Any wreck on the beach highlights what could have been done to avoid it. Knowing safe lines of latitude and longitude on the final approach is a good place to start.

There is a wreck just south of Isla Mujures that serves as a stark reminder that blindly following a waypoint heading can lead you astray, or worse, on to the rocks. Every time I sail by the sadly raked masts and listing hull, I wonder if a seemingly harmless waypoint was to blame? Yes, even today with helm mounted combination chart plotters that provide more information at a glance than Captain Cook acquired during his lifetime, waypoint navigation is a risky proposition when making difficult landfalls.

Problems arise when you approach the mark. Unless you are right smack on course, cross track corrections become more significant and often result in a heading that is impractical or impossible to steer, a situation especially true in current ripped waters and when you’re hard on the wind. Further, the corrected course to steer may lead you into danger as you angle back toward the waypoint. Adding or amending waypoints during the approach just adds to the confusion. There is a better way to make landfall, and it’s one Captain Cook would have understood.

In those not-so-far away days before little black boxes took most of the art out of the art and science of navigation, navigators relied on a technique known as “latitude sailing.” The concept was simple, sail until you reached the latitude of your destination and then do everything possible to stay on that parallel until land turned up on the horizon. This technique endured much longer than most people realize as even hack celestial navigators could reckon latitude at noon or by Polaris, the north star. In my early days as a delivery skipper, before navigation satellites skipped benevolently across the sky, I knew plenty of captains that navigated by a combination of latitude sailing and hailing commercial ships on the VHF and pleading for position.

“No part of a voyage promotes more anxiety than the approach to its end,” writes John Rousmaniere in his intriguing book, “After the Storm.” Even today, landfalls are the most stressful aspect of any voyage. Ironically, a variation of the old technique of latitude sailing combined with the accuracy and reliability of GPS can take all the pressure off as you ease your way into an unfamiliar harbor under difficult conditions.

One advantage of coming across a ship on the high seas is that it’s crew likely knows their position, if for some unfathomable reason you are unsure of yours. Whether they’ll answer your VHF call is entirely another matter.

I have conducted many offshore training passages during the last five years, it’s a way to get paid for doing what I love, and to keep me from doing what I definitely don’t love, finding a real job. While my crews have learned some useful tips about passage making, the aspect of each voyage that generates the most interest is landfall. A recent passage to the above-mentioned Isla Mujures provided an ideal opportunity to use a form of latitude sailing to transform what might have been a difficult nighttime approach into a trouble free landing.

We had sailed from Key West three days before, riding fresh southeast trades as we neared Cape San Antonio on the western tip of Cuba. The Yucatan Channel is the birthplace of the Gulf Stream and the north setting current between Cuba and Mexico occasionally has a drift of five knots, it’s one of the most powerful ocean currents in the world. Our long-range waypoint for the approach to Isla Mujures was a position two miles south and east of the island’s southern most point.

The current is stronger on the western side of the Yucatan Channel and the last 15 miles found us battling an impatient three-to-four knot rush of water. We hauled in the sheets as our course to the waypoint became increasingly more close winded as we compensated for the current. Naturally our speed slowed too as we were forced to head further south taking the current head on. The crew studied the chart and noted that there was a bright light on the southern tip of Isla Mujures and another flashing light two miles further south marking the dangerous Roca La Bandera. “All we have to do is sail between the lights,” it seemed like a no-brainer approach.

Unfortunately, I knew from previous voyages that lights along the Mexican coast are about as reliable as one of Shaq’s free throws and even when they do work their actual luminous range is always less than charted. Further, the hideous bright lights of Cancun, that blight on the coast just south of charming Isla Mujures, create a blinding backscatter that makes it difficult to pick out navigational marks when approaching from the east. I cautioned them not to put too much faith in the lights and not to underestimate how swiftly the current would set us north once we straightened out our course.

As we neared the island it became impractical to lay the waypoint without luff sailing, or short tacking, which would take us too close to shoals for my liking. Also, the light marking Roca La Bandera was nowhere to be seen. Instead of worrying about the light we carefully studied the chart and determined a series of safety parallels and meridians and let them guide us into the protected waters in the lee of the island. It worked like this:

The southern most tip of the island stretched just a whisker below 21.12 minutes north latitude. The rocks at Roca La Bandera were just below 21.10 minutes, with each minute of latitude translating into one nautical mile, this is a two-mile wide pass. We chose 21.11 minutes, or right in the middle, for an approach parallel. The chart also showed that we needed to be south of 21.12 by 86.42 minutes west longitude, so we selected this line as our safety meridian. With the GPS mounted at the helm, we immediately had a “sense of position,” by simply monitoring our latitude and longitude. Never, and this is really important, never underestimate the value of a “sense of position” especially with respect to point of sail. One thing you never learn in navigation classes is that position is evolving minute by minute, especially when making landfall, while a waypoint is a stagnant point that forces you to start and stop navigating over and over. By just observing the latitude and longitude on the GPS we knew we were not in any trouble as we came on soundings.

Reduced visibility can leave the feeling of flying blind, but careful chart work can take the edge off. If doubt persists, head back out to sea.

We crossed the meridian of 84.42 W at latitude 21.11.3 N, not quite what we hoped for but far enough south to free the sheets a bit and later course toward the west. By the time we reached 84.43 W we had dipped down to 21.11 N, right on course due south Isla Mujures and a mile north of Rocas La Bandera. By the way, neither light was readily apparent. The crew was impressed how little stress was involved, especially because a squall line had rolled in during the approach momentarily reducing visibility to a few feet. I was pleased that we managed the entire affair under sail and didn’t resort to dropping canvass and steaming in like a bloody powerboat.

From 21.11 N and 86.43 W we had to adjust our course north to approach the wonderful natural harbor on the west side of the island. We also had to avoid a wide shoal marked by a light, Bajo Pepito. While the Mexican shoals have great names their lights leave much to be desired, we couldn’t find the light. Instead, we again plotted a couple of safety parallels and meridians. To stay in relatively deep water we needed to be west of 86.45 W, and as long as we didn’t stray over to 86.46 W, we couldn’t get into much trouble.

We ambled north under jib alone. It was almost midnight and we decided to drop the hook and enter the harbor at first light. We eased along until we touched latitude 21.14.2, headed east toward the island until we found 15 feet on the depth sounder and kicked the anchor over the side. Once we were certain the anchor was holding, okay, or maybe a bit before we were certain the anchor was holding, we had a tot of rum in the cockpit. We toasted Ix Chell, the Mayan Goddess who had a soft spot for sailors, and our GPS which by selflessly serving up position coordinates had allowed us to make a stress free landfall.