How To Read Nautical Chart Symbol Letters The Easy Way!

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How to Read Nautical Chart Symbol Letters the Easy Way!

Do you know the difference between slanted and straight nautical chart symbols on your navigational chart? Is there an easy method to help you identify at-a-glance how an aid to navigation--buoys, beacons or lighthouses--would look in reality?

Slanted Letters

Cartographers use hunched over, slanted letters to identify chart symbols that move, change or shift in tides, currents or storms at sea. This isn't really an italicized slant, but more like a "leaning" cluster of letters. (See example below). Bottom characteristics also change as the tide moves in or out, so you will find the same slanted lettering on chart symbols like sand S, Mud M or coral Co.

Floating aids to navigation interpretation

The Coast Guard maintains close to 36,000 floating and fixed aids to navigation in the United States and its possessions. Every small boat cruising skipper must be able to interpret at-a-glance the meaning of chart symbol letters near such symbols.

This lighted buoy shows RW "SW" Mo (A). The painted color--RW in this example, always comes first. This stands for red and white vertical strips. The vertical line down the middle of the buoy body represents these stripes.Notice the small lollipop shape on the end of the buoy symbol. This shows that this buoy carries a topmark to further enhance daytime identification.Other painted colors include G for green; R for red'; Y for yellow; RG for red and green horizontal banded (red band on top); GR for green and red horizontal bands (green band on top); BR for black and red horizontal bands. Next comes the name that appears on at least two sides of the buoy. All aids to navigation lettering show the name inside quotation marks. In this case, you find "SW" as the name of this red and white vertical striped buoy.

After the name, you will find the light characteristic. Our buoy flashes the morse alpha character A, which is a short-long flash. Colored lights show an R (red), G (green), or Y (yellow). If no color symbol appears, the aid carries a white light. Some floating aids to navigation carry sound characteristics. If they do, you will find one of these in all capital letters: BELL, WHISTLE, GONG OR HORN.

Break the code into plain language

Now, imagine you glance at your navigational chart, turn to your sailing crew and tell them to keep a sharp lookout for this buoy. You want to make it short, easy to remember and clear. What would you tell them? "Keep an eye out for a red and white vertically striped lighted buoy named "SW". It carries a white light, and you'll see a short flash followed by a longer flash."

Vertical Letters

Fixed, immovable objects are named, lettered or identified with straight up and down letters. These include light structures, daybeacons and lighthouses don't move with the tide (at least you hope they don't!).

Fixed aids to navigation interpretation

Notice the straight up and down lettering on this fixed light structure. At night, this light shows a white light that flashes once every six seconds (Fl 6s).

Most fixed structures show their height above high water (66ft). Next, they show the distance they can be seen on a clear night followed by the letter M, which stands for nautical miles (6M). The name of the light comes next and may be shown as numbers or letters enclosed in quotation marks. If no name is shown, as in the illustration, look near the light. In this case, you see the phrase "Rebecca Shoal" nearby, so this would also be this light's name. Sound signals, if any, are shown last in all capital letters.

Complete your code breaking

Notice the abbreviation PA to the east of the light symbol. It rests alongside a fishbone chart symbol, which shows a dangerous wreck. PA means "position approximate", so this wreck may or may not be in that exact location (wrecks tend to move around with undersea currents). To the south of the wreck, a note indicates that shoaling to three fathoms has been reported.

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Use this simple sequence each time to break the code of any nautical chart symbol on your chart. Practice this at every opportunity to build the confidence to enter any harbor under sail or power--day or night!

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