The following scenarios mainly refer to racing on a medium to large size keel boat. Some of the info would be of use when cruising as well. For a small keel boat, like a J24 e.g, or for a mega large yacht the procedures would be adjusted slightly.
Before the start the Bowman often sits on the front pulpit (if one exists) talking or gesturing to the tactician about other boats and distance to the start line. The position at the very front of the boat gives an excellent view, which the back of the boat doesn’t have.
For the Bowman to correctly assess the distance to the line it’s beneficial to check the transit lines before the start, i.e. sighting some land mark on the extension of the start line.