Driving the Aegis Cruiser Postscript
Commander Kevin S. J. Eyer, U.S. Navy
A number of experienced ship drivers contacted me after my December 2002 Proceedings professional note on handling the Aegis cruiser (pp. 70-72). At least one of the comments is worth mentioning here, because the writer was right and I was wrong. I reminded conning officers they should not "shift the rudder" when going from an ahead bell to an astern bell (or vice versa) until the ship has passed through a stop while moving to the other direction-otherwise, the rudder would do the opposite of what they intended.
It was pointed out to me that although this is true in going from ahead to astern, it is less true when going from astern to ahead. In the latter case, the propellers create an immediate and dramatic wash over the rudders that far outweighs the relatively trivial amount of flow generated by ship motion astern. Experimentation proved this to be true. While here, I would like to take another opportunity to pass along additional lessons I learned in my years of driving Aegis cruisers.
Poor Man's Tug
I learned to use a "poor man's tug," which is providing a simulated tug for yourself when you want to get under way without one. To do this, let go the anchor as you breast your ship into a berth. Simply let it go and walk it out, leaving it laying perpendicular to the ship, perhaps 200 feet to seaward. If necessary, this technique enables you to get the ship under way from a tight berth, without tugs, by moving in a perfectly lateral direction.
It is quite easy to use the poor man's tug once it is set up. Order the forecastle to start heaving around on the anchor. In general, let the anchor team drive the pace of the problem; if necessary, you can order the team to "avast heaving" long enough for you to let the stern catch up. As the anchor comes in, the bow naturally will be pulled toward the anchor lying on the bottom, 90° to starboard. To move the stern in this case, execute a port twist. The art lies in how the twist is carried out. I was at Naval Station Newport, Rhode Island, and had a 16-knot, on-setting wind pressing me into the pier, so I ended up using a lot more engine than I might have in benign circumstances. A big, one-third twist worked like a charm. Still, the cruiser will start to move slowly astern in a one-third twist, ultimately increasing to an astern speed of about 1.5 knots. To avoid this, I would periodically increase the speed of my starboard engine to ahead two-thirds.
Twisting on or off a pier using a single tug is more common and even easier. In the past-despite extensive experimentation in simulators-I usually used two every time to minimize risk. Now I think it necessary to practice with one tug because you never know when you will need to get under way or go alongside the pier with only one. When using a tug, it is the stern twist that takes the lead and it is the tug that keeps pace. Of course, the tug always is made up on the bow, because while you can easily move the stern, the bow is just along for the ride. When twisting toward the pier, be gentle. There is no tug on your stern to arrest the ship's motion if she starts moving too quickly. Closely control the stern walk.
When Stop Doesn't Mean Stop
In controllable reversible pitch propulsion systems, when engines are at stop, the propellers still turn at 55 revolutions per minute. The screws continue to turn, but they are at 0% pitch, so their effect is negligible. For various reasons, however, stop seldom results in 0% pitch. During construction (and subsequently during certain maintenance periods), a ship's controls are calibrated to what occurs at the propeller. At that point, stop actually may be 0% pitch. For whatever reason, over time and specific to each ship, the controls' representation of what is occurring typically becomes incorrect. In any number of Aegis cruisers, stop seldom means stop.
It is important to know which particular engine order causes the ship to truly stop. When you bring engines on line while preparing to get the ship under way, actually having minus 10% pitch rung up when you mean to stop may have unintended and ugly consequences. It is essential that the conn knows how to keep the ship still until it is time to go. Just as important, differences of 10%, while appearing trivial on paper, are significant when trying to finesse the ship into a tight spot.
How to Drive Backward
Because of the cruiser hull's twin screws, the ship backs straight, without the stern walk experienced in single-screw ships. Moreover, maneuvering is a much more forgiving task when operating in astern propulsion than when going ahead. Because you are leading with the rudders, there is no propeller wash landing on them. As we know, propeller wash across the rudder face makes the ship turn. While operating astern, it is only the flow of water created by the ship's motion that affects the rudder. This gentle force results in the ship taking longer to be affected when you put the rudder over. Thus, when you give a rudder command, give it early-and do not be shy about it. You will need to use more rudder to get the effect you desire and it will be slower in coming.
