Piloting Course Chapter 5 Beginning GPS Navigation Piloting 2004 - Chapter 5 4/14/2018 United States Power Squadrons ® Piloting Course Chapter 5 Beginning GPS Navigation Introduce USPS and what we do Introduce the Instructor(s) and Proctors Explain the logistics for the session Pre-release - Spring Governing Board

Courtesy: Garmin, Standard Horizon Piloting 2004 - Chapter 5 4/14/2018 GPS Receivers Figure 4-30 GPS Receivers – A range of models and types of GPS receivers are available. Virtually all provide very accurate position information using 12-channel receivers. This means that each monitors up to twelve satellites simultaneously and selects the best four for a navigation solution based on signal strength and position. Handheld GPS models are portable and operate on batteries or external power. They include a self-contained antenna and must be positioned nominally upright to receive the best coverage of satellites. The smaller number of buttons and smaller screen make working with it a little more complex, but they are accurate and reliable and can provide digital signals to other devices if suitably connected. Fixed GPS models tend to include chartplotting capabilities. The model at the upper right uses charts provided on a small chip-cartridge that is inserted into the unit. The display is color which enhances the viewability of the charts. Your GPS position is indicated directly on the chart. The fixed units provide larger screens that can accommodate more information and data fields. They also have a greater number of buttons to facilitate accessing its various functions. The model at the bottom-center also is a chartplotter, but it also includes a depth sounder capability that shares the display. Both of these fixed mounted GPS models use external antennas that can be placed outside the cabin for optimum reception. Courtesy: Garmin, Standard Horizon © 2004, “The Weekend Navigator” Pre-release - Spring Governing Board

GPS Features What GPS can do… What GPS cannot do… POSITION - latitude & longitude COURSE to steer if waypoint is used ETA – estimated arrival time What GPS cannot do… Warn of HAZARDS Determine DEPTH of water Tell you about what is at that location

GPS Provides… Calculates… A 3-D position in space Related to a mathematical model of the EARTH Datum e.g., WGS-84 Grid System e.g., latitude & longitude Calculates… Speed and Direction Bearing and Distance to a stored Waypoint

Interacting with GPS You communicate with your GPS via… Buttons The GPS communicates with you via… Screens

What your GPS does GPS determines position… Piloting 2004 - Chapter 5 4/14/2018 What your GPS does GPS determines position… Latitude Longitude All other functions are calculated… By comparing changes in L and Lo, Speed Direction or, Differences between current position and waypoint(s) Bearing Distance To reiterate, GPS core mission is to provide your current position (latitude and longitude). All else is calculated by comparing positions: Current to recent past to determine speed and track over ground Current to stored waypoints to determine bearing and distance Pre-release - Spring Governing Board

