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Aids to Navigation
Markers, Lights, Buoys
So how do you get from point A to B safely? Obviously, using charts and knowing how to navigate is very important, but you do have some help. Just as when driving on the highway where there are signs and lights and marks on the road to help you get from one place to another, on the water there are aids to navigation. These are buoys, day marks (signs) and lights. These tell you where the channel is, which way to turn, what to avoid and give you useful information.
Buoys: There are various kinds of buoys and each has a specific use and color.
Some may have lights. The lights flash at a specific rate that is marked on charts so you can identify the buoy. They may also have a bell or whistle for identification in fog. However, not all buoys are lighted. This is why it is necessary to have charts so you can identify the various aids.
Nuns: Named nuns because of their conical shape. Usually red, marks the right side of the channel when returning from the sea, or going upstream. On the left when leaving or going downstream. They will have even numbers on them.
Cans: Shaped like a can. Green. Marks the left side of the channel when returning, the right side when leaving. They will have odd numbers on them.
Spars: Tall thin buoys. Mostly used by states on inland lakes and other state waters. White with orange symbols on them, a square, a circle, or a diamond. These are not lighted.
Day Marks: These can be a sign on a post or they can be on the shore. They are also red or green depending on which side of the channel they are on. They also have odd or even numbers. Red have even numbers and green have odd numbers.
See the following link for more information on aids to navigation.
U. S. AIDS TO NAVIGATION SYSTEM (pdf) USCG NAVCEN Lights List.
Lighthouses: Lighthouses usually are placed on prominent points of land, or mark serious
hazards such as rocks or shallow areas. These are usually on the coast but large inland seas such as the Great Lakes, Puget Sound, Chesapeake Bay and major rivers will also have lighthouses. Each lighthouse has a distinctive paint scheme for daytime use and the light has a distinctive pattern of flashing so they can be easily identified at night. Most can be seen from many miles away. Some lights have both red and white sectors. The white sector is the safe zone and the red is the danger zone. Many lighthouse also have a fog horn and can be identified by the sound of the horn.
Range lights and marks. Often just referred to as a "range", these are lights or marks that are aligned with each other such that when you are approaching them they line up one above the other. This indicates you are in the middle of the channel. If they are not aligned you are not in the mid channel. These may be lighted at night.
Land Marks: Prominent structures and natural features ashore can be used for navigation as well. These are often shown on nautical charts with some information to identify the landmark. Towers, large buildings, prominent hills or mountains, are shown. A navigator can take bearings on these as well as nautical aids to establish their boat's position on the water. The photo at right shows the Clock Tower in Port Townsend WA. It is marked on the chart and is easily seen from several miles. It makes a good landmark to use for navigation.
Navigation is covered in many books on boating, especially in Chapmans, Piloting, Seamanship and Small Boat Handling. This is a book that should be owned by every boat owner. What else do you need? A chart, a hand held compass, binoculars for reading numbers on marks and identifying them, a pencil and paper for writing down bearings and times, and a watch. The watch is for timing the distance from one mark to another and determining your actual speed. You should also have a tide and current table for your area if you are on salt water. The hand held compass is for taking bearings on aids and landmarks. A pair of dividers is good for measuring distances on the chart, and a nautical protractor is used for laying out courses and transferring compass direction from the compass rose on the chart to your course.
So how are Aids to Navigation used? Prior to leaving on a voyage you should check your charts and plan your trip, noting aids to navigation and landmarks along your route, so that you can identify each one as you pass it. This way you can more easily determine exactly where you are, how fast you are traveling, whether currents or wind are pushing you off course, and avoid any dangers along your route. If you have a GPS mapping capability you can also lay out a course ahead of time with waymarks and course changes programmed into the GPS. But do not rely solely on GPS or the charts. Charts get old and GPS charts are infrequently updated. Aids can be changed, moved by a storm, a light could be out, or even be decommissioned. The U. S. Coast Guard publishes a Local Notice to Mariners on their web site, that lists any changes to charts such as missing or moved aids, channels that have become shallower, and obstructions such as wrecks. http://www.navcen.uscg.gov/?pageName=lnmMain Use both charts and GPS and visually site each mark along the way taking a bearing and fix for each landmark. This way you can tell if you are off course or approaching danger. If you are not sure of your position, slow down or stop and take a fix on aids or landmarks and fix your position before you continue. By being careful and keeping track of your position and speed you will arrive safely at your destination.
Nautical Charts: Charts are no longer being printed by NOAA (National Oceanic and Atmospheric Administration). They can now be downloaded from their web site NOAA Chart Catalog and printed on your own printer or you can go to a marine retailer and they will print them full size. You can also buy them in waterproof booklets which are much more convenient for small boats. NOAA also has an on-line viewer at NOAA Charts Online. Or you can use electronic charts with a computer or chart plotter. The advantage is they can be updated very easily from the internet. Also most electronic charting systems can be connected to a GPS receiver, or have one built in, to show you your location, course and speed on the screen.
Nautical charts are available for some large lakes and impoundments, such as Lake Powell in Utah or Lake Mead in Nevada. These may be produced by the US Park Service, Army Corps of Engineers or by state agencies. Some are published by private companies. Usually these are available at Visitors centers or marinas on the lake. But on most lakes and rivers you will have to rely on Geological Survey charts.
Many of the companies producing chart plotters or sonars (fish finders or depthsounders) specifically aimed at sport fisherman, also make available charts of many popular sport fishing lakes. These can often be downloaded off the internet, but may require a fee. An example is Garmin Garmin Map Updates.
GPS: Global Positioning System. Many people use GPS as their only means of navigation. This is a huge and potentially disastrous mistake. GPS is only another navigation aid, a tool. Admittedly it is a very useful and sophisticated tool but should never be used as the sole means. It should only be a backup for charts. Far too many people have found the limitations to GPS when they ground their vessel or run into something that is marked on charts but not on their GPS screen. Learn the basics of navigation first and then supplement them with GPS.
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