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The Bowlsline Measuring System

Measuring has always been a topic for debate in bowls games and many matches have been won or lost on the outcome of a close measure.

Some years ago a method of measuring was devised for Flat and Crown Green Bowls which overcame many of the difficulties and accuracy of carrying out this critical operation. Bowlsline was tested and approved by World Bowls, Bowls Australia and the British Crown Green Bowling Association.

The distances of the bowls from the jack are measured in turn and a comparison is made, the object being to determine the shortest distance between the bowl and jack (remembering that the bowls are not perfectly round).

The Bowlsline system uses the horizontal distance between two vertical planes set against the bowl and jack.

This can be achieved either by using a special indexing device on the free end of the string of a modified box measure, with both ends positioned firmly on the ground or, alternatively, by using a vertical target plate for the horizontal ray from a laser measure.

This is straightforward and repeatable and as a standardised method, allows less-experienced measurers to achieve the same result and accuracy.

This Bowlsline method attracted criticism from a few, the argument being that the horizontal distance is not a fair comparison when bowls of different sizes at the same horizontal distance are in fact different distances from the jack. Whilst this is true, distances cannot be measured accurately by a freely held line and only distances up to 200 mm can be measured in practice with calipers.

Furthermore, the conventional box string measure is inexact, for reasons explained below.

Diagram 1 shows three circles representing, in simplified form, a jack and two bowls and two verticals.

bowls measure diagram 1

 

The bowls touching the vertical represent bowls of different sizes or shapes, either upright or leaning.

Only if the smaller bowl touches the vertical at the same distance from the floor as the jack would the measure be horizontal. Any other situation and the lines would be at an angle.

At 200mm separation the two circles on the right represent bowls (not to scale, the small bowl is depicted smaller to see the problem more clearly), one large 127 mm dia (size 5) and one small 116 mm dia (size 0), separated by 200 mm from a jack 63.5 mm dia.

Measured with the Bowlsline string or laser measures these bowls would be at the same distance. Checking the geometry of this, the large bowl is 201.70 mm from the jack and the small bowl is 200.64 mm from the jack. The small bowl is therefore closer by 1.06 mm.

DRAWING COMPARISONS

Diagram 2 shows the bowls measured with a conventional box string measure.

bowls measure diagram 2

The outlet from the box, 60 mm from the floor and 70 mm nearer the bowls, is now the fixed point from which the measures are made.

Again using simple geometry the distances are now 130.03 mm for the large bowl and 130.13 mm for the small bowl. The large bowl is now shown to be closer by 0.10 mm, which is incorrect.

At 300 mm between jack and bowls, using the same calculations the large bowl would be a true 301.27 mm from the jack, the small bowl 300.47 mm, the small bowl being closer by 0.80 mm.

Measured with the box string measure the distances would be large bowl 230.02 mm and the small bowl 230.15 mm, the large being closer by 0.13 mm, which is incorrect.

The conventional string box measure is, therefore, inaccurate and can award shot to the wrong bowl.

Furthermore, there is no standard size and the height at which the string leaves the box can vary between 35 mm and 60 mm, so different box measures will give different results.

For measures over 200 mm, the range for calipers, where positioning of the pointer, straightness and tension in the line are important, the Bowlsline measuring system is more reliable and consistent as a standardised method.

For long measures the laser measure must be preferable with a straight line and no line tension.

However, the laser measuring devices are sometimes said to be of insufficient accuracy quoting +/- 1.5 mm or +/- 3 mm. These numbers refer to the accuracy of measuring distance and not the precision or resolution of the laser which will be normally be within 1 mm.

As only a comparison is being made, not an accurate distance measurement, providing the vertical flat target plates have, importantly, the same surface and colour, the measurements will be accurate and repeatable.

You can also download this article as published on Bowls International here >

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UK, Bowlsline String

Prompt supply of quality item.

Peter H  9 May 2020

Excellent service.

Mr G R Sayers  7 February 2020

Great product.  Great service

SJN  20 September 2019

Exactly as described

Danapa  13 September 2019

This should stop the cheaters

Derek Kay  6 August 2019

Fab, no cheating anymore, spot on

Peter Hardcastle  17 July 2019

Bought for Bowling Club

Mrs C M Walker  17 June 2019

Exactly what I wanted

Brenda  17 June 2019

Good efficient service

D W Chisholm  26 May 2019

Excellent purchase.

Amazon customer 21 May 2019

Excellent.

Ronald Clarke 29 April 2019

High quality product, happy with purchase.

Robert S  17 April 2019

Great service.

RC  13 April 2019

a1

Ian W  17 March 2019

vexcellent.

Amazon customer  8 February 2019

Very pleased with this product.
bh 30 December 2018

Great, thankyou.
Mrs C Wheatley 12 November 2018

Better measure than old design.
Amazon customer 8 September 2018

Very good.
D A Hudson 1 September 2018

….works well, stops cheating when measuring between jack and bowl.
Mr James Fernie 29 August 2018

Being someone who teaches the laws of the game of Crown Green Bowls…….., a great item.
Bryan C 24 August 2018

Best measure out there. A must for any bowling green. Easy to use.
Geoff Jones 14 August 2018

Measure is good compared to previous types. Less room for error or cheating!
RA 1 August 2018

Far superior to the basic measures and gives a true measure.
Collingham Bowling Club, West Yorkshire 29 July 2018

Does what it says on the tin. Everyone happy, it provides a more accurate “measure”, less room for error.
RW 24 July 2018

This is a major improvement for bowls measuring.
EW 19 July 2018

Excellent buy. Perfect for crown green bowling measure. Recommend all referees should use them.
Joan Wrigley 19 July 2018

Brilliant.
JS 13 July 2018

It is an excellent product and I would recommend it to others.
IM 2 July 2018

Excellent product.
TCB 2 July 2018

Very easy to use. Pleased with purchase.
HS 24 June 2018

1st time not the last.
Fred 23 June 2018

Excellent product. All Bowls Clubs should purchase them.
By John Shooter on 25 April 2018

Will stop those who insist on waving the pointed bit in all directions on older type of box measures. I would definitely recommend.
By David A on 22 April 2018

It’s just arrived – next day delivery was brilliant. Tried it out at the indoor club where it created a lot of interest. The concept is good and everyone commented on its accuracy. It removes doubts about the validity of results. If everyone had one it would prevent many of the tricks I have witnessed over the years watching bowls being measured by opponents trying to gain an advantage.
By Brian Slinn on 26 March 2018

Very pleased with this item. Makes measuring a lot easier. Highly recommend this item.
By Lynda C. on 20 March 2018

Good stuff. Essential for the discerning bowls player.
By Basso on 25 January 2018

Great product, great service
By Mark Broadway on 10 January 2018.

I am a crown green bowler of 30 years plus. These are the best bowls measures I have used as every measure will now be accurate.
By Gwill on 08 January 2018.

Quick delivery – works very well.
By Ian Humphreys on 14 November 2017.

Excellent
By safe on 30 September 2017.

Excellent measure. Brilliant concept, well made.
By mary haydock on 4 August 2017

Cleverer than a normal measure!! Perfect, love it.
By Amazon customer 20 June 2017

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Australia, Bowlsline Laser

The unit has performed exceptionally well. I especially appreciate the one-man operating ability for long measures, and the ability to record each measure, giving players added confidence in the decision by showing the results. Very easy to use as well, and plenty of interest from players and spectators alike seeing it in operation.

Rodney Bates, Australian National Umpire