Prepositioning: Getting There First’est with the Most’est
By John M. Collins
The U.S. National Military Strategy demands abilities to employ sufficient forces of the right kinds at the right times and places to protect U.S. interests wherever threats arise—a large order, given the proliferation of perceived trouble spots and declining U.S. military presence overseas. A comprehensive Mobility Requirements Study in 1992 estimated what mix of long-haul airlift and sealift, plus heavy weapons, equipment, and supplies prepositioned around the world, would best yield a “moderate-risk . . .strategically prudent force that is fiscally responsible.” Major refinements followed in March 1995.1
Prepositioning forward-deployed war reserves afloat and ashore has become a major part of U.S. strategy, but some issues remain to be resolved.
A Prepositioning Primer. Cost-effective crisis response capabilities cannot rely excessively on airlift, which is fast but expensive, or on sealift, which is relatively frugal but slow. Prepositioning concepts call for lightly armed and equipped personnel to arrive in operational areas by air, where they rendezvous with the wherewithal they need to reinforce troops already in place or to establish a presence. Subsequent expansion, if essential, depends primarily on sealift.2
Prepositioning ashore is most appropriate within or near a few high-priority problem areas. Attendant preparations, tailored to fit potential contingencies, inform friends and foes alike of intent to protect the interests of possessors and allies against aggression. Prerequisites include climate-controlled warehouses and one or more air terminals of sufficient capacity to accommodate predetermined rapid-reaction forces. Host-nation approval is enhanced when sponsors and recipients perceive similar threats, but logistic support varies. Hosts may oppose the use of prepositioning for emergencies elsewhere and, even if they agree, benefits would be offset by increased cost and transit times.
Prepositioning afloat, which is not optimized for any given contingency, avoids some of the deficiencies just described, and thereby benefits from enhanced flexibility. Prepositioning ships that are based in foreign ports where treaties or other formal agreements define basing rights may leave without host country permission and proceed through international waters wherever and whenever directed, before full-blown crises develop if desired. Ships sometimes may reduce vulnerabilities by maneuvering out of harm’s way and the cargoes they carry may be tailored to satisfy requirements in more than one theater.
Prepositioning afloat nevertheless exhibits significant shortcomings. Optimum locations are not always available. Thailand, for example, recently rebuffed U.S. requests to anchor or moor in its territorial waters, midway between Diego Garcia and Guam, where squadrons presently are stationed. Table 1 reflects the effects.
The most expeditious link-up of airlifted forces with forward-deployed cargoes on board ships demands an adequate seaport in addition to one or more airfields—a scarce combination in many potential trouble spots; few open beaches are collocated with international air terminals and requisite land routes. Costs ordinarily are higher than for stocks prepositioned ashore, partly because prepositioning ships normally are under way at least 25% of the time, rather than in port or at anchorage. This percentage reflects security concerns and the requirement to steam to overhaul facilities periodically to maintain the on-board equipment: proximity to salt water increases maintenance requirements.
Prepositioned assets ashore and afloat share several characteristics. High-density, oversized, relatively low-maintenance stocks such as tanks, artillery, tracks, engineering gear, munitions, fuel, meals-ready-to-eat, and general supplies are well suited for long-term storage. Light aircraft, sensitive electronics, and perishables are not. Units for which they are earmarked must train with duplicate items, which adds to the expense. Prepositioned weapons, equipment, and supplies constitute high-priority targets that require protection against theft or attack.
Transfer points where airlifted personnel collect prepositioned stocks and prepare for action must occupy benign territory or lie within a previously secured perimeter, because such forces are vulnerable until joined with their gear.
Army and Marine Corps Prepositioning Programs. All the U.S. armed services and the Defense Logistics Agency (DLA) preposition stocks overseas. Locations as of December 1995 reflect the preponderance of Army-Marine Corps prepositioning and the importance of U.S. interests in Southwest Asia. (See Table 2.)
