- Boating Safety Tips
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Rocky shoals to the right. Coral heads to the left. You need to sail through this “ship-killing” pass before sunset! Read this excerpt from Captain John’s highly popular eBook “101 Sailing Navigation Secrets” to discover one little-known sailing navigation technique that can help you keep your small sailboat in safe water when sailing or cruising.
Use the power of your nautical chart along with your GPS when you need to sail a course that runs due north or due south. On your nautical chart or plotter, Longitude lines run due north and due south. Let’s see how we could use these lines of Longitude for sailing safety. Follow the five steps below.
Tools You Will Need:
- Large Scale Nautical chart.
- Parallel Rules, Protractor, or Weem’s Plotter.
- Dividers or Plotting Compass.1. Study your chart and determine if it’s safe to run a due north or due south course through a pass, between two islands, or down a channel. If so, you can use the longitude of your course line as a virtual “highway” to help you stay in the deeper water of the north/south pass.2. Use your Parallel Rules, Protractor, or Weem’s Plotter. Plot safe courses through the passage. Label each course line with the magnetic course. Double check all along each plotted course to make sure that it keeps you in deep water and does not cross over dangers. Program waypoints at turn points. In the illustration, we enter a waypoint at that point where we turn onto 000°M (red).
3. Find the closest longitude line drawn on your nautical chart. Note that the cartographers have drawn in the longitude line 70° 50’W. You can use this as a reference longitude line in the next step. Highlight this line so that it stands out.
4. Measure from the highlighted longitude line over to your due north or due south course (dashed blue horizontal line). Determine the longitude of the course line. Write it onto the chart (70° 50.8’W). We have written this to the side to keep the chart readable and clutter-free.
5. Turn onto the new course line as soon as your GPS longitude reads 70° 50.8’W. Watch your GPS to help you maintain this course until you are in clear water again. Use these easy steps to help you sail through a passage where the safe course lies in a due north or due south direction. You can use similar steps when your destination lies due east or due west.
Realize that GPS represents just one form of navigation. Back up any GPS with dead-reckoning, visual bearings, and soundings. Use at least two or more different methods of navigation to strengthen your confidence in any position. If you cannot get agreement between the various position resources, stop your boat, anchor, or heave-to in safe water. Work things out BEFORE you proceed.