Highlights in this issue include an interview with Orbital UAV's CTO Geoff Cathcart and a closer look at the Aurrigo shuttle that kept the Wales Open golf tournament in operation. Our dossiers detail the Saab Sabertooth AUV acting as a permanent janitor for deep-sea infrastructure and the Hirth 3507-01M two-stroke engine. The focus articles dive into the subjects of IMUs and additive manufacturing. Our insight looks at UUVs and we report on the virtual Oceanology International show. Our digest features the hydrogen fuel-celled, VTOL-transitioning, Zepher Flight Labs Z1 UAV plus much more...