Half the fun is getting there, provided you’ve been keeping track of where you were, when you left, and where you are.

Navigation, whether in life or on a boat, is the art of knowing where you are, where you’re going, all based on where you’ve been and that crucial element governing the cosmos: time. In many ways it has become something of a lost art. Except for a stalwart few, mariners no longer sling sextants around their necks shooting the sun, the stars, and the moon and their various angles above the horizon using complicated mathematical equations to figure out where they are. Instead the GPS has come and trumped all with a push button accuracy that can pinpoint a boat, or now an SUV, within feet. But even with knowing where you are at all times, there are some plotting issues that need to be addressed. For instance, many charts of the South Pacific and Central America were surveyed by navigators of the golden age of sail, and while they did a pretty good job, it’s not uncommon for a GPS fix to put a boat on land. Discrepancies between yesterday’s navigation and today’s exist and the most important tools are still open eyes and a cool head. Entire books have been written on navigation, Chapman’s Piloting is one book that should be on all boats, Chart Number One is another--a few tips will be all that follows.

So you press on the GPS and it spits out a few numbers and you know where you are. There’s the latitude and the longitude. And while the figure has an accuracy that would make Captain Bligh envious, how you go about putting it on the chart--depending on the chart’s scale--will determine if it is as accurate as it can be. On our cruises, we’ve often bought used charts and noticed that the care taken in putting a fix on the chart by the previous owners varied from surgical precision to slipshod blobs of pencil lead or ink. The more precise you can be, the better. It’s tempting to use parallel rulers as a T-square, lining up one side with the latitude, making a line where you think you’re longitude will be, moving the edge of the parallel rulers back to the longitude side and intersecting with the latitude line, drawing a circle around it, noting the time and having that be that. A more accurate way is to use compass dividers. This is a bit cumbersome to describe, so bear with me. Nautical charts have intersecting lines of latitude and longitude already drawn on them, usually at 10-degree intervals. Put one end of the dividers on the closest major intersection, scroll up or down to you latitude on the edge of the chart. Then slide that over to the closest major intersection of longitude and make a tiny pinhole in the chart. Now do the same thing at the top of the chart for your longitude and slide it down. Find your latitude pinhole and use the parallel rules to have a straight edge to use your longitude figure. Twist the compass and put another pinhole in the chart. Circle it with a mechanical pencil and write the time next to it. Voila!

The rhumb line is the shortest distant between the point that you‘re leaving and the point that you hope to get to. When you’re drawing your rhumb line, keep clear of land masses, submerged rocks, and other minor navigational hazards like underwater volcanoes. And while it’s not always the track sailboats follow, based on ever shifting winds and currents, and mechanical breakdowns, it’s at least a good idea to know where that line is as you move from one anchorage to another so you can try to move as efficiently as possible on the high seas.

The main things to know before you set off are course, speed, and direction. The course is the compass course that you will be steering between two points on your chart. We’ll take this time to mention that the earth is not uniform when it comes to its magnetic field and that variations exist in it from location to location, something that can make it hard to get out of the bunk depending on where you are and the amount of rum in your area. The magnetic variation can change your compass course, so first work out the true course between the two points. Each compass rose has a true north compass rose on the outside, and a magnetic one on the inside that list the magnetic variation for that area. So if you’re true course is 90 and the magnetic variation is 3 degrees East the course you’ll steer, assuming your compass is perfect, is 87 degrees. If the magnetic variation was Westerly, you’d add 3 degrees. Three degrees isn’t a lot, especially when under sail the compass can bob hither and thither, but three degrees over a couple hundred miles adds up to a significant amount of mileage off your rhumb line. Navigation isn’t something that’s just done and over with and crossed off the list like an onerous boat chore, it’s an on going affair that varies from hour to hour and day to day. The boat that is in the middle of sailing across the ocean is going to do less chart work than a boat making its way close to the coast, namely because there are more things to run into closer to land.

Taking compass bearings off of a point, a marker on shore, and a buoy give a navigational fix.

Your boat’s average speed gives you an idea of how long it will take to get to where you’re going. If you’re heading off on a journey that will take you a couple of days to get to and a harbor that has a tricky entrance or is one that you’re unfamiliar with, arriving at daylight is usually the better option. So slow down or fire up the iron genoa as necessary. Sometimes the current is with a boat, sometimes it’s against, sometimes it‘s at the side. Here’s another way to tell current and direction other than looking at the GPS. Say you’re sailing along a six knots. Mark the position on the chart. Then measure off six knots along the latitude scale (never the longitude! One minute of latitude equals one mile. The distance between longitude becomes narrower as one gets closer to the poles while latitude remains equal throughout.) Apply this distance forward along the course you’ve been sailing for a Estimated Position. Sail for another hour. Plot your position again. Draw a line between it and your Estimated Position. If it’s above this point, you’re being set north, below it, south. Measure the distance between the two, and that’s the amount of current and it’s direction. If you’re still on your course but further than your Estimated Position, the current is behind you, and if you’re not quite as far, the current is against you.

Despite advances in navigation like GPS, there’s no substitute for proper chart work and paper charts underway.

Another good Dead Reckoning skill is to triangulate off lighthouses, prominent land features like smokestacks or radio antennas, buoys or other navigational aids. Binoculars with compasses in them are great for this. Basically, just find what the chart is telling you is there. Take a bearing and draw a line from it to your approximate position. Then find two other objects--the further they are from each other the better. Ideally these lines will intersect and that will be where you are. More often than not they will not quite intersect due to the boat bouncing around and inevitable errors in plotting and taking a bearing on a small boat at sea. They will hopefully at least come together to form a triangle on the chart, and hopefully a small one, that will tell you that you are here.

When it comes to navigation the most important thing is in fact the little maxim written on each chart: The prudent mariner will not rely on one navigation aid. And although it’s unlikely, Big Brother can throw the switch off on satellites, electronic charts can freeze up on computer screens, and the depth sounder (also a good navigational tool) can suddenly stop working. Hopefully they all won’t stop at the same time. But if they do, with some practice, you’ll still be able to get to where you’re going.