Sailing at night requires adequate and accurate navigational lighting. An experienced hand will see the vessels lights and clearly understand what it likely is, what it is doing and which way it is going. This does require that the lights are properly installed and operated.
Central to all this lighting is having green showing on the starboard bow and red on the port bow. To remember this “Port red wine” so the port bow has a red light showing. These bow lights must show from the heading line forward to 22.5 degrees abaft (behind) the beam.
Another way to remember is the port side has all the words with fewer letters. red vs green, port vs starboard and left vs right. The most important thing is to get these right on your boat. You have to remember the rules regardless of your position while installing them. If you are hanging over the rail for all intents and purposes you are oriented upside down, get it right or starboard in this case.
When sailing at night I am pretty observant, what with rocks, shoals, navigation aids and other boats. Last Mango was on our Port beam. Immediately I noticed something wrong with the lights Mangos were showing. I did what Captains have been doing for ages and eons “Mary Lynn is there something wrong with Mangos’ lights”? “What has John done” she asked. She immediately knew it was the man who had screwed up.
We had a close encounter with some kind of a shrimping trawler that resembled a sea monster as it thrashed about seeming to come after us. These same fishing boats and commercial traffic parted and did their best to clear the path for the upside down sailing vessel on its way to them.
The rules about all these things boating are contained in the COLREGS or International Regulations for the Prevention of Collisions at Sea. There are rules about giving way and standing on but the main rule implied to prevent any collision at sea and do everything you can do to avoid the situation.
Commercial vessels and some others will carry other lighting on their masts. A good working knowledge of these mast lights will help you protect your vessel and the others sharing the sea with you.
Link for your review Definitions and Mnemonics for Sailors and Powerboaters