Finnish propulsion company Steerprop has received a further thruster order from shipbuilder TKMS for a new German research vessel, ‘Polarstern’.
The addition of two Steerprop SP 40 TT ARC tunnel thrusters means that Steerprop will now provide the complete, fully-integrated propulsion thruster package for one of the most advanced research icebreakers.
The order builds on Steerprop’s earlier contract to deliver two SP 160 Pull azimuth thrusters and hydrodynamic design of shaftline integration for the new vessel. It means that the new Polarstern will be the first Polar Class (PC) 2 icebreaker project in which main propulsion, tunnel thrusters and hydrodynamic integration have been awarded to a single supplier.
Yngvar Frodell, Polarstern Project Director, TKMS, said: “Steerprop’s integrated propulsion approach and their capability to meet stringent ice-class and noise specifications made them a natural fit for this project. We value the close cooperation and the technical competence they bring to this highly demanding vessel.”
Polarstern is being built for the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI).The new order is a result of a strong working relationship developed between Steerprop, TKMS and AWI during discussions around design and delivery of the vessel’s main propulsion units.
Detlef Wilde, Polarstern Project Director, Alfred Wegener Institute, added: “The new Polarstern is a long-term investment in advancing polar science under the most challenging environmental conditions on Earth. Reliable, quiet and efficient propulsion is essential for our research missions, especially in sensitive polar ecosystems. Steerprop’s solutions support our ability to operate safely and effectively in both Arctic and Antarctic waters.”
The extended order is said to reinforce Steerprop’s strategy of playing a leading role in the development and construction of propulsion concepts for ice-going and special-purpose vessels, positioning the company at the forefront of technically demanding research-icebreaker projects.
Riku-Pekka Hägg, CEO Steerprop, said: “This project represents a defining moment for Steerprop. Being the first company to be entrusted with the complete propulsion thruster package and hydrodynamic integration responsibility for a PC2 icebreaker demonstrates the value of delivering a unified, carefully engineered propulsion concept—and underscores the strength of our expertise in ice-class and research-vessel applications.”
Steerprop’s gridless SP 40 TT ARC tunnel thrusters are specifically engineered for heavy ice operation engineered. They will work seamlessly with the main azimuthing units to meet the vessel’s demanding operational requirements.
The ICES 209 acoustic requirements applicable for the vessel are among the strictest set for a polar research vessel, meaning that all potential sources of underwater radiated noise (URN) must be minimised. According to Steerprop, this is influenced by propeller design, but more significantly through optimising tunnel design and ship structure together to eliminate propeller cavitation. Flexible mountings for the tunnel thrusters further reduce URN by preventing propeller vibrations from reverberating against the ship’s hull.
The delivery includes a full bridge propulsion control system and tunnel extensions, ensuring seamless integration with the vessel’s hydrodynamic design. Deliveries are scheduled for 2027.
The new Polarstern is designed to operate self-sufficiently during extensive scientific expeditions in some of the harshest environments, in both the High Arctic (including the North Pole) and Antarctica. It is expected to be among the largest and most capable polar research icebreakers constructed, with a length of about 160m, a beam of 27m, a draught of nearly 11m and a gross tonnage of about 26,300gt.
Image: Polarstern will feature Steerprop’s complete propulsion package (source: Steerprop)



