Making waves in the Southern Ocean

December 2017 marked the start of the 57th annual South African National Antarctic Expedition (SANAE), with the SA Agulhas II setting sail for Antarctica, loaded with supplies, vehicles, and scientists.  Among those on board were the new SANAE IV base team, students from various universities, meteorologists, and a construction crew set to finish the renovations on the base.

Forming part of the ship-based scientific personnel were two of Prof Annie Bekker’s students – Brendon Nickerson (second-year PhD student) and Gerhard Durandt (first-year MEng student) of the Sound and Vibration Research Group (SVRG) at the Department of Mechanical and Mechatronic Engineering.  Also included in the team was Andrei Sandru from Aalto University in Finland, one of the SVRG’s research partners.  Their goal on board was to monitor and maintain the various measurement systems installed on the ship by the research group.  These systems included full-scale vibration monitoring, hull strain monitoring, shaft-line monitoring, and ice observations by means of stereo cameras.  The SVRG has been involved in this project since 2012 and has been aboard the SA Agulhas II, recording data for each of the SANAE voyages.

The aim of the research conducted by the SVRG on the SA Agulhas II is to investigate dynamic ship responses, shaft-line fatigue, and structural fatigue.  This is extremely valuable information for the vessel owners and operators in order to operate the ship safely for, and efficiently with, a known Antarctic loading profile for the planned 30-year lifetime.  Furthermore, research shows that continuous full-scale measurements of ship dynamic responses are rare, meaning that the SVRG is one of the few groups to have this opportunity.

The data recorded on board the SA Agulhas II increases the scientific basis for ice-going vessels and aims towards real-time monitoring, decision aiding and digital twin solutions for the future maritime industry.  Slamming investigations are aimed at identifying, categorising, and analysing impulsive events within the very large data sets recorded during a voyage.  The shaft line investigations focus on determining ice induced torque and thrust loads on the propeller, for the monitoring and prediction of fatigue failure.  Structural dynamic investigations are purposed towards estimating ice loads on the hull using a novel technique, which incorporates rigid body and elastic motion using operational modal analysis.

This year’s voyage was quite an experience for the SVRG team, as they not only had the opportunity to conduct research aboard the SA Agulhas II in the ocean, but they also assisted with the logistics and resupply of the SANAE IV base.  This entailed helping with the off-loading of cargo and fuel pumping onto the ice shelf at Penguin Bukta, as well as towing the off-loaded cargo to the SANAE IV base.  The team was furthermore present during the takeover function at the base, where the SANAE 56 team handed over the reins to the new SANAE 57 team, who are planning to spend the next year in Antarctica.

The SA Agulhas II returned home on 13 February 2018, with everyone on board feeling overjoyed at the prospect of reuniting with their loved ones.  The SRVG team would like to thank all those involved in the planning and execution of the voyage, and for all the amazing opportunities and experiences.

Photo (from left to right):  The SVRG team – Brendon Nickerson, Gerhard Durandt, and Andrei Sandru – waiting to board the SA Agulhus II.