Table 1 | ||||
From: Afloat Prepo Locations | To Kuwait | To Korea | ||
Nautical Miles | Days | Nautical Miles | Days | |
Diego Garcia | 3,080 | 8.0 | 4,830 | 12.6 |
Guam | 7,500 | 19.5 | 1,600 | 4.2 |
Bangkok | 4,950 | 12.9 | 2,600 | 6.8 |
Composite capabilities are complementary rather than redundant, in accord with respective responsibilities assigned to each service by Title 10, United States Code. The Air Force, in response to lessons learned during Operation Desert Storm, has modified its mix of prepositioned munitions to improve aerial combat power at the onset of armed conflict. Navy-Marine Corps components are flexible enough to handle low-intensity conflicts near sea coasts and, in most anticipated situations, seem strong enough to “hold the door open” until reinforcements arrive if armed conflict escalates. Armor-heavy Army prepositioning packs a powerful wallop and contains the foundation for a theater-wide logistic base able to sustain land combat during a major regional contingency.3
Table 2 | |||||
Ashore | Army | Navy | Marines | Air Force | DLA |
West Europe | X |
|
| X | 50 million POL barrels at 400 terminals around the world |
Italy | X |
|
| X | |
Norway |
|
| X |
| |
Korea | X |
|
| X | |
SW Asia | X |
|
| X | |
Afloat |
|
|
|
|
|
Diego Garcia | 9 ships | 1 ship | 5 ships | 2 ships | 2 tankers |
Guam/Saipan | 5 ships |
| 4 ships |
| 1 tanker |
Mediterranean |
|
| 4 ships | 1 ship |
|
Prepositioning Ashore. These programs have been intended primarily for use by Army armored and mechanized brigades. The 1961 Berlin Crisis prompted the establishment of Prepositioned Overseas Material Configured to Unit Sets (POMCUS), which—at the Cold War’s peak—provided for three divisions plus support in Germany. Sets for four brigades remain, although critics consider them almost anachronistic, as the stocks deployed in Norway for a U.S. Marine Expeditionary Brigade (MEB) that originally was to help defend NATO’s north flank against a Soviet invasion. Most agree that Army heavy brigade sets prepositioned in Korea, Italy, and Kuwait currently are more relevant. Qatar has agreed to accept another set; funding negotiations are in progress. A third set for Southwest Asia, sited in the United Arab Emirates, soon will help deter rash moves by Iraq or Iran.
Prepositioning Afloat. These programs assumed a high priority in 1980, soon after the Defense Department formed a Rapid Deployment Joint Task Force in response to perceived Soviet threats throughout Southwest Asia. The resultant Near-Term Prepositioning Force (NTPF) suffered from significant deficiencies. The ships lacked temperature and humidity controls, and could neither use shallow- water ports nor unload in the stream.
Thirteen Maritime Prepositioning Ships (MPSs), leased until 2009-2011, presently correct most of those shortcomings. A five-ship squadron, plus a sixth ship with fleet hospital gear on board, calls Diego Garcia home. One four-ship squadron is based at Guam- Saipan, and another roams the Mediterranean. Each squadron is prepared to outfit tailored Marine formations up to and including a 17,300-man Marine Air- Ground Task Force (MAGTF), which it can sustain for 30 days with rations, ammunition, petroleum, oil, and lubricants (POL), repair parts, potable water, and general supplies. A Naval Support Element—1,193 strong—provides pierside and in-stream offloading services as well as beach survey, obstacle clearance, and anti-swimmer defense.
MPS is by no means perfect. Five of the six Navy cargo-handling battalions needed to unload prepositioning ships for a full MAGTF reside in the Naval Reserve, and thus may not be available for crises that erupt unexpectedly. Port-opening capabilities also are modest.
The Navy, Marine Corps, and relevant commanders-in-chief have validated requirements for three additional MPS ships, one per squadron, each bearing a naval mobile construction battalion (SeaBee), equipment to establish a fleet hospital ashore, and an expeditionary airfield (runway matting, approach apparatus, lighting, arresting gear, prepackaged control, supply, and maintenance facilities). Those assets are in the current inventory, but must rely on expensive airlift or slow sealift for transportation until three more prepositioning ships enter the inventory. Congress funded one in fiscal year 1995 and may fund another in fiscal year 1996.
Prompted by the Mobility Requirements Study, the Army established an interim Army Prepositioned Afloat (APA) program in November 1993. No arms or equipment had to be purchased, because all became surplus during the post-Cold War drawdown in Europe; 123 M1A1 tanks, 154 Bradley fighting vehicles, 100 armored personnel carriers, 24 self-propelled 155-mm howitzers, nine Multiple Launch Rocket Systems (MLRS)—enough for a heavy combat brigade—and 15 days of essential supplies were loaded on board five refurbished roll-on/roll- off (RO-RO) ships retrieved from the Maritime Administration’s Ready Reserve Fleet.
They are moored at Diego Garcia, together with a heavy-lift prepositioning ship, sometimes called float-on/float-off (FLO-FLO), for port operations (its cargo includes tug boats, landing craft, a 100- ton floating crane, heavy-duty tractors and forklifts, plus other gear for a port construction- and a terminal-service battalion. Three lighter-aboard-ship (LASH) vessels, also at Diego Garcia, are loaded mainly with munitions. The trio, when augmented by five ships from Guam, contains sufficient supplies for a three- division contingency corps to sustain combat operations 100-150 miles inland for 30 days while normal logistic pipelines are established.
The APA package, known as Army War Reserve Three (AWR-3), is scheduled to expand to a 14-16 ship force by fiscal year 1999. Eight new large medium-speed (24-knots) RO/ROs will replace the aging seven now in service, increasing storage space from 807,000 to 2,000,000 square feet. A second heavy- lift prepositioning ship will be acquired for port operations, while capabilities to receive and support follow-on forces from the United States and Europe will improve commensurately.
Command and control arrangements, local security, and maintenance requirements for prepositioned stocks create some contentious issues.
