The, Use, History, and Meaning of Marine Navigation Lights for Ships and Pleasure Craft

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Today, the standard is, Red lights are on the Left of a ship (Port side), Green on the Right (Starboard), and White at the back (aft or stern) and front (fore / bow). The lights are visible head-on (straight ahead) and "22.5 degrees abaft the beam" (visib

If you've ever spent any time aboard a ship or boat, it won't take long to notice that there are two colors prominent on most vessels. Those colors being Red and Green. Most people know that they have something to do with navigation and which side of the ship the color is on, but beyond that, its a mystery. This article plans to shed a little "light" on the subject, and the next time you are on the water, you can sound like an expert mariner.

In the United States a law (or act) was passed in 1838 requiring steamboats running at night to carry at least one signal lamp. The color and location at that time was not specified. It wasn't until 1848 in the United Kingdom, that boats were required to carry specified colored lamps, and the location of the lamps on the boats were specified. It wasn't until the first International Maritime Conference in 1889 that the United States and other international dignitaries started to place importance on navigational lights aboard ships to prevent collisions at sea.

Today the navigational lights aboard ships are determined by the International Maritime Organization, and they have established an entire set of criteria based on the size and type of vessel. The purpose of the lights is to be able to determine the heading (or angle) of travel of the vessel, and the length. This is so that in darkness, the entirety of the vessel can be avoided, and evasive maneuvers can be established by simply assessing the lights of the boat.

Today, the standard is, Red lights are on the Left of a ship (Port side), Green on the Right (Starboard), and White at the back (aft or stern) and front (fore / bow). The lights are visible head-on (straight ahead) and "22.5 degrees abaft the beam" (visible to the side of the widest part of the boat). This is what allows another ship to determine the direction (heading) and length of the opposing vessel.

The concept of red and green also applies to navigational buoys, but is reversed when headed upstream. The main reason for this is because of an old saying. The old mariners’ saying goes “Red, Right, Return”. What this means, is when returning from sea (headed upstream), the red buoy is always on your right side; the green to your left. The 3 R’s are easier to remember and make an easy saying, but technically, in marine terms, rivers are always spoke of as headed downstream, towards the ocean. The right bank of the river, which is on your right side headed downstream, is still the Right Bank when you’re headed upstream; even though technically the riverbank is on your left side. What this all means is that when you are headed TO sea, the Red buoys are on your left, just as the Red lights on your boat are on the left.

The simplest way to remember this all, is when traveling on a river, “Red, Right, Return”. The Red buoys are always on your Right when headed upstream, away from the ocean. As for the lights on your boat, well they are the opposite. When headed upstream, the Green light on your boat, will be on the same side as the Red buoy; the Red light the same as the Green buoy. If you always think in terms of returning from the sea, it’s much easier to keep it all straight, and ensure that your vessel is navigating the proper course. Smooth Sailing!!

3 comments

Sandy James
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Posted on Mar 15, 2012
+Paulose
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Posted on Mar 10, 2012
Donata L.
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Posted on Mar 10, 2012