This post is about the red and green signs and buoys that we follow while navigating the waterways. These always mark the sides of dredged channels, and often mark shoals, harbor entrances, and other spots to help mariners find their way. Red markers on posts, called daymarks, are always triangular signs, and greens are square. Similarly red buoys have conical shaped tops and are called nuns, and greens are square tops and are called cans. Buoys can come in many sizes from very large sea buoys to small markers in private channels. The photos below show a variety of markers and buoys.
Markers are always numbered with greens having odd numbers and reds even. These run sequentially from the sea entrance, or from some defined point along the ICW. Sometimes it can be confusing which marker you are seeing, so it can be important to match the marker number to the chart.
The simple memory aid for markers is ‘red-right-returning’, or when returning from the sea keep red markers to the right (starboard). That seems simple enough, but as it turns out it can be anything but simple. The photo below shows the entrance channel to the marina we are in at the moment, and is looking out toward the sea. In this case, while transiting in the direction shown, you would need to keep the green markers to the right, and reds to the left since you would be going out to sea. And you can also see the shoals encroaching on each side of the channel.

When following a waterway that parallels the coastline (called an intracoastal waterway or ICW) the same color markers are used, but they are also marked with a tiny yellow triangle or square depending on the type of marker they may be. These are hard to see from a distance, and sometimes it can be confusing. The markers shown at the top of this post are all ICW markers as they have the yellow marks. The convention for the ICW is that red marks stay to the land side, or you could think of it as red-right-returning to Texas.
Another thing that has to be accounted for is places where two channels cross. These intersections can be marked with a green over red, or vice versa, with the top color being for the primary channel, and the lower color for the secondary channel. It is often hard to know which channel is primary, and you often have to study the charts to understand what the markers are trying to indicate.
Now this is where it can get very confusing. Sometimes you can be following a channel that is a primary red-right-returning, but is also marked as an ICW with reds and greens kept to the opposite sides. One place this happens is in Kings Bay, Georgia (buoys shown below) where the markers are for the primary channel for entry to the submarine base from the sea, but the same channel is also the ICW. In this situation the markers marked as reds, but with the yellow square for an ICW green, and the greens are also marked with an ICW triangle. This is a place where seeing the yellow marks becomes especially important.


I also saw a marker shown below that incorporated all of these twists. This marker is at Longboat Pass (hence the ‘LP’ marking) at the north end of Longboat Key. It is marked as a red over green, and it has a an ICW yellow square, meaning it is an ICW green. This marker’s meaning is the primary channel is out to the sea through Longboat Pass, and if going that way you would keep it to port (left). If you are following the secondary channel southbound, the ICW, you would keep it to starboard (right), which is what we were doing. If you got it wrong in either direction you would have been hard aground. The marker is shown on the chart in the second photo, and I annotated it with an arrow. The yellow dashed line in the photo is our path through this area.

I hope this gives some insight into following the navigation markers and the need to be paying attention all the time.