The Secretary of Defense, advised by the Chairman of the Joint Chiefs of Staff, relevant commanders-in-chief (CinCs) of combatant commands, and each military service, determines how much of what should be prepositioned where. He also controls where and when prepositioning is appropriate. That system seems to work reasonably well, according to all concerned (for dissenting views, see end note 2, RAND, pages 24-27).
All treat prepositioning stocks ashore no differently than other forces assigned to the CinCs. The main issue concerns responsibility for prepositioning stocks afloat prior to employment. The Army, in sharp contrast with the Joint Staff and the other services, believes that such stocks should be controlled by service secretaries to carry out military department functions, rather than be assigned to any given CinC, reasoning that the afloat stocks are configured for use worldwide. Abilities of service secretaries to manage such forces, however, are debatable.
Prepositioned stocks are apt to be prime targets before they can be picked up by U.S. troops airlifted from afar. Shore stocks are sitting ducks susceptible to air, missile, and ground attacks, as are high-value ports, airfields, and marshalling areas where troops and equipment must link up. Unarmed prepositioning ships, vulnerable at home ports and while en route to operational areas, rely on naval escorts for protection. Some observers question whether present safeguards ashore and afloat are sufficient to secure prepositioned stocks against military, paramilitary, special operations, and terrorist assaults.
The Military Sealift Command maintains all prepositioning ships. The Army Materiel Command is relieving geographic CinCs of responsibility for maintaining Army stocks ashore and, with contract assistance, maintains most Army afloat equipment at Charleston, South Carolina. Contractors at Blount Island, Florida, maintain most MPS cargoes, while active-duty Marines conduct quality control inspections. Ammunition is moved by railroad to Naval Weapons Station Charleston for rotation and repacking.
These arrangements seem to work reasonably well, according to all concerned. Problems related to rusty munitions and unserviceable supplies have been corrected. Whether separate facilities at Blount Island (leased land) and Charleston (U.S. property) are cost-effective constitutes one serious issue. Whether either facility could handle all prepositioning ships well is another. Congress has requested a Cost and Operational Effectiveness Analysis, which the Joint Staff is scheduled to submit to the Secretary of Defense by April 1996. It will recommend continuation of current relationships or consolidation.4
Official inputs to this report indicate that prepositioning balances between Army and Marines, ashore and afloat, combat forces and support are about right or soon will be, A few questions, nevertheless, may merit exploration:
- Should Sections 162 and 165 of Title 10, United States Code explicitly assign prepositioning responsibilities to CinCs and/or service secretaries?
- Do present and projected threats justify planned expansions of afloat prepositioning programs?
- To what extent would U.S. allies share financial burdens if the United States prepositioned additional heavy brigade sets in Southwest Asia?
- Should prepositioned equipment in Western Europe and Norway be repositioned in places closer to probable needs?
- Are defenses adequate for stocks ashore and afloat? If not, what improvements seem advisable—dedicated security detachments, additional air-missile defenses?
- Would joint capabilities improve significantly if MPS allocated space for some Army fire support and communication units? If so, who should maintain them? Who should pay?
- Should the Army transfer port opening and operation functions and forces to the Navy?
Regardless of answers to these question, U.S. prepositioning programs have expanded and improved remarkably since stocks were stashed ashore at Adana, Turkey, in the 1950s to support Middle East Contingency Plan Swaggerstick. They will continue to enhance military capabilities as long as U.S. planners carefully weigh benefits against liabilities and estimate where the law of diminishing returns is likely to take over.
1 Mobility Requirements Study, Washington, Office of the Chairman, Joint Chiefs of Staff, 23 January 1992, Sections I-IX, not paginated consecutively. Secret, with unclassified Executive Summary, pages 1-6; Mobility Requirements Study Bottom-Up Review Update (Unclassified), March 28, 1995, Sections I-IV, with Appendices A-H (Secret).
2 For additional discussion see David Kassing, Army and Marine Corps Prepositioning Programs: Size and Responsiveness Issues, Santa Monica, California, RAND, April 1995; and Colonel Paul A. Gido, Army and Marine Corps Capabilities, draft Issue Papers, Washington, Commission on Roles and Missions of the Armed Forces, February 15, 1995.
3 Lieutenant Colonel Paul D. Wisniewski, “Dueling Prepo," Armed Forces Journal, September 1994, pages 22-24; General Carl E. Mundy, Jr., “Thunder and Lightning: Joint Littoral Warfare,” and Brigadier General Robert A. Chilcoat, “Army Prepositioning Afloat,” both in Joint Force Quarterly, Spring 1994, page 50 and page 67.
4 For discussion, see Raymond A. Schiable, et al. Army Requirements for a West Coast Containerized Ammunition Port, Afloat Prepositioning Maintenance Facility, and Watercraft Maintenance Facility, Bethesda, Maryland, Logistics Management Institute. September 1993, Chapter 3 and Appendices G, I, M. and R.
Mr. Collins was the Senior Specialist in National Defense at the Congressional Research Service, Washington, D.C., from June 1972 until January 1996. Proceedings published his “Military Options in Bosnia" in August 1995, pages 37-39.
