![Scientists undertaking a beach profile survey in 1970s, NZ](http://static.sciencelearn.org.nz/images/images/000/000/128/full/Beach-survey20150807-30590-9p1ndr.jpg?1674163735)
Undertaking a beach profile survey to analyse changing sand volumes along the New Zealand coast. Surveys in the 1970s used a jet boat to echo-sound the offshore profile and an instrument onshore to measure the boat’s position. Willem is in the bow of the boat, monitoring the echo sounder.