CCC Underwater Engineering is preparing to resume the second phase of a 2,000-kilometre pipeline survey in the Arabian Gulf, totalling 316 pipelines.
They are inspecting the final 102 pipelines using their Saab Seaeye Leopard underwater robot, which CCC says is the best vehicle for the task.
Their objective is to achieve the most precise repeatable survey data possible, to a baseline accuracy below 0.5 metres. This kind of accuracy, whilst working in extremely shallow water along different sized pipelines for extended periods, requires a large array of high definition filming and sensing equipment.
Abu Dhabi-based CCC Manager, Tavis Letherby, says that position repeatability accuracy is essential to secure a solid baseline for future surveys.
The necessary array aboard the Leopard includes three HD cameras with movie quality 1080i interlacing, two Kongsberg M3 profiling sonars, Sonardyne Mini-Ranger and SPRINT-Nav 500 Hybrid INS, Valeport bathy suite including altimeter, Valeport mini sound velocity profiler, MCS’s photo-realistic 3D cloud system, laser line generator, CP and UT probes.
“For accurate data acquisition,” says Tavis Letherby, “only a Leopard has the manoeuvrability, control and payload to stay steady and on course without problems in shallow water when faced with strong cross currents and wave motion – sometimes working in less than six metres of depth.”
He points to the vehicle’s specification of 11 thrusters, 500 kgf of forward thrust, 200 kg payload and iCON intelligent control architecture, as making it suitable for very shallow water working whilst fully loaded with equipment.
When long excursions are necessary the operating vessel must stay around 70 metres clear of platforms for safety reasons. On those occasions the Leopard needs to navigate for up to 100 metres to fulfil the pipeline inspection, which is a particular challenge in shallow water.
For Tavis Letherby the Leopard has advanced underwater robotics further into the digital world and offers operators a work vehicle costing half that of an equivalent hydraulic system.