In 2014 we found many shallows and reefs
that were not charted accurately if at all on Navionics
, Garmin or CMap. We eye-balled everything in time, as we made it a rule
to move only in daylight if at all possible. A friend lost
her boat, however, on an overnight passage
-- hit a reef just before sunrise. The "true" position of this killer reef wanders greatly if you look at different digital chart products, different updates. Having good clear satellite
imagery is definitely a good idea.