Abstract: The long-range passive towed sonar was first modernised a few years ago. Building on operator experience over that period, a concept was developed of optimising the tasks performed by sonar operators, and improving forms of imaging to inform about object detection and support object tracking. The concept was implemented and successfully tested during ships’ manoeuvres. The optimisation of operator tasks was designed to keep listening for signals from an object separate from object tracking. Operator tasks have been made easier by rearranging the imaging, improving interaction between monitors, extending the navigation imagery module, adding new tools for building an acoustic database of potential targets; and improving the recording, browsing and playback of key recorded data. The article gives a more detailed account of the project and its results.