a high-speed, oceangoing 320-ton hydrofoil research vessel, is about to start construction. She will be capable of maintaining speed in sea conditions which ordinarily require reducing the speed of conventional ships. The purpose of the AGEH will be to provide information for an optimum design for large oceangoing hydrofoils and to evaluate tactical capabilities of hydrofoil, particularly for ASW. When delivered in late 1964, the AGEH will have subcavitating foils and two gas turbine engines capable of driving her at speeds above 45 knots. Provision has been made for the addition of two more engines and supercavitating foils which will allow speeds of over 70 knots.
The foils of the AGEH will be in an airplane-wing configuration, will retract completely out of the water and will be of the variable incidence type to provide control.
For amphibious warfare, an LCVPH is being built which carries a payload of 8,000 pounds at 40 knots between ship and shore. Her foils and drive shaft are retractable to permit landings. In addition, two Marine Corps amphibious vehicles (LVH) are being constructed, which can proceed inland as wheeled vehicles after retracting their foils and landing.
Hydroskimmers
A hydroskimmer program has evolved in a pattern similar to that of the hydrofoil program. Beginning in 1959 several small test craft were built to investigate various hydroskimmer configuration. Although too small to demonstrate military capability, they were helpful in orienting a research and development program and proved that larger craft could be built with confidence. The 20-ton hydroskimmer, SKMR-1, is now under construction for delivery in June. She will be large enough to permit development of design criteria and specification requirements and will provide guidance as to the military capability of an oceangoing hydroskimmer.
A peripheral air jet curtain in SKMR-1 contains the air cushion, which is segmented longitudinally and transversely to provide stability. Direction control and attitude control are provided respectively by a rudder and by “spoiler” vanes in the air ducts to the jets. Four Solar Saturn gas turbine engines with a 4,320 h.p. output drive the craft. Propulsion is provided by two shrouded air propellers and lift by four fans. The SKMR-1 will fly 18 inches above the water at a speed of 70 knots and will be able to maintain a speed of 50 knots in a State 3 sea. She has a basic flat- bottomed configuration but can be fitted with rigid side skegs or trunks (flexible extensions of the air jet nozzles). All three configurations will be evaluated in the operational unit in order to determine their relative merits.
Present plans call for construction of an oceangoing hydroskimmer of from 150 to 300 tons displacement beginning in Fiscal Year 1965. Again, the configuration of this ship and her mission will be determined in large measure by the results of the SKMR-1 tests.
Advanced Concepts
The hydrofoil and hydroskimmer were attempts to disengage surface ships from the water-air interface. There have been a number of other radical hull designs studied for this purpose. One is the semi-submerged ship, essentially a submarine hull with a strut or superstructure which breaks the surface and carries intakes and exhausts, antennas, and perhaps limited ASW weapons, depending upon the size of the strut. It is very necessary, when considering the semi-submerged ship and other advanced concepts in ship design, to distinguish between technical feasibility and operational desirability or usefulness. The semi-submerged ship is technically feasible; she will have less motion in heavy seas and will be capable of higher speeds than her surface counterpart. On the other hand, she will cost more, carry a smaller payload, and, due to stability considerations, will provide for very limited topside equipment.
In the Bureau of Ships, the Advanced Concept Section has studied many radical ship forms including a spar ship, a submarine tanker, a submarine landing ship, a submerging aircraft carrier and a lens (early experimental ground effects machine) ship. In each case, technical feasibility has been demonstrated but the maximizing of some operational feature generally has led to poorer performance in other areas. The over-all characteristics of these ships, including cost, has ruled against serious consideration of further work on their designs and it is very doubtful if any of these concepts will be in design or under construction in the next ten years.
Nevertheless, the Bureau of Ships will continue to explore every avenue which gives any promise of increasing the effectiveness or decreasing the cost of our ships. Systems concepts will be investigated as will be the advantages of modifying traditional ship design and construction procedures. A vigorous research and development program must continue the vital work of investigating all aspects of ship design and of developing the ships and equipment to meet the challenges of the future.
The Bureau of Ships, in whatever organizational form it may take by 1973, hopefully as a truly comprehensive Ship Bureau, will face that challenge with an open-minded, aggressive and forward looking ship engineering approach that befits its roles as the designer and the builder of the most powerful Navy in the world.