85 



b) SESAM, General North Sea Work (Gaudillere, 1978) 



SESAM has been operating their RCV-225 with various diving companies in the 

 North Sea. The following description of its works is taken from the above 

 reference. 



"The first time divers hear of or see the RCV-225 they despise it. They 

 are scared, and they don't like the 'spy.' But it doesn't take long 

 before they ask for it at each dive. The vehicle is so small and light 

 that it is not a danger. They just push it away if it comes too close 

 (this is not the case with other types of vehicles) . 



Much diving time is saved in using the RCV to search for the exact 

 place to work. The vehicle is sent first, and the place is identified 

 by people on the surface without ambiguity. The diver is then sent 

 out of the bell and can go straight to the job by looking for the 

 lights of the vehicle. With diving bells which can accommodate only 

 two divers there is only one out at a time and having the RCV watching 

 makes the diver feel much safer. (It is not only a feeling because 

 he is really not alone anymore.) The RCV is even used to give the 

 diver some light to the job he is working on. As a light source it 

 can be placed right on the work. The work can be checked after com- 

 pletion and corrected as necessary from the surface." 



c) Martech International, Sub-Sea Valve Inspection, Gulf of Mexico (Macdonald, 

 1978) 



After mooring the ship in the area indicated by the surveyor, TREC was launched 

 and dived to the sea floor. Based on surface positioning information and the 

 Honeywell RS-7 positioning system, the TREC was directed on a course to 

 intersect the pipeline. Once the pipe was in sight it was "flown" until the 

 valve was located. TREC was then positioned in accordance with instructions 

 from the diving supervisor. The RS-7 mini-beacon on the TREC then was used 

 as a reference point which permitted mooring cables to be adjusted such that 

 the bell launching system was directly over the valve. The bell was then 

 lowered which maintained a one- atmosphere environment. The beacon on the 

 bell was used to direct mooring adjustments until the position of the bell 

 and TREC were near-coincident. The divers were able to see the TREC lights 

 and they then commenced bell pressurization which was followed by exit and 

 inspection. The TREC maintained position and acted as a known reference point 

 for the dive. 



In view of the fact that these applications of ROVs are incidental to their intended 

 utilization, it is impressive to review their accomplishments. Indications 

 are that as more experience is gained through application of vehicles in the 

 diver assist mode, their role in deep, saturation diving will increase. 



3.1.5 Search/Identification 



Tasks within this category have included the following: 



Location and identification of lost equipment and materials 

 Location and identification of acoustically- located objects 

 Debris identification and location 

 Location of sub-bottom pipeline taps 



