Distance of spotting ? GWX2.1

[Hartmann]

True,
and more if the boat use a camo paint.

usually the boat is a "Heavy" object in the sea, with the waves cover¡ng the deck with only the little tower visible at some distance.
it´s the cause of the importance of allied radars late in the war.

For example a 2 meters men can walk on the grass, but a mice could detect the men and evade before he can see it.