GPS Keyboard Functions Small number of buttons… Provides for many functions

Buttons Typical buttons Power/light - Turns unit on, off and backlight Piloting 2004 - Chapter 5 4/14/2018 Buttons Typical buttons - Not all used on every GPS model Power/light - Turns unit on, off and backlight Page - Scrolls through various screens Menu - Displays menu of functions Enter - Like Enter on keyboard Mark - Used to “Mark” current position Quit - Like “Esc” key – go back one step GoTo (or Nav) - Used to select place(s) to go Zoom In/Out - Sets scale of map page Cursor - Highlight a field or scroll on map page MOB - Man OverBoard – emergency action This slide shows a selection of buttons some of which may appear on your GPS. All of these functions generally are available on every GPS, but they may not have a dedicated button. Some buttons are share similar functions but different manufacturers use unique names. The functions associated with these buttons are as follows: “Power/light” – usually this button does double-duty. It turns the GPS on and off. To turn on the GPS as you just did, you press it briefly until something appears on the screen. To turn off the GPS, you press and hold it in for typically three seconds. The GPS usually will show a countdown screen. It’s off when the screen is blank. While it’s on, you often can control the backlight by pressing the button briefly. On some models, each sequential press of the button gives you a different backlight level (typically three). On other models, a separate display will come up with what appears to be slider bars. Typically, up or down controls the backlight, and left or right controls the screen contrast. The “Page” button – is used on Garmin and some others to “page” through the various screen presentations. The “Menu” button is used to display a list of menu options. Often multiple presses of this button will produce other menus. Not all units have a menu button. The “Enter” button – is used much like the Enter key on a computer. It is used to execute or select and action. Once pressed, the GPS will do something. The “Mark” button – is not a unique button on most handheld units. Mark is used to record the current location as a waypoint. On many units, the Mark function is a second function for the button and is labeled beside the button. ON those units, usually, you will need to press the button twice to implement the second function. The “Quit” button – is used much like the ESC button on a keyboard. In this case, it generally takes you back to the previous screen. The “GoTo” button – is used to initiate navigation to a place, usually one stored as a waypoint. Some models use a NAV button, once pressed, offers GoTo as one of the options. The Nav button on some models (Magellan) is used to navigate to different screens instead of the Page button. Zoom buttons – are offered on many models. There are two buttons labeled, IN and OUT, that change the scale of the map and highway screens explained shortly. The Cursor button – is a multi-direction rocker switch that is used to move the cursor on the map screen and move the highlight on menus. The “MOB” button – usually is not a separate button on handheld units. It represent Man OverBoard and is used in the event of such an emergency to immediately store a spot and cause the GPS to navigate back to that spot. © 2003, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Typical GPS Layout ANTENNA p CURSOR t u q GO TO PAGE POWER (LIGHT) Piloting 2004 - Chapter 5 4/14/2018 Typical GPS Layout ANTENNA p CURSOR t u q GO TO PAGE POWER (LIGHT) MARK QUIT ENTER A basic GPS has buttons as shown. The model in this example is a GPS12. It has been on the market for over five years and represents a quality basic unit that has endured a lot of changes in the market. It has an antenna imbedded in the housing at the top of the unit. In order to function, this antenna has very broad coverage, but it must be pointed upward to see the sky. The unit was designed to be held at a comfortable angle in the hands. If you lay the unit on its back, some of the sky coverage will be lost. If you want to set a handheld GPS for hands-off use, you should use a mounting bracket. The screen provides the navigation information and tells you what the GPS is doing. It also is used to set up the GPS. This unit has six buttons and a cursor button. The cursor button is a four-way rocker switch that is used to move a cursor on the screen, or to enter data. The power button, you already have used. SCREEN © 2003, “GPS for Mariners” (courtesy Garmin). Reprinted with permission Pre-release - Spring Governing Board

GPS 76 Layout ANTENNA IN (ZOOM) OUT p CURSOR t u q NAV PAGE Piloting 2004 - Chapter 5 4/14/2018 GPS 76 Layout ANTENNA IN (ZOOM) OUT p CURSOR t u q NAV PAGE POWER (LIGHT) MENU QUIT ENTER This model adds a MENU button and Zoom buttons. It also uses a NAV button in lieu of a GoTo button. This model offers a larger, higher resolution grayscale screen and a built-in marine database. SCREEN © 2003, “GPS for Mariners” (courtesy Garmin). Reprinted with permission Pre-release - Spring Governing Board

Magellan Meridian Layout Piloting 2004 - Chapter 5 4/14/2018 Magellan Meridian Layout ANTENNA SCREEN IN (ZOOM) OUT ENTER ESC (QUIT) p This unit is typical of Magellan handheld GPS receivers. It uses NAV to navigate between screens (like Page) and a GoTo button for navigation. It also uses the term ESC instead of Quit. This model has a large, high resolution screen and offers a map data base. CURSOR t u q NAV MENU GO TO POWER (LIGHT) © 2003, “GPS for Mariners” (courtesy Magellan). Reprinted with permission Pre-release - Spring Governing Board

GPS Screens Set of Screens Each provides unique information Uses for marine navigation…

Satellite Screen Quality Indicator Some models… Satellites in view Level of FIX Estimate of Accuracy Some models… also provides Position

