Emerson’s VRC on 220m-long offshore crane vessels

The 220m-long vessel is designed for the installation and removal of large offshore structures, such as oil and gas platforms, subsea production facilities, foundations, moorings, and deep water floating structures. Each of the ship’s two revolving cranes is capable of lifting up to 10,000t.

The critical task of stabilising Sleipnir during lifting operations will be carried out by the ship’s ballast control system, which transfers water between onboard tanks to counter-balance the weight of shifting loads.

“Not only must the ballast control system operate reliably in demanding marine conditions, but it must do so on an extraordinary scale,” Emerson said.

To address these unique challenges, Emerson’s experts worked closely with the stakeholders to design a custom, fully-redundant Damcos VRC solution for the ship’s fluid management and ballast systems that includes a total of 847 valves, actuators, local power units (LPUs), and eight interface cabinets connected by a P-NET communication bus.

Emerson’s Damcos LPUs are rated at IP68, meaning that they are able to operate while submerged at a depth of three bar (30m) for at least 24 hours. The LPUs are mounted directly on the actuators and connected to the P-NET network, saving the shipyard installation man-hours by eliminating hydraulic tubing and greatly improving reliability with their short circuit-tolerant design. This configuration allows any LPU to fail entirely without affecting the other units in the loop.

“A groundbreaking project like this called for us to partner with automation experts who could provide a VRC solution that minimised cost, weight, size, and energy use while ensuring years of safe operation in some of the toughest situations imaginable,” said Leo Stobbe, commissioning manager for Sleipnir at Heerema.