Red right returning, what the shapes and numbers mean, junction and safe-water marks, the ICW’s yellow symbols, regulatory buoys and the diver-down flag — the US Aids to Navigation system in the order you meet it running in and out of an inshore pass.
Returning means heading from the LARGER body of water into the smaller — from the sea into the bay, up a channel toward the marina, upstream. When you are returning, keep the RED markers on your RIGHT.
Heading back out to open water? Flip it: reds on your LEFT, greens on your RIGHT. Same markers, opposite side.
| Marker | Buoy shape | Daybeacon | Numbers | Rule |
|---|---|---|---|---|
| Red markers | “Nun” buoys — pointed (cone) top | Triangle daybeacons | EVEN numbers — 2, 4, 6… | On your RIGHT when returning |
| Green markers | “Can” buoys — flat top | Square daybeacons | ODD numbers — 1, 3, 5… | On your LEFT when returning |
Marker numbers INCREASE as you head in from open water — a quick position check: numbers climbing means you are heading in, numbers falling means you are heading out.
Mark a junction where the channel splits. The TOP band color tells you which side the preferred channel is on — treat the whole marker as that color. Top band red: treat it as a red marker. Top band green: treat it as green.
Mark channel centers and entrances. Safe water all around — you can pass them on either side.
Along the Intracoastal Waterway, markers carry small YELLOW symbols. Yellow TRIANGLE: treat the marker as red. Yellow SQUARE: treat it as green — regardless of the marker’s own shape or color.
A red flag with a white diagonal stripe means divers or snorkelers are down — flown from a float, a buoy or the boat itself. Vessels may also fly the blue-and-white “Alfa” flag. Either way: give them room, watch for bubbles, and assume someone is about to surface.
Stay at least 300 ft away from a diver-down flag in open water and 100 ft in rivers, inlets and navigation channels. If you must pass closer, slow to idle speed.
Markers are step one — the boat safety page covers the required equipment and the pre-launch ritual, the VHF radio guide covers hailing and mayday, and your water’s page has the live tide so you know which way the current is pushing you through the channel.