NASA Waterjet Stripping Technology Is Helping Vessels To Stay Ship Shape

Technologies derived from America’s space program are helping the nation’s ship repair and overhaul industry.

A waterjet coating-removal system was developed at NASA’s Marshall Space Flight Center in Huntsville, Ala., to remove thermal protective coatings from the Space Shuttle Solid Rocket Booster non-motor elements. The down-to-earth applications for such a stripping system led to the establishment of Pratt & Whitney Waterjet Systems, Inc., in Huntsville.

The first commercial application of the waterjet stripping technology was to clean gas turbine engine parts. Airlines using the system include Delta, Northwestern, United, USAir, Lufthansa, Japan Air Lines, and Air Canada. The system also is in use with the U.S. Air Force at the Oklahoma City Air Logistics Center. The aircraft engine cleaning system -- Engine ARMS® (Automated Robotic Maintenance System) -- sprays water at a pressure of 55,000 pounds per square inch to quickly remove gaskets, seals, abradable rub strips, and metal- and plasma-sprayed coatings. Engine parts cleaned with the system can range in size from six-inch diameter shafts to 120-inch diameter inlet fan casings. Most airlines have reported the Waterjet Systems, Inc., Engine ARMS® system has paid for itself within two to three years of operation.

Now, waterjet coating removal technology is being used to remove coatings and encrustation from ships, submarines and floating drydocks.

According to Waterjet Systems, Inc., spokesman Robert L. Hawkins, “Today’s shipyard industry needs new technologies to replace existing decoating methods. Current methods are either too costly to continue or have become restricted by environmental regulations. Ship decoating presents complex technical challenges because of the wide range of coatings and complex environmental issues involved.”

“Coatings include multilayer anticorrosive and antifoulant paint systems with marine slime and barnacle encrustation,” he added. “Environmental issues related to the release into the air or water and disposal of heavy metals such as copper, cadmium and lead that are used in marine coatings are working to prohibit the use of current grit and sand blasting technologies.”

Challenges facing today’s shipyards include both the enormous size of modern ships and the need to contain virtually all of the effluent from the coating-removal process.

Waterjet Systems, Inc., has met these challenges with its Ship ARMS® product. It is designed for use on ships, boats, barges, floating drydocks and other watercraft. The system includes a modular water reclamation unit for water filtration and recirculation. The only waste product is the solid coating residue it removes from hulls and decks. The system is transported on wheeled trailers. A nozzle shroud and vacuum ports on the device remove the process effluent as the coatings are stripped, leaving the surface dry and rust free.

The system has been successfully demonstrated by the US Navy on a variety of vessels, including the aircraft carrier U.S.S. Nimitz, the submarine U.S.S. Sturgeon, and the destroyer U.S.S. Leftwich.

The mobile, self-contained Ship ARMS® product is suitable for use in commercial drydocks and shipyards, as well as in Navy yards.

The system, in addition to being environmentally friendly, offers a number of financial advantages. There is no need for containment, scaffolding, or masking. There is no flash rusting. Stripping time is reduced, meaning less time for the vessel to spend in drydock. This means a faster turnaround for both the ship’s owner and the drydock’s operators. There is less cleanup with 50:1 reduction in solid waste compared to dry abrasive blasting. Recoating can begin immediately after removal of the old coating and less manpower is needed.

For further information on the system, contact Waterjet Systems, Inc., 6000 Technology Dr., Building C6, Huntsville, AL 35805-1955 or call (205) 721-2728/1-800-239-2773.