For the same reason that it takes more time for the rudder to take effect when moving astern, the effect of a rudder can be terminated almost immediately. In addition, the "lever arm" (distance between rudder and the leading end of the ship) is short. Even if going astern at 5 knots, using a full rudder, the ship will steady almost immediately on a return to "rudder amidships." Unlike ahead bells, there is little if any continuation of swing after you take the rudder off.
Many officers, including me, are uncomfortable driving astern in Aegis cruisers. Because you cannot see either quarter of the ship, let alone the transom, it feels unnatural and you have to give rudder orders in reverse. At the same time, it is much easier to maneuver a ship into a narrow slip while moving astern than while moving ahead. Everything is dampened and that makes it hard for things to get out of control. It just takes practice.
Anyone Notice the Sonar Dome?
It is enormous—and there are several things worth knowing about its effect on your ship-driving problems. First, it is my experience that most pilots who are not intimately familiar with cruiser hulls miss the obvious point that the gigantic dome sticking out in the water will affect ship motion. When working two tugs against the ship—for example, while pushing her into the pier laterally-the bow tug has to work much harder to overcome the resistance of the sonar dome. Second, I discovered the ship's bow moves sluggishly in shallow water. I do not know why, but I observed it twice while getting the ship under way from the pier at Naval Station Rodman, Panama.
As the ship moved away from the pier, a tight turn to starboard was required to pass under the Bridge of the Americas. I had to get under way without tugs and was comfortable in doing so-it looked like an easy evolution and conditions were benign. It took a slight port twist to get the bow away from the pier, followed by a vigorous turn to starboard once clear of the pier head. All went well until I began the 90° turn to starboard—then, nothing seemed to work. Ultimately, we had to execute a two-thirds twist, and even then we turned with agonizing slowness. Once it was over, I studied the tides, currents, and winds, and concluded that having only three feet of water beneath the dome must have been the culprit. The dome generates enormous drag when trying to move the bow, especially in shallow water; you should plan accordingly.
Working the Lines
I am not much of an expert when it comes to working lines. In the Thomas S. Gates (CG-51), we never put the lines over to the pier until we were against the fenders and properly positioned. Then we simply dropped them to the pier. We took in all lines when ready to get under way. And that is about the extent of it. Frankly, I was strongly affected by the old training movie, "Synthetic Line Snapback," and did not want to be in a position where getting alongside depended on putting huge strains on lines. Even so, I am aware that some ships (especially smaller ones) "spring" on lines. They will keep a line to the pier-for example, number 2 line, which tends aft from the forecastle to the pier. If this is the only line left attaching the ship to the pier and a gentle ahead bell is ordered, the bow will fall naturally into the pier and the stern kick out.
My father, who spent his career in a variety of warships no larger than a frigate, considered this to be a bread-and-butter technique. But I have never seen cruisers spring on lines and I do not recommend it. Cruisers are much too heavy and powerful for that. The chances of parting lines far outweighs the potential benefit of kicking out the stern—an effect accomplished more safely in a twin-screw ship by employing a simple twist.
Pilots Come in all Shapes & Sizes
Trust the pilot no more than you would any "expert" who can walk away from a disaster. In any group, skill, experience, and the ability to work with others will vary widely, and such is the case with pilots. The commanding officer (CO)'s eternal dilemma is choosing from these options: Shall I advise the conning officer? Shall the pilot advise the conning officer? Shall we both advise him? The dilemma is complicated by the fact that while the skipper may wish for one thing, the pilot may wish for something entirely different. Also, either the CO or the pilot may be unwilling to have a dialogue that leads to an amicable arrangement. Both tend to have significant egos. I do not know of a solution; neither do several thoughtful pilots I asked about this problem.
Nonetheless, my advice is to remember that the pilot has no responsibility, whereas the skipper has total responsibility. Always bear in mind the pilot knows more than you do about the port and the peculiarities of the environment. he lands ships for a living and you do not. On the other hand, he will seldom, if ever, be as familiar with the peculiarities of your ship as you are. And, because he is human, it is possible his level of concentration may be insufficient to the situation at hand, whereas the CO undoubtedly pays the closest of attention. We all need backups.
Watch the pilot like a hawk. If you feel uncomfortable with what he is doing, ask him. The best solution is for the conning officer to talk to the pilot a lot and get the pilot to explain his or her intentions well in advance. If the conning officer simply talks, it tends to diffuse tensions between the pilot and the CO. We know what the conn is thinking and can guide rather than direct. Above all, I try to remember that my ego and its feeding are less important than safe navigation. I try to cooperate.
