The RRS Sir David Attenborough completes ice trials during its maiden voyage to Antarctica – a critical milestone in the commissioning of Britain’s new polar ship. This is the first in a series of trials to get the ship ready for multi-disciplinary science missions.
The purpose of ice trials is to test the ship’s capability and performance in ice. The trials team tested the ship’s capability over 10 days in January by following a set of standard procedures to ensure the ship fulfils its contractual specifications to perform in ice. British Antarctic Survey (BAS) operates the RRS Sir David Attenborough, which is owned by UKRI-NERC.
The ship was tested through ice, at every power level, to measure its performance and compare it to the expected, modeled results. The team also performed a range of other maneuvres including reversing, turning, as well as impact tests at different speeds in areas of sea ice around the Antarctic Peninsula and Bellingshausen Sea.
The team enlisted the help of satellites to locate suitable areas of ice for the trials. Most manoeuvres took place in fast ice – ice that is attached to the coast and not moving. This allowed the team to calculate accurately the amount of energy required to break the ice. Tests in various ice conditions and concentrations, such as open and closed pack ice, give a complete picture of the ship’s performance.
To fully understand the ship’s performance, the trials team took measurements of the ice, including ice thickness and the amount of snow, as well as physical properties of the ice such as temperature and salinity.
“Overall, we’re really pleased with the ship’s performance in ice trials – in some trials it actually performed better than we expected. The trials did highlight some issues with the ship which need to be addressed but this was expected – the SDA is a bespoke ship with a complex design, and the purpose of trials is to find the things that don’t work so well,” BAS’ Ralph Stevens, Captain of RRS Sir David Attenborough, says. “The thing that surprised us most was how comfortable the ship was while breaking through the sea ice. The bow breaks the ice in a completely different way to our previous vessels, and is much quieter than expected.”
The ship encountered unprecedented sea ice conditions after the ice trials – second-year sea ice, covered in a thick 1.5 meter layer of snow. This hampered efforts to reach Stange Sound to deliver critical science cargo in support of the International Thwaites Glacier Collaboration.
The RRS Sir David Attenborough is a Polar Ice Class 5 (PC5) ship, meaning it can operate year-round in medium, first-year ice. The ship can break through ice one-metre thick at a speed of three knots (5.6km/h). When ice breaking, the ship rises up on the ice and uses its weight – 15,000 tonnes – to break through.
The RRS Sir David Attenborough will return to the UK in June 2022 at the end of the Antarctic season. The ship will spend several weeks in refit to rectify the issues identified during ice trials, and to finish commissioning science equipment, which was delayed due to Covid-19. The ship will also spend around 30 days at sea conducting initial science trials, testing acoustic and winch equipment. These trials are to ensure all the complex science equipment on board the ship is functioning correctly and will provide the crew and science teams the opportunity to establish new protocols and ways of working. Further science trials will take place during the 2022/23 Antarctic season.