Space Provides Real-Time Combat Identification
By Commander Austin Boyd, U.S. Navy
Marines who embarked last month on board the USS Guam (LPH-9) for an Atlantic Fleet deployment and possible support to peacekeeping operations in Bosnia are equipped with a new global tracking system—the Situational Awareness Beacon with Reply (SABER)—to provide Combat Identification (Combat ID) and reduce fratricide.
Recognizing the need for rapid low-cost solutions to the Combat Identification (Combat ID) problem, the U.S. Navy last year embarked on a new concept to identify positively “friendly” assets. The Office of the Chief of Naval Operations (CNO-N6) and the Naval Space Command have taken the new technology from concept to field-tested hardware in only one year—addressing the need for a Beet-wide system.
A small ultrahigh-frequency (UHF) transceiver, a Global Positioning System receiver, and a simple packaging system enable SABER-equipped platforms to report their positions to a variety of users—automatically or on demand—using UHF satellite communications or line-of-sight transmission. Each user can display his own position and that of every other user on the network, providing a bird’s-eye view of the battle space. By building a variety of concurrent networks, SABER can provide data to many separate shooters and command-and-control nodes, creating an awareness of the battle space never before attained. Combining the platform’s SABER view with SABER data relayed through Link 16 and the Officer-in-Tactical-Command Information Exchange System, improves naval forces weapons planning and delivery capabilities without posing hazards to friendly forces—eliminating the last-minute dependence on traditional Identification Friend-or-Foe (IFF) queries.
The program began in response to the August 1993 Secretary of the Navy war game focus on the lack of combat identification systems across the naval force spectrum. The April 1994 shoot- down of two U.S. Army UH-60 Blackhawk helicopters in northern Iraq accelerated concept development of a UHF-based system. Responding to tasking from the Vice Chairman, Joint Chiefs of Staff, SABER technical development and testing shifted to high gear, culminating in a September 1995 joint service field evaluation. During the All Service Combat ID Evaluation Team ground-to-ground and air-to-ground exercises, 27 air, ground, and surface ship platforms were configured with beacons, antennas, and display devices.
Ground platforms included M1A1 Abrams tanks, M2A2 Bradley fighting vehicles, Marine Corps light armored vehicles, and an Avenger air-defense battery. The Abrams tanks and Bradley vehicles fought daily engagements against Soviet-era T-72 tanks and assorted armored vehicles. Without SABER, the Army crews experienced difficulty identifying the distracters as friendlies—and fired on friendly assets on three occasions. With SABER, the Army crews had a complete picture of the battlefield and successfully distinguished friend from foe with no fratricide events.
Army UH-60A Blackhawks, Navy SH-60B Seahawks, a Marine AV-8B Harrier, and an Air Force C-130 Hercules aircraft participated as airborne test platforms. With SABER, the Blackhawks were able to obtain a complete picture of the armor battle without exposing their positions. The helicopters navigated directly over ground units in simulated and actual low-visibility conditions based on bearings provided by their SABER computer display terminals. Furthermore, the Blackhawks and Seahawks were able to identify one another positively when operating airborne with actual Soviet Hind and Haze helicopters.
Working with their SH-60B Seahawk detachment, the USS Cape St. George (CG-71) and the USS Anzio (CG-68) used SABER for return-to-force operations with no Mode IV IFF, for helicopter navigation to the ship with the ship’s TACAN out of service, and for constant location of the UH-60B helicopter on logistic runs to the beach.
A SABER man-pack was tested in special operations force (SOF) insertion and recovery operations. Flying actual SOF flight profiles, the Blackhawks inserted SABER-equipped teams and then monitored SOF movement from a remote position. The Air Force C-130 served as an on-scene commander to follow the team’s movement in the midst of other battlefield assets.
SABER demonstrated its ability to interoperate with other DoD command-and- control systems—critical to joint operations. Tracks passed to OTCXIS displays on Aegis and to Link 16 on Air Force airborne early warning and control (AWACS) E-3s and Navy E-2Cs gave shooters and the joint task force commander a complete view of the air, ground, and sea battlespace
There were no fratricide events in any SABER-equipped engagements during the September evaluation. The system added an extra dimension of battle space awareness and friendly identification to tanks and helicopters that presently lack any real capability.
The SABER operational evaluation validated a hypothesis: If you know where you are—and you can tell someone—you are less likely to kill friendlies or be targeted yourself as hostile. The development and demonstration effort also proved that combat identification tools can transition from concept to tested hardware rapidly, with great tactical value to warfighters.
Combat identification must receive significant attention in the near term to save lives and equipment. Situational awareness can prevent fratricide, and space support—through concepts such as SABER—can save lives.
Commander Boyd, a naval aviator, is assigned to the Space Plans Division at the Naval Space Command, Dahlgren, Virginia.