Conclusions
Some day, as a ship's CO, you will be in a position where everyone has lost the bubble. It is hard to find a skipper who does not have at least one story of near disaster on the high seas, during which, but for the grace of God, he would have either gone aground or had a collision. I rely on the grace of God daily. But I also think that, although the pilot did not speak English, the conning officer was frozen, dangerous forces were acting on the ship, and God had bigger fish to fry, the reason these captains did not meet with disaster had more to do with their willingness to act than with the Almighty's benevolence.
In my experience, the essence of good ship driving is to act with prudence but firmness, minimi/c risk without being hamstrung by tear, and be willing to try things on the fly to keep the grounding and collision wolves from your door. Try something. If that does not work, try something else. There are countless ways to skin a cat, and I am confident your officers are imagining the possibilities.
Commander Eyer formerly commanded the Thomas S. Gates (CG-51). He is currently the operations officer on the staff of the Commander, Cruiser Destroyer Group Three.
Complexity Science Will Transform Logistics
Major Kelly G. Dobson, U.S. Marine Corps
Among the critical challenges that we face today are finding and allocating resources to recapitalize the Navy." Chief of Naval Operations Admiral Vernon Clark thus described Sea Enterprise, an essential element of "Sea Power 21." He went on to say, "We will make our Navy's business processes more efficient to achieve enhanced warfighting effectiveness in the most cost-effective manner . . . Drawing on lessons from the business revolution, Sea Enterprise will reduce overhead, streamline processes, substitute technology for manpower, and create incentives for positive change."1
One response to the challenge of Sea Enterprise might be to capitalize on previous experience and incrementally improve current Navy business processes. As recent events suggest, however, Sea Enterprise also must develop solutions capable of supporting emerging military tactics. On board the Abraham Lincoln (CVN-72), President George W. Bush noted, "Operation Iraqi Freedom was carried out with a combination of precision and speed. . . . Marines and soldiers charged to Baghdad across 350 miles of hostile ground in one of the swiftest advances of heavy arms in history"2
When discussing the capabilities required to support concepts such as Sea Basing, Vice Admiral Charles Moore, Deputy Chief of Naval Operations for Fleet Readiness and Logistics, and Lieutenant General Edward Hanlon, Commanding General, Marine Corps Combat Development Command, asserted that the future naval logistics enterprise must "leverage information to achieve efficiencies and provide support at the time and place of greatest impact." They emphasized that naval service logistics must shift toward "anticipatory, responsive logistics."3
The challenge of Sea Enterprise asks three questions: How does the supply chain need to change to support a broader range of conflict? What are lessons can be gained from the business revolution? How can these lessons be applied to naval supply to reduce overhead and improve effectiveness?
Lessons from Business
* Complexity Science. This is not a new field of study, but a new approach for studying complex, adaptive systems consisting of numerous, varied, and simultaneously interacting parts. Its goal is to uncover the underlying principles and emergent behavior of complex systems that often are invisible using traditional approaches.
The difference between traditional methods of analysis and complexity science involves a shift in focus and methodology. Traditional methods rely on cause-and-effect analysis: by knowing all the factors that affect a situation, one can predict the outcome. Conversely, complexity science holds that behavior is often unpredictable and analyzing the factors of a situation may not yield the requisite insight. For example, complexity scientists discuss the steering behaviors of birds: each bird maintains separation, alignment, and cohesion with the other birds in the flock. Given these three behaviors, it is not obvious that birds would mass-but they do so as emergent behavior from their steering behavior interactions.
* Agent-Bascd Modeling (ABM). To capitalize on complexity science's insight, scientists and corporations have developed ABM, which uses collections of autonomous decision-making entities called agents. Each agent in the simulation assesses the current situation and makes decisions based on its set of rules. The rules themselves are not the essential product of the simulation; rather, the benefit comes from interactions between agents and the emergent behavior those interactions produce.
To observe emergent behavior requires numerous iterations-many times the number required for traditional simulations-and until recently, there was insufficient computing power to make these multiple simulation runs in a cost-effective manner. Because of recent capabilities and product improvements, analysts can run the simulations hundreds or thousands of times to develop a distribution of emergent behavior for minimal costs. By comparing this behavior to historical data, they validate the accuracy of the model.
