2013 New York Safe Boating Textbook - (Page 59)
Learning all aspects of navigation is beyond the scope of this course. However, all boaters need some basic knowledge about finding their way on the water. This section will introduce you to the basic features of a nautical chart and navigation aids and discusses how weather pertains to navigation. Boaters can learn more about charts and enhance their navigation abilities by attending courses through the US Coast Guard Auxiliary, US Power Squadron, or commercial courses specifically aimed at the subject.
Charts are oriented with True North at the top. Nautical charts usually have one or more compass roses printed on them. These are similar in appearance to the face of the compass. Directions on the chart are measured by using the compass rose.
Nautical charts describe the characteristics of the bottom of a body of water, information that is vital to a boat operator. The chart uses combinations of numbers, color codes, and underwater contour lines to mark channels, hazards and other bottom characteristics. The numbers on the chart represent “soundings,” or measurements of the depth of the water at average low tide. Since the greatest danger to navigation is during low tide, a number of the depths of low tide are averaged to produce the average low tide. Contour lines (also called fathom curves) connect points of roughly equal depth and provide a profile of the bottom. These lines are either numbered or coded according to depth using particular combinations of dots and dashes. Generally, the shallow water is tinted darker blue on a chart, while deeper water is tinted light blue or white. Depth of water may either be in feet, meters or fathoms (a fathom equals six feet). The chart legend will indicate which unit (feet, meters or fathoms) is used.
Introduction to Charts
The art and science of navigation is an ancient skill. For thousands of years, sailors navigated by using the stars as their guide. The art of navigation has expanded from using the stars and planets (celestial navigation) to sophisticated
Symbols for Buoys
The basic symbol for a buoy, which is an aid to navigation and is discussed in depth in the next section, is a diamond and small circle. The small circle denotes the approximate position of the buoy mooring. The diamond is used to draw attention to the position of the circle and to the description of the aid. The initials “N” or “C” will indicate the shape of the buoy: (N) Nun Buoys, and (C) Can Buoys. If the buoy is painted red, the diamond will usually be indicated in red on the chart; if the buoy is painted green, the diamond will be green and so on. Other markings by the buoy symbol may indicate a buoy identifier, a sound signal, or note that it is a lighted buoy.
satellite navigation systems. You won’t enjoy boating, and you won’t be a safe boater, if you don’t have at least basic navigation knowledge. The nautical chart is one of the mariner’s most useful and most widely used navigational aids. Navigational charts contain a wealth of information to you as a boat operator. They show channels, depth of water, buoys, lights, lighthouses, prominent landmarks, rocks, reefs, sandbars, and much more useful information for the safe piloting of your boat. The chart is the most essential part of all navigation equipment. Navigational charts feature coastline characteristics, points of interest, rocks, wrecks and obstructions, and describe the type of bottom. Not all waterways have been charted, but if a chart exists, you can find it at the Office of Coast Survey of the National Oceanic and Atmospheric Administration, or NOAA. The web address is:http://nauticalcharts.noaa.gov/.
Aids to Navigation
Waterways, just as roads, are marked to provide direction, advise caution and to point out specific hazards. Understanding the waterway marking systems is important as these markers will assist in navigation, mark safe waters, and convey important information to the skipper. Aids to Navigation systems use red and green markers to indicate the right and left sides of the channel. 59
Table of Contents for the Digital Edition of 2013 New York Safe Boating Textbook
2013 New York Safe Boating Textbook
Boats and Motors
Registration of Boats
Fueling and Ventilation
Safe Loading and Powering
Preparation for Getting Underway
The Marine Environment
Rules of the Road
Boating Related Activities
Accidents and Emergencies
Frequently Asked Questions
Chapter Review Questions Answers
2013 New York Safe Boating Textbook