Features August 1, 2002 Issue

Hand-Bearing Compasses

Bow-and-beam bearings, running fixes, collision-course bearings, anchored position—the oft-ignored hand-bearing compass can provide all these and more.

Aboard ships and boats, compasses with which to take bearings by hand have always been central to the navigator's toolkit. You can get by without them in a pinch, but it's better not to. 

For all-around accuracy and utility, PS prefers
a hockey-puck compass like the Plastimo Iris 50.

The bearings needed usually are of objects on land, and the first such man-made example was the lighthouse called the Pharos in Alexandria. It took the first two in a long line of Egyptian politicians named Ptolemy 20 years to build the 450-foot navigational mark. (It made the original list of Seven Wonders of the World, but was eventually replaced by Graceland.)

With decent landmarks combined with what a Greek named Pythagoras had taught them, sailors of ancient days had the means and the mark, if only they'd had a compass. Unfortunately, it didn't come along until the 12th century.

Today, on big modern ships, military or civilian, there's usually a bearing instrument, called a pelorus, on each wing of the bridge. They're large-diameter ring devices with sighting vanes and "dumb" compasses set by the ship's standard compass. They take precise bearings relative to the ship's heading.

Aboard pleasure boats, the bearing compass once was a beautiful, expensive, flat-card, prism-sighting instrument kept safe in a mahogany box. With "D" cells stored in the long handle, it resembled Julius Caesar's scepter. Like sextants, there must be thousands of these instrument stowed away in lockers and closets.

Although cumbersome, such instruments were often used when rounding points, to make sure the course being steering didn't take the vessel into dangerous water, or to adjust courses (by steering no more or less than a carefully developed bearing) to avoid shoals and hazards.

The ritual of unlimbering the hand-bearing compass was made much easier and more casual with the invention of what came to be known as the "hockey puck."

The first hockey puck, called a Morin Opti, burst out of France in 1975. A simple, accurate compass, it is still sold as the Vion MiNi 2000. They initially sold like popcorn, until competitors like Plastimo, Plath, Silva, Suunto, and others fragmented the field.

The hockey pucks have flat cards with tiny numbers and a viewing prism both to magnify the numbers and turn them 90°, like a plumbing elbow. Some early versions suffered because they tended to develop bubbles, but most manufacturers have switched to flexible cases that act as diaphragms. On the chart on pages 12-13, this type is called "Compact, Prism."

Next to explode on the scene in 1987 was the Autohelm Personal Compass, a thin, flat fluxgate instrument that was a sensation (30,000 sold the first year) because it was so very different. The Autohelm discounted for about $100, stored nine bearings, and had glow-paint sights and lithium batteries to illuminate the digital display. Because it could not be gimbaled, it had to be held within 3° of level, which made it difficult. Practical Sailor tested the Autohelm against the MiNi Morin in the Dec. 1, 1988 issue, and concluded, "We still prefer…the MiNi Morin 2000." The Autohelm sang its swan song in the 2000 West Marine catalog.

Next came the Datascope, originated in the late 1980s by a little company called KVH, on the same island in Rhode Island as Practical Sailor's early offices. (We reviewed it in the April 15, 1989 issue.) Following the success of the hotdog Datascope, KVH grew quickly. It now has a big, fancy building and million-dollar contracts for sophisticated military equipment.

In the mid-'90s, another fluxgate compass, the Outback (first called the Wayfinder), elbowed its way into the market. It was made in the Far East and wasn't much to begin with, because it ate batteries like a sumo wrestler eats rice. Now trained to be more conservative, the Outback has been widely marketed by several sales organizations.

Because of the success of these new electronic instruments, Practical Sailor presented in the Feb. 15, 1995 issue a thorough discussion of the fluxgate compass.

Throughout all this world-of-tomorrow stuff, Davis Instruments has stuck steadfastly to its simple and inexpensive sighting instrument with a domed compass and pistol grip. And Ritchie, seeking something even less expensive, brought out its little Sportabout, which also has a domed card and direct reading.

Practical Sailor gathered up all the handbearing compasses we could find, including a few that really are for use on land, by hikers, hunters, and the like. If any marine compasses were missed, they probably will make an appearance in the magazine as an Update report.

The lot includes an unusual number of compasses made by Suunto and Silva, two Scandinavian companies that, if you count marine and landsman's compasses, make an outsized percentage of the world's compasses. (It was in Scandinavia that a Finlander named Tuomas Vohlonen invented in the early 1930s the liquid-filled compass; Suunto claims him as their man.)

The 16 compasses finally chosen and shown throughout this article are from companies in the US, Sweden, France, Finland, China and England.

The Testing
To test these hand-bearing compasses for accuracy, we set up on a point of land with two prominent (and fixed) objects in plain view. They provided two bearings—one north-south at a range of a mile and a half, and one roughly east-west at a range of 0.7 of a mile. Measured very precisely on a new chart, the bearings were 000° and 306°, and we believe them to be accurate to within one degree.

With each of the 16 compasses, bearings were taken and double-checked, as carefully as possible, and recorded. The data is displayed on the chart.

As was the case among Orwell's animals, all these compasses are equal, but some are more equal than others. In other words, they were acceptably accurate across the board, with the single exception of the Ritchie Sportabout, whose errors seemed excessive. Considering the supremacy of Ritchie steering compasses (reviewed in the Aug. 1, 2001 issue), the Ritchie Sportabout, even for $25, is not easy to understand. Maybe we had a bad copy.

The accuracy of most of these instruments made it even more important to consider how easy each compass was to bring to bear and, then, how easy the bearing was to read—with judgments made in good daytime visibility.

Night operations for these compasses (facilitated by a wide range of lights ranging from LEDs to chemical light sticks) were evaluated, as shown in two columns on the chart. However, because sailors don't use hand-bearing compasses at night too often, the lighting was given minor weight. If you do take a lot of bearings at night, the data shown will be of interest.

