Boaters have come to rely on GPS so much that few new boats leave the factory with a compass at the helm. Yet GPS jamming is becoming a common problem—one which could leave you in the middle of the bay, with no clue how to get home.
The first signs of problems came in Moss Landing Harbor, in 2002, when a boater’s malfunctioning UHF TV antenna jammed GPS units up to 2,000’ away. Then in 2006, solar flares knocked out GPS for several hours. Just over a year ago, GPS at Newark airport in New Jersey seemed to malfunction on and off throughout the day, until investigators located a delivery truck driver working near the airport who had a GPS jammer in his truck. The reason why: he was tired of his employer keeping tabs on his location.
It’s not a question of if you’ll lose GPS capabilities on your boat, it’s a question of when. Either nature or human intervention is sure to flip the switch off, sooner or later. So ask yourself: do you remember how to use that compass? Do you even have one onboard? If the answers to these questions are “no,” go out and get a compass today—and use these old-fashioned nav tips to get yourself back home, when your GPS fails you.
- Always note your compass course when leaving the dock. Your reciprocal (opposite) course will always be the original course plus or minus 180. If the original is under 180, add 180; if it’s above 180, subtract the same amount to determine the reciprocal.
- You can quickly determine your location on a paper chart, by taking three readings with a compass pointing to charted items, and drawing lines to represent those readings on the chart. For example, take a reading with the compass pointing at a fixed channel marker, a water tower on shore, and a point of land. Then draw lines on the chart which cross through each of those items, along the bearings the compass showed when you pointed at them. (If the marker was was at 120-degrees, draw a 120-degree line through it on the chart, and so on). You’ll end up making a triangle on the chart where the three lines meet, and your location is in the middle of the triangle.
- Use the compass as a reference when cruising; don’t stare at it and steer by its movements. On most boats, it’s nearly impossible to hold a steady course if you stare at the compass. Instead, get the boat on course and pick out a landmark, cloud, or star. Then steer for that object, while glancing down now and again to make sure your course is still correct.
This boat has plenty of electronics, but no compass at the helm. When GPS gets jammed, it'll be an issue.
