What you see
You are looking at the vessel from 0 degrees, where 0 is dead ahead. You see: green light, red light.
Lesson 3 Sailing, motorsailing and rowing
No masthead light on a sailing boat
A sailing vessel (zeilschip) is a vessel that is moved by its sails only. This lesson is about a small sailing vessel. Here we simply call it a sailing boat (zeilboot).
At night a sailing boat shows no masthead light (toplicht). It shows a green and a red sidelight (boordlicht) and a white sternlight (heklicht). The sidelights are right next to each other or together in one lantern, on the centreline at or near the bow. The sternlight is at the stern.
So from ahead you see only red and green, no white light.