Testing of a Non-Abrasive Diver Operated Propeller Cleaning System Using Enhanced Cavitating Jets, DYNAJETSField Tests on a Navy Ship.

Under a recently completed ONR SBIR Phase II a non-abrasive diver tool for propeller cleaning was developed using DYNAFLOWs cavitating and resonating waterjets. This non-abrasive tool uses the collapse of cavitating microstructures in the submerged jet over the fouling to remove it. It also uses a self-rotating head to achieve high removal rates, a counter-thruster to reduce diver fatigue, and a silencer to reduce noise. The tool was extensively tested on surrogate fouling on NAB plates and on a fouled propeller in the laboratory. Finally field tests were conducted on the USS Leyte Gulf. Recommendation from those tests were to reduce weight and length of the tool for ergonomic considerations. Further R&D since has addressed these recommendations and significantly improved removal ratesIn the proposed effort, the improved tool will be first tested at DYNAFLOW on an APU propeller, then, in coordination with NAVSEA cleaning tests will be conducted on a Navy ship in Norfolk. A well performing pump will be rented and Navy cleared divers from Seaward Marine will conduct tests with the tool and record videos of its performance on the Navy propeller. A report of this effort will be delivered following completion of the tests.