Just to correct some misinformation. A class B receiver (recreational boat) will only show up on MT when it's within range of a receiver station (about UHF distance). A class B will also show up if a ship with a class A receiver is also running a receiver station (like some of the cruise ships do). Otherwise, there won't be any signal. They do not show up as a satellite based transmitter unless they actually have a satellite transmitter (mostly only commercial vessels). If the signal is older than X number of days, it may show up in the same location for a period of time, but then will disappear.
If your buddy is going straight from Bermuda to Boston, the transmitter will be out of range most of the time unless a ship with a satellite and receiver station happens to pick it up.
You don't have to have a paid version to use MT, but there are a few advantages (like being able to see nautical charts and getting notices of boat movements). If you run your own MT station, you get some of the paid stuff as a thank you!