maneuver to avoid a collision
you are following another vessel on it's starboard side. the stern light and stbd running light are visible
The red light should be on the right side, or port side, of the boat. The green light should be on the left, or starboard, side of the boat.
give way
A green light is on the starboard side of the vessel. So it may mean that the starboard side is directly facing you.
You must maneuver to avoid collision.
The right side of the vessel is the starboard side, the light is green. The light is coordinated to the starboard side of the vessel no matter how you look at it. Refer to Rule 21 of the 72 COLREGS, a link is provided below.
You should take early and substantial action to steer well clear of the other craft.
If you see a red, green, and white light from another boat, it indicates that you are likely approaching a vessel head-on or crossing its path. The red light represents the port (left) side, the green light represents the starboard (right) side, and the white light is typically the stern light. In this situation, you should take measures to avoid a collision by altering your course to either starboard or slowing down. Always prioritize safety and be prepared to signal your intentions to the other vessel if necessary.
Starboard (right side).
During nighttime transit another boat's lights show: Green - the right, or starboard side, of that vessel; Red - the left, or port side, of that vessel; White - the rear of that vessel. The vessel is heading directly toward you
Seeing only a green light on another boat at night indicates that the vessel is likely facing towards you and is on your starboard (right) side. In navigation, a green light signifies the starboard side of a vessel, while a red light indicates the port side. This means you should give way to the other boat, as it has the right of way. Always ensure to maintain a safe distance and navigate cautiously.
The head and starboard side of the vessel is toward you