Aviation and maritime...
Interesting parallels between aviation and maritime but some differences If we compare a 747-400 freighter with the equivalent in the maritime world you would get a container ship such as the Maersk Emma. A few numbers
Length: 1200ft
Width: 170 ft
Weight: 200 000 tons fully loaded
Single engine of 88 000 kW
Speed: 25 knots
Cruising range: 50 days / 30 000 miles
Crew: 13 for round the clock operations.
At night, in high seas navigation a single person on duty at the bridge is enough. (Fully automated engines). No doctor. At best, a paramedic trained crewmember.
Different world, really!