A minor plus was given to compasses that provide a simultaneous reciprocal bearing or "backsight," but because this isn't usually so important in this context, it must be said that the single-bearing numbers, in most compasses, permit the greatest clarity.

To their credit, the compasses display the primary bearings either in larger numerals or a bolder black and use a lighter black or a color for the reciprocal.

Also deemed not very significant was the fineness of the graduations on the card. Five degree graduations certainly are not preferable to one- or two- degree graduations. That's because the 5° marks call for a level of visual and mental extrapolation that may make errors more likely than with 1° marks. As a practical matter, utilizing 1° fineness is almost impossible (even though it's nice) and that goes for our test procedure, too.

Bottom Line
The hockey puck type remains our favorite. A puck embodies the best combination of accuracy, stowability, ruggedness, and readability in lumpy conditions. All the pucks in this evaluation are good. Pushed to rank them, we'd rank them thus: 1. Nexus Model 80 ($75) 2. Vion MiNi 2000 ($100) 3. Plastimo Iris 50 ($60) 4. Weems & Plath ($100) 5. Suunto KB-20 ($65) 6. Suunto KB-14 ($160) 7. Brunton Sightmaster ($69).

If you're dollar-conscious, the Plastimo Iris 50 comes first, with the Suunto KB-20 second and the Nexus Model 80 third.

If you're really concerned with cost and want something absolutely foolproof, your choice should be the $38 Davis, which is both simple and accurate. It's not a thing of beauty, but what a bargain. The other domed compass, the $25 Ritchie Sportabout is cheaper, but not preferable.

If you have a smaller boat and want a combination steering and bearing compass (or wish to mount the bearing compass over the chart table so you can keep an eye on the helmsman), the choice is between the Nexus Model 70UNE and the French-made Plastimo Iris 100. Both are excellent, but because the Plastimo has better damping, it gets the nod.

Of the three odd compasses in our sampling, two are mirror-reflecting, flat-card instruments. Although used almost exclusively on land, they could be used on boats, if the user takes care to keep the card level (they're not gimbaled).

The Brunton 15TDCL, one of the world's most successful landsman's compasses, has been unchanged for 60 years (that may be why it has all those letters in the model name). The other is the very clever Suunto DP-65, which is an oversized matchbox with a rotatable card and a bottom mirror that drops down when the box is opened. (In the April, 1996, issue we presented in the Chandlery column a compass made by a Swiss company called Recta AG/SA, which seems identical to the Suunto DP-65.)

The third oddball is the Suunto M-9, a wrist compass that was surprisingly pleasant to use, very accurate, and only $29. It's basically a top-reading flat card, but has a crafty rim-reading feature and a rotating bezel that makes it grid-steering. It might make a good compass for one-design racing.

Finally, there are the two fluxgate instruments—the KVH Data-scope and the Chinese-made Outback. Both require calibration.

The KVH Datascope, which we first reviewed when it appeared in early 1989, remains the king of the hand-bearing compasses. In this era, when electronic wizardry rarely lasts very long, the "totally-waterproof" KVH Datascope is amazing. Besides being a plum accurate bearing compass and keeper of nine bearings (which it will average for you), it's also a five-power scope, a chronometer, and a rangefinder. The compass is internally gimbaled through plus or minus 20°. Its two liabilities are: 1. it's very difficult to compensate, and 2, it's expensive ($350). The copy we got for this evaluation was also a bit difficult to calibrate, in that one impatient person wasn't able to do it at all, and even the patient one got a bit frayed before success.

The Datascope's competition is the Outback, and compete it does, at one-sixth the price ($56). The Outback takes and stores (but does not average) 10 bearings and has a quartz clock and various timing functions. It also, in its "Multi-Leg"/"Trailblazer" mode, will store the headings and times of up to 10 legs and bring you back the same way—even giving you "come right," "come left" directions to get home. Besides being less expensive, the Outback is much easier to calibrate. A major negative: It's not waterproof; a minor negative: The index in the instruction book is a mess.

If you truly like and are adept with somewhat complicated electronics, the KVH is a trophy piece, the Outback is a Best Buy. Unfortunately (and this is a little late-breaking news), there are reports that the Outback will be discontinued at the end of this year. Stay tuned for other developments.

Overall, for the money and especially when you need an accurate bearing in a hurry, we'll take one of the top three hockey pucks or the simple Davis.

 

Also With This Article
Click here to view "Value Guide: Hand-Bearing Compasses."
Click here to view the compasses reviewed.

Contacts — Brunton (Nexus/Silva), Brunton Marine, 620 E. Monroe, WY 82501; 888/284-2667; www.bruntonmarine.com. Davis, Davis Instruments, 3465 Diablo, Hayward, CA 94545; 510/732-9229; www.davisnet.com. KVH, 50 Enterprise Center, Middletown, RI 02842; 401/849-0045; www.kvh.com. Plastimo, MariSafe, 1721 Independence, Sarasota, FL 34234; 866/383-1888; www.plastimo.com. Ritchie, Ritchie Navigation, 234 Oak, Pembroke, MA 02359; 781/826-5131; www.ritchienavigation.com. Speedtech (Outback), Speedtech Instruments, 10413 Deerfoot, Great Falls, VA 22066; 800/760-0004; www.speedtech.com. Suunto, Suunto USA, 2151 Las Palmas, Carlsbad, CA 92009; 800/543-9124; www.suunto.com. Vion, Pioneer Research, 97 Foster, Moorestown, NJ 08057; 800/257-774; www.vion-marine.com. Weems & Plath, 214 Eastern, Annapolis, MD 21403-3318; 410/263-6700; www.weems-plath.com.

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