The validated model provides something most traditional approaches cannot: the ability to model changes to the system, such as obstacles or bottlenecks, and predict how real system agents would adapt to those changes. This ability changes ABM from a purely analytical tool to a predictive tool. It offers the potential to accurately model the main elements of the naval supply chain, an exceedingly dynamic system with myriad interactions and "workarounds." The ability to extract useful information from agent interactions led Procter and Gamble (P&G) to use ABM tools in an effort to reduce supply chain inventory.
* Procter and Gamble Case Study: An Evolutionary Approach. In 1998, P&G already had achieved a 50% reduction in its inventory and was looking for an additional 25% reduction to help control costs. The company's desire to reduce inventory seemed counter to its need to keep products on store shelves. Using ABM, P&G found that a "seemingly logical policy of sending out only full trucks actually created disruptions along the supply chain . . . [thus resulting in] supermarket shelves that were empty of its key products." Supply chain agents within P&G's ABM recognized this self-induced obstruction and modeled a new, evolutionary approach: let some trucks travel with less than full loads and make delivery times more flexible."4
The proposed solution not only met, but exceeded, predicted results. Having implemented ABM modifications, Procter & Gamble saves $300 million annually on an investment of less than 1% of that amount.5 Although the return in this example is impressive, similar results could well have been attainable by traditional methods and are evolutionary in nature.
* Air Liquide Case Study: A Revolutionary Approach. Air Liquide, a Houston-based industrial gas firm, supplies liquid oxygen, nitrogen, and other gases to 10,000 customers from more than 300 sources through 30 depots, using 200 trucks and 200 trailers. The scope and complexity of Air Liquide's supply chain was daunting, with 3 trillion daily combinations among all its constituent parts; it took 22 fulltime logistics analysts nearly half a day to generate a delivery schedule.
Using ABM, the truck agents found the shortest routes, remembered those routes, compared them with other routes found, optimized shortcuts and compiled new routes from sections of previously optimized routes. Most important, because of the power of ABM, "just one Air Liquide analyst is needed to create daily shipping and production schedules across its numbingly complex supply chain in about two hours."6 Given the proven cost savings and overhead reduction of P&G's efforts and the manpower reduction and adaptive supply chain of Air Liquide, ABM obviously offers key lessons to the naval service.
Military Applications
As an example of a real-time adaptive system, imagine a critical node in an existing supply chain: Naval Air Station (NAS) Sigonella, Italy. When a ship currently deploys to the Mediterranean, she typically leaves an expeditor at NAS Sigonella to rescue frustrated cargo and ensure that cargo destined for the ship actually makes it there. Expediters rely on ship-to-shore communications for priorities and a shore-based information system to identify cargo that is inbound or lost en route. The expeditor maintains a list of high-priority cargo that takes precedence over other cargo. While highly effective, the expeditor represents a manpower-intensive workaround to a supply chain problem. In addition, the work of one expeditor may well prove counter to the work of another, which creates inefficiency in the system.
Contrast this with an ABM supply chain that leverages dynamic tracking, where each piece of cargo becomes its own expeditor. Using radio frequency identification (RFID), each small tag retains knowledge of its host's contents, destination, required delivery date, and associated cargo necessary for it to accommodate the end user. (See Figure 1.) Because this data is stored on the RFID tag (rather than a remote system at NAS Sigonella), loss of a facility or system has no effect on the system's ability to deliver cargo. By capturing dynamic tracking data via remote interrogation and feeding it in real time to the ABM, the system constantly optimizes itself, even allowing cargo synchronization with partner cargo en route. This capability alone makes ABM worthwhile, but the new system really shows its strength when something goes wrong.
Imagine that a terrorist bomb detonation shuts down the node and kills or wounds all the expeditors. For a traditional supply chain to respond, news of the bombing must first make its way back to the supply managers, possibly taking hours or days. Armed with knowledge of the lost node, supply managers must determine alternate routes and activate them. Then they must assess the effect of the alternate routes on other nodes and adjust accordingly. One likely result would be the routing of too much cargo through ports with insufficient handling capacity. This would further congest the supply chain, potentially leading to actions by individual supply chain managers that create even more congestion.
