@pn
Seriously, a submarine is not best suited as a radar search platform, pretty useless, and very uncomfortable, as a visual platform, and exactly what is it expected to detect on sonar?
I did not really mean radar as I envisaged having the sub just submerged so it is safe from shipping above and then searching the surface above and ahead of it. Surely they must have some kind of echo based technology that could detect objects awash ?