Don't feel dumb, its an easy mistake for a beginner to make.
units must be different than car GPS's simply because there are no streets. Although, it is possible to load nautical charts
in some automobile type GPS units. Generally though, the resolution you need for boat GPS systems is much greater than that for car units although many do get away with car type GPS units on boats.
What you do with a boat GPS/chart plotter is you have to create a route
. A route
is a series of waypoints from point A to point B with straight lines between the waypoints. Of course, you could set a route right across a coral
reef if you chose to do so. There is no artificial intelligence to prevent you from making an impossible or dangerous route for the boat to follow. You will need to learn how to read nautical charts
in order to create a safe route, along with a few other nautical skills such as understanding tides for example.