It's simple - you need it when you need it. The rest of the time you don't.
There have been many times when I felt I needed it, and couldn't avoid needing it. But you can get by without it. It is a luxury that in my opinion is handy enough to justify for me.
We took off on our first boat's first overnighter to meet up with some other cruisers. We took off late due to a technical problem. We got to the San Juan
Island of Sucia in the pitch
black dark. Couldn't even see the island one mile away. Had an old radar but didn't really know how to use it. Thought we were going to have to sail around all night staying well away from other islands or rocks using the depth sounder
, and the GPS
. Not fun. We were literally freaking out. Finally turned on the radar and fiddled with it enough to get the island on the screen
. Went back and forth along the south side and found the little narrow inlet and came in on radar and picked up a mooring
ball. Made several mistakes
and got lucky. The entrance to this inlet has claimed many boats in the day time. The other experienced cruisers (we were newbies) were amazed that we even tried it. Lots of other stories where radar saved the day. Those times are when it is foggy, at night, or too much rain, i.e. poor or no visibility. If you avoid those times you don't need it. And sometimes at night you can use navigation
aids to get in to harbors so you don't need it then either. But if it is foggy you do. But a chartplotter
can get you in places too but that doesn't help with movable obstacles - other boats primarily or places that aren't well charted - other countries mostly. But most of the time you don't need it, only when you do.