Divine Angel said:

So you know how flight MH370 disappeared from radar and everyone’s like, “how does a plane just fall off the radar?”, do ships do that too?

Yeah. They aren’t tracked by radar for very long after leaving the coast so they have satellite transponders to send their positions (and other information no doubt) so they can be kept track of. Depending on the ship, the militaries around the world might also track it visually from orbit.