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Map measure of the month: W&HC navigation dividers

W&HC nautical dividers
W&HC divider caliper

This month’s measure is a navigators divider, sometimes called divider calipers, made by W&HC. It is such a simple instrument, little description is required.

The two sharp stainless steel points are used for measuring distances on a nautical chart by transferring the gap between the pointed legs to or from a scale. Using the dividers and the latitude scale on a nautical chart, it is possible to measure a distance in nautical miles. The upper part of the legs and the hinge are made from solid brass in a semi-circular form. This shape enables the user to alter the gap distance using only one hand, hence this type being known as a ‘one hand divider’. The selected gap in the tips is maintained by friction at the pivot hinge, the large slotted screw can be tightened if necessary. The maximum width the calipers can be opened to is eight inches (203mm) but would normally be used at far less a division.

Navigation dividers come in various lengths. The English-made dividers shown here are eight inches long and have a brass head with 18/8 stainless steel legs. The first number- 18, refers to the amount of chromium present and the second represents the amount of nickel. So, the 300 series stainless steel on these calipers has 18% chromium and 8% nickel. The all metal construction means these are quite weighty at 87g.

Calipers can be 'walked' across a chart to measure distance
Dividers can be ‘walked’ across a chart to measure distance
Screw tightener on pivot
Screw tightener on pivot

My pair of dividers have had a life. They are dinged, worn, scratched and tarnished. Testament to considerable use and far removed from the shiny brass dividers so frequently seen elsewhere. Yet such is their simplicity that they still work. No doubt GPS has decreased their usefulness in modern times but knowledge on the use of navigation dividers is still a requirement for those in charge of sea going vessels.

They are a simple tool and similar instruments have been used by navigators for centuries. I have included here an image from the Bianco World Map of 1436. Note that sailor and cartographer Andrea Bianco has included a cherub with easily recognised navigation divider on one of his drawings.

Tondo e quadro (circle and square) from Andrea Bianco's 1436 atlas. Note cherub with nautical dividers
Tondo e quadro (circle and square) from Andrea Bianco’s 1436 atlas.
Makers name reveals little
Makers name reveals little

These dividers are quick and easy to ‘walk’ across a map or chart and surprisingly accurate. These were an essential tool for the sailor and my pair have a family connection. These were used by my uncle in the 1970s and ’80s in his role as Tug Master.

There is almost nothing I can add to this scant description and am frustrated in not being able to expand on the maker. I know nothing of W&HC and welcome any additional information.

Three Points of the Compass has looked at a few more Map Measurers in detail. Links to these can be found here.

2 replies »

  1. Hello there.

    Perhaps I can help – albeit only a little – with your quest for information about W&HC. I happen to own two pairs of W&HC dividers, which I bought in the nineteen-seventies from a traditional marine chandlery in Poole, Dorset. I recall discussing the quality of the dividers with the owner of the chandlery (whose name was Harold Pipler) and he told me that W&HC was a family business – very much a “cottage industry” venture – and that the dividers were hand made by two elderly brothers in a small workshop at their home.

    I can’t recall the names of “W and H” or where they lived, but as Mr Pipler tended to source his wares locally W&HC are likely to have been based in the west country, possibly in or close to a commercial port in Dorset or Hampshire. As that was half a century ago, I sadly feel it’s fairly unlikely that either of the brothers – who were elderly at the time – are still alive.

    Like your relative, I too was a tug master (deep sea towing and salvage in my case) but I also skippered many other types of vessel, and in those days a pair of W&HC dividers was pretty much a standard item on almost every British ship’s chart table. So over a long period of very many years the two brothers must have produced thousands of their dividers.

    Finally, a caveat for anyone who wishes to own a pair. You’ll see for sale on Ebay and elsewhere similar dividers with “W&HC” stamped on the pivot screw. Some of those examples are old and genuine W&HC products, but others are brand new and are made in the far east. The quality of the brass, stainless steel, and the general construction of the far eastern copies does not appear nearly as good as that of the genuine W&HC product. However, looking on the bright side, imitation is the sincerest form of flattery!

    Hope this might be of some interest.

    Kind regards,

    Chris Bingham
    (sea captain – ret’d).

    Liked by 1 person

    • Many thanks Chris for the helpful additional information on W&HC navigation dividers. Also the timely word on modern copies!


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