We engineers are naturally drawn to specific technologies or design challenges, informed by our backgrounds and disciplines. The challenge in achieving IMO Degree 4 autonomy1 is often said to require new skills and new ways of thinking. This is the 4th RINA Autonomy Conference and RINA’s technical committees for technology and for safety are already engaged in the topics herein. These committees keep close links to the Nautical Institute, to IMarEST’s Special Interest Group (SIG) for autonomy and to regulators. Forums such as the UK Maritime Autonomous Systems Regulatory Working Group (MASRWG) have usefully contributed for some years [1]. Acknowledging the Defence sector has certain unique legal considerations, some insights and lessons are offered to the broader community.