By John Jamieson
One single spark and you can lose your black box navigation That’s all it takes to fry the electronics. So, let’s take a minute to get back to the dead simple basics that you should use every moment you are sailing along the coast or offshore.
This isn’t the textbook version, but the realistic version of sailing navigation made dead simple. Which means, no chart table, heeling, taking spray over the bow, and feeling a bit green all at the same time. It all begins long before you cast off that first docking line.
These seven super simple steps will work on any boat any size anywhere in the world. Here’s how to complete 90% of your chart navigation for safer nautical navigation wherever you choose to go sailing:
1. Plan Your Sailing Route
Use the largest scale navigation chart for the sailboat cruising area. Larger scales show greater detail for entering harbors, anchorages, passing near dangers, and using aids to navigation. Look beneath the title of the chart at the ratio. The smaller the second number, the larger the scale.
For instance, in US waters, the best charts for coastal navigation are scaled at 1:80,000. This means that one inch on the chart equals 80,000 inches on the earth’s surface. Once you get inside the coastline and enter harbors, you will want an even larger scale, such as 1:40,000 for much better detail.
Use the “what if” factor when choosing the proper scale chart to use. What if the weather turns rotten, or you have an injury aboard and need to enter a harbor at night, or you need to find an anchorage for the night. Your navigational chart needs to offer the best detail for the safest navigation day or night, in any marine weather.
2. Draw Your Tracklines (TR)
Plot your sailing courses–called “tracklines”–onto your chart with a pencil. Use the outer ring of the compass rose to plot in true direction. Many folks like to use the magnetic (second ring) compass ring, but not all charts have a magnetic ring. Those used offshore show only true direction. Convert the true direction to a magnetic course with the variation shown in the center of the compass rose.
Add westerly variation and subtract easterly variation. For example, if you plotted a true course of 038 true, and the center of the compass rose showed a variation of 3E, you subtract variation from true course to find the magnetic course (035M).
Some charts lack compass roses altogether. Instead they show magenta (purplish) dashed, diagonal lines ever so often that span the real estate of the chart. These are called isogonic lines. Look along the line to find the variation. Use the same rules above to convert your true course to a magnetic course.
3. Label Your Magnetic Steering Course
Write the magnetic course on the top of each of your tracklines. Label the course with three digits and a capital M (for magnetic). For example, for a magnetic course of 35 degrees magnetic, you would write 035M onto the top of the line. For a magnetic course of 8 degrees magnetic, you would write 008M onto the top of the trackline.
To make your labels clearer, draw a small arrow that breaks between the magnetic label, with the arrowhead directed in the direction of travel. For example -035M-> or -008M->
4. Scan for Dangers and Annotate
Take time to scan with great care to the right, left, and ahead of your trackline. Look for any dangers such as hazardous wrecks, shoals (shallow spots), rip current notations, or other areas that could place your vessel in harm’s way.
Mark these with colored pencils so that they stand out day or night, in any type of weather. Do not use red for annotating, as this will become invisible if you use red lights to maintain night vision. Instead, stick with blues, greens, magenta (nautical purple), or black.
5. Tape Over Your Tracklines
Purchase removable Scotch tape or any similar brand that can be removed and written on. Tape over the penciled tracks and add a strip above and below (for labeling or plotting positions). That way, you can reuse the chart over and over and the tape provides a protective barrier against the ravages of pencil lead, erasers, and the needle points of your navigation dividers.
6. Make It Black and Bold
Use a black fine-tip felt tip pen to trace your penciled sailing tracks onto the top of the tape. Write in your course labels on the top of each trackline with the felt tip marker.
7. Lash it to a Board
Make your chart ready to use in the cockpit. Fold the chart to show the area of navigation. Lash it to a legal size clipboard or use an artist sketch-board with rubber bands. In rainy weather, slide the board into a super-size plastic ziplock-type bag.
Use these seven super simple sailing tips to make your cockpit chart navigation fun, safe, and easier than ever before. You will become a more confident sailing navigator, always prepared to get your boat home safe and sound!
Captain John teaches sailing skippers the skills they need to learn to sail like a pro! Get his popular free report “Ten Top Boat Safety Checks for Cruising Boat Skippers” at Learn to Sail at Skippertips.com.