A New course for the Panama Canal

Carroll, James Vincent

Ninety years ago, the United States built the Panama Canal by combining innovative engineering strategies with state-of-the-art technology. Now, on the eve of the Canal’s transfer to the Republic of Panama on 31 December 1999, a prototype GPS (Global Positioning System) navigational system enables safer and more efficient operationsthanks to the technical know-how of an engineering team assigned to the Department of Transportation’s Volpe National Transportation Systems Center in Cambridge, Mass.

A Lesson in Geography

The continuing importance of the Panama Canal to international commerce and U.S. national-security affairs may be demonstrated by the school child’s exercise of tracing the alternate route around South America and north again on a globe-a lengthy transit of thousands of miles each way, avoided by a 45-mile canal across a narrow strip of land. The lesson of this simple demonstration is borne out by the 13,000 oceangoing vessels that use the Canal every year. Even in today’s “information age,” livelihoods around the globe depend on the oceanic movement of sugar, steel, oil, and ores. Fortunes rest on the time it takes for goods to move from one part of the world to another.

While transits through the Panama Canal save considerable time and fuel, navigating this narrow waterway also presents many challenges. Canal navigation is such a complex affair that all vessels transiting the Canal (even U.S. Navy warships) are directed by a Canal pilot who is responsible for the vessel’s movements until the transit is completed.

As pilots direct ships past landslides, around comers, and over submerged rocks, they navigate by a system of buoys and land-based markers. Relying primarily on visual cues and experience, a pilot aligns the ship within the channel and recognizes when to adjust ship heading or speed. Unfortunately, when rain or fog obscures visual navigation aids, a pilot may be unable to determine if the ship is on course, drifting perilously close to the bank, or heading into the path of an oncoming vessel.

The Canal’s navigation difficulties are closely tied to the impediments that hindered its construction, such as the fractured geology that causes recurring landslides. Today, dredges are regularly at work, clearing the channel of rocks and mud. Torrential rainstorms previously caused floods that swept away construction equipment and laborers; now the floods are tamed by two dams, but the daily downpours can reduce visibility to barely the width of a vessel. The fog that develops almost every night was once thought to be the precursor of malarial fever; now sailors know that the real danger of fog is the thoroughness with which it obscures navigation aids.

With the aid of the Volpe National Transportation Systems Center, Canal pilots have a new piloting tool: a CTAN (Communications, Traffic Management, and Navigation) system. This new system, developed for the PCC (Panama Canal Commission) by Volpe Center staff in the Center for Navigation, makes the Canal safer and more efficient by using satellite data to create a real-time display that shows the location of every vessel within the Canal. This bird’s-eye view gives Canal pilots and traffic managers an entirely new all-weather perspective from which to view the complex choreography of 50,000-ton vessels slipping into narrow locks and passing one another around tight comers.

“A Stupendous Undertaking”

Ever since Vasco Nunez de Balboa crossed the Central American isthmus and named the Pacific Ocean in 1513, seafaring countries have dreamed of a passage that would broach the narrow strip that separates the world’s two greatest oceans. Engineers soon began to explore the challenge. Where to build such a canal? How shall it be excavated? What shall be done with the rock? The first real effort to build a canal began during the 1890s, when French entrepreneur Ferdinand DeLesseps, having just completed the Suez Canal, turned to Panamapouring billions of francs and 25,000 lives into an unsuccessful attempt to build a sea-level canal. The French effort was thwarted by plagues, unreliable machinery, and almost a billion cubic yards of rock.

The failed canal sat idle until the turn of the century, when the United States turned its gaze in earnest towards Panama. President Theodore Roosevelt, influenced by Alfred Thayer Mahan’s book The Influence of Sea Power on History, realized that a Central American canal would be an important strategic asset to a country that bordered both oceans and whose international reach extended both east and west.

The U.S. construction effort used technology in unique and innovative ways to make construction of the Panama Canal possible. It was truly “a stupendous undertaking,” in the words of the day. One by one, U.S. engineers solved the major challenges that had thwarted French efforts. The engineers instituted a massive mosquito eradication and sanitation program to protect laborers from malaria and yellow fever; they used a flexible system of movable railroad tracks and one-sided boxcars to ferry away excavated material and dump it quickly; and, rather than dig a sea-level canal, they built a dam and locks to lift vessels up to the level of a new man-made lake.

The key features of the Canal are its three monumental locks. In order to accommodate two-way traffic, each lock has two lanes. Individual lock chambers are 1,000 feet long and 110 feet wide-large enough to hold the Titanic, had it ever reached the isthmus, or an Iowa-class battleship. Vessels must pass through three such chambers, each chamber changing elevation by 28 feet, in order to reach the elevation of Gatun Lake, 85 feet above sea level. All water moves by gravity-flowing from the lake through the locks and into the oceans.

About one third of the vessels that use the Canal are known as “Panamax” ships-those up to 970 feet long and 105 feet wide, with a 39-foot draft. For these behemoths, transiting the Canal is a complicated endeavor. Slipping into a lock, navigating the Gaillard Cut, and encountering oncoming vessels present challenges for the Canal pilot and strain navigation and propulsion systems designed for sailing the open seas.

