Six Azimuth Thrusters for Østensjø’s new flagship

November 15, 2024

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Brunvoll has signed a contract with Astilleros GONDAN for the delivery of an azimuth thruster package for an Ocean Energy Support Vessel . The vessel designed by Salt Ship Design will feature six thrusters from Brunvoll, where three are azimuth propulsion thrusters and the other three are retractable azimuth thrusters. Østensjø Rederi is scheduled to take delivery of the vessel in the second half of 2027

Figure 1. Østensjø’s new Ocean Energy Support Vessel. Illustration: Salt Ship Design AS

Brunvoll’s delivery for the OESV consists of 3 azimuth propulsion thrusters in the aft of the vessel, with a power output of 1900 kW each. In the bow, the vessel will feature three retractable azimuth thrusters of 1600 kW, whereof two of the thrusters will also act as a tunnel thruster in retracted position. All thrusters are designed for the established strict requirements for rapid, safe, and accurate DP operations. This includes high rotation speed and quick propeller acceleration.

This configuration with three retractable azimuth thrusters in the bow on this type of vessel is quite unique. Traditionally, similar vessels are equipped with a single retractable azimuth thruster and two tunnel thrusters. This new arrangement improves DP capability while also enhancing system redundancy and operational performance.

The combined retractable azimuth and tunnel thrusters are of Brunvoll’s latest and most compact design, with a significantly lower building height compared to traditional combined azimuth/tunnel thrusters. This enables for an efficient arrangement with great utilization of the space available.

“Østensjø takes a hands-on approach when developing a new vessel, thoroughly evaluating different options. Based on our experience, selecting Brunvoll for this project was a straightforward decision. We value long-term relationships, product quality, and reliable service, and the shipyard also recognized Brunvoll’s delivery accuracy and support.

We wanted a vessel with good DP capability and high efficiency, and that’s the reasoning for having three retractable azimuth thrusters in the bow of the vessel. We sometimes experience that tunnel thrusters ventilates during DP operations in high sea states, and the retractable thruster solves this issue and at the same time make the system more redundant and efficient.”, says Egil Arne Skare, Chief Project Officer at Østensjø Rederi.

Brunvoll’s delivery also includes its own propulsion and thruster control system, BruCon PTC. For enhanced monitoring and decision support for maintenance and energy efficient operation, the vessel will be equipped with Brunvoll’s condition monitoring system, BruCon CMS.

The OESV designed by Salt Ship Design is equipped to perform a wide range of operations within offshore energy, including Inspection, Maintenance, and Repair (IMR), construction, walk-to-work/flotel services, and cable laying. It is a versatile platform that ensures that the vessel can operate across multiple segments within the ocean space, ensuring efficiency and operational flexibility. The main particulars for the vessel are a length of 120 meters, a beam of 23 meters, and a capacity to accommodate a crew of 180 persons.

Figure 2. Profile view of the vessel with it six azimuth thrusters. Illustration: Salt Ship Design AS

“To be able to equip another of Østensjø’s flagships is quite an honour. Edda Freya is one of Brunvoll’s best references and we are confident that this groundbreaking vessel will be among the best as well.

I would like to take this opportunity to thank Østensjø, Salt, and GONDAN for the trust they have vested in us”, says Bernt Rune Riksfjord, VP Sales at Brunvoll.