then how come you are such a dumb squat when it comes to radar?

I probably spend more time as
radar observer, on my week off, than you do in a year.

indeed, you didn't even know you need nearly flat water to see low rocks with
radar, as witness your statement below:

nor
uncharted rocks low in the water with any seas running,

Without seas running, may. With seas running, still may .... might pick
up added sea return in a specific area