MOTC Manual - edited

Definitions:
Sidelights – red and green lights can be separate or combined and are visible to another
boat approaching from the side or head-on. The red light indicates a boat’s port side;; the
green light indicates a boat’s starboard side. Each light must show an unbroken light over a
112.5-degree arc from dead ahead to 22.5 degrees abaft the beam on their respective side.
On a vessel less than 20 meters the sidelights may be combined into one fixture placed on
the boat’s fore-aft centerline.
Sternlight – a white light seen from behind the boat showing an unbroken light over a
135-degree arc from dead astern to 67.5 degrees on each side of the boat’s centerline.
Masthead Light – A white light placed over a vessel’s fore and aft centerline, showing an
unbroken light over a 225-degree arc from dead ahead to 22.5 degrees abaft the beam on
either side. Required on all powerboats. If the boat is greater than 50 meters a second
masthead light is required.
All-round light – Shows an unbroken light over a 360-degree arc. This light may be
white, red, green or yellow depending on its descriptive function.
DOI – Motorboat Operator Certification Course Chapter 3 - 14