Laser Measures 

      Laser Measures EBF /EBA,  

October 2020 Laws Committee Guidance on the Use of Laser Measures

New measuring devices appear on the marketplace on a regular basis. Several models of laser measures have recently been introduced for use in lawn bowls. These devices have been designed by incorporating third-party laser measuring devices into a patented assembly, with components, which adapts them for use on a bowling green to measure for shot bowls.

World Bowls is working continuously to assist and encourage the development of the sport, and this includes the adoption of technological innovations that will assist players and officials. The World Bowls Laws Committee does not need to give permission for new measuring devices (each MNA has this authority), but the LC will comment if they do not comply with the Laws of the Sport.

The LC recently evaluated some of the new laser measures and has determined that it is appropriate to issue some guidance to MNAs and bowlers on their use. This guidance is intended to inform bowlers and bowls administrators of some considerations that should be given when assessing laser measures for domestic use, and to describe some limitations on their use, without commenting on any specific model.( When the guidance mentions "laser measures for domestic use," it is distinguishing between two different levels of competition:

1. Domestic Use (Club & National level) Use laser measures.

• Where: Your local club matches, league games, county competitions, and national championships.

2. International Use (Elite level) Do not use laser measures.

• Where: World Championships, Commonwealth Games, or matches between different countries.)

Background

The LC initially evaluated the prototype for a new laser measure in 2015. At the completion of this review process, the LC approved the measure for domestic use. This assisted the manufacturer with refining the design and commencing production of the measure, and it enabled MNAs to consider adoption of the laser measure for domestic use. Approval of this device was based on three principles:

1. The bowls laser measure worked on the concept of measuring the horizontal distance between two vertical planes, achieved by the design of the mount of the laser and incorporation of a vertical reflective target plate placed against the object being measured. The LC accepted this procedure as a proxy for measuring the sloping line between the nearest points of the jack and a bowl, as the intent of measuring is to determine the relative difference in distances between two or more bowls and the jack, rather than the absolute measurements.

2. The measuring process was consistent and easily replicable.

3. The third-party laser measure was manufactured by a reputable company in the field of optics and was deemed to provide a suitable level of measuring accuracy.

The World Bowls Umpire Development document was not updated to include the laser measure at that time.

Recommended Guidance

The laser measure may be used as an alternative to the box measure, subject to any restrictions adopted by any MNA, and it is now listed in the “alternative equipment” section in the Umpire Development documentation on the Word Bowls website. Due to a variation in tolerances among laser measure models and as they do not measure directly between the nearest points of the jack and a bowl, there is a recommended minimum distance for their use. The recommended minimum distance for using a laser measure in an ideal situation is 300 mm.

[Note: The LC has amended the recommended minimum distance for using a box measure to be 200 mm, as callipers (or feeler gauges) are ideal for measurements less than 200 mm.]

The maximum distance for using a laser measure can vary, depending on the ambient lighting conditions, the measuring range of the laser beam, and the reflectivity of the target. The LC does not have any recommendations regarding maximum distance.

There are now several models of available laser measures for bowlers. Each model has a unique design and instructions on their use. The Umpire Development document has been updated to include generic instructions on how to use a laser measure; however, bowlers should use each laser measure in accordance with the manufacturer’s instructions to obtain optimal results. This also includes all health and safety guidelines pertaining to the use of lasers.

All other types of approved bowls measures are used to determine the relative differences in the distance between the jack and various bowls. The laser measure is unique, in that it provides a digital reading of the actual distance between two objects, and the user must perform a mathematical calculation to determine the difference between any two readings. For this reason, it is not necessary to return to the original bowl to recheck the distance. As a result, the user may be expecting to achieve a greater degree of accuracy when using a laser measure; however, there are some limitations which must also be taken into account.

Laser measures should be used with a degree of caution. All laser models display metric units to three decimal places (i.e. 1 mm), but their technical specifications indicate various levels of typical measuring accuracy, ranging between +/-1 mm and +/-3 mm. The LC recommends that MNAs adopt some protocols in response to measurements that fall within these ranges, such as:

a) to recheck the measures to the closest bowls to confirm the result;

b) to alter the method of measuring or choose an alternate measuring device.

Another limitation of any laser measure is that it can only be used when the jack and all bowls are on the green, and nothing is in the ditch. The laws state that any measurement involving the jack or a bowl in the ditch must be carried out using a flexible or string measure whenever possible.

In the world of English Bowls Federation (EBF) games—commonly known as "Federation" bowls—the rules around measuring equipment are slightly more traditional than standard lawn bowls, but they have evolved.

Yes, you can use a laser measure, but there are specific conditions and "best practice" hurdles you should be aware of.

1. Official Approval

While the EBF has historically relied on "certified measures" (like string measures or tapes), they generally follow the guidance of the English Bowls Umpires Association (EBUA). The EBUA officially includes laser measures as an approved option for umpires.

• The Gold Standard: The Bowlsline laser measure is the primary model recommended for official use because of its high accuracy and specific design for the sport.

2. Distance Restrictions

Laser measures aren't used for every distance. Because of how the laser bounces off the target, they have specific "working windows":

• Minimum Distance: They are generally not recommended for distances under 300mm (about 1 foot). For anything closer than that, you should stick to callipers or a box measure to ensure a "feel" for the gap.

• Maximum Distance: While lasers can measure long distances, lighting (bright sun) or a lack of a clear target plate can make them less reliable at extreme ranges.

