Getting on the water for an afternoon is fun, and something most of us can do easily. But an overnighter or a cruise calls for a little more preparation, with careful attention to navigation along the way. You need a plan to reach the other side of the horizon – before you leave the dock.
Learning to plot a course using charts and electronics – and maintaining that course in the face of tides and currents – takes practice, and it never hurts to watch someone else first. So in order to learn, we are going to look over the shoulder of a fictional friend we will call Bill, and see how an experienced boater might approach a weekend trip.
The journey from Norfolk, Virginia, to the town of Cape Charles on the eastern shore of the Chesapeake Bay is about 33 nautical miles. It requires navigating busy harbors, traveling through miles of open water and cutting across shipping lanes.
Bill wants to see the Eastern Shore, and decides a weekend trip to Cape Charles would be a good way to start. Because it will include crossing Chesapeake Bay at its widest point, about 16 miles of open water, much of it out of sight of land, he needs to plan ahead of time.
PLANNING A TRIP
The first thing Bill does is check marine weather forecasts and call a marina at Cape Charles to reserve a transient slip. That done, he lays out the appropriate chart and examines his route options. The chart will give him much of the information he needs, including the quickest route, the proper compass headings, depths and the location of the navigation markers he can expect to see along the way. He can also use it to calculate the length of his journey and how much time it will take, allowing him to target optimum light and weather conditions.
Bill decides it would be quickest to go straight to Cape Charles from Thimble Shoal light, which is 3.5 miles outside his harbor. It would also give him some open-water navigation practice, which he always values. Since the first 13 miles will be in familiar local waters, he concentrates on the open Bay portion. He can follow the buoys to Thimble Shoal light, so he starts his planning from there.
Bill could lay out a course straight from there to the light at Old Plantation Flats at the entrance to Cape Charles. The direct route would be 15.8 miles. About half way there, he would cross the main ship channel up the Bay. However, if he were to aim for one of the buoys marking that channel, say Bell 22, he would add only a little more than a mile to his course, but he would have a nice check on his progress at about the halfway point. That would give him confidence that he was on course, and it would break the route down into shorter legs. Making the trip in shorter legs will minimize the effects of any errors in steering.
First he lays out the course lines on the chart, then he uses a parallel rule to get his headings from the magnetic compass rose on the chart (his boat’s compass is fully compensated, so he can steer magnetic courses directly). Above the line on the chart, he writes the compass course toward Cape Charles. Below the line, he writes the distance of that leg of the journey (see photo). He now has a great deal of information in one place, in a format that does not depend on his boat’s electrical system.
USING A GPS
Of course, electronics can also be useful. Bill wants to maintain his skills piloting by chart and compass, but he also owns a hand-held GPS, so he prepares to use that too. He uses the chart to determine the latitude and longitude of (1) the entrance to his home waters (Hampton Roads); (2) Thimble Shoal light; (3) bell buoy 22; and (4) the entrance to the well-marked channel to Cape Charles. He enters these into the GPS as waypoints, which form a route. He gives this route a name (or number). When he gets underway, he will bring up that route and the GPS will indicate the course to the next waypoint along the route.