Satellite Screen Piloting 2004 - Chapter 5 4/14/2018 All models offer a satellite screen. This screen is intended to provide you with information regarding the satellites that are being viewed and received. A skyview display shows where the satellites are located looking down on your present location. In this case, north is up. The bars represent the strength of the received signals from each satellite – the higher the better. A hollow bar means that the satellite signal is being received. A solid bar (as shown) indicates that the satellite is being received and is providing navigation information. Today, most GPS receivers have up to 12 channels. This means that a channel is dedicated to constantly monitoring each satellite, up to 12. This screen also tells you something about the quality of the fix. This model provides an indication of EPE (Estimated Position Error). This is a computed estimate of just how accurate your position will be based on the satellite geometry and signals. It is just an estimate, and is usually given in feet. The status in this screen indicates “3D Nav” for 3-D navigation using four or more satellites. Other labels here include, “Acquiring Satellites” (no fix yet), “2D Nav” (only 3 satellites providing a fix), and others such as “Lost Signal” The signal bars are meaningful in that they can be used to help you position the GPS. Locate the unit where the bars are as high as possible. If you block the antenna, you will find that some of the bars for that portion of the sky are very low or not indicating a signal. © 2003, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Satellite Screens Garmin – GPS 76 series Magellan – Meridian series Piloting 2004 - Chapter 5 4/14/2018 Satellite Screens Figure 8-7 Satellite Screens – Typical GPS satellite screens are shown for a Garmin and a Magellan GPS. This screen indicates which satellites are providing signals that are being received and processed by the GPS. A hollow bar indicates that a signal is being received. A solid bar indicates that the signal is being processed. On the left screen, a “D” indicates that the differential corrections are being received and processed to further improve accuracy. The height of each bar indicates the strength of the received signal. This screen is meaningful to the navigator in that it indicates the quality of the position fix provided by the GPS. A 3D (3-dimensional) fix provides the best accuracy and requires strong signals from four satellites that are arranged in a favorable geometric pattern. If signals were being received from only a few satellites and from only one direction, you should look for a misaligned antenna or obstruction blocking the signals. The Garmin screen on the left also provides position and several data fields including a measure of accuracy. Garmin – GPS 76 series Magellan – Meridian series © 2003, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Position Screen Provides… Other GPS position Data fields Latitude Longitude Time & Date Other Data fields “Compass Presentation” – direction of motion

Position Screen Not available on all GPS sets Piloting 2004 - Chapter 5 4/14/2018 Position Screen Many GPS models have a “Position Screen.” As the name suggests, this screen provides your current position. This screen also is used to present a great deal of other information. For example, on this model, an analog ribbon compass represents your actual course over ground (COG). The same information is shown digitally labeled as “Track” on this model. Also shown is Speed over Ground (SOG), a Trip odometer, Altitude and Time. Many of the data fields are user selectable from a repertoire of choices that can be set using menus. Some GPS models, such as the GPS 76 do not offer this screen. That model has sufficient screen size and resolution to place much of this information on the Satellite screen making the extra screen unnecessary. Not available on all GPS sets © 2003, R J Sweet, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Position Screens Piloting 2004 - Chapter 5 4/14/2018 Figure 8-8 Position Screens – Many GPS models have a separate screen that provides position – latitude and longitude. Usually, this screen provides a number of other data fields, often user-selectable. This particular screen also shows what appears to be a compass. It is important to recognize that a GPS is not a compass. It will provide a direction of motion over ground if there is motion. It will not provide a useful direction on a stationary boat. © 2004, “The Weekend Navigator” Pre-release - Spring Governing Board

Map Screen 2-D Top View Other Scaled representation of map/chart No features Only shows Your current position Positions of objects stored in GPS Other Shows track of where you have been Selected data fields

Map Screen Piloting 2004 - Chapter 5 4/14/2018 The Map Screen is one of the most popular and widely used screen on the GPS set. It presents a map-like view of your current location (position) with respect to other objects that are stored in the GPS. Data fields present your bearing and distance to the selected waypoint, as well as your current course and speed over ground. The map scale is shown, usually representing the width of the screen in nautical miles (or other units that you have selected). This model uses the screen to set the zoom instead of buttons. By moving the highlight (using the cursor button) to the scale as shown and pressing enter, you will be given a choice to zoom in or out. This screen is presented as North-Up. On some models, you can select Track-Up as an option. © 2003, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Map Screens Piloting 2004 - Chapter 5 4/14/2018 Figure 8-9 Map Screens – The Map Screen is the most used screen by many GPS users. It provides your position in a map view relative to other objects stored within the GPS. You can zoom in or out and change the scale of the screen as indicated by the bar at the bottom-left of both screens shown. Your position is indicated by a black triangle. It’s sharp pointed end indicates your direction of motion. The GPS on the left from Garmin provides a marine data base of navigation aids. The GPS on the right from Magellan also provides a base map of land features. © 2003, R J Sweet, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Compass Screen Provides… Other Direction of motion – in compass card format Not a compass! Direction to active waypoint Other Data fields

