Measuring boule to jack

Determining which boule is closest to the jack is at the heart of petanque. There are a number of different ways to do it.


(1) VISUAL INSPECTION (aka “eye-balling”)

Visual inspection is the technique of first resort. The trick to being able to tell which of two boules is closer to the jack lies in where you stand. Don’t stand over the boules, looking down on them. Stand back from the boules a meter or more, so that you are the same distance from each of the boules. Look across the boules at the jack. Imagine a line between the boules, and imagine a second line extending out from center of that line. You will probably be able to see that the jack falls on one side of that second line; that is, you will probably be able to see that the jack is closer to one of the boules than the other.  
petanque_visual_estimation

Visual inspection is fast and there is no danger of accidentally touching and moving anything.  But it is not precise.  When two boules are almost the same distance from the jack, it may not be possible to tell which is closer. That is when you need to remember the old adage— “When in doubt, measure.”


(2) COMPARISON

In comparison we use some physical object whose length can be adjusted to compare the distances between the boules and the jack.  Various objects can be used to make the comparison. The traditional Provençal method is to hold two sticks together, as in the photo below.  A telescoping metal rod like an old radio antenna or a pointer will also do the job nicely.

Chopstick calipers – a modern version of a traditional Provençal technique

Another traditional technique is to use a piece of string, as in the picture below.  It is not a reliable technique.  It is amazing how much the string mysteriously stretches depending on whose boules are being measured. Thanks to the Brighton-Hove Petanque Club for several photos, including the next three.

One of the best comparison tools is a folding rule with an extensible end piece.
comparing_with_folding_rule

A tape measure can be used as a comparison tool. Ignore the numbers on the tape. Extend it between the boule and jack, and lock it.

The most precise tool for comparing short distances is a set of calipers.

Some tape measures have a small built-in set of calipers.
A folding rule can be used as a calipers.

Unfortunately, comparison isn’t practical for longer distances. For those distances, we need to measure.


(3) MEASUREMENT


The third technique is to measure the distances between the jack and the relevant boules, and then to compare the measurements.  (Measurement involves assigning numeric values to distances, which comparison does not.)  The most common tool for measuring is a retractable steel tape measure. (See our page on buying measuring tools.) The proper way to use a tape is to measure across the top of the jack to the boule. Keep the tape above the jack, without touching it. Look straight down at the jack, and measure to the edge (not the top) of the jack.

Measurement is difficult to do.  It requires squatting or kneeling and holding the tape measure steady, with two different parts of the tape microscopically close to boule and jack (but without moving either of them), then reading the numbers on the tape to the precision of one millimeter while avoiding distortions due to parallax.  It requires strong legs, steady hands, and good eyes.  And of course, it involves placing a tape measure close to the jack and the boules, which means that bumping and moving one of them is a real danger.


(4) DEVICE-ASSISTED VISUAL INSPECTION

Le Juge

The first step along the path to device-assisted visual inspection took place around the year 2000 with a device called Le Juge (the Judge)— a circular piece of plastic with concentric lines painted on it. You centered the view on the jack, and (in theory) the concentric rings made it easy to determine the relative distances of the boules. Le Juge didn’t actually work very well, but the basic idea was quickly adapted for smartphone cameras.

There are a number of smartphone apps that work basically the same way that Le Juge worked. (See our post on smartphone apps for measuring.) In theory, smartphone-assisted visual inspection could be the best way to decide which boule has the point. There is no risk of touching and moving boules or jack. You don’t need to squat or get down on your knees. It requires a smartphone, but smartphones are becoming ubiquitous. On the other hand there are many different smartphone apps so they surely vary in reliability, accuracy, and ease of use.

Another device for visual inspection is a “laser tape measure”. These devices are widely used in construction, but as devices for making petanque measurements they are clumsy. A laser beam can’t see though intervening boules or through rocks or bumps on the terrain. And a laser tape measure is pretty expensive compared to a tape measure.


Some finer points

Before we end, we should mention a couple of the finer points of the art of measuring.

wedges_and_calipersWhen the distances are close and an umpire wants to make sure that nothing is disturbed during the measuring, he/she can place wedges under boules. In this YouTube video we can see the umpire placing wedges and then measuring with calipers. It looks like she is measuring the “second” boules to determine whether the winning team scored one point or two.

feeler_gauge_spread_outAnother standard item in an umpire’s toolkit is a set of feeler gauges, the kind that you would use when gapping spark plugs. An umpire will use them when there is daylight between boule and jack but they are so close that you can’t fit a calipers between them.

measuring_with_a_thickness_gauge


FURTHER READING

  1. Measuring distance between boules and the cochonnet by former Southern Counties Petanque Association Regional Umpire Richard Powell. (Also available HERE.)
     
  2. The Umpire’s Training Manual by Petanque New Zealand
     
  3. A guide to measures by Pen-Y-Coed petanque

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