Buoys are floating markers that are anchored to the sea bottom with solid concrete blocks, most commonly referred to as “sinkers.”
Beacons are structures that are permanently fixed either to land or to the sea bottom. The most common recognized are single piling type structures, but can also be more complex such as those mounted on the end of breakwaters or built on off lying dangers.
There are basically (6) types of buoys or beacons found under both the IALA-A or IALA-B Buoyage Systems:
While some lists show only (5) different types of buoys or beacons, incorporating "Safe Water Marks" into the Lateral Marks category, I have kept them separated. "Safe Water Marks," in essence have no lateral significance. In other words safe water marks can be safely passed on any side in any direction or circled endlessly without endangering your vessel.
During the hours of daylight, a buoy or beacon’s identification can be easily determined by observation of a number of factors including:
During the periods of darkness we have much less information available to rely on in identifying any particular ATON. Namely:
Markings - Depending on the type of mark, it may be lettered, named, or numbered and in many cases you may see a combination of both numbers and letters.
Shapes - There are five basic buoy shapes (see below): can, nun, spherical, pillar, and spar. With the exception of pillar and spar buoys, the shape of the buoy indicates the correct side on which to pass.
Can buoys are often referred to as cylindrical, and nun buoys as conical. The term pillar is used to describe any buoy that is smaller than a large navigational buoy (LNB). Lighted or sound producing buoys in the United States are often referred to as "Combination Buoys," but the correct term is "Pillar Buoy."
Colors - Aids to Navigation can be solid colors or they may be horizontally or vertically striped of different colors. Regardless, there are only (6) colors used; Red, Green, Yellow, Blue, White, and Black.
Topmarks - Five topmarks are used in the IALA buoyage system and consist of Cylinders, Spheres, X’s, Crosses, and Cones. When beacons are used as lateral marks, the cone topmark is often replaced with a triangle and the cylinder is often replaced with a square. The cylinder topmark may often resemble a rectangle or square and the cone topmark may resemble a triangle, especially at distances.
Light Characteristics - If lighted, as mentioned before, a lights characteristics are comprised of (3) items; the lights color, the lights phase, and the lights period.
Light’s Color - There are only (5) light colors authorized on marine ATON’s; Red, Green, Yellow, Blue, and White. Red, Green, and White are the colors most often encountered by the mariner. Yellow is seen regularly and Blue rarely.
Light’s Phase - This is probably the most complex and confusing of any of a light’s characteristics. There are (6) primary light phases:
The problem is that within the primary phase categories are many sub-categories and that is where the problem lies. Let us take a look at the Flashing light sub-categories, you have:
Composite Group Flashing
Group Quick Flashing
Interrupted Quick Flashing
Very Quick Flashing
Group Very Quick Flashing
Interrupted Very Quick Flashing
Interrupted Ultra-Quick Flashing
And that’s just "one" of the six primary categories of light phases!
Light’s Period - This is simply the time, measured in seconds, in which the light’s phase repeats itself.
There are a number of publications available to help in identifying Aids to Navigation and their characteristics, including: The USCG Light List, NGA List of Lights, and Chart #1. These are available and can be downloaded from our website or if you prefer hard copies; they can be found through the many links on our pages. Regardless whether you prefer electronic copies or hard copies the above listed publications should be carried on your vessel as part of your navigation library.