Challenge Athena II: Plan Strikes . .. and ’Phone Home
By Lieutenant Commander Edward Engle, U.S. Navy (Retired)
Producing precise strike plans with short turnaround times is a key element in projecting force, but severely restricted communications capabilities at sea have complicated the job for Navy strike mission planners. Project Challenge Athena II has changed things.
Some strike-planning background is in order. During combat, strike planners normally receive target assignments for the next day’s operations from the Air Tasking Order (ATO). During peace, planners normally keep a list of high-priority potential targets as contingencies. The description of these contingency targets will be detailed; more important, planners normally receive a set of mensurated coordinates produced by the Defense Mapping Agency (DMA).
These coordinates, in turn, flow from a precise mapping, charting, and geodesy data base at DMA that is referenced to World Geodetic System 84 (WGS 84)— the agency’s current geodetic model of the earth. The Global Positioning System (GPS) is referenced to this model, which is—most important—a global geoid, referencing all points to a common frame. Unfortunately, the world is full of other data bases, or datums, that apply only to limited, specific regions. Charts that are referenced to many datums and the use of different charts for a single mission require planners to deal with the discontinuities between them.
Worse, some areas of the world were last surveyed in the 19th century. During the Vietnam War, for example, charts covering the Ho Chi Minh Trail in the Steel Tiger operating area of Southeastern Laos were printed by the Air Force Map Service (a precursor to DMA) from French surveys performed in the 1930s and referenced to the local datum. Until the area was mapped into a photogram- metric mathematical data base by the U.S. 7th Air Force at Royal Thai Air Base Nakhon Phanom, errors of up to 600 meters were common.
Coordinates listed on the ATO can be meaningless for precision attacks unless they include the reference datum. Fortunately, for navigational purposes, the errors are small enough that any good fix in the target area will permit attackers to correct and get close to the target.
Whether the target is large (the Republican Guard in Operation Desert Storm) or small (a single tank), a single aiming point must be decided upon to represent either the beginning of long sticks of high-explosive bombs or the impact point for a single precision-guided munition. If the target has significant dimensions and a readily defined axis, e.g., a large building, a bridge, or a runway, attackers probably will be using more than one weapon and must first decide on the bomb fall line—a vector whose origin, orientation, and magnitude are the aim point, azimuth, and length of the bomb stick, respectively.
To derive the vector, planners use large-scale charts—the larger the scale, the better—but even a 1:50,000 topographical chart has a stated accuracy of only 50 meters in the horizontal plane and 20 meters (linear error) in the vertical plane.
Further, there is the effect known as cartographers’ license (DMA refers to it as displacement) which is a DMA-authorized displacement of certain features not to exceed the basic accuracy of the chart, e.g., 50 meters on a 1:50,000 chart, to make the features legible. Consider Rand McNally’s problem in showing road and a railroad running alongside a river on a map—the man-made features will be larger than scale. The lesson: don’t use a map like this to plan a mission.
Finally, there are the errors associated with the original survey from which the chart was derived and the difference between the datum to which it is referenced and WGS-84. These kinds of errors are significant enough that planners cannot use such charts to establish a vector and an aim point for conventional weapons. What to do?
Access to a computer terminal linked to an imagery database at some distant command would be a start. An image of the target, perhaps recent enough to look the way it does now, might help—but only if it contains the vector decided upon; if it does not, it will not solve our problem because it is nonlinear and cannot be used to make measurements.
What planners really need is primary imagery, which contains the support data necessary to perform geolocation and mensuration. Such imagery is voluminous and could not be sent to ships at sea until recently because the communications have not been available.
Challenge Athena II was designed to demonstrate that primary imagery can be delivered to the afloat strike planner with today’s technology. Given this capability, we can derive aim-point coordinates and a vector. An accurate measurement of the aim-point’s altitude above sea level is required but will be ignored here for the sake of brevity.
Planners must look back along the vector—using either an overview of the primary image or an appropriate chart—about 10-16 miles for a significant natural feature that can serve as an initial point (IP). The significance of this point cannot be over-estimated. It is not only the point which ensures we are lined up with the vector, but it is the point at which air crews accelerate to attack speed, arm weapons, and commit to an attack.
To increase confidence in finding the target, it is a good idea to locate features in the neighborhood of the target that can almost certainly be found in flight. These offset aim points (OAPs) permit air crews to execute an attack by offset bombing even if they are unable to locate the target.
If for any reason forced to attack from another direction, planners may have to identify new OAPs visible on the new run-in heading. Such changes typically happen late in the planning cycle when insufficient time is available to query a remote data base; if the primary image is still at hand, any changes can be accommodated quickly.
The data provided with primary images can support geolocations to within hundreds of meters with respect to WGS-84. Those same data, however, will support measurements between different points on the image at accuracies within one meter; offset aim points are not located with geocoordinates but by their range, bearing, and differential altitude from the target aim point itself.
Once air crews pass the IP, locate the first OAP using sensors, and update the navigation-attack computer, they have in effect shifted to a grid referenced to the target aim point’s coordinates measured from the primary image. Chances are, they will be unaware of the shift; once they have completed the update, the computer calculates a release point based on the relative measurements made of the OAPs—not the absolute position of the target aim point. Of course, this is just as true if the sensor is an eye and the computer a brain.
