Please select your home edition
Edition
Southern Spars

Seven navigation 'Rules of thumb' for safer sailing

by John Jamieson on 26 May 2012
Sailing navigation - rules of thumb to keep it easy .. .
If you are anything like me, it's rare that you look forward to another mathematical calculation 'rule of thumb'. Here are seven simple rules that will enhance your sailing navigation safety--without a whole lot of math! Follow these sailing tips to keep your sailing crew or partner safe and sound wherever you choose to cruise!

1. Double-check Courses.

Parallel rules and protractors tend to slip when underway. Just a slight bit of slippage could throw a course or bearing off by several degrees. Take the extra step and measure your plotted course twice. If both measurements agree, you will know you’re right!

2. Keep Bearing Spreads to 60-90-120.

Shoot two or more bearings with a minimum angle of 60 degrees between the bearings. This will reduce errors and gives a more solid fix. If you shoot just two objects, the best spread between objects will always be 90 degrees. With two objects the maximum angle should never exceed 120 degrees. Scan your nautical chart ahead of time; find and highlight objects you can use for bearings. This will make your plotting faster, easier, and more fun.

3. Measure Distance with Care.

Because chart projections have some error after being flattened from a 3-dimensional image, distances can distort. This becomes more critical on charts with smaller scales, such as those used in coastal or offshore navigation. Measure distances on the Latitude scale adjacent to your current position for more accuracy.

For example, let's say you are navigating on an offshore chart with a scale of 1:250,000. If you are located in the center of the chart, measure distances from the central part of the latitude scale. If located near the top of the chart, use the latitude scale near the top to measure distances. If located near the lower part of the chart, use the latitude scale near the lower part of the chart to measure distances. This gives you more accurate distance measurements for planning, provisioning, determining arrival times, and for conservation of water and fuel.

4. Shoot Bearings Ahead or Astern First.

Take visual bearings on objects near the bow or stern first. Bearings to these objects change slowest as you move through the water. Take visual bearings to objects near the beam last. Bearings to these objects change fastest. Mark the time of the position when you have taken the final beam bearing. Enter the time of the fix into the navigation log along with your bearings. This allows you to reconstruct your path over the earth's surface and provides a historical and legal record of your vessel's journey.

5. Become Plotting Compass Savvy.

Learn to become super proficient with the plotting compass. This tool has a needle point in one leg and a small sliver of pencil lead in the other. Few navigation tools are more versatile. Use the plotting compass to plot Latitude and Longitude one-handed, swing an arc from a radar bearing, or project a series of Dead Reckoning positions ahead of your last fix--with a simple sweep of the pencil-lead across the course line. Some navigators might prefer dividers—a navigation tool that has a needle point in the end of each leg. But dividers require a separate pencil for plotting. The plotting compass does twice the work in half the time!

6. Know Your Sounding Datum.

Before you start to use any nautical chart, find the sounding datum. Look on the top or bottom margins, or near the title block. You chart will show Sounding in Feet, Soundings in Meters, Soundings in Feet and Meters, or Soundings in Fathoms. These are the most common soundings. For example, let’s say you see a sounding of two on your chart. You must determine if the chart datum shows feet (Two feet), meters (6 ½ feet), or fathoms (12 feet) for sailing safety. Pass on this super vital information to your sailing crew so that they understand what the soundings on that particular chart mean.

7. Allow for Leeway Error.

Sailing vessels slip sideways (called 'leeway') when beating or reaching. There are fancy calculations to determine leeway, but always work your way upwind of your intended destination to account for unexpected wind shifts or navigation errors. Some navigators like to set their course two to three miles upwind or up-current on purpose. This gives them a good margin of safety and allows them to fall off to a reach or run to the final destination.

Follow these seven easy 'rules of thumb' to enhance your sailing navigation safety. Keep your small sailboat and sailing crew safe and sound on the waters of the world--wherever you choose to go sailing!

John Jamieson (Captain John) with 25+ years of experience shows you the no-nonsense cruising skills you need for safer sailing worldwide. Visit his website for a free issue of the highly popular 'Captain John's Sailing Tips' newsletter. Discover how you can gain instant access to hundreds of sailing articles, videos, e-Books and more!

