David Edgar Cartwright. 21 October 1926 — 2 December 2015

David Cartwright was one of the world's leading authorities on the tides. However, when reflecting on his life, Cartwright made the point that his early scientific career was not a success. Indeed in 1953, at the age of 27, he had virtually despaired of any creative scientific future. At the time he was being pressurized to stop his work on the statistics of ship motions but his prospects rapidly changed when he was invited to apply for a post at the new National Institute of Oceanography (NIO) being set up by George Deacon. At NIO he soon made important contributions to the study of ocean waves, especially the calculation of directional spectrum and wave climate. His earlier involvement with ship motions also culminated in a successful joint study with Louis Rydill on the response of ships to the spectrum of waves. Following this, his use of computer methods for time-series analysis led to an invitation to the Scripps Institution of Oceanography where, with Walter Munk, he developed the response method of analysing tides making use of the very long tidal records collected from Hawaii and Newlyn. He was also made aware of the significant lack of good tidal data from the deep ocean. Returning to the UK, he continued these interests, studying the deep-ocean tides of the Atlantic and leading an international collaboration that measured deep-ocean tides. He also investigated the effect of tides on storm surges around the UK. He became assistant director in charge of the Institute of Oceanographic Sciences (IOS) Bidston laboratory, where he continued these activities and started research on estimating the tides using data from the Seasat radar altimeter. After retirement he successfully extended this work with Richard Ray at the Goddard Space Flight Center. Using Geosat altimeter data they generated accurate global maps of the tides in a set of papers that Cartwright considered to be his best work. He wrote a successful book titled ‘ Tides: a scientific history ’, and later published further work with Ray on the internal tides of the ocean.