Since the end of World War II, U.S. military services have faced a logistical problem in terms of strategic sealift capabilities. The United States has worldwide treaty obligations that range from Europe to East Asia to the Persian Gulf. But the bulk of the U.S. Army's forces remain in the continental United States far from any potential conflict.
Although some troops can be airlifted to any crisis, approximately 95% of military equipment must be sent by sea because of its weight or bulk. The intermediate solution to this problem was the purchase and conversion of SeaLand's eight SL-7 fast cargo ships in the mid1980s. These vessels can travel as fast as 33 knots and make a transatlantic crossing in a little less than six days after a 96-hour activation period. Four days can be a long time in a fluid military situation, however, and the SL-7s require a partially intact port facility for unloading their cargo.
Even overseas, the Army and the Marine Corps face a major problem in moving forces in theater. Troops can be moved for deployment or training by air, but their equipment is so heavy it must travel by sea. As a result, both the Army and Marine Corps are experimenting with high-speed, wave-piercing catamaran ferries to move soldiers and material within theaters of operation. Two summers ago, the Marine Corps chartered a high-speed catamaran, the WestPac Express, for two months to carry Marines to training missions in the West Pacific. This Australian-built vessel is capable of traveling at 37 knots. It can carry 950 Marines, 100 high-mobility multipurpose wheeled vehicles, 12 helicopters, and 4 heavy trucks. In the fall of 2001, the Army started a three-year proof-of-concept trial with a similar catamaran ferry, the Incat 50, on behalf of the other services. This passenger and vehicle ferry also carries 800 tons of cargo and it travels at 35 knots. Assuming these trials are successful, the Army plans to acquire as many as 14 similar catamaran ferries for in-theater transportation.
Wing in ground effect (WIGE) vessels could complement fast ships such as the SL-7 and serve as alternatives to catamaran ferries in meeting the military's fast sealift problem. They can operate at much higher speeds than hulled ships because, once cruising, they float on a dynamic cushion of air that is created between the vessels' wings and the surface of the water. By operating close to the surface of the water, WIGS vessels face less induced drag and greater lift because of ground effect—the high pressure that builds beneath the wings when the ground is approached. This leads to an increased lift/drag ratio and greatly reduces the amount of power (thrust) required to propel a craft of a certain weight. By taking advantage of ground effect, WIGE vessels potentially could carry "50% more payload with 35% less fuel consumption than a similarly sized aircraft and 75% less fuel than comparably sized hydrofoil ferries."
The WIGE vessels are flying watercraft that take advantage of the aerodynamics of ground effect. They operate 6-50 feet above the water, though some designs can operate at higher altitudes with greatly reduced efficiency. They generally operate over open water, but also can operate over sand and snow, and most military designs are amphibious. Water also poses WIGE vessels' greatest problem: getting out of it. The hump drag on the vessel just before it leaves the surface of the water requires much more power to overcome than that required for normal cruising.5 This means that many WIGE designs are "overengined." Russian and Chinese designs have dealt with this by placing engines in front of the leading edge of the vessel's wings, which creates an artificial air cushion beneath the wing known as a power augmentation ram-wing.
Military applications of WIGE technology were most fully developed by the Soviet Union at its Central Hydrofoil Design Bureau from the 1960s until the fall of the Berlin Wall. Rostislav Alexeev began his research while working on torpedo hydrofoil boats for the Soviet Navy. He found that hydrofoil cavitation limited the efficient operation of hydrofoils to less than 54 knots, and he began research on a vessel that would have no direct contact with the surface of the water. The Soviets called these WIGE vessels ekranoplans.
With the direct backing of the Soviet government, Alexeev built a number of models and prototypes before producing the Korabel Maket (KM). It was the largest ekranoplan ever built, weighing 544 tons, cruising at 270 knots, and flying 10 feet off the surface of the water.6 (The KM was nicknamed the "Caspian Sea Monster" by Western intelligence officials who photographed it during trials in the mid-1960s.)
The Soviets continued ekranoplan development in the 1970s and 1980s, but at a slower place. They built five of an initially planned 120 Orlyonok ekranoplans in 1972. The Orlyonoks, which were intended to be small troop carriers, could carry 20 tons of cargo and cruise at 188 knots. After Alexeev's death in 1980, the Central Hyrofoil Design Bureau built the Lun, which could carry six antiship missiles and was intended to attack and outrun surface ships as part of the Soviet fleet. She had a cruising range of 1,350 nautical miles (nm) and a payload capacity of more than 50 tons. Only one was built before the collapse of the Soviet Union; the Lun's sister eventually was converted into a search-and-rescue ekranoplan.
The Chinese are continuing ekranoplan development with the assistance of the Russian Central Hydrofoil Design Bureau and have produced a prototype called the Hubei TY-1. It is much smaller than any of the Soviet military designs and is intended for the commercial market.
The primary advantages of WIGE technology are speed and range. Unlike an SL-7 or catamaran ferry, which travel at 33-37 knots, a modem ekranoplan could travel at speeds of 216 knots. While the catamaran ferries being tested by the U.S. military are limited to a range of 1,050 nm, Soviet ekranoplans, such as the Lun, had a cruising range of 1,350 nm. The Defense Advanced Research Projects Agency recently analyzed a WIGE vessel that could transport 1,500 tons over a range of 10,000 nm without refueling. Additional military advantages identified by Transport Canada (equivalent of the U.S. Department of Transportation) include:
- Low radar and infrared signatures because of low operating altitude
- Difficult to detect from satellites
- Fast troop deployment and ability to operate from both land and sea
- Formal port facilities not required for unloading; can operate from a beach9
A U.S. Army separate mechanized brigade—including soldiers, vehicles, and equipment—weighs approximately 27,000 short tons. Thus, a complete brigade could be transported 1,350 nm in seven hours on just 18 WIGE vessels at a much lower cost than using C-17 aircraft.
Why the Navy?
The Department of Defense should aggressively pursue development of WIGE technology and the Navy should take the lead. The International Maritime Organization plans to issue design guidelines for WIGE vessels that will clearly classify them as maritime craft. Even if they eventually are classified as aircraft, they will interact with traditional ships, rely on shipping navigation systems, and normally take off and land on the sea.
Only the Navy has the skills and expertise to handle this hybrid technology. The WIGE vessels clearly meet one of the Navy's mission profiles—quick and efficient projection of U.S. forces by sea. The Military Sealift Command does this today through a mixture of Navy roll-on/roll-off ships, including the SL-7s and commercial vessels. The WIGE vessels would present options requiring minimal investment in dockside infrastructure. They are faster than sea transport and cheaper than air transport. They also would be able to fulfill many of the missions being considered for catamaran ferries.
The United States studied WIGE technology in the early 1960s before deciding to develop the C-SA Galaxy aircraft instead. The WIGE vessel's time for military applications may have come. The Army has included WIGE vessels in its Advanced Mobility Concepts Study, which is scheduled for completion next month. NATO's Research and Technology Organization also has sponsored a study entitled "A Overview of WIG Vehicles for Military Operations," which is scheduled for completion in 2004.
The Boeing Company's Phantom Works recently announced it is studying the feasibility of an enormous WIGE "aircraft"—the Pelican—in anticipation of the completion of the Army's Advanced Mobility Concepts Study. This vessel would fly 20 feet above the water with a payload of 1.5 million pounds and a range of 10,000 nm over water. This should be the first step in the development of a fleet of fast sealift WIGE vessels for the U.S. armed forces of the future.
Mr. Jacobs is the Director of Transportation for the Borough of Staten Island, New York.