Consider the same scenario, using ABM to manage the supply chain. Because of the dispersed nature of ABM, the system would recognize a problem with the NAS Sigonella node before learning of the bomb. Recognizing the effect on cargo in the system, ABM would consider the time-sensitive nature of shipments and automatically reroute critical shipments. Simultaneously, ABM would downgrade the priority of items in the chain that depend on other items unavoidably delayed. Finally, leveraging its predictive nature and emergent behavior analysis capabilities, ABM would anticipate the effect of routing changes on the entire system, preemptively eliminating possible bottlenecks. If cargo is somehow isolated from the master ABM network, it still retains all its destination information.
Turn Supply Chains into Supply Networks
In 1999, retired Marine Lieutenant General Paul Van Riper provided a general perspective on complexity at a national security conference. He reminded the audience, "If you do not cast your net widely and look at places that traditionally Marines wouldn't look, you are not going to find the right answers."7 Using complexity science and agent-based modeling to manage the naval supply chain would be a wide cast of the net.
Proctor and Gamble was so impressed with its supply chain transformation, it renamed it a supply network. The company interpreted "chain" as something that requires handing off in sequence; instead its managers believe the system must operate like a network, where all the parts will interact dynamically.
The payoffs in cost savings and effectiveness from applying this way of thinking about logistics to Sea Enterprise can be huge. By transforming how the military thinks about supply, the naval service has the opportunity to lead the transition to the supply networks needed to support tomorrow's warfighting requirements. Moreover, these techniques could allow leaps across the bounds of traditional service-specific supply lines to the formation of an advanced joint supply network.
1 Adm. Vernon Clark, USN, "Sea Power 21," U.S. Naval Institute Proceedings, October 2002, p. 40.
2 The full text of the President's speech is at www: http://www.washingtonpost.com/wp-dyn/articles/ A2627-2003Mayl.html.
3 VAdm. Charles Moore, USN, and LtGen. Edward Hanlon, USMC, "Sea Basing: Operational Independence for a New Century," U.S. Naval Institute Proceedings, January 2003, p. 82.
4 Gene Bylinsky, "Look Who's Doing R&D," Fortune Industrial Management and Technology Pamphlet (BiosGroup: 27 Nov. 2000), p. 5.
5 G. H. Anthes, "Agents of Change," Computerworld, 27 January 2003. At www.computerworld.com/softwarctopics/erp/story/0,10801,77855.00.html.
6 Thomas Mucha, "The Wisdom of the Anthill," Business 2.0, November 2002. At www.bu.sines.s2.com/articles/mag/print/0.1643.44528.00.html.
7 LtGen. Paul Van Riper, USMC (Ret.), address to the conference on "Preserving National security in a Complex World," Cambridge, MA, 13 September 1999. (Conference summary brochure.)
Major Dobson, a former Commandant of the Marine Corps national fellow with IBM, is the aviation maintenance officer for Marine Tactical Electronic Warfare Squadron 2 at Marine Corps Air Station Cherry Point, North Carolina.
Systems Engineering Contributes to Expeditionary Force Protection
Lieutenant Commander Ronald Higgs, Lieutenant Commander Eric Higgins, Lieutenant Commander Gregory Parkins, Lieutenant Vincent Tionquiao, and Lieutenant Christopher Wells, U.S. Navy
A watch phrase for the advanced degree programs offered at the U.S. Naval Postgraduate School (NPS) is "educate to innovate." One of the newest programs, the systems engineering and analysis (SEA) curriculum, leads to a master of science degree in systems engineering and makes innovation and discovery its theme. (Details on the SEA curriculum are at http:// www.nps.navy.mil/sea.)
The curriculum covers a wide range of material from maritime strategy to applied physics, and includes the requirement for a team of officers to conduct a large crosscampus interdisciplinary study relevant to the Navy's future. Study subjects are selected by the board of advisors to the Wayne E. Meyer Institute of Systems Engineering, which is chaired by the Deputy Chief of Naval Operations for Wartime Requirements (OpNav N7) and composed of other flag officers and distinguished civilians. The board chooses a field that would prove academically challenging and relevant to Department of Defense (DoD) interests and needs.
In 2002, the board selected expeditionary warfare as an area of interest and tasked the Meyer Institute to conduct a bottom-up review. In the first year of this two-year project, a group of students designated as SEA-3 used a system-of-systems (integrated group of systems) approach to engineer an architecture with an overarching set of requirements for conducting expeditionary operations in littoral regions, exploring interfaces and system interactions, and comparing current, proposed, and conceptual sea-based platforms against these requirements. The SEA-3 group also completed excursions to examine the effects of speed, reduced footprints ashore, sea basing, modularity of design, and reduced manning in the execution of ship-to-objective maneuver (STOM) operations.
