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but software must be modified to gain smoother reactions from the thrusters. 

 All visual data can be recorded on tape to provide a permanent record of 

 such factors as abrasion, burial depth, suspended sections, links and coils. 

 Since the RCV-225's depth sensor is capable of measuring depth to -0.1m (0.3 ft) 

 accuracy, it is sometimes positioned to permit rapid measurements of cable 

 or pipe suspensions or depth of scouring around such structures. 



3.1.1.C Structure Inspection (NDT) 



A major portion of structural inspection consists of merely looking at the 

 structure and recording the observations on videotape or photographically. 

 Such observations, on steel jacketed structures, may consist of: 1) assessing 

 potential damage to members due to ship impact, storms or earthquakes; 2) 

 noting the presence or absence of anodes; 3) locating and identifying debris 

 which is caught on or rests against the structure and 4) assessing the degree 

 of scouring (or absence of such) at the platform's foundation. 



The foregoing describes typical inspection activities in U.S. waters, however, 

 in the English and Nojrwegian sectors of the North Sea government regulations 

 regarding periodic certification of offshore structures require knowledge 

 of the structure beyond that which can be obtained from visual observations. 

 To supply such information several ROV operating companies have developed 

 and employ a variety of Nondestructive Testing (NDT) techniques. One of 

 the more progressive firms in this area of ROV application is England's 

 Sonarmarine Ltd. The entire ROV system (SiMT 2) is designed specifically 

 for application from deep-water production platforms and operates as an inde- 

 pendent unit from the platform with its own launch/retrieval system, power 

 supply and operations modules. The "package" is certified by Lloyds Register 

 of Shipping to operate from a production platform and conforms with the safety 

 requirements of platform operators. The following list of NDT instrumentation 

 has been developed for their vehicle and is offered for inspection services: 



Video Cameras 



The three cameras mounted on the vehicle are used for inspection work. One 

 of the cameras, a wide-angle S.I.T. low-light design, is mounted on a tilt 

 mechanism and used principally by the pilot . It operates in very low light 

 conditions and obtains video data in murky conditions. The second camera 

 is a vidicon design and is mounted either on a pan and tilt mechanism or iii 

 a manipulator. One unit obtains high definition video of specific standard 

 features. The third camera, a neuvicon design, can be interchanged between 

 viewing positions as conditions dictate or mounted in a stern position as a 

 navigation aid when working in a platform. Two 3/4 inch cassette recorders 

 are available-one operating continuously to record the complete dive profile, 

 the other to record specific data required by inspection engineers. 



Color photographs of specific features can be taken using a stereoscopic 

 camera pair fitted on a pan/tilt unit. On-site processing is available. 



C.P. Probe 



The C.P. probe checks the level of protection of the platform's sacrificial 

 anode system. A silver/silver chloride reference is held in the jaw of one 

 of the two manipulators and is connected via the umbilical to a high impedance 

 digital voltmeter. The circuit is completed by attaching the other side of 



