An effective underwater hydraulic jet unit would be useful mainly for 

 selective cleaning. It would be a desirable addition to the diver's 

 arsenal of equipment for the purpose of cleaning small recesses, ducts, 



and similar contoured surfaces. Small recesses and ducts cannot presently 



129 

 be cleaned by brushes. Although the single lance jet cannot match the 



cleaning rate of the rotary brush, a new automatic remote controlled 



multijet device which is clamped magnetically to the ship's side has been 



129 130 

 reported. This device is purported to be able to clean a ship hull 



in port or under way. The effectiveness of cleaning is not known. However, 



it is discussed here because it may be necessary to develop an automatic, 



remote controlled, multijet device or system to clean the interior ducts 



of the warm water and cold water exhausts and possibly the warm water 



inlet. 



123 125 128 129 

 Cavitation jets ' ' ' are in the preliminary stage of 



development. Although they have the advantage of operating at much lower 



pressures than conventional jets, research is necessary to control the 



powerful impacts which can cut metals. While developments in jetting 



should be of great interest to OTEC, it is currently not a commercially 



available underwater cleaning tool. 



Required Diver Equipment . The diver requires the following equipment: 



1. Surface supplied air using Kirby Morgan KMB-9 masks with communica- 

 tions capability or Jack Brown mask (limited to a depth of 40 m) . 



2. Diving bell. 



3. Decompression chamber. 



120 



4. Equipment for mixed-gas systems (for operations below 40 m) . 



5. Photographic equipment for inspection: 



a. Waterproof 35-mm camera with special close-up lens. 



b. Underwater movie camera, 16 mm. 



c. Underwater strobe flash and movie light. 



6. Visual and audio communication equipment - underwater damage and 

 assessment television system (UDATS) . 



62 



