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Piloting a small boat along the coast of Maine is a joy, but it's also a job. You've got to know where you are at all times. There are literally thousands of islands, strong tidal and river currents, many rocks and shoals, and magnetic anomalies that induce compass errors. And then there's the fog. From sea smoke to the proverbial pea soup, it can descend in moments, enveloping everything in a damp shroud that defies the senses.

Just as in engineering, coastal piloting involves tradeoffs. One of my preferred sailing buddies is an EE who, like myself, knows that you cannot rely on any one system. When we sail together, we plot a dead reckoning course on our paper charts, update it at every opportunity, and check our position frequently with visual fixes, beacons, GPS, and LORAN (LOng RAnge Navigation).

LORAN? Yes indeed. Although slick GPS nav tools overshadow most everything else these days (and there are some fine GPS receivers with built-in high-resolution full-color nautical charts), it's important to have more than one source of information. LORAN fills the bill nicely. It's also practical on a small sailboat that relies on a couple of 12-V automotive batteries for accessory power.

I enjoy using my 20-year-old Sitex LORAN receiver, especially when I switch its digital display from LAT/LON (latitude and longitude) readout to TDs (time differences). LORAN receivers display the TDs between pairings of master and secondary shore-based radio stations. The TD numbers correspond directly to TD lines on charts.

Most importantly, the TD display -- in microseconds -- permits instant transfer of readings to a LORAN-compatible paper chart. Bingo--you know where you are. And you can mark up your chart for future reference.

The handheld GPS unit (appropriate for a 25-foot sloop), on the other hand, winks at you through an LCD giving geographic position in LAT/LON. That's reassuring, but it forces transferring the data into information that needs to be located on paper coastal charts. The process is error prone and problematical, especially in a seaway, where wind and waves can pound a small sailboat, and it's often difficult to brace yourself to steady dividers as you pick off LAT/LON along the edge of a chart. I’ve broken many a pencil point trying to pick off coordinates.

Still, there are boaters who deride LORAN. These folks typically sail larger sailboats and motor vessels. They usually enjoy enclosed wheelhouses and lots of spare amperes. Full-tilt GPS systems, with color LCDs and all the bells and whistles, point the way. I've noticed a lot of recreational boaters tend to rely on their GPS gizmos, to the exclusion of dead reckoning and every other common sense approach to navigation.

Although GPS devotees consider LORAN obsolete, the US Coast Guard still maintains the LORAN system, and is indeed upgrading and modernizing it. Other countries are doing the same. Surprisingly, the civil aviation community is also an advocate of LORAN. The IFALPA (International Federation of Air Line Pilots Associations) and Litton Aero Products have condemned utter reliance on GPS, noting it's "fundamentally unsafe" to navigate using any one system.

Today's decades-old shore-based LORAN system is still easily maintained, doesn't require rocket launches when satellite upgrades are due, and can work in conjunction with GPS. Enhanced LORAN, or eLORAN, is also part of an ongoing modernization program. eLORAN will actually increase the accuracy of traditional LORAN, so I will be able to use it to spot position to within 8-meters or so. That's as good as one can expect with GPS, and will certainly help find your way to port on a foggy day.

LORAN is a great complement to GPS. If the eLORAN system comes to fruition, everyone will benefit from a hybrid that’s more capable and reliable than either GPS or LORAN alone.

Comments? Questions? Do you have your own opinions about LORAN and GPS? Do you use these systems for navigation or precision timing? Write me at amm at en-genius dot net, or post your comments on our blog.