Unlike the roads and highways that we drive on, the waterways we go boating on do not have road signs that tell us our location, the route or distance to a destination, or of hazards along the way. Instead, the waterways have AIDS TO NAVIGATION (or ATONs), which are all of those man-made objects used by mariners to determine position or a safe course.
These aids also assist mariners in making a safe landfall, mark isolated dangers, enable pilots to follow channels, and provide a continuous chain of charted marks for precise piloting in coastal waters. The U.S. Aids to Navigation System is intended for use with nautical charts, which provide valuable information regarding water depths, hazards, and other features that you will not find in an atlas or road map.
The term "aids to navigation" includes buoys, day beacons, lights, lightships, radio beacons, fog signals, marks and other devices used to provide "street" signs on the water. Aids To Navigation include all the visible, audible and electronic symbols that are established by government and private authorities for piloting purposes.
The Coast Guard is the agency responsible for maintaining aids to navigation on U.S. waters that are under federal jurisdiction or that serve the needs of the U.S. armed forces. On bodies of water wholly within the boundaries of a single state, and not navigable to the sea, the Coast Guard grants the state responsibility for establishing and maintaining aids to navigation. The U.S. Corps of Engineers is responsible for many of the canals, dams, locks, and other man-made waterways in the country. The Corps also is responsible for the regulation of mooring buoys in all navigable U.S. Waters.
The individual Coast Guard districts also may grant permission to private groups and citizens to place "Private" Aids to Navigation. These aids allow individuals or organizations the ability to mark privately maintained channels, zones or waterways. These aids must be pre-approved, and must be maintained by the individual or organization.
The term "aids to navigation" encompasses a wide range of floating and fixed objects (fixed meaning attached to the bottom or shore), and consist primarily of:
Both Buoys and Beacons may have lights attached, and may have a sound making device such as a gong, bell or horn. Both Buoys and Beacons may be called "marks".
Caution: Do not count on floating aids to always maintain their precise charted positions, or unerringly display their characteristics. The Coast Guard works constantly to keep aids on station and functioning properly, but obstacles to perfect performance are so great that complete reliability is impossible. Only use floating aids for use as a navigation fix when you cannot see a fixed point of reference.
Depending on where you boat in America, you may see several differences in how navigational marks are colored, numbered, or lighted. Regardless of the location, buoys and beacons are placed in very specific locations, to mark either a particular side of a waterway, or some other navigational feature. The primary system in use is referred to the "U.S. Aids to Navigation System". The U. S. Coast Guard maintains this system in conformance to the International Association of Lighthouse Authorities (IALA), which is an international committee which seeks to ensure safe navigation, primarily through the use of common navigation aids and signals.
The "LATERAL" system is the familiar RED RIGHT RETURNING system, meaning that on all navigable waters returning from sea, the red even-numbered marks are on the starboard (right) side of the channel and the green odd-numbered marks are on the port (left) side of the channel. Numbers on the marks ascend when traveling from sea to harbor--if you don't have a compass and become disoriented on the water, you will always know you are heading upstream if the buoy numbers get larger as you travel.
Port side numbered aids are green in color, odd numbered and may be lighted. Port side marks are located on the left side of the waterway as you travel upstream, and the buoy numbers will increase as you head upstream. (Chart depictions are shown next to the marks) Port-Side Buoys have a cylindrical above-water appearance, like a can or drum floating on its axis. Commonly referred to as "CAN" buoys. Beacons - Port side beacons have square marks attached to them, with two shades of color and a reflective border.
Starboard aids are red in color, evenly numbered and will be on your right side as you travel upstream. Buoy numbers increase as you head upstream, and may have a red light. Starboard-side buoys have an above-water appearance like that of a cylinder topped with a cone, pointed end up. The cone may come to a point or be slightly rounded. Commonly referred to as "NUN" buoys. Starboard-side Beacons have triangular marks attached to them, with two shades of color and a reflective border.
For the sea buoys that delineate channels off the coast of the United States, and for the Intracoastal Waterway (ICW), red is on the right (shore side) when proceeding clockwise around the U. S. from the East Coast to the Gulf Coast, or proceeding north along the West Coast.
ICW marks are further identified by a small yellow reflector at the bottom of the mark. The same port and starboard marks shown above will look like the following.
Numbers on the marks ascend when traveling in this direction. Where the IALA-B and ICW marks meet, one must be very careful to observe the change in meaning by referral to local charts.
