Prepare to be amazed! Specialist divers are preparing to plunge into the frigid waters of the Weddell Sea, Antarctica, this festive season (December 22-29, 2025). Their mission? To push the boundaries of polar research and test the capabilities of the UK's state-of-the-art polar research ship, the RRS Sir David Attenborough. But here's where it gets controversial: they're not just taking a swim; they're embarking on a groundbreaking mission to understand how this vessel navigates through challenging sea ice conditions.
Imagine the scene: divers, tethered to a cage lowered directly from the ship's stern, venturing beneath the icy surface twice a day. Their task? To gather crucial data on how the ship's propellers interact with sea ice, using specialized instruments deployed for only the second time in the Antarctic.
The RRS Sir David Attenborough, which made its maiden voyage to Antarctica in 2021, has already proven its mettle in breaking through sea ice. However, these trials are designed to test its performance in specific ice conditions, providing invaluable insights into the challenges faced by polar research vessels. And this is the part most people miss: the results of this mission will significantly advance our understanding of how these vessels cope with sea ice and, most importantly, contribute to maritime safety in polar environments.
So, what exactly are they testing?
Central to the ice trials is an instrumented propeller blade. This blade will meticulously record the forces and loads experienced by the propellers as the ship cuts through the ice. The instruments have a limited battery life, which is why the divers must deploy twice daily – morning and evening – to download the data and recharge the instruments.
The ship will be put through its paces in two distinct types of ice: level fast ice – ice that's attached to the coast and stationary – and large ice floes containing pressure ridges. These ridges form when ice floes are pushed together by wind and ocean currents. Understanding how the vessel responds to these features is crucial for determining its operational limitations.
The testing process is carefully choreographed. For level fast ice, the ship will drive through the ice, recording data as it goes. Teams will then measure the ice's properties, including thickness, salinity, and temperature, and collect ice cores for crushing strength testing. To test the ship's performance in ice ridges, the team will take ice measurements before the vessel breaks through. The ship will then move through the ice ridge, again collecting data on the propeller's performance.
The trials also include turning maneuvers in pack ice and 'glancing impact' tests, where the ship drives at an angle into the edge of an ice floe while sensors record the pressure on the hull.
Data-driven Ice Operations
The data collected by the instrumented propeller, combined with measurements from strain gauges on propeller shafts, borescopes (which will capture photos and video of the ice moving under the ship), and pressure sensors on the hull, will provide unprecedented insight into ship-ice interactions. This data is critical for understanding how the ship performs in various ice conditions.
Location, Location, Location
The trials will focus on areas around James Ross Island and the eastern Antarctic Peninsula.
Andrew Fleming, Head of Mapping and GIS at BAS, is leading the ice trials and will play a key role in selecting the testing locations, using satellite and drone imagery. He explains that the area they've selected is where the Weddell Gyre – a circular ocean current – creates a conveyor belt of sea ice that moves northward along the coast. This area typically has sea ice year-round and should provide good testing conditions.
The timing is crucial. The team needs fast ice, ideally first-year ice, around one meter thick with approximately 20 centimeters of snow cover. The sea ice conditions are extremely variable, so they'll be using a combination of satellite imagery and drones to hunt for the perfect ice conditions for their tests.
A Team Effort
The project brings together international expertise in polar vessel design and performance. Aker Arctic Technology is leading the ice trials, drawing on extensive experience in polar ship design and full-scale ship-ice interaction measurements. Lloyd's Register has installed strain gauges and borescopes, whilst Kongsberg Maritime has provided the instrumented propeller blade. American Bureau of Shipping Canada is contributing lidar, camera, and thermal imaging systems to characterize ice conditions in real-time. Experts from the British Antarctic Survey will coordinate operations, using satellite imagery and drone surveys to identify optimal ice conditions.
Rob Hindley, Head of Consultancy & Technology Development at Aker Arctic and leader of the Aker Arctic ice trials team, states that these trials are truly one of a kind. Direct measurements of propeller ice loads are fundamental to advancing dimensioning practices for safe and sustainable polar shipping, yet their complexity has meant they are rarely undertaken.
What makes this program genuinely groundbreaking is that, for the first time, propeller, shaft, and hull ice loads will be measured simultaneously. This will deliver an unprecedented understanding of the strength levels required for ships like these, helping to shape the next generation of vessels capable of operating safely across a wide range of ice conditions.
Chris Hall, Senior Hydrodynamicist, Kongsberg Maritime, adds that at Kongsberg Maritime, they've spent decades refining ice-class propulsion systems, and this trial aboard the RRS Sir David Attenborough is 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, they 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.
The results could have implications for the ship's scientific program, potentially enabling operations in ice conditions previously considered too challenging. The data will also help optimize engine performance, with potential benefits for fuel efficiency and carbon emissions.
These new experiments will build on lessons learned from earlier sea ice trials, which took place in 2022. The vessel faced second-year fast ice with over one meter of snow coverage – conditions beyond the ship’s design specifications.
The research vessel, owned by NERC and operated by the British Antarctic Survey, is the UK’s flagship polar research platform, enabling scientists to study climate change, biodiversity, and ocean processes in the Earth’s polar regions.
What do you think? Are you fascinated by this groundbreaking research? Do you believe these findings will significantly impact future polar expeditions and maritime safety? Share your thoughts in the comments below! Photos of dive operations will be available from December 30, 2025.