What this all boils down to is that planners need access to the primary image. Challenge Athena II has filled that need—at least for Carrier Air Wing (CVW)-7, embarked on board the USS George Washington (CVN-73) during her maiden deployment to Europe and the Middle East (May-November 1994).
Challenge Athena II is the imagery delivery demonstration follow-on to Challenge Athena I, which proved the concept of using commercial satellite communications to deliver primary imagery to an aircraft carrier at sea. The Chief of Naval Operations sponsored Challenge Athena II, and the Operational Support Office was the lead office for systems engineering and integration. The project ship was, once again, the George Washington. This time, however, the installed system had a transmitter and incorporated a multiplexed wave form that carried many services.
Beginning last year, the Navy component of the Joint Service Imagery Processing System (JSIPS-N) began supporting strike mission planning on board the George Washington and the USS Carl Vinson (CVN-70). The necessary input imagery in near real time is provided by the reliable, affordable, wide-band communications system whose connectivity was demonstrated during Challenge Athena II on the George Washington's first operational deployment.
Limited space on board ship dictates small antennas, which can accommodate data rates of only 128 to 256 kilobytes per second from the Defense Satellite Communications Service (DSCS)—and most of that is dedicated to essential command-and-control traffic. Ultrahigh-frequency satellite communications, used extensively by the Navy, cannot support wide-band communications—1.544 megabytes per second.
The U.S. Navy recently turned to the commercial International Maritime Satellite (InMarSat) system to provide its ships with commercial telephones. Unfortunately, this service is expensive and can provide only four telephone circuits. Challenge Athena II replaced the InMarSat system scheduled for the George Washington with a 2.4-meter stabilized, commercial C-Band microwave antenna and transceiver. To provide adequate power to the dish, the Navy leased an entire 36 mega-Hertz transponder from the COMSAT with a global beam to eliminate the need to track the ship; any unit within the satellite’s footprint could have received the same imagery.
Since the volume of primary imagery required to support mission planning and intelligence functions is relatively small, much of the communications capacity can be made available for other uses—which makes the space-segment lease cost- effective. This multiuse concept was designed into the Challenge Athena II architecture.
Figure 1 is an architectural overview. The Naval Communications Detachment at the Naval Operating Base, Norfolk, Virginia, was the telecommunications hub for the entire network. Once multiplexed, the aggregate signal rode another leased line to the satellite earth station at Holmdel, New Jersey. The station provided the duplex communications with the satellite and monitored the quality of the signal coming from the ship. All the equipment was commercially available and proved to be reliable and easily operated and maintained by the ship’s company.
The figure’s lower right-hand corner depicts the services that were multiplexed onto the network with bandwidths allocated to each function selectable by the ship. As the operational situation dictated, services could be added, deleted, increased, or reduced within seconds. The data rates indicate those that were nominally allocated to each service illustrated. Not all services were provided at all times.
The 22 secure telephones were a great improvement over the four-channel InMarSat installations on the other carriers. Not only were there more than five times as many telephones available to conduct official business, but their “804” area codes (Norfolk area) cost the ship only $48 each per month plus long-distance fees.
The ship’s Emergency DSCS Restoral Service refers to the capability of the Timeplex multiplexer to seek bandwidth. Since the Ship’s DSCS circuits were also routed through this multiplexer, the Timeplex had been programmed to take the bandwidth it needed from the Challenge Athena II telephones to restore the DSCS circuits. This was done successfully several times and occurred almost instantaneously.
A ten-telephone service provided two Radio Central Order Wires to enhance satellite tracking, and eight separate lines that the crew could use to “phone home.” Routed into the U.S. Sprint commercial network, these telephones were installed at convenient locations throughout the ship; they could not be dialed from outside, and accepted no money. Charges were deducted from special credit cards sold by the ship’s store for $20. Each card was good for 40 minutes of calling anywhere in the United States. Almost 29,000 cards had been sold by the end of the deployment; calls averaged 1,000 per week.
The Defense Secure Network Version 3 (DSNet-3) Joint Deployable Intelligence support System (JDISS—a secure Internet) circuit offered higher data rates than the DSCS. Further, it was routed through the Army’s Trojan Router at Fort Belvoir, Virginia—a fixed architecture independent of the ship’s operating area. The existing JDISS architecture changes between U.S. Atlantic Command and U.S. European Command, generally causing long outages to complete the switchover.
The DSNet Version 1 (DSNet-1) JDISS was added under the auspices of the Navy’s Tactical Exploitation of National Capabilities (Project Radiant Cirrus) together with a high-quality digitizer to give CVW-7 the capability to send tactical reconnaissance imagery acquired by F-14s to recipients in soft copy in near-real-time—eliminating the requirement to make multiple hard copies in the photographic laboratory and fly them off to a shore site for further distribution. Since Navy F-14s provided the only U.S. tactical reconnaissance asset in the Bosnian theater, this proved an important service for the European Command.