These diamond shaped marks are used to help the vessel operator determine location on a nautical map. When you see a dayboard, and find the corresponding mark on the chart, you know your precise location. They may be lettered, and may be lighted with a white light. Their color reflects that of nearby lateral marks.
These marks are used to mark fairways, mid-channels, and offshore approach points. They have unobstructed water on all sides. These marks may be lettered, and may be lighted with a white light. They may also have a red top mark.
These indicate a danger which may be passed on all sides. They are erected on, or moored on or near danger. They should not be approached closely without special caution. They may be lighted, and they may be lettered.
Special marks have no lateral significance (meaning they don't tell you which side of the channel or river you may be on). These marks are used to mark a special feature or area. These include area limits for anchorages, fishing grounds, or dredging/spoil areas. These buoys may be lighted, and if they are it will be a fixed or flashing yellow light. Shape is optional, but usually follows the shape of the navigation buoys that it is positioned near.
Mooring buoys come in two different shapes; spherical and cylindrical. Both have white bodies with a solid blue horizontal band on the center of the buoy. Mooring buoys may have a white reflector, or a white light attached to them. Mooring buoys are the ONLY buoys to which you may legally tie your boat. Buoys are generally placed in marked anchorage areas, and you must take caution if you are traveling near buoy areas. Check your state boating guide for particular operating restrictions in anchorage areas.
These are pairs of unlighted or lighted fixed aids that when observed in line show the pilot to be on the centerline of a channel.
Regulatory Marks re designed to assist boaters by informing them of special restrictions or dangers that they are approaching. Regulatory marks are white "can" buoys that have an orange shape on them. The mark will give either a warning or instructions on how to proceed. The shape determines what type of mark it is.
This system was originally intended for use by states on lakes and inland waterways that weren&#;t covered by nautical charts. The buoys used in the Uniform State Waterway Marking System (USWMS) used colors, shapes and marking patterns that differed greatly from the U.S. Aids to Navigation System (ATONS).
In , the U.S. Coast Guard decided to phase out the USWMS to avoid potential confusion of boaters and instead, favored using the more widely recognized ATONS. By , the USWMS was completely phased out. Below are a few of the differences from the federal system you should know about.
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Here's a summary of the important changes regarding the phase out of USWMS:
The state system differs in several ways, in case you happen to encounter them. These aids also assist mariners in making a safe landfall, mark isolated dangers, enable pilots to follow channels, and provide a continuous chain of charted marks for precise piloting in coastal waters. The U.S. Aids to Navigation System is intended for use with nautical charts, which provide valuable information regarding water depths, hazards, and other features that you will not find in an atlas or road map.
Red-topped White Buoys
Black-striped white Buoys - Inland Waters Obstruction Mark
Black-topped White Buoys
A Seaport Museum Blog
by Malcolm Martin, Fleet Captain
May 13,
The ship&#;s magnetic compass has been around in various forms for more than a millennium. Navigators all over the world discovered the properties of magnetic compasses.
Since their development, ships carry compasses to help navigate when conditions required a reference aboard the ship to provide orientation. At night, or otherwise out of sight of familiar landmarks, a compass provides vital information for the navigator.
The compass on ships is often mounted in a binnacle which is a stand or housing. Its delightful name Binnacle derives from Latin habitaculum meaning &#;little dwelling place&#;.
This &#;little house&#; helps to protect the delicate compass from the elements. They usually contain a gimbal arrangement to hold the compass card horizontal despite the motion of the ship. In addition the binnacle usually contains a light of some sort to illuminate the compass face to facilitate reading it in the dark and shades to make reading it in sunlight easier. Binnacles are typically made of wood or brass or other non-ferrous metals. They are located in a place on the ship to allow the ship&#;s navigator to determine position and course. They may be located near the helm so that the sailor steering the ship can maintain the correct course.
Left: This particularly beautiful binnacle in the Seaport Museum&#;s collection was made by John Bliss and Co. which had offices in the seaport district from -. (Seamen&#;s Bank for Savings Collection, South Street Seaport Museum .072.)
Right: Commonly, as part of the binnacle, there are adjusting magnets, flinders bars, and often external iron spheres which allow for adjustment of the compass. The iron adjusting balls attached on each side of the binnacle, as we can see in the above Seaport Museum&#;s Kelvin and Hughes Binnacle. (South Street Seaport Museum Collection .004)
But why would the compass need adjustment, it is always supposed to point North, right? The reason is that as a critical piece of navigational equipment the accuracy of a ship&#;s compass can literally mean the difference between life and death for a ship and her crew. The compass&#; accuracy must be maintained at the highest possible precision while at sea.
