Powerful new Østensjø tug will feature Steerprop propulsion

Image: Skipsteknisk

The largest and most powerful tug ever ordered by Norwegian shipowner Østensjø Rederi will feature the most powerful ducted propulsors ever developed by Finnish propulsion specialist Steerprop.

On order at Spanish shipbuilder Gondan, the tug is being built to a completely new Skipsteknisk design, designated ST-933, developed in close cooperation with Østensjø. It will have a bollard pull of 150 tonnes and a DP-2 dynamic positioning system. It will be equipped.with a diesel-electric hybrid propulsion system for fuel-efficient operations and prepared for methanol fuel.

Operational roles for the ST-933 include: offshore construction support; offshore terminal and field support / escort duties; anchor handling / ocean towing; salvage and rescue; oil recovery (support role); ship assistance, firefighting, cargo transfer

Key specifications include:

• Length: 50 meters
• Beam: 17 meters
• 150 tonnes bollard pull
• Dynamic Positioning DP-2
• High-standard accommodations for 14 crew (10 single cabins, 2 double cabins)
• Diesel electric hybrid propulsion system

Gondan Shipbuilders has now placed an order with Steerprop for the vessel’s azimuth units.

Steerprop will supply dual-end versions of its SP 50 W D propulsors—the most powerful ducted units it has ever delivered—providing the vessel with the flexibility to operate main propulsion using a diesel engine, an electric motor, or a combination of both. The 150-tonne bollard pull vessel will also feature DP2 dynamic positioning capability, meeting the high demands of offshore tug and towage operations.

The contract marks Steerprop’s first collaboration with Gondan and a renewed partnership with Østensjø Rederi. It follows close cooperation between the companies throughout the development of the new multipurpose tug design.

“The newbuild represents a major step in further strengthening our offshore towage fleet and will be our flagship in the tug segment, achieving the highest possible efficiency through a hybrid propulsion configuration tailored to its operating profile,” said Østensjø Rederi CEO Kristain Helland Vea. “The compact size and simplicity of Steerprop’s solution—while fully meeting our demanding performance requirements—made it a clear choice for this vessel.”

In addition to delivering excellent performance and efficiency, Steerprop’s compact propulsor design provides greater flexibility in vessel arrangement—an important advantage in more complex hybrid configurations. A robust mechanical propeller drive and fixed-pitch propeller concept ensure the reliability required for challenging offshore operations, where uninterrupted vessel availability is critical.

Steerprop’s dual-end propulsors are particularly well suited to hybrid propulsion, with the ability to connect and operate two power sources. On the new tug, the majority of operations will be carried out using the electric motor, while the diesel engine will provide additional power when higher bollard pull is required.

Ducted propulsors are deployed where efficiency and thrust at low speeds and maneuverability are a priority, making them particularly well-suited to the tug segment.

Juho Rekola, director, sales & project management at Steerprop, said: “Working closely with the shipowner from an early stage, we were able to contribute a propulsion solution that delivers benefits both to the shipyard in terms of initial cost and to the shipowner through lifecycle efficiency and proven performance. We are proud to support Østensjø Rederi, Gondan Shipbuilders, and Skipsteknisk in bringing this new hybrid tug design to life.”