The Original Rally “Poti”?

A few years ago I was looking for a magnified map reading light that I could use in an upcoming rally.  I ended up buying a map reading light that apparently was used by Royal Air Force bomber navigators during World War II.  This map reading light is shown below.

Navigator Light (3)

World War II RAF Bomber Navigator’s Map Reading Light

It is an interesting piece of equipment to have in my navigator’s toolbox, however I only have used it in one rally.  I now have a modified “poti” that I prefer to use in rallies where it is necessary to follow a course shown on a map.

The map reader has a rotating switch at one end that can be used to turn on and modulate the intensity of the light in the reading lens.  Holding this map is very much like holding on to a typical flashlight.

I have wondered if these bomber navigator lights were the inspiration for famed English rally navigator Don Barrow who has successfully developed, marketed and I believe named the classic English “poti”, which is a rally staple for many English navigators.

Navigator Light (9)

The Map Reading Light Is Powered By “D” Batteries

This reading light has an 80mm (3 inch) diameter magnified lens with a slight magnification, say a two times magnification.  The light has several concentric circles or rings each separated by 1 centimeter.  These rings can be used to estimate distances.

Navigator Light (12)

The Rings Are Used For Measuring Distance

Recently I have been collecting Michelin maps for the Rallye Monte Carlo Historique.  These maps have a scale of 1:150,000.  As the space between the circular rings is 1 centimeter, then the distance on the map between each line is 1.50 kilometres, or just under 1 mile.  The image below shows one of these Michelin maps of an area north and west of Monaco as seen through the RAF navigators map reader.

Navigator Light (15)

The Light Is Very Useful For Map Reading And Estimating Distances

As can be seen in the above image, the map reader makes it rather easy to see the map and estimate distances.  The light has a slight orange tint to it, but I think that this results from a bulb and electronics from 70 years ago.

As I stated earlier, it is an interesting and useful piece of equipment to have on hand that might have inspired the “poti”.

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1 Response to The Original Rally “Poti”?

  1. I’ve wanted one of these for years. I’m looking at the new battery version from Basic Roamer.

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