The compass contains a magnet (or magnets) that orient predictably to the magnetic field of the earth. In an ideal situation the compass would respond only to the earth&#;s magnetic field and would indeed always point to the Magnetic North Pole. In reality however, the compass magnet responds to the local magnetic field around it. That local field is a combination of the earth&#;s field modified by nearby magnetic influences. Anything containing iron&#; everything from ballast stones with high iron content to ferrous (iron containing) metals such as nails and other fasteners, rigging, electrical equipment, engines and other machinery and of course iron and steel hulls&#; distort the local magnetic field around a compass. Ships with hulls made of iron or steel have very significant local distortion but even wooden (or fiberglass) vessels contain sufficient ferrous metals to influence the local magnetic field around the compass.
You will notice that on Wavertree the binnacle is located on a platform up over the deck and away from other structures. This is in an attempt to minimize the effects of the magnetic properties of the iron ship and to place the compass close to the magnetic center of the ship.
The binnacle located on the catwalk of the cargo ship Wavertree
In fact, it is common for the standard compass to be mounted away from the helm position even on modern vessels. Also note that in addition to her main compass which was remote from the helm, Wavertree was equipped with two steering compasses located by the helm on the quarterdeck. These would be the references the helmsman would use to steer a steady course.
Left: This image shows one of a pair of steering binnacles by the wheel on Wavertree&#;s sister ship, the Leicester. (South Street Seaport Museum Archives)
In fact there may also be other compasses aboard a ship such as a &#;Tell-Tale Compass&#; in the Captain&#;s quarters by which the Master could see the course being steered without going on deck. Some larger ships are required to carry a spare compass in addition to thor standard compass to this day.
In this picture you can see that the Wavertree&#;s dismasting off Cape Horn carried away the binnacle containing the standard compass along with the boat skids. Lucky for her crew, they had the steering compasses aft still intact! (&#;Wavertree dismasted, looking aft&#; n.d., original ca. -. Gift of Joe King and Stanley Senior School Photography Club, Falkland Islands, South Street Seaport Museum .002.)
Anyway back to compass corrections. Whatever the cause, the local distortion of the earth&#;s magnetic field makes the compass inaccurate for use in navigation. As stated above, much depends on the accuracy of the ship&#;s compass. Luckily, at least some of the distortions caused by the structure and gear of the ship remain fairly constant so it is possible to correct the errors by using small adjuster magnets, iron rods and compensating balls. These are often incorporated into the binnacle. The arrangement of the latter iron spheres was developed by William Thomson (Lord Kelvin) in Scotland. Collectively, these devices also distort the local magnetic field around the compass but are arranged to distort the readings of the compass back to correct!
A professional Compass Adjuster is a person who corrects the compass as best as possible using the compensating devices in a process called swinging the compass. The compass errors vary depending on which way the boat is pointed (the Heading of the ship), so it is a fairly involved process to measure the error and adjust the compass to read correctly no matter what the ship&#;s heading is. Even after the best adjustments, there are still residual errors. These errors are collectively called Compass Deviation. The Compass Adjuster creates what is called a &#;Deviation Card&#; for the compass which shows the known compass errors for all headings of the ship. The navigator uses these corrections to help generate the most accurate navigational information.
Above: Compass Deviation Card from American Practical Navigator, Nathaniel Bowditch
A new ship or one that has been significantly repaired or modified would have its compass swung by an adjuster upon launching. International maritime treaty regulations require that all ships carry a compass that has been swung at least every two years. Even so, it is a regular part of the &#;Day&#;s work&#; for the Ship&#;s Navigator to check the accuracy of the compass by piloting methods if close to land and methods of celestial observation while at sea. This regular check ensures that the accuracy of the compass has not been lost inadvertently and unnoticed by some event which has altered the local magnetic field of the ship or the adjusters. If errors are found they would be noted and used to correct compass bearings. If gross errors (as might be expected after a lightning strike or physical damage to the binnacle) are discovered then the navigator would need to be prepared to make compass adjustments at any time during a voyage.
Even to this day with all the modern electronic and satellite instrumentation ships carry, the &#;little house&#; and the compass within remain a critical piece of equipment. They are a refined and delicate navigation instrument. This ancient tool is still carried and maintained to provide critical navigational information should other systems fail.
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