Collision Regulations:  (Nav. Lights & Shapes, their names and characteristics)

Note:  Precise angles at which lights are visible do not have to be memorized for the test.  But it is necessary that you can tell by the lights you see, whether vessels are coming towards you, or going away from you.  By understanding the lights & shapes on this and the following page, you will be able to easily tell if its a vessel under sail coming towards you, or a power driven vessel.  You'll know if it's a vessel under tow, or a fishing vessel.  You'll know when it's a police or government vessel on a mission!  And, you will know that the white light (that suddenly appears very near to you), must be either a rowboat, canoe or a very small sailboat!  You'll know to drop down to idle speed, to avoid swamping them.  They'll know that you are a competent, courteous operator!

masthead light;

• white light placed over the fore & aft centreline of a vessel,
  
• visible over an arc of the horizon of 225° (visible from directly ahead to  22.5° abaft the beam on either side of the vessel),
  
• not visible from directly behind.
  

stern light;

• white light placed as near to the stern as practicable,
  
• visible over an arc of the horizon of 135°
  
• visible to vessels approaching from directly behind, or up to 67.5° right aft on either side, (not visible to vessels approaching from ahead or at right angles to you)
  
• it makes lighted, the unlighted sector of the masthead light, so that a white light (at least) is always visible to vessels, regardless of their angle of approach.
  

side lights;

• a green light on the starboard side & a red light on the port side,
  
• each showing over an arc of the horizon of 112.5°
  
• visible to vessels approaching from directly ahead and to vessels approaching from up to 22.5° abaft the beam on either side of the vessel, (they are not visible to vessels approaching from directly behind)
  
• vessels approaching from directly ahead will see both the red & green,
  
• vessels approaching from your right or left side, will see only your red or green.  (if they see your green, they are to your right, and therefore have the right of way.  If they see your red - it's like a stoplight, reminding them that you have the right of way this time)
  

all-round light;

• white light,
  
• visible over an arc of the horizon of 360° (visible from any approach)
  
• while at anchor between sunset & sunrise, it must be displayed.
  
• a Black Ball must be displayed during the day whenever anchored in a narrow channel, fairway or anchorage where boats normally navigate.
  

towing lights;

• on the towboat, a yellow sternlight, (above its white sternlight),
  
• on the towboat, two masthead lights in a vertical line, (three if the tow exceeds 200 m)
  

• must display sidelights and a sternlight, or an all-round light at the stern and bow.  (be aware that lights on the vessel being towed are often faint)
  

A vessel being pushed;

• may display a yellow light at the bow.