Compass Screen Piloting 2004 - Chapter 5 4/14/2018 The Compass Screen shows a compass rose with cardinal points representing your current direction (UP) and an arrow graphically indicating the direction (bearing) to the selected waypoint. Data fields provide similar information as shown on other screens. This screen generally is more useful to hikers than boaters since the graphic does not provide refined enough information. © 2003, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Compass Screens Piloting 2004 - Chapter 5 4/14/2018 Figure 8-11 Compass Screens – This screen is nominally useful for marine navigation. It provides a limited amount of information about the current direction of motion and the direction to the active waypoint. The Magellan compass screen on the right also indicates the bearings to the sun and moon for visual reference. © 2003, R J Sweet, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Highway Screen 3-D View of imaginary Highway Other Highway depicts course to waypoint Shows current position relative to highway Direction of travel relative to waypoint Other Data fields

Highway Screen Piloting 2004 - Chapter 5 4/14/2018 The Highway Screen, along with the Map Screen, is one of the two most useful screens for boaters. This screen provides a 3-D representation of your position placed on an imaginary highway. Your position is represented by the “*” at the front-center of the display. You are on-course if you are located on the center of the highway. In this example we are 0.5 nm to the right of center. You are on course if the highway extends straight ahead. In this case, we are moving further to the right of the highway. Data fields provide much useful information in digital form. At the bottom, we have selected a data field called cross-track error (XTK). It indicates that we are 300 feet away from the center of the course line (highway). This screen provides an easily viewed means to stay on course. You simply line up the highway and go. © 2003, R J Sweet, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Highway Screens Piloting 2004 - Chapter 5 4/14/2018 Figure 8-10 Highway Screens – This screen is probably the best to use for navigating at the helm. It is easy to read and interpret. Your mission is to stay in the middle of the highway with the highway extending straight ahead. The Garmin screen on the left shows not only the active leg but the next leg of the active route and other waypoints. Both screens offer a variety of layouts including user-selectable data fields. The name of the active waypoint appears prominently in both screens. © 2003, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Waypoints Points of Interest stored in GPS Waypoint Points to Navigate to Landmarks for reference Places to Avoid – danger Waypoint Latitude and Longitude Name

Waypoints Specific points along a cruise Generally associated with a Piloting 2004 - Chapter 5 4/14/2018 Waypoints Specific points along a cruise Generally associated with a Stop Change of course or speed May be Navigation aids, or Arbitrary spots selected for a course change Landmarks Identified by Latitude & Longitude A unique name or number Waypoints can be any specific point that you choose to enter into the GPS by supplying its coordinates. For navigation purposes, the waypoints will be points defining legs of your cruise. For establishing position, avoiding danger, and general reference to the world around you, waypoints can be any point of significance. Waypoints are identified by a name or number and its coordinates. Pre-release - Spring Governing Board

Getting Waypoint Coordinates Measure L, Lo on a Chart Chapter One Pre-plotted on Commercial Charts Waypoint Books Mark (on the water)

Opportunities for Error Be Careful… it’s easy to make a mistake Coordinates are just numbers They have no ‘physical’ significance Typical Errors Incorrectly reading coordinates from the chart Incorrectly entering numbers into GPS Incorrectly selecting the wrong waypoint for navigaiton

Naming Waypoints Limited number of characters… Must have an efficient system Navigation aids on water Use redundant numbering system Recommended First 2 characters… relate to locale Remainder… relate to object

Waypoint Naming Example R “2” Buoy at Entrance to Falmouth Harbor Location: FH (Falmouth Harbor) Buoy: R “2” Result: FHR2 Note on chart so no confusion Advantages All waypoints for given locale – grouped together Nav Aid matches chart

What GPS Does… Once Select & Activate a Waypoint Piloting 2004 - Chapter 5 4/14/2018 What GPS Does… Once Select & Activate a Waypoint GPS computes the course From your current location Course angle (C) Distance (D) Plots course From current location to waypoint Map Page – Course Line Highway Page – highway As soon as you have entered a waypoint for navigation, the GPS goes to work and computes the course (Bearing) and distance from your current location to that waypoint. It also plots a line on the Map Screen from the point that you activated the waypoint to the waypoint. And, it sets a highway on the Highway Screen that corresponds to the same path. You are navigating!! Caution – REMINDER – the GPS has no knowledge of what lies between you and the waypoint. It’s up to you to check on a chart to make sure the path is clear! Pre-release - Spring Governing Board

