Table of Contents:

U.S. ATON System

Private Aids to Navigation

Safety Tips

Lateral System

Non-Lateral Aids to Navigation

Uniform State Waterway Marking System

Western Rivers Marking System

Visual Buoyage Guide

Nautical Chart

Bridge Lighting & Other Signals

ATON Abbreviations

USCG District ATON Offices

Report ATON Defects

Aids to Navigation — Road Signs of the Waterway

Western Rivers Marking System (As Seen Entering From Seaward

Note: The USWMS is presently merging with the U.S. Aids to Navigation System and will be discontinued on December 31, 2003. Vessel operators may encounter both types of systems during this transitional period.

Port Side or Right Decending Bank
green square Green or white square White Lights


Flashing
 Illustration of a flashing green light, which appears as a sequence of a short flash followed by a short pause.
ISO Illustration of a green ISO light, which appears as a sequence of a medium flash followed by a longer pause.
Illustration of a light, which appears as a green square with a dark green border, mounted on a pole. A light is attached to the top.
Center 		Illustration of a lighted buoy, which has a green platform and green rectangular structure with a green square at upper left. A light is attached to the top.
Lighted Buoy		 Illustration of a can buoy, which appears as a green cylinder with a green square at upper left.
Can
Illustration of a passing daybeacon, which appears as a green square with a dark green border, mounted on a pole. A caption at right reads SG.
Passing Daybeacon		 Illustration of a crossing daybeacon, which appears as a diamond with two green diamonds inside stacked vertically and two white diamonds stacked horizontally, surrounded by a white border. A caption at right reads CG.
Crossing Daybeacon		 May Be Lighted
 
  Illustration of a mile board, which appears as a white rectangle with the black number 176.9 in the center.
Mile Board (Marker)		  

 

Preferred Channel
Mark Junctions and Obstructions
Composite Group Flashing (2)

Preferred Channel to Starboard
Topmost Band Green		 Preferred Channel to Port
Topmost Band Red
FI (2+1) G
Illustration of green flashing light, F1 (2+1) G, which is shown as a sequence of two short flashes separated by a short pause, followed by a medium pause, one more short flash and a long pause. 		FI (2+1) R
Illustration of green flashing light, F1 (2+1) R, which is shown as a sequence of two short flashes separated by a short pause, followed by a medium pause, one more short flash and a long pause.
Illustration of a lighted buoy, which has a green platform and a rectangular structure that is green on the top and red on the bottom. A green square appears at upper left and a green light is affixed to the top. Illustration of a can buoy, which appears as a narrow cylinder that is green on the top, red in the middle, and green on the bottom. A green square appears at upper left. Illustration of a lighted buoy, which has a red platform and a rectangular structure that is red on the top and green on the bottom. A red square appears at up left and a red light is affixed to the top. Illustration of a nun buoy, which appears as a narrow cylinder with a tapered top. The top is red, the middle is green, and the bottom is red. A red square appears at top left.
Lighted Buoy Can Lighted Buoy Nun
Illustration of a passing daybeacon, which appears as a square that is red on the bottom, green on top, and surrounded by a corresponding border of dark red and dark green. It is mounted on a pole. A caption to the right reads JG. Illustration of a passing daybeacon, which appears as a triangle that is green on the bottom, red on top, and surrounded by a corresponding border of dark green and dark red. It is mounted on a pole. A caption to the right reads JR.
Passing Daybeacon Passing Daybeacon

Starboard Side or Left Decending Bank
green square Red or white square White Lights


Flashing
 Illustration of a flashing (2) red light, which appears as a sequence of two short flashes separated by a short pause and followed by a longer pause.
ISO Illustration of a red ISO light, which appears as a sequence of a medium flash followed by a shorter pause.
Illustration of a light, which appears as a red triangle with a dark red border, which is attached to a pole. A red light is attached to the top.
Light 		Illustration of a lighted buoy, which has a red platform and a red rectangular structure. A red square appears at upper left and a red light is attached to the top.
Lighted Buoy		 Illustration of a nun buoy, which appears as a cylindrical red structure with a tapered top. A red square appears at upper left.
Nun
Illustration of a passing daybeacon, which appears as a red triangle surrounded by a dark red border, mounted on a pole. A caption to the side reads TR.
Passing Daybeacon		 Illustration of a crossing daybeacon, which appears as a diamond with two red diamonds inside stacked vertically and two white diamonds stacked horizontally, surrounded by a white border. A caption at right reads CR.
Crossing Daybeacon		 May Be Lighted
 
  Illustration of a mile board, which appears as a white rectangle with the black number 123.5 in the center.
Mile Board (Marker)		  

Western Rivers Marking System is a variation of the standard U.S. Aids to Navigation System (ATONS) and is found on the Mississippi River and tributaries above Baton Rouge, and on certain other rivers which flow toward the Gulf of Mexico. Red daybeacons, lights, and buoys mark the starboard banks and limits of channels as vessels "return for sea" or proceed upstream. Green daybeacons, lights, and buoys mark the port banks and limits of navigable channels while going upstream. The Western River System varies of the standard U.S. system as follows:

  1. Buoys are not numbered.
  2. Passing daybeacons are not numbered but normally have an attached "Mile Marker" board that indicates the distance in statute miles from a fixed point (normally the river mouth).
  3. Diamond-shaped non-lateral dayboards checkered red-and-white or green-and-white, similar to those used in the U.S. Aids to Navigation System, are used as Crossing Daybeacons where the river channel crosses from one bank to the other.
  4. Lights on green buoys and on beacons with green daymarks show a single flash, which may be green or white.
  5. Lights on red buoys and on beacons with red daymarks show a double flash [Group Flashing (2)], which may be red or white.
  6. Isolated danger marks and Safe water marks are not used.

River Bank Names: When traveling downstream the banks are named "right" and "left". The right bank has green aids and the left bank has red aids, thus the west bank of the Mississippi is its right bank and it has green aids. To avoid confusion, commercial river traffic often calls the right bank the right descending bank and the left bank the left descending bank, expressed in this way, leaves no room for doubt.

Mile Markers: These markers are some of the most useful aids on a river. They are attached to daybeacons or displayed in other easily seen places. Since the U.S. Corps of Engineers erects them, they show distance in statute miles rather than nautical miles. With the exception of the Ohio River, mile markers indicate the distance up stream from the mouth of a river. Ohio River markers start at its headwaters and indicate the distance downstream. Mile Markers also help a vessel operator locate his/her position on a river chart.

Crossing Daybeacons: Because the navigable channels of rivers swing from bank to bank as the river bends, diamond-shaped crossing daybeacons are used to assist river traffic by indicating where the channel has changed from one side of the river to the other. Crossing daybeacons are always on the opposite side of the river. When a diamond-shaped crossing daybeacon is sighted, the vessel operator should head for the "diamond", and treat the color of the daybeacon as a channel mark (i.e. red mark keep to the left bank when traveling downstream).

River Buoys: Changes in river channels caused by fluctuations in water level, current speed and shifting shoals make buoys maintenance a continuous task for the Coast Guard. In wintertime where rivers freeze, buoys are lost or moved from position. Because of their somewhat temporary nature, river buoys do not have letters or numbers and are not usually shown on river charts.
USCG red rod
Customer Accessibility • Webmaster (Technical Website Issues) • Disclaimer, Privacy & Internet Link Policies
Copyright 2005