Navigation rules - page 11
3.11 Rule 20
The Rule - Vessel lights and shapes
Rules in this Part shall be complied with in all weathers. The Rules concerning lights shall be complied with from sunset to sunrise, and during such times no other lights shall be exhibited, except such lights as cannot be mistaken for the lights specified in these Rules or do not impair their visibility or distinctive character, or interfere with the keeping of a proper look-out. The lights prescribed by these Rules shall, if carried, also be exhibited from sunrise to sunset in restricted visibility and may be exhibited in all other circumstances when it is deemed necessary. The Rules concerning shapes shall be complied with by day.
Night sailing requirements
Your responsibility, when sailing in diminished lighting conditions and after sunset and before sunrise is to turn your navigation lights on. Don't assume they are working - the sea salt environment is a poor environment to expect electrical contact to continuously work. Visually check for operation after you turn them on.
All vessel types have a unique distinguishing set of lights that they must adhere to depending on the type of vessel. i.e. Sailing, towing, fishing, restricted in ability to maneuver, constrained by draft, dredging, etc. It would be prudent for you to learn all the differences in these lights. However, there are Apps, lookup charts and tools that you can stow on board so that you don't have to rely on 100% functionality of your brain cells.
The rule for sailing vessels
For sailing vessels the lights required internationally are:
Bow – red (port side) and green (starboard side) with a 112.5 degrees arc - remember "is there any red port left".
Anchor Light - white 360 degrees at top of mast (for anchored only).
Mast head - white 225 degrees facing forward (for under power only sometimes called a steaming light).
Stern - white with a 135 degrees arc.
Optional - Masthead 360 degrees red over green in addition to the lights on the bow and stern.
Sailing vessel underway
Towing light: means a yellow light having the same characteristics as the “sternlight”.
All-round light: means a light showing an unbroken light over an arc of the horizon of 360 degrees.
Flashing light: means a light flashing at regular intervals at a frequency of 120 flashes or more per minute.
Special flashing light: means a yellow light flashing at regular intervals at a frequency of 50 to 70 flashes per minute, placed as far forward and as nearly as practicable on the fore and aft centerline of the tow and showing an unbroken light over an arc of the horizon of not less than 180 degrees nor more than 225 degrees and so fixed as to show the light from right ahead to abeam and no more than 22.5 degrees abaft the beam on either side of the vessel.
Power driven vessel over 50m with a second masthead light abaft of and higher than the forward one, underway from starboard.
The diver flag that you need to be aware of to indicate that this vessel has scuba divers below. You are required to stay 100 meters away from such a vessel.