Navigational Improvements

Since its inauguration in 1914, more than 700,000 vessels have used the Canal. In accordance with the Panama Canal Treaty of 1977, the U.S. Canal Zone was disestablished in September 1979. Full responsibility for the Canal’s administration, operation, and maintenance will shift to Panama when ownership is transferred on 31 December of this year. A related Neutrality Treaty guarantees that the Canal shall remain open, safe, neutral, and accessible to vessels of all nations. Treaty provisions stipulate that the United States has the right to “expeditious transit” through the Canal in times of conflict. It also reserves the right for the United States or Panama to intervene militarily should it be necessary to reopen the canal or restore its operations.

Recognizing the Canal’s role as a key link in the world’s economy, the PCC continuously seeks ways to make the Canal more efficient and safer. As the volume of ship traffic hovers near Canal capacity, better scheduling and traffic control are key elements of the proposed improvements. Canal traffic is so consistently near or over capacity that even slight complications can cause expensive delays. Canal authorities recently installed closed-circuit-television cameras at strategic vistas along the Canal in order to monitor traffic, but these cameras are limited in their usefulness, and their imagery is not helpful to Canal pilots on board ships.

In 1995, the PCC requested Volpe’s Center for Navigation, a known leader in the development of radio-navigation systems, to design a satellite-based system that would track the location of transiting vessels and PCC tugs, launches, and dredges. The Center for Navigation was the logical choice to develop such a system, having already proven its ability with a similar system it developed for the St. Lawrence Seaway Development Corporation. That system utilized GPS navigation satellites to determine vessel location, which was transmitted to a shore-based control center and then rebroadcast to all participating vessels.

While the Center for Navigation’s experience in the St. Lawrence Seaway was important, the scale of the Panama system was considerably larger. Furthermore, the new system utilizes DGPS (differential GPS) to produce even more precise navigation data. The two DGPS reference stations built at the Canal can pinpoint a ship’s location in the Canal to within three meters. These stations conform to U.S. Coast Guard specifications for its Maritime DGPS system for U.S. waterways.

Thanks to the technical and management expertise of the Center for Navigation staff, a high level of collaboration between the Volpe Center, PCC engineers, and Canal pilots was nurtured and maintained throughout the design and development of the navigation project. This collaboration often prompted the development of new design features that were not envisioned when the system was first planned. One such feature is the system’s ability to predict the meeting point between two vessels. Using this information, pilots can modify their ship’s speed in measured waysadjusting the meeting point to a more desirable location, if necessary.

The result of this collaborative effort is a coordinated system composed of more than 150 mobile units-about half installed on PCC tugs, launches, and dredges-that enable communication with six shore-based stations and a master communications center. The system provides for redundant coverage of the entire Canal. The mobile units consist of a GPS receiver and antenna, a notepad computer, and a UHF digital radio. Once the mobile GPS unit has determined a vessel’s location and speed, it transmits this information on the two-way UHF data link to the communications center, from which it receives navigation and other useful data on the other vessels in the Canal-updated approximately once per second.

A System for Today and Tomorrow

In August 1998, the new navigational system proved its worth by preventing a potentially serious accident. A 740-foot-long bulk carrier in Gatun Lake, transiting north from the Pacific, lost rudder control just as a heavy rainstorm developed. The vessel grounded crosswise in the channel. Meanwhile, a 600-foot car carrier traveling south was not aware of the situation just around the bend. However, both pilots used their CTAN units to avoid what they later said would have been a certain collision had CTAN equipment not been on board.

The CTAN system, while addressing today’s navigational requirements, also was designed for adaptability, flexibility, and utility in the future. The Panama Canal will continue to present navigational challenges during the years ahead. Its construction baffled engineering minds for centuries, ruined one of the world’s foremost entrepreneurs, and killed thousands of laborers. This epochal engineering achievement demanded the full attention of the United States for almost 10 years; 80 years later, it continues to give heartburn to seasoned Canal pilots.

Throughout the Canal’s history, great minds have turned their attention to the challenges of the day; when the time is right, as it was in 1908, the confluence of innovation and technology yielded remarkable results. Now, the Volpe Center’s engineering teampartnering with the Canal’s administrative staff and pilots-has added its names to the list of noteworthy engineers, technicians, and laborers who have successfully tackled an endless parade of formidable technical hurdles for more than eight decades.

The Canal’s modern DGPS navigational system has reinvented the experience of navigating a vessel through the Canal. Much as those pioneers of 80 years ago who planned the Canal, operated the steam shovels, designed the locks, poured countless tons of concrete, and dredged the channel, they have made a new Panama Canal–one that is designed to serve the world’s maritime transportation and commercial needs efficiently and safely well

Dr. James Vincent Carroll, a senior engineer at the U.S. Department Of Transportation’s Volpe National Transportation Systems Center, is the project-team engineer responsible for the design, development, and installation of a modern GPS navigation system at the Panama Canal.

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