1. School of Mathematical Sciences, University of Adelaide, Adelaide, SA 5005, Australia
2. School of Mathematical and Physical Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
3. Department of Mechanical Engineering, University College London, London WC1E 7JE, United Kingdom
4. National Centre for Maritime Engineering and Hydrodynamics, Australian Maritime College, Newnham, TAS 7248, Australia