Mark McPherson, Jennifer Williams - Sonsub
The newly developedInnovator Leviathan is Sonsub’s most powerful heavy work class ROV to date, providing high levels of power and control for deepwater operations.
In 2007, Sonsub, the subsea division of Saipem, announced that the first of these newbuild, 250-hp (186-kW) ROVs would be delivered by the end of the year, adding to the company’s worldwide fleet of over 60 vehicles.
Sonsub’sInnovator Leviathan.
The first three units have since been deployed on Saipem’s IRM vesselChloe Candies and the ROV support vessel HOS Mystique in the Gulf of Mexico, with one vehicle also performing basic platform drill support for a major operator. A further two followed in 2008 onboard the Sonsub multi-purpose subsea construction vessels Normand Cutter and Bourbon Pearl, operating in the North Atlantic and Mediterranean regions, with a sixth on its way to Saipem’s new plough support and construction vessel Far Samson which was due to be launched in the second quarter of this year.
These new generation systems have been built in Houston under the guidance of Sonsub’s research and development team in Venice, Italy, and with special features driven by the Aberdeen and Stavanger divisions. They have undergone four months of engineering and three months of configuration testing, and are designed to operate continuously despite harsh weather, high current, or extended dive conditions, while retaining the established advantages of the Innovator class.
With an upgrade to 250 hp dual-shaft electric motor, theInnovator Leviathan is capable of delivering high levels of power through seven hydraulic thrusters – four 17-in. (43-cm) horizontal and three 15-in. (38-cm) vertical – allowing the ROV to operate in currents of up to 4.5 knots. Enhanced control for harsh operating conditions is facilitated by mechanical thruster repositioning providing 30°, 45°, or 60° thrust angle with respect to the fore-aft vehicle axis, while the vertical thrusters also have pitch and roll control.
Other features include a state-of-the-art heavy weather launch and recovery system (LARS), and a new, fully electric umbilical winch incorporating active heave compensation. This provides the capability to launch and recover the vehicles in higher sea states than would previously have been considered with theInnovator 150, along with higher speed deployment to working depth (up to 120 m/s, or 393 ft/s) and safer docking with the tether management system (TMS).
Being electric as opposed to hydraulic, the winches also run more quietly than the previous systems, making deck operations safer as well as healthier, with the new A-frame allowing secure deployment from a higher freeboard.
Finally, inside the control van the ROV interface is upgraded to include a touch screen human-machine-interface (HMI), providing a higher level of ergonomics for the pilots.
According to Sonsub operations manager John Ewen, “The overall design enhances the operating capability of the ROV system and allows safer operation when working at the higher end of the allowable weather parameters.”
Acting as a stable work platform for all of Sonsub’s future subsea intervention and support systems, theInnovator Leviathan has many other operational and control features to help minimize subsea downtime.
This new level of ROV capability has allowed theBourbon Pearl to operate recently in what was Sonsub’s most northerly work site to date, performing electromagnetic offshore exploration for PetroMarker in the Barents Sea from a base in Hammerfest in northern Norway. Sonsub AS General Manager Mark Underhill says: “With increased activity north of Hammerfest, it is important to have heavy weather capability on our vessels to maintain productivity, even during the summer months in the Barents Sea where we can experience hostile conditions.”
The Sonsub ROV newbuild program is committed to producing 20 additional Innovator systems, including the newLeviathan, over the next few years.