As part of its final report, the group recommended areas of additional study. Its recommendations were intended to describe areas where further study could enhance the understanding of expeditionary warfare from a system-of-systems perspective and form the basis for the second year's study effort. Based on input from OpNav N7 and the SEA-3 team's recommendations, force protection of the sea base was selected as the best subject for the 2003 follow-on study. Thus, SEA-4 endeavored to develop solutions to problems raised by SEA-3: providing force protection to conceptual sea base and transport assets performing forcedentry STOM operations in support of a Marine expeditionary brigade.
The SEA-4 team also was tasked to work closely with total ship systems engineering students on a littoral combat ship (LCS) design specifically suited to force protection of the sea base. At the same time, the team was to incorporate work completed by students at Singapore's Temasek Defense Systems Institute into a conceptual system-of-systems solution for sea base force protection.
The Process
The 2003 Expeditionary Warfare Force Protection Integrated Project represented the combined efforts of approximately 60 officer and civilian students and 15 faculty members from different NPS departments. The SEA-4 Team integrated those efforts into the final product. It accomplished this with a distinct systems engineering methodology: define the problem, create a scenario, conduct analyses, and use modeling and simulation tools to draw conclusions and determine results.
The systems engineering and management process was used as the primary approach in completing the team's multidisciplinary task. It is an iterative, fourphase process designed for solving complex engineering problems: problem definition, design and analysis, decision making, and implementation. Within each of these phases are several iterative steps.
Defining the problem was the most critical study task. At that stage of the process, the team outlined critical assumptions, identified primary functions of the system, addressed critical issues, assessed the threat environment, and generated system requirements. Survivability was determined to be the most critical factor for assessing the protection of the sea base and its transport assets. Survivability is the measure of all defensive actions; it consists of susceptibility and vulnerability. Survivability can be increased by reducing susceptibility (probability of being hit) and reducing vulnerability (probability of being killed by a hit). Threats to the sea base were reviewed, analyzed, and prioritized. The problem was simplified by generalizing threats in the form of threat categories, and by identifying and aiming force protection efforts at the primary threats identified in the analysis.
Preliminary Analyses
After defining the problem, SEA-4's system design and analysis efforts focused on detailed deterministic modeling of concepts for sensors, search, and weapon engagement. The critical first step in effectively countering any threat is the ability to detect it. Analysis began by assessing the ability of various sensors-radar, light detection and ranging, infrared, and sonar-to detect potential threats. Deterministic models of proposed sensors demonstrated that a distributed sensor network offered greater detection ranges by extending the sensors' horizons and achieving greater target aspects. The analysis also offered insight into which sensors were best at detecting specific threats. For example, the modeled infrared sensor performed better than radar when detecting a high-diving, supersonic, antiship cruise missile. Various threat-sensor pairs were then developed, studied, and analyzed to determine potential detection ranges of the sensors against associated threats.
The search analysis applied search detection models based on area or volume covered through beam spread or field of view for each sensor to determine probabilities of detection for each threat-sensor pair. Probability of detection equations were applied in addition to the detection ranges calculated in the sensor models to provide insight to the type of sensor architecture needed to best protect the sea base. The preliminary analyses identified capability gaps that drove the need for a sensor system capable of detecting threat platforms with ample time to counter those platforms before they reach their weapons' release ranges.
Functional analyses identified the basic functions of deployment, detection, defeat, prevention, and ability to withstand damage as the capabilities required to protect a sea base. Using these factors, the team proposed architectures based on characteristics of force composition, sensor architecture, weapon architecture, and weapon type. Supporting studies from student theses and student faculty teamsincluding those from the Temasek Defense Systems Institute-were the bases for developing these characteristics and associated architectures.
Modeling and Simulation
After completing the preliminary analyses and integrating the applicable sensor and weapon system concepts identified in the individual theses and group projects, SEA-4 began an extensive modeling and simulation phase. Comprehending the complex nature of sea base force protection required the use of several different modeling and simulation tools. The tools initially considered included the Joint Army-Navy Uniform Simulation, Joint Theater Level Simulation, Naval Simulation System (NSS), Enhanced Irreducible Semiautonomous Adaptive Combat Neural Simulation Toolkit (EINSTein), EXTEND, and Microsoft Excel. After completing a detailed risk analysis, the team used NSS, EINSTein, EXTEND, and Microsoft Excel.