Zhik ZKG 660x82Bakewell-White Yacht DesignWildwind 2016 660x82

Related Articles

Coast Guard Foundation receives donation from Ice Hockey Team
Coast Guard Foundation announced today that it received a donation from the Guilford High School Ice Hockey Booster Club The Coast Guard Foundation, a non-profit organization committed to the education and welfare of all Coast Guard members and their families, announced today that it has received a donation from the Guilford High School Ice Hockey Booster Club for $2,568, to benefit the Coast Guard Foundation’s Fallen Heroes Fund and Scholarship Fund.
Posted on 25 Feb
Bavaria Yachts to introduce Cruiser 34 and Nautitech 46
The Cruiser 34 will be on show at the Bavaria Yachts display at the Strictly Sail boat show at Bayside’s Miamarina The Cruiser 34 will be on show at the Bavaria Yachts display at the Strictly Sail boat show at Bayside’s Miamarina, from February 16th to 20th.
Posted on 13 Feb
Unique Transatlantic Sailing Event - Building friendship across oceans
Rendez-Vous 2017 Tall Ships Regatta, organised to celebrate Canada 150, 150th anniversary of the Canadian Confederation. Sailing in the wake of the great explorers, international friendship and understanding is at the core of this once in a lifetime adventure - The Rendez-Vous 2017 Tall Ships Regatta, organised to celebrate Canada 150, the 150th anniversary of the Canadian Confederation.
Posted on 10 Feb
Frigid flying – Coast Guard aircrews take on New England Winter
Freezing rain? Teeth-chattering temperatures? Limited visibility? Coast Guard aircrews are still ready to fly. Freezing rain? Teeth-chattering temperatures? Limited visibility? Coast Guard aircrews are still ready to fly. At Air Station Cape Cod, aviation maintenance and electronic technicians work around the clock to ensure the MH-60 Jayhawk helicopters are prepared and ready to launch. There is one thing the maintenance crews and pilots cannot control: winter weather.
Posted on 9 Feb
On board interview with Lisa Blair - solo Antartica circumnavigation
So far, Lisa is tracking very well in her attempt to become the first woman to sail solo around Antartica. So far, Lisa is tracking very well in her attempt to become the first woman to sail solo around Antartica. After the setbacks of a delayed departure due to gremlins in the electronics, we are delighted to have these answers from her on board. She is well and enjoying her time. Climate Action Now, her Hick 50, left Albany in Western Australia on January 22, 2017.
Posted on 8 Feb
Yachting cartoonist Mike Peyton dies at 96
“The World’s Greatest Yachting Cartoonist” died on January 25, 2017 just five days after his 96th birthday. Mike Peyton, dubbed “The World’s Greatest Yachting Cartoonist”, died on January 25, 2017 just five days after his 96th birthday. A modest, shy man, he eschewed the spotlight and seemed unaware of the esteem which in sailors all around the world held him.
Posted on 27 Jan
Zhik Xeflex® - your shield against cold environments
This radiant barrier mid-layer nearly defies description. This radiant barrier mid-layer nearly defies description. How do you make a water resistant garment that really breathes, yet reflects your own body heat back to you? Where do you find a compression resistant and extremely insulating filling that is nowhere near as bulky as the Michelin Man, yet gives you that kind of warmth and comfort?
Posted on 17 Jan
Sounds like a boat - Lisa Blair's departure delayed due to electronics
Final preparations of her yacht, Climate Action Now by Sydney-based sailor Lisa Blair have uncovered an electrical issue Final preparations and safety checks of her yacht, Climate Action Now by Sydney-based sailor Lisa Blair have uncovered an electrical issue.
Posted on 15 Jan
Lisa Blair starts Solo Circumnavigation of Antarctica
Over 3,500 people have climbed Mount Everest, only two men have sailed solo, non-stop and unassisted around Antarctica. Over 3,500 people have climbed Mount Everest, over 500 have rowed across the various oceans and 12 people have landed on the moon. Only two men have sailed solo, non-stop and unassisted around Antarctica. Sydney-based Lisa Blair, 32, intends to become the first woman, the fastest and the third person in history to conquer such a challenge.
Posted on 14 Jan
When whales meet sails
CAMPER helmsman Roberto ‘Chuny’ Bermudez found himself nearly face to face with whale in middle of North Atlantic Ocean. Currently the database for marine mammal strikes is very sparse. We are requesting sailors and boaters help to submit information on current and past incidents, however long ago that may be. By giving a location, date, identification if possible, and any other relevant information you can help scientists better understand where marine mammals are at risk for strikes
Posted on 8 Jan