$3-Million Surface Effect Ship Award To Philadelphia Gear

Philadelphia Gear of King of Prussia, Pa. 19406, has been chosen to design, manufacture and test the propulsor reduction gearbox for the 3,000-ton Surface Effect Ship (3KSES). The planned cost for this effort through design, development, test and delivery of one ship set of four propulsor r e d u c t i o n gearboxes, plus one development propulsor, will exceed $3,000,000 in the next four years.

An SES is a marine vessel that operates on a cushion of air to significantly reduce its drag. As a result of the reduced drag, a large SES can be propelled at speeds ranging up to 100 knots. By comparison, conventional ships have maximum speed limitations, depending on size, mission, hull configuration, etc., of less than half that of the SES.

The Navy's 3,000-ton Surface Effect Ship Program represents the culmination of 15 years of research and development to produce an oceangoing operational surface effect ship prototype. Advanced ships of this type are capable of extraordinarily high speeds, since they ride over the water on a cushion of air contained under the ship.

The 3KSES design has an approximate length of 270 feet, a maximum beam of about 105 feet, and a cushion height of 18 feet. The ship will be able to carry a crew of 125 men at speeds three times that of conventional ships. For propulsion, General Electric LM 2500 gas turbine engines will drive four Aerojet water jet propulsors. Cushion air will be provided by six Aerojet centrifugal fans powered by two LM 2500 gas turbine engines. The ship will be equipped with helicopters and/or V/STOL aircraft, as well as weapons and sensors for test purposes.

Philadelphia Gear was selected because of its experience in large marine gearbox fabrication for the U.S. Navy and shipbuilders throughout the world. Their experience includes fabrication of supercavitating propellers used on the U.S. Navy 100-ton Surface Effect Ship that recently set a speed record of 103 mph. The award is by the Aerojet Liquid Rocket Company of Sacramento, Calif., under a subcontract from Rohr Marine Incorporated, a subsidiary of Rohr Industries, Inc. of Chula Vista, Calif.

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