84 



Diving support ship positioning assistance 



Continuous monitoring of the diver in terms of safety 



Initial diving gear check out for leaks 



Augment surface understanding of diving conditions 



Precise location of dive site prior to diver deployment 



Evaluate diver site conditions in terms of safety 



Provide mobile, independent light source 



Inspection of potentially diver-hazardous areas 



Inspection of area too small for the diver 



Assist diver in monitoring of equipment installation 



Monitor/inspect diver's work 



Document diver's work photographically or with video TV 



To exemplify the ROV s application 'to the above tasks, three work instances 

 are presented. 



a) Taylor Diving Co. , Cognac Platform Installation, Gulf of Mexico (Michel, 19l 



During all deep diving operations, the RCV-225 accompanied the divers. During 

 each diving bell run, the launcher was lowered to working depth first and the 

 RCV moved in place to monitor the bell's descent. While the diver was pre- 

 paring to exit the bell, the RCV was moved to the work site and personnel 

 topside made a pre-survey of the upcoming task to insure the diver had proper 

 tools, etc. 



As the diver left the bell, the RCV aimed toward it. This accomplished two 

 things. First, it provided a visual target (the vehicle's lights) to which 

 the diver could swim. Secondly, it allowed barge personnel to observe the 

 diver. As the diver arrived at the work site, the first task was to move 

 the RCV behind him, checking his diving gear (much as a buddy diver would do) . 



Tremendous amounts of time were saved. Visibility at 305m (1,000 ft), even 

 in clear water, is poor due to a complete lack of sunlight penetration at 

 extreme depths. A diver carrying a hand light can see about 9m (30 ft) at 

 best. The RCV on Cognac provided a clear field of view up to 122m (400 ft) 

 away. The RCV s silicon intensified target camera produces a usable picture 

 with as little as .002 foot-candles of light. This feature, plus the onboard 

 compass, allowed the RCV to maneuver almost directly to an object that might 

 take a diver hours to find. Another time-saving feature was the extreme 

 maneuverability of the RCV, particularly on a vertical axis. Speed is 1.7 

 knots forward, 1 knot reverse, 1 knot port or starboard and .5 knots up or 

 down. A diver saturated at 305m cannot safely ascend more than a few meters above 

 this depth. 



On one occasion, a burning umbilical was fouled at the 152m (499 ft) level. 

 The RCV which had been observing the diver quickly ascended to 152m and 

 the RCV operator directed barge personnel to take up and relieve tension on 

 certain cables and hoses to the JBS , thereby freeing the rig. Had the RCV 

 not been on board, the alternatives would have been to saturate another team 

 of divers in the second chamber or decompress the saturated divers to 152m. 

 The latter method would have taken five days. 