GPS Track and Speed Piloting 2004 - Chapter 5 4/14/2018 Figure 4-32 GPS Computers Track and Speed – Your GPS receiver displays latitude and longitude based on signals from the GPS satellites. It also displays Track (Course over Ground) and Speed (Speed over Ground) based on computations performed within the local GPS receiver’s navigation computer. Track and Speed are derived by comparing the current position with the most recent previous position (typically one-second earlier). The angular difference provides the Track, the distance traversed in the time interval between positions provides the Speed. © 2004, “The Weekend Navigator” Pre-release - Spring Governing Board

Bearing and Distance Piloting 2004 - Chapter 5 4/14/2018 Figure 4-33 GPS Computes Bearing and Distance – If a waypoint position is stored in your GPS and activated, the GPS will compute the difference between its current position and the coordinates supplied for the waypoint. The angular difference provides a Bearing from you to the waypoint. The Distance between the two waypoints is computed and displayed. The Bearing and Distance is recomputed at every GPS position update and displayed. The GPS has no inherent knowledge as to what lies along the path from your GPS and the waypoint. © 2004, “The Weekend Navigator” Pre-release - Spring Governing Board

What GPS Does not Do… Tell you what is there… or, qualify the path YOU NEED CHARTS FOR THAT!!! Plot your position Plot the path Check the path for clearance

Constructing Routes Must create ‘legs’ around obstacles Can navigate sequentially… As arrive at 1st waypoint, Enter next waypoint Until arrive at destination Or, construct a Route Pre-programmed in GPS Loads next waypoint automatically

Sequential Waypoints Can be entered manually… Piloting 2004 - Chapter 5 4/14/2018 Sequential Waypoints Can be entered manually… One at a time As each waypoint is achieved Takes time, when Attention needed to maneuvering Can be pre-entered as a “Route” Underway, you can select the intermediate waypoints for each of the legs automatically. Alternatively, you can create a route in advance and activate that route. Pre-release - Spring Governing Board

What is a route? One waypoint isn’t enough Seldom can we go straight to our destination

Creating a Route GPS can store a route Routes Sequence of waypoints Piloting 2004 - Chapter 5 4/14/2018 Creating a Route GPS can store a route Sequence of waypoints Creates a sequence of “legs” Route has a name Routes Can be activated – forward or reverse Can be edited Route page shows course and distance between waypoints The GPS can record a sequence of stored waypoints at a Route. Routes have names, and can be activated in either direction. Pre-release - Spring Governing Board

Multi-leg course around obstruction Piloting 2004 - Chapter 5 4/14/2018 Multi-leg course around obstruction In most cases, it is not possible to go directly from one spot to another on the water. You will need to build a sequence of straight-line segments around obstructions to get to your final destination. Each of these legs are marked by waypoints which must be stored in the GPS. © 2003, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

SKILL – Checking Waypoints Waypoints are just Names Numbers (coordinates) Important to check SKILL Navigating & checking Waypoints

Exercise 5-1 - Checking Waypoints Use Bowditch Bay chart Follow instructions in Student Manual

Exercise 5-1 You will be using the right side of a Bowditch Bay chart You have entered three waypoints

Solution: Exercise 5-1

Exercise 5-2 – Route Planning Take out Bowditch Bay chart Route planning & implementation 1st of 4 sequential exercises You select vessel and weather options You select the best route Follow instructions in your Student Guide Be prepared to explain your decisions in class

BREAK FOR THIS CHAPTER

Before Activating a Waypoint Where are you? GPS constructs course from your current location Is the path safe? Alternatives Activate waypoint from one end of pre-qualified path, or Must plot current position and draw course line on a chart

Activating a Waypoint Select Waypoint Activate the Waypoint Stored in GPS Select from List – make sure it’s the right one Activate the Waypoint Observe Bearing & Distance on GPS Is this reasonable? Check with the Chart Is the path clear? Does the bearing and distance match?

Activating a Route Select Route Activate the Route Stored in GPS Select from List – make sure it’s the right one Activate the Route Forward or Inverse? – go right way Observe Bearing & Distance on GPS to 1st wpt Is this reasonable? Check with the Chart Is the path clear from current position to 1st wpt?

