Earlier quoted context omitted.
Sailors can make calls using the ships Wi-Fi via full sized Starlink dishes, they need coverage on land. But even ignoring that the contention is low in the middle of the ocean and satellites have hardware either way, driving down the market rate for calls at sea.
The setup cost for Starlink on a boat is still massively higher than on land.
Calls are ~0.75 MB/minute allowing a 24/7 conversion for for a full month for 250$, or more realistically mostly sending other kinds of data and a sub cent per minute opportunity cost for using that data on calls. The actual hardware installation is relatively trivial compared to operating a boat.