136 



displayed to 1cm. The Control and Display Unit (CDU) is the means 

 for controlling and displaying the results of the total system. 

 Another use of the GENIE is to provide the vehicle with both a computing 

 capability and also a source of control and steering signals." 



5.8 PIPELINE INSPECTION SYSTEM INTEGRATION 



The Marseille-based firm INTERSUB is in the final stage of developing an ROV 

 pipeline inspection system which integrates various of the instruments listed 

 in Section 2.1.7 onto an ROV and then further integrates the ROV, the navigation 

 system and the support ship into a single operating entity. Significantly, 

 where all commercial and most government ROVs operate from a support ship of 

 opportunity, INTERSUB has dedicated and converted a ship to sole support of 

 its inspection system. 



The basic components of this system can be divided into three main parts: 

 1) the support ship; 2) the underwater vehicle; and 3) the equipment. 



The Support Ship : INTERSUB FIVE was converted to operate both an unmanned, 

 tethered underwater vehicle and a manned submersible. The ship is 57m 

 (187 ft) long, 11.5m (38 ft) wide and has a draught of 4.8m (16 ft) with 

 twin screws, gill jet bow and stern thruster and full dynamic positioning. 

 There is accommodation for 30 and a ship's crew of 16 with two computers 

 and space to process all data and produce drawings onboard. 



Underwater Vehicle : The vehicle is a TROV specially designed for pipeline 

 inspection using INTERSUB DEVELOPPEMENT survey equipment. It has a diving 

 depth of 900m (2,953 ft), weighs 2,700kg (5,952 lbs) with dimensions of 

 300cm X 132cm x 155cm (118 in. x 52 in. x 65 in.). The propulsion is 

 provided by four 440v motors with variable pitch screws in kort nozzles, 

 the two longitudinal thrusters are lOhp while the vertical and transverse 

 are 7hp. The umbilical is 1,067m (3,500 ft) in length and controlled by 

 a winch comprising level winder, reel, water tank, slip rings and hydraulic 

 drive. The reel accommodates 1,219m (4,000 ft) and is situated in a water 

 tank to keep the cable cool. 



Equipment: To carry out a full inspection the following equipment will 

 be mounted on the unmanned tethered vehicle: 



a. Short Base Navigation System: The Simrad HPR Short Base Navigation 

 System is an acoustic system which provides an accurate position of 

 the vehicle in real time, relative to the support ship axis. 



The sea state and structure of the water will also affect the accuracy 

 of the equipment. The Short Base System is interfaced with a Surface 

 Navigation System through a computer with a plotter giving the 

 coordinates of the vehicle in real time. 



Any Surface Navigation System can be used such as Pulse 8, Hi-Fix, 

 Argo, Trisponder or Syledis, etc. The total error using Syledis is 

 better than ± 5m (16 ft). 