Once Activated, GPS … Calculates & Presents… Course, Bearing and Distance to Waypoint Or, to 1st Waypoint if a route is selected Course line on Map Screen Entire sequence of course lines if a route is selected Highway on Highway Screen Entire sequence of highways if a route is selected

Map & Highway Screens Zoom to desired scale… Piloting 2004 - Chapter 5 4/14/2018 Map & Highway Screens Zoom to desired scale… Here are examples of the Map and Highway Screens. © 2003, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Steer Set Heading of Boat toward Waypoint Compass nominally direction of magnetic course Ensure (any of the following) Position indicator aligned with course line Map Screen You are located in center of highway and pointing toward waypoint Highway Screen Direction of motion and direction to waypoint indicators align Compass Screen

Once Underway… You need a chart! GPS continuously provides your… Piloting 2004 - Chapter 5 4/14/2018 Once Underway… GPS continuously provides your… Current Coordinates Course Direction & Speed [over ground] & continuously updates… Bearing & Distance to selected Waypoint Position on Map & Highway screens Original Course Line & Highway Unchanged – provides reference Remember – the GPS has no idea of the hazards around you… Once underway, the GPS… Updates the display to reflect your current position, and It updates the bearing and distance from your current location to the selected waypoint. IMPORTANT It keeps the line on the Map Screen and the highway on the Highway Screen as they were when you initiated your navigation and shows where you are with respect to these. REMEMBER You need a chart! You need a chart! Pre-release - Spring Governing Board

Other Data Cross Track Error ETA, ETE Also called XTK, XTE, Off Course Indicates distance L or R of Course Line Indicated in feet or miles Alarm can be set ETA, ETE Estimated Time of Arrival Based on current speed, remaining distance, and GPS clock Estimated Time Enroute Based on current speed & remaining distance

Locating Position on a Chart Using GPS Information Plot Latitude & Longitude Requires access to L, Lo scales Dividers or Plotting Tool Read numbers carefully Plot Bearing & Distance to Waypoint Requires Plotting Tool Access to Distance Scale

Plotting GPS Position Piloting 2004 - Chapter 5 4/14/2018 Figure 8-15 Plotting GPS Position – You can plot your GPS position by using a pair of dividers. First, set the latitude using one point of the dividers and place the second point on the nearest grid line. Then transfer this distance across the chart to your approximate location. Make a light pencil mark. Second, repeat the process for the longitude. Make sure that you read the numbers accurately and select the appropriate point on the latitude and longitude scales. © 2004, “The Weekend Navigator” Pre-release - Spring Governing Board

Where are we on the Chart? Piloting 2004 - Chapter 5 4/14/2018 Where are we on the Chart? GPS indicates: L 38° 53.0 N Lo 94° 49.3 W You must plot the GPS coordinates on a chart 38° 53.0´ N As in the earlier example, you need to plot your position to know where you are. There are two techniques that we will show. In the first, you plot the coordinates from the latitude and longitude scales as shown. 94° 49.3´ W © 2003, R J Sweet, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Position by Bearing & Distance Piloting 2004 - Chapter 5 4/14/2018 Position by Bearing & Distance Figure 8-16 Position by Bearing and Distance – An even better and more intuitive approach uses another feature of the GPS, namely, the distance and bearing from your current location to a waypoint. If you place a protractor plotting tool over the waypoint and set the reciprocal reading on the arm, you can draw the bearing line and measure the distance directly to your position. You will need to set the protractor arm to the magnetic bearing if you have set up your GPS to magnetic direction. You can do this by converting the magnetic to true or use a plotting tool with a variation scale incorporated on the arm as shown. You can make your own distance scale by making pencil marks on the protractor arm using the latitude scale. © 2004, “The Weekend Navigator” Pre-release - Spring Governing Board

Where are we on the Chart? Piloting 2004 - Chapter 5 4/14/2018 Where are we on the Chart? GPS indicates: Bearing 20° Distance 1.2nm The GPS provides continuous updates of Distance & Bearing to the Waypoint Distance 1.2 nm Bearing 20° An alternative technique uses the GPS provided Bearing and Distance to the waypoint to plot location. You simply draw a line going through the Waypoint at a 20° angle to the grid line, and then mark off the distance of 1.2 nm along that line. That is your location. This technique is less likely to produce and error and it is more intuitive than plotting coordinates. It’s also quicker. This approach is quicker, more intuitive, and less prone to error than plotting coordinates © 2003, R J Sweet, “GPS for Mariners”. Reprinted with permission Pre-release - Spring Governing Board

Exercise 5-3 – Route Planning Take out Bowditch Bay chart Route planning & implementation 2nd of 4 sequential exercises You select vessel You select the best route Follow instructions in your Student Guide Be prepared to explain your decisions in class

Cruise Homework Do Part II of Cruise

Questions ? … Comments Piloting 2004 - Chapter 5 4/14/2018 Surely, you have questions. Pre-release - Spring Governing Board