Copyright 2008 Coast Guard Auxiliary Association, Inc. The Weekend Navigator Basic Level I

What is Navigation? Not the same as driving your grandparent’s car A major part is to avoid hazards while traveling from Point A to Point B On the water, you make your own roads!

Chapter 2: Lesson Objectives Piloting versus navigation The three steps of navigation Pre-voyage components –What to include in pre-voyage planning Planning on the fly What to watch for when underway

Double checking Piloting without electronics Using ATONs, plotting courses and distances, dead reckoning, visual bearings, ranges, and relative bearings Lesson experience using the sample cruise experience Chapter 2: Lesson Objectives

The Three Steps of Navigation Step #1: Pre-voyage planning or deciding which path to take Step #2: Navigating underway or following the selected path Step #3: Double-checking or confirming by independent means that you are where you think you are A skilled navigator will not rely only on his electronic equipment but will also use his ship’s compass, his eyes, charts, and other tools

What is Included in Pre-voyage Planning? Charts and how to use them How much planning is enough? –The kind of boating –The waters where you will boating –The conditions under which you will be operating

What Will Your Voyage Look Like? Proceeding directly from one point to another? Tacking into wind and waves? Meandering freely while fishing or just enjoying yourself?

Step #1: Pre-voyage Planning Consider pre-plotted charts and course segments Plot your own courses Plot areas that you want to avoid

Step #1: Pre-voyage Planning Impulsive behavior can be dangerous Make sure to choose a safe path Plot your current position and locate hazards

Step #2: Navigating Underway Follow your plan Regularly monitor your course and progress along your course Know where you are at all times!

Step #2: Navigating Underway How might real-life conditions cause you to stray from your intended path?

Step #3: Double - Checking Remember that electronic gear is not fool- proof! Know where you are at all times! What are some simple techniques for double-checking?

Step #3: Double - Checking Use your seaman’s eye to confirm your position Use radar and other devices to confirm GPS readings Do not rely on any one device for navigation!

Piloting Without Electronics Navigation with the aid of landmarks, land features, and charted navigation aids Try to begin and end your course at a navigation aid Take bearings from your boat to a charted object in view

Navigation Aids

Plotting Courses and Distances Intended course is the planned route you will follow Track or line of motion is the course you cover over ground What factors cause a deviation from your intended course?

Plotting Courses and Distances Course direction can be measured using a protractor Distance can be measured using a pair of dividers

Estimating Your Position by Dead Reckoning Dead reckoning is a way to approximate a boat’s current position using a known past position and intervening times, speeds, and directions of travel DR plot or DR track is the result of dead reckoning

Determining Position by Visual Bearings Taking a bearing is the process of measuring the direction to a charted landmark you can see from boat –Taken with a hand-held compass Powerful tool independent of GPS or dead reckoning

Determining Position by Visual Bearings Each bearing taken is considered a line of position Your position is somewhere along your course line, but where? What factors might alter your line of position?

Determining Position by Visual Bearings A fix is the intersection of two or more bearings –More accurate than dead reckoning

Determining Position by Visual Bearings The intersection of three bearings will form a triangle –Your position is considered to be in the center of the triangle

Ranges Any visible pair of landmarks can constitute a range What might be some examples of ranges?

Ranges Your position will lie on the plotted range line when the two landmarks are in perfect alignment Some specifically designed navigation aids may serve as ranges

Relative Bearings Relative bearing is any bearing taken with respect to your boat Must be converted before plotting on your chart How to convert a relative bearing?

How Do We Convert a Relative Bearing?

Converting Relative Bearings Consider how many degrees the relative bearing lies clockwise from the heading of your boat, then add that number to you boat’s magnetic heading to get the equivalent magnetic bearing Example: Boat’s magnetic heading is 30 o and a port bearing is 270 o, then a port beam bearing is 30 o o = 300 o M (magnetic)

Sample Cruise