Research and Development of a Cavitating Water Jet Cleaning System for Removing Marine Growth and Fouling from U. S. Navy Ship Hulls.

At present, the majority of underwater cleaning operations are performed with various types of rotary brushes. Although brush cleaning is readily available for immediate use by the U. S. Navy, more advanced techniques are needed so that the removal of marine growth may be accomplished with minimum time and interruption to other ship mission activities. A relatively simple technique is needed in order to remove light fouling from ship hulls more frequently, as compared to removal of heavy fouling infrequently, through the use of complex equipment. With these objectives in mind the Office of Naval Research (ONR), Code 221, has conducted an initial research and development program to prove the feasibility of utilizing cavitation for hull cleaning and ocean platform cleaning applications. With this technique, water is pumped under pressure through a nozzle of a properly designed system. The high speed jet emerging from the nozzle produces cavitation bubbles which collapse on the surface to be cleaned. The basic principle involved in the cavitation cleaning technique is discussed in Appendix A.