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Feature Article

Electric ROV Systems Take on More Tooling
Improvements in Power Capabilities Enable Mini-ROVs To Perform Tasks Previously Carried Out by Work-Class Vehicles

Jon Robertson
Engineering Director
Saab Seaeye
Hampshire, England

A diagram of Saab Seaeye's Panther XT Plus with some system options.
Not long ago, some people likened an ROV to simply a truck onto which kit was loaded and sent off to do a job or two. Times have changed. Today, no one would consider the ROV as anything other than a sophisticated multimission vehicle packed with advanced electronics.

This transformation has resulted from a focused revolution in underwater technology driven by collaboration between ROV manufacturers, underwater system builders and innovative end users. Smaller camera, sonar and sensor technologies have given ROV operators the chance to undertake more tasks with more power in a smaller vehicle in a single dive. ROV users have also driven key developments by combining new technologies to create unique solutions to underwater challenges.

When meeting the challenge to increase a vehicle's scope by adding more systems of different size, weight and shape, the critical consideration is that the vehicle must remain dynamically stable and not left operating at the edge. This is where collaboration pays off, with all parties working to find the location on a vehicle where a system functions most effectively.

The Rise of Electric Work-Class ROVs
Significantly more power and tooling has been introduced into the electric-work ROV, allowing it to tackle more work previously undertaken by hydraulic vehicles, such as drill support, full pipeline survey and some construction tasks. This boost in power means that an electric ROV has the equivalent power and lift capacity of a 100-horsepower hydraulic ROV.

For instance, an electric-work ROV now has the tooling power to run Tritech International Ltd.'s (Aberdeen, Scotland) Merlin ROV excavator on maximum load, while still operating its thrusters at full force and keeping the vehicle steady. For such a cable-laying dredging task, a 150-horsepower hydraulic ROV would normally be needed and take up twice the deck space, among other costs.

Regardless of size or class of electric ROV, the advantage of the new multimission vehicle has been to find more ways to fit additional equipment on board without increasing its size. These can include a seven-function position feedback manipulator, heavy-duty five-function grabber, hydraulic hot stab tooling, linear actuator override tool, torque tool, flying lead orientation tool, AX/VX ring change-out tool, single- or dual-point tool deployment units, 6-inch rotary or 4-inch anvil cutter, high-pressure water-jet or cleaning brush tools, zip jet suction tool, contact probe, anvil cutter and custom tooling.

Innovatum Ltd. (Bury St. Edmunds, England), for example, has created the SMARTRAK 9, a system capable of sensing AC or DC cables, as well as those carrying no current or signal. It can also sense steel pipelines. The SMARTRAK uses three different methods to acquire target data: a passive magnetic mode for pipeline survey work and for cable survey; an active DC mode for tracking live high-voltage DC cables and transoceanic telecommunication cables; and an active AC mode for locating, tracking and surveying cables. The system creates reports and charts that show the cable route and depth of burial. This data is required by installation contractors, owners and regulatory authorities to ensure that the cable is properly buried and not in danger of being exposed to damage.

Saab Seaeye's Falcon ROV was fitted with a Tritech Super SeaKing profiler system; a Tritech Micron-Nav ultrashort-baseline navigation transducer, with pitch and roll sensing for underwater ROV positioning; an accurate flux gate compass; a high-accuracy altimeter; and a pressure sensor for depth. Two people per shift are needed to launch and operate the system, with one controlling the ROV and the other the survey equipment.

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Jon Robertson joined Saab Seaeye in 1998 with a responsibility for special projects. He was appointed engineering director in 2004. During his time with the company, he has led the continual development of the product portfolio and innovations that are shaping the future of ROV technology.

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