Quick Turn-around

“Drop-in-place” actuators facilitate marine turbine damper upgrade in three days

Established in the aftermath of World War II, the US Military Sealift Command plays a vital role in providing sealift and ocean transportation for all military services and a multitude of other government agencies. MSC ships have transported troops in every overseas military campaign from the second half of the twentieth century to today, in addition to their support needs: millions of tons of wheeled and tracked vehicles, helicopters, ammunition, dry cargo, billions of gallons of fuel, and other supplies and equipment crucial to the various war efforts. Given the scope and consequences of their duty, the US Military Sealift Command might well be considered the most important delivery service in the world.
However, for the MSC to do its job—like any military expedition—each part has perform its role in conjunction with others. On board the MSC cargo ship SS Cape Isabel, a propulsion system was in severe need of an upgrade and when the time came to look for powerful and reliable components for this mission—that could be completed quickly—Rotork answered the call of duty. The choice of Rotork Type K vane type actuators to replace existing equipment has enabled the control upgrade of the ship’s main propulsion intake dampers to be completed in three days.


SS Cape Isabel is a 655 foot (200 meter), 15,000 ton (13,607 tonne) roll on/roll off cargo ship based at Long Beach. Launched in 1976, the ship is powered by two steam turbines. The ship’s two turbine intake radial vane dampers were equipped with pneumatic controllers, which had become obsolete. The old actuators did not respond quickly and accurately to signals from the control system, resulting in potentially inefficient combustion and undesirable emissions. Replacing the actuators was necessary to increase efficiency, reduce maintenance and the associated costs that could result from unplanned shutdowns.


The equipment selected to upgrade the old actuators was Rotork Type K damper drives, which provide a direct ‘drop-in-place’ replacement that exactly matches the existing damper drive footprint and output shaft location. Duplication of the existing drive’s dimensions simplifies the installation, enabling the upgrade to be swiftly completed in a matter of hours.
Type K damper drives incorporate vane type actuators that offer high speed full stroke capabilities of less than 5 seconds, combined with accurate and responsive positioning. The rugged construction is designed to withstand the harsh environments associated with power stations and combustion plants.


Once the two Type K pedestal mounted damper drive units had been delivered to the ship, installation of both units was performed by engineers from Rotork Site Services within three days. All the work was coordinated prior to commencement by the ship’s Chief and First Engineers. Days one and two were taken up with the removal of the old equipment and the installation of new, enabling commissioning, testing and hand-over to be completed during day three.


Type K rotary and linear damper drives are designed for utility power plants, refineries, and other industries that require precise combustion air and flue gas handling solutions. Type K retrofit damper drives have proven to increase operating efficiency, reduce maintenance, and downtime and lowering harmful emissions. In the electric utility industry, Type K damper drives play a critical role in boiler control, efficiency, reliability, improve heat rate, and contribute to improving boiler emissions. Power producers are continually investing in control systems and instrumentation components, such as damper drives, to meet emission regulations, reduce fuel and operating costs and avoid costly boiler trips and outages. Power generating stations, whether fueled by coal, natural gas, biomass, hydro-electric energy, or solar, are all potential candidates for Type K damper drives. ■ [clear]
Sarah Kellett is a communications specialist for Rotork Fluid Systems. She can be reached at sarah.kellett@rotork.com. For more information, visit www.rotork.com. For more information about Type K rotary and linear damper drives, visit www.typek.com.
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