To adequately determine relative performance of the proposed architectures developed by the team, a thorough and systematic design of experiments was developed to maximize model runs. The primary characteristics of the proposed architectures were force composition, sensor and weapon architecture, and weapon types. Force composition levels were identified as courses of action (COAs) A and B. COA A was a cruiser-destroyer-based protection force comprised of three guided-missile cruisers (CGs), three guided-missile destroyers (DDGs), three guided-missile frigates, and one nuclearpowered attack submarine. COA B was a littoral combat ship (LCS)-based protection force comprised of one CG, one DDG, 12 LCSs, and one nuclear-powered guided-missile submarine.
Sensor and weapon architectures were point and distributed; weapon types were current and conceptual. Point sensors and weapons were classified as those located in close proximity to the defended assets. Distributed sensors and weapons were classified by their location near the outer edge of the area of operations. Current weapons were defined as weapon systems in current inventories. Conceptual weapons were modeled as those planned for possible use in 2015-2020; they included a free electron laser and higherspeed, longer-range variants of current weapons.
Survivability was determined to be the key function in sea base force protection. The primary measure of effectiveness was determined to be survivability of the sea base and its transport assets, and the output of each model was designed to facilitate collection of the information needed to determine that survivability.
A process-based, discrete-event modcling and simulation tool, EXTEND, provided a macroview of sensor, weapon, and threat interactions. Results from the EXTEND model demonstrated that submarine-launched torpedoes were by far the highest threat to the sea base. Torpedoes, which in this model made up approximately 10% of the threat, caused approximately 90% of the mission kills. (See Figure 1.)
The NSS, an object-oriented Monte Carlo modeling and simulation tool, provided a means of analyzing the characteristics of the two proposed force protection architectures. The model results showed that distributed architecture provides improved survivability for defending assets placed along the threat axis. They revealed that the distributed architecture facilitated a quicker reduction of threats. Further, the NSS model showed that distributed architecture is more effective in its use of weapons because of its ability to provide better targeting information and more effective threatweapon assignments. Finally, the distributed architecture was more often able to detect and defeat threat platforms before they could launch their weapons.
Conclusions
* Distributed sensor and weapon architectures improve force survivability by providing increased available reaction times and more engagement opportunities. These architectures are particularly effective against undersea warfare threats because submarines can be detected and engaged prior to closing within effective torpedo ranges. Limited torpedo defense capabilities were identified as the primary cause of mission kills in the point sensor architecture.
* When paired with distributed sensors, conceptual weapons improve survivability by increasing available reaction time. Detecting threats at greater ranges provides commanders with more time to evaluate threats before committing weapons.
* Distributed architecture conserves weapons by detecting targets at ranges close to the maximum range of the interceptor. Longer detection ranges, in conjunction with increased maximum ranges of conceptual weapons, allow threat platforms to be engaged before they can launch their weapons. For example, if an aircraft capable of launching four antiship cruise missiles is destroyed before launching those missiles, only one interceptor is used instead of four. Also, the greater reaction time provided by distributed sensors permits improved targeting, which contributes to weapon conservation.
* The selected cruiser-destroyer-based force compositions and LCS-based force compositions were equivalent tactically. Ultimately, however, other measures of effectiveness-such as manning and lifecycle costs-will be necessary in selecting the preferred concept.
Additional findings and details regarding the recommended architecture are available at http://www.nps.navy.mil/SEA/ SeaBaseDefense/. Figure 2 summarizes the conceptual solution for sea base force protection.
Recommendations
Because the SEA-4 analysis had a broad scope, its results were equally broad-based. Further study efforts should be conducted to provide more thorough analyses of the following areas:
* Reliability and maintainability of the proposed architecture
* Acquisition strategies, deployment timelines, and associated trade-offs
* Current classified systems and emerging technologies
* Nonlethal weapon technologies
Lieutenant Commanders Higgs and Higgins are aerospace engineering duly officers; Lieutenant Commander Parkins is a SEAL; Lieutenant Tionquiao is an information professional; and Lieutenant Wells is a surface warfare officer. They graduated from the Naval Postgraduate School in December 2003.