North Sea wind farms no match for Seakeeper

Sima Charters BV's Amethyst with Seakeeper 26 installed

Wind farms, often located far offshore, need regular maintenance. While a source of low-cost, renewable energy, wind also causes stability-robbing waves to form, making personnel transfers from service boats to turbines unsafe. With even a modest 2-foot sea, access often seems unattainable to the technician standing on a rolling deck.

Netherlands-based Sima Charters BV's newest vessel, Amethyst, has a competitive advantage for crew transfers: its Seakeeper 26. Taming the rough waters of the North Sea, the gyro achieves up to a 90 percent reduction in roll, allowing service personnel to safely enter and exit the turbines.

Installing a Seakeeper was a wise business decision for Ruud Lievaart, owner of Sima Charters BV. The company prides itself on finding the best, safest solution to its clients' crew transportation needs. When other companies stay ashore due to a rough sea state, Amethyst is able to go out and safely transfer workers. Passengers and crew are also safer onboard, and less fatigued. "A vessel with a Seakeeper is chosen sooner by a customer," said Lievaart. This business edge keeps Amethyst in high demand within a very competitive market.

Plying the cold, grey waters off Rotterdam, the 66-foot heavy duty service and pilot vessel ferries up to 12 technicians and their equipment to and from their work assignments. Powered by twin Volvo Penta IPS D13s, it has a cruising speed of 22 kts and a range of 700 nm. It is the latest in safety-centric design, due in part to its state-of-the-art Seakeeper gyro.

Lievaart chose a Seakeeper-equipped monohull over a catamaran or SWATH when designing Amethyst. There is more available storage space below deck and the movements are more natural and subdued, especially at low or zero speeds.

The Seakeeper 26 is designed for vessels up to 100 tons and requires minimal power to operate. Spinning a flywheel in a vacuum environment, these gyros offer exceptional righting force while underway, or at slow or zero speed. Unlike passively-controlled systems, Seakeeper gyros feature active control that allows them to operate at full torque over a wide range of sea conditions. Compact and completely internal, all Seakeepers are extremely quiet, easily-installed and virtually maintenance-free.

"The offshore wind power industry has seen unprecedented growth over the past few years," said Andrew Semprevivo, Seakeeper VP of sales and marketing. "With its new Seakeeper-equipped Amethyst, Sima Charters BV has poised itself to lead its regional business sector."

A video on Amethyst is available at Additional information on Sima Charters BV can be found at

By Professional Mariner Staff