But you seek hints of troubles. There are boggies around there -- some to the east, west, and north.
Click through the Navionics.com / WebApp / Navionics+/South Indian Ocean/then click and zoom in. You can drag the chart around a bit.
You don't have "Camden Harbor" level charts -- there you can pick-out your slip and dock.
The resolution on some charting systems varies by the resolution of your screen or plotter. In their case it looks like they had multiple higher quality portable screens with good accelerators. Certainly that wasn't the issue.
Zoom, zoom, zoom...
Situational awareness is a virtue
Curiousity is rewarded; and,
Complacency is often punished.