The project had several valuable spin-offs. The Naval Medical Information Management Center installed a 16-bit digitizer and soft-copy system in sick bay that was capable of transmitting X-rays to the Naval Hospital at Bethesda, Maryland, where they could be examined by specialists. The ship transmitted 264 images to Bethesda during the deployment; the capability saved several costly medical evacuations and improved diagnoses.
The ship’s public affairs officer sent imagery to the Chief of Information within hours of the event. A Video Information Exchange System, a Navy-wide network that connects all major Navy commands, enabled the ships to participate in conferences supported by this network.
Challenge Athena II made much of this possible, but there is room for improvement—some of which appears to be on the way.
The antenna that was installed on the George Washington was literally taken off the commercial production line. The antenna feed was connected to the pedestal via a long cable that allowed the ship to make continuous 270° turns in one direction before having to be unwrapped (automatically). This arrangement has proved satisfactory in cruise ships, but it does not work well on carriers that operate in racetrack patterns for flight operations. The current antenna has a slip-ring arrangement that should impose no restrictions on maneuvering.
The more difficult improvement involves suppressing interference caused by AN/SPS-48 and AN/SPY-1 radars during Challenge Athena II. Most capital ships carry the SPS-48; the SPY-1 is the main sensor for Aegis cruisers and destroyers. The Norfolk Naval Shipyard installed a notch filter in the wave guide of the SPS-48 that eliminated the problem entirely without degrading the performance of the radar, but the interference from the SPY-1 has proved a more difficult problem. The Aegis Program Office, the Operational Support Office, and the Joint Spectrum Center are working on the problem, and a solution appears to be in hand.
Operation Desert Storm is only the latest instance to highlight the problems in the system used to disseminate national imagery to deployed units; the same problems have been with us for a long time. Commercial satellite communications are available and capable of providing the relatively large bandwidths required. Once in place, this wide bandwidth capacity can be used for many important things without disrupting mission planning.
Commercially available technology and hardware can be used to accomplish all this reliably—and at costs no higher than units pay today for a small number of telephone lines. To exploit this capability fully, however, the Navy must solve the interference problems between battle group radars and commercial C-Band systems.
Commander Engle is a consultant to the National Reconnaissance Office’s Operational Support Office. He was a bombardier-navigator with VA-165 and VA-52 and flew 300 combat mission during the Vietnam War. He has a Masters in Aeronautical Engineering (Avionics) from the U.S. Naval Postgraduate School, Monterey, California.
Why Didn’t I Slow Down?
By Captain John G. Denham, U.S. Navy (Retired)
A collision at sea can ruin your day, but what takes place afterward ruins a lot of days. The process of resolving a collision between two consenting vessels in the privacy of their own space is complex, prolonged, and expensive. Preparing a case for trial is a monumental and expensive task requiring expert guidance and exceptional ability.
From the anguish and frustration of those involved, a single thought frequently emerges: Why didn’t I slow down?
The procedures that admiralty courts and other agencies undertake to determine the cause of a maritime collision differ in their purposes, each with its own profound effect. Normally, the admiralty court is looking for a violation of law (statutory fault) that can be singled out as the prime cause. It simplifies things if some egregious conduct or act can be pinpointed and the blame established. It also helps to determine apportionment of liability—who pays how much to whom—which is the real purpose of the trial. In most cases, the courts are successful in determining at what point the more guilty party exceeded the bounds of good seamanship—and/or violated a law.
U.S. Coast Guard and local pilot authority investigations and hearings, in contrast, are usually remedial and punitive, as documented in a Tulane Law Review article (Volume 58) entitled "Disciplining Maritime Pilots.” Regardless of process, the most important question often remains unanswered—why did the collision occur?
When examining collisions between vessels, several key factors involving all parties are immediately scrutinized:
- Who was directing the movements of the vessel?
- What was the status of lookouts?
- What speeds were involved?
- What action was taken to avoid the collision?
Captain Richard A. Cahill, in his works on seagoing mishaps, characterizes collisions as what occurs when two vessels get too close together. Given this definition, certain questions based on the key factors should be considered:
- When an inbound vessel collides with an outbound fishing boat near a bridge (an obstruction) should not the person directing the movements of the vessel have been aware that fishing boats are normally in that area and may be out of sight until one is almost upon them?
- Upon entering a large body of water, such as a bay, from a narrow channel, should not one expect to encounter pleasure boats, fishing vessels, tugs, and barges?
- Is this not “local knowledge?” Most seagoing vessels are required to have licensed pilots on board when navigating in inland waters. They may be either a ship’s officer with pilotage endorsements or a local pilot employed for a specific movement. In any case, the primary purpose of pilotage is to provide the vessel with local knowledge.
