Cool technology delivers polar performance

Operating in the world’s harshest environments demands more than robust engineering – it requires innovation and collaboration.  
Kongsberg Maritime took both to new levels during a pioneering trial aboard the British Antarctic Survey’s (BAS)-operated research vessel, RRS Sir David Attenborough, where a sensor‑equipped propeller blade captured real‑world loads as the ship worked in Antarctic sea ice. 

Built to Polar Code standards and Polar Class 3, the vessel regularly operates in ice up to one-metre thick while maintaining a maximum draft of 7.5 metres to access remote polar stations. Silent operation is critical for scientific accuracy, so the hull form, twin skegs and bow design minimise bubbles and underwater noise. Inside, advanced laboratories, container‑ready decks and mission‑support features, from anti‑roll tanks to a hospital and gym, enabled complex science at the frontier. 
 

At the heart of the propulsion system is Kongsberg Maritime’s Promas solution, a five‑blade controllable pitch propeller (CPP) optimised for ice milling and integrated with a hydrodynamic rudder profile. For the trial, engineers installed strain gauges inside one stainless‑steel blade to measure forces encountered under true Antarctic conditions. The installation was carried out at Kongsberg Maritime’s propulsion facility in Kristinehamn, Sweden, where recesses were milled, two gauges were embedded and welds were executed to withstand the rigours of repeated ice contact. 

The programme focused on the Weddell Sea, with test sites around James Ross Island and the eastern Antarctic Peninsula, areas influenced by the Weddell Gyre’s ‘conveyor belt’ of sea ice. Divers entered the water via a tethered cage lowered over the stern and connected to a port at the blade root to download data and recharge the instrumentation. With an eight to 10-hour battery window, dive operations took place twice daily. The ship was exercised in two principal regimes: level fast ice (attached to the coast and stationary) and large floes with pressure ridges formed by wind and current. Turning manoeuvres in fast ice and controlled “glancing blow” passes at floe edges added complementary hull‑pressure data. 

BAS and partner teams combined multiple measurement streams. In addition to the instrumented propeller and strain gauges on the propeller shafts, borescopes captured imagery of ice moving under the hull, and hull‑mounted pressure sensors logged contact events. Aker Arctic Technology led the ice trials, drawing on its experience in polar vessel performance. Lloyd’s Register provided strain‑gauge and borescope systems, while the American Bureau of Shipping (ABS) Canada contributed lidar, camera and thermal imaging to characterise ice conditions in real time. BAS specialists coordinated operations, using satellite and drone imagery to select optimal sites and quantify ice properties – thickness, salinity, temperature and crushing strength – before, during and after transits. 

The objective was to validate propeller performance under representative ice loads and to understand whether operating approvals could, in the future, be extended to higher ice classes. The measurements also informed optimal pitch strategies in varying ice types, promising gains in safety, efficiency and fuel use. For BAS, the potential benefits included shorter transits, wider operating windows and more resilient science scheduling. 

Chris Hall, Kongsberg Maritime’s Senior Hydrodynamicist, was onboard and analysed datasets daily. He says: “We’ve spent decades refining ice-class propulsion systems, and this trial aboard the [RRS] Sir David Attenborough was a unique opportunity to validate that expertise in some of the most demanding conditions on Earth. By capturing real-world data on how propellers interact with sea ice, we can push the boundaries of vessel performance and safety in polar regions. The insights gained here could transform how ships operate in ice, improving efficiency and resilience for future generations of polar research and commercial vessels.” 

From BAS’s perspective, location and timing were pivotal. Andrew Fleming, its Head of Mapping and GIS, notes: “The area we selected to conduct the trials is the Weddell Gyre, a circular ocean current. This creates a conveyor belt of sea ice that moves northward along the coast. This area typically has sea ice year-round and provided good conditions for testing. The timing was crucial – we needed fast ice, ideally first-year ice, and around one-metre thick with approximately 20 centimetres of snow cover. The sea ice conditions are extremely variable, so we looked for the perfect ice conditions for our tests using a combination of satellite imagery and drones.” 

The project demonstrated how Kongsberg Maritime supports customers wherever they operate in the world. Chris adds: “There was excellent collaboration from all parties to plan and execute this trial in very challenging conditions. We were proud to have supplied the instrumented blade, hydrodynamic analysis and propulsion domain knowledge, and for me, it was the chance of a lifetime. This type of trial is unusual, but I’m sure the findings will provide a much better understanding of just what’s possible for manoeuvring through heavy ice.” 

Whatever the final outcomes of the post‑voyage analysis, the trial strengthened the evidence base for ice‑class propulsion and will inform future designs, operational guidance and training.