What is the intent of Rule 6 of the Rules of the Road—the rule for speed? Essentially, it dictates that one proceed at a speed no faster than that which permits full control of the vessel at all times. Under most circumstances speed is adjusted by the person directing the movement of the vessel to accommodate current, tide, longshoremen, schedule, etc. Prudent mariners also adjust for vessel traffic. Few collision cases are resolved on the issue of speed alone. Cases involving damage caused by wake and the precursor bow wave created by the vessel’s displacement and speed, however, are legend—and often are very expensive for the guilty party. Rule 6 requires a speed, whether over the ground or through the water, that is safe at that time and place for one’s vessel and all others in the vicinity. Vessels are liable for damage caused to other vessels or property by their movement. Speed, therefore, is intimately related to the immediate circumstances at hand.
The questions of “a proper lookout” and “the lookout” seem frequently to be misunderstood. Unquestionably, as Rule 5 prescribes, there must be a proper lookout at all times when under way, regardless of weather, time, or place. The lookout may be an officer on the bridge or an able seaman in the bow—or where he or she can best fulfill the duties of a lookout. As Captain William P. Crawford states: “ A lookout can’t be just anyone on board. He must be instructed in how to observe and report.” Regardless of who is assigned to be the lookout, the person directing the movement of the vessel also is a lookout to complete the obligation of “by all available means.” The primary purpose of the bridge watch is to maintain “a proper lookout,” and 33 CFR Part 164 paragraph 164.11 of the Navigation Safety Regulations requires everyone on the bridge to be competent in their assigned duties and equipment operation.
In limited visibility all the key players are alerted to the possibility of danger. The master, the officer on watch, whoever is directing the movements of the vessel, the lookout, and maybe a few others are intently involved in proceeding with caution. Great emphasis is placed on complying with the rules for a proper lookout, safe speed, and conduct in restricted visibility. The focus is specific: prevent risk of collision. But what happens when the visibility improves? The lookout relaxes, the watch officer assumes additional duties as the radar observer, the engines are returned to unalerted operation, etc. The emphasis is placed on other things that seem more important than avoiding risk of collision. Why is it so many collisions occur during periods of unrestricted visibility?
One word that appears frequently throughout the Navigation Rules is “doubt.” It is not defined in 33 CFR Part 164, or in the Inland Navigational Rules Act of 1980, or the Senate Report 96-979 that explains the congressional intent of those rules. Webster defines doubt (as a verb) to mean “uncertainty of belief or opinion that often interferes with decision making, distrust.” One should note there is no reference to irritation, frustration, egregious conduct of another vessel, or its status. Doubt means, simply— I am not sure!
The rules provide two instruments to help resolve doubt:
- The bend signal—Rule 34 (e)
- Procedure for determining risk of collision (Rule 7)
Application is simple: If you cannot see around or through an obstacle, let the world know you are there. Blow the horn; get on the radio—and if in doubt whether risk of collision exists, assume it does and act accordingly. The rules also provide a sound signal to announce one’s doubt (Rule 34 [d]).
The act of slowing down to provide time to resolve doubt appears to be an unused tactic in modern-day ship management. If used when doubt initially occurs (as defined above) fewer accidents would occur. Ship management is a subset of seamanship and good seamanship is required by the ordinary practice of seamen (Rule 2).
Consider the following example of the way vessels get close to each other. Vessel A and B come in sight of each other dead ahead at 1 mile, both are on reciprocal courses and have a steady bearing and decreasing range. Consider:
Time Activity
00:00 Vessels are visible to each other
00:12 A sights B
00:18 A watches B
00:24 A is in doubt as to B’s plan
00:36 A calls B on radio/sounds whistle
00:54 B answers radio
01:00 A tells B what he plans to do
01:12 B agrees with A/sounds whistle
01:18 A orders action
01:30 A responds to action
01:42 A’s action is effective
In this typical example the process takes 1 minute and 42 seconds for an alerted and responsive unit (A) to accomplish an effective action. If both vessels are under way at 15 knots they are now very close to each other. How much room is left for any error? Several naval collisions have resulted because of failure to understand this dead time—as detailed by Vice Admiral Harold Hickling, Royal Navy (Retired).
What causes most ship collisions? They get too close to each other because the person directing the movement of the vessel does not recognize that doubt exists and, when he does he hesitates to take the required action to avoid risk of collision. The whistle signal of five short blasts essentially means: “1 AM IN DOUBT.”
Remember: Rule 8.(e)—If necessary to avoid collision or allow more time to assess the situation, a vessel shall slacken her speed or take all way off by stopping or reversing her means of propulsion.
A recent review of a number of standing orders on board U.S. merchant ships produced this gem: “If you have any doubt as to what I mean by ‘Call me if in doubt,’ call me now!”
Captain Denham is a maritime consultant and a licensed Master Mariner, First Class Pilot for the San Francisco Bay area and Puget Sound. He commanded the USS Estero (AKL-5), the USS Ozbourn (DD-846), and the USS Sacramento (AOE-1), and founded the Rules of the Road workshops while a Department Head at the California Maritime Academy. He wrote “Organizing and Managing the Bridge Team,” Proceedings, September 1994, pp. 111-114.