3. Practical Limitations

Before you whip one out in a competitive match, keep these rules in mind:

• The "Ditch" Rule: You cannot use a laser measure if the jack or a bowl is in the ditch. The laws usually require a flexible or string measure in these scenarios to navigate the change in levels and surfaces.

• The Maths: Unlike a string measure where you simply see which one is shorter, a laser gives you a digital reading. You (or the umpire) must mathematically compare the two readings.

4. Etiquette and Opponents

In EBF games, if you are measuring yourself (rather than an umpire), your opponent must agree to the equipment being used. If they object to a laser measure because it’s not a "certified string measure," you may be forced to use the traditional kit.

Quick Comparison Table

Scenario                                              Use Laser?                                       Use String/Tape?

Distance > 300mm                      Yes (Recommended)                                          Yes

Under Distance < 300mm                 No (Too tight)                                   Yes (Use Calipers/Box)

Under Distance < 200mm                         No                                                   Use Calipers

Bowl in the Ditch                                       No                                                         Yes

Official EBF Match                    Yes (If EBUA approved)                                        Yes

Here is the breakdown of how the Impulse measure fits into EBF play:

1. Approval Status

The Impulse Laser Measure is widely recognized and used in the UK.

• For Players: Under World Bowls regulations (which EBF often looks to for equipment standards), players are allowed to use approved laser measures like the Impulse to determine shots during an end.

• For Umpires: While the Bowlsline laser is often the "official" umpire choice, the Impulse is frequently used by players because it is smaller, fits in a pocket, and is calibrated for the specific height of a jack.

2. The "300mm" Rule

The biggest restriction you will face in an EBF game is distance. You should not use the Impulse measure if the distance between the bowl and the jack is less than 300mm (about 12 inches).

• For these "tight" measures, a laser's margin of error (+/- 1mm to 3mm) is considered too high.

• In these cases, you must use callipers or a traditional box measure.

3. Surface & Ditch Restrictions

• The Ditch: If the jack or a bowl is in the ditch, you cannot use the Impulse. EBF laws require a flexible or string measure for any measurement involving the ditch.

• Stability: If the green is particularly uneven or if the bowl is leaning, the laser might be difficult to keep steady. Always "chock" or wedge a leaning bowl before measuring.

4. Opponent Agreement

In "Federation" bowls, the Number 2 (or the players at the head) usually agrees on the shots.

• If you want to use your Impulse laser, your opponent must agree to it.

• If your opponent insists on using a traditional string measure because they don't trust the laser's digital readout, the traditional measure usually takes precedence unless an official umpire rules otherwise.

Summary Checklist for Using Your Impulse

• [ ] Is it a close measure? (If under 1ft, use a string/caliper).

• [ ] Is the bowl in the ditch? (If yes, put the laser away).

• [ ] Does your opponent agree? (Always check before placing it on the green).

In both English Bowls Federation (EBF) and English Bowling Association (EBA/Bowls England) games, the use of a laser measure—including the Impulse—is increasingly common, but the rules vary depending on whether you are a player or an official umpire.

Here is the breakdown for both codes:

1. English Bowls Federation (EBF)

In Federation bowls, the rules are often slightly more traditional.

• Player Use: You can use an Impulse laser to measure for your own shots, provided your opponent agrees. In EBF play, the "Number 2" usually agrees on the score. If your opponent objects to the laser (e.g., they prefer a "certified" string measure), you may have to use the traditional kit.

• The "Pole" Rule: In some EBF formats, a long pole is used to count shots within a 2-meter radius. A laser is a great alternative for these longer distances, but it cannot replace the official "measure" if the game reaches a stalemate.

2. Bowls England (EBA)

The EBA follows the World Bowls "Crystal Mark" Laws, which were updated in 2023.

• Approved Status: The Bowlsline laser is the only one officially recommended for EBUA (English Bowls Umpires Association) umpires because of its high precision.

• Impulse Usage: While the Impulse is popular among players because it's portable and cheaper, an umpire may decline to use it if they feel it doesn't meet the +/- 1mm accuracy required for a championship-level decision.

Here is the quick-start guide to using and "calibrating" your Impulse for EBF and EBA games.

1. How to "Calibrate" for Jack Size

Technically, you don't calibrate the laser's internal electronics (they are set at the factory), but you calibrate your technique to the jack size.

• Targeting the Jack: The Impulse is designed to be placed against the bowl and aimed at the center of the jack. Because EBF/EBA jacks are a standard 63\67mm, the laser height on the Impulse is pre-set to hit the widest part of that sphere.

• The "Base" Check: If you are using the detachable base plate, ensure the laser is seated flush. If the laser beam is hitting too high or too low on the jack, you aren't getting the "true" shortest distance.

• The "Zero" Point: Remember that the Impulse measures from its back edge. When you place it against a bowl, the distance shown on the screen is the gap between that back edge and the jack.

2. Step-by-Step Measuring (The Right Way)

To avoid disputes with opponents (especially the traditionalists), follow this sequence:

1. Chock the Bowls: Always place wedges under the bowls you are measuring. If a bowl moves even $1$mm while you're placing the laser, the measure is void.

2. Shadow the Jack: In bright 2026 summer sun, the laser "dot" can be hard to see. Ask your marker or teammate to cast a shadow over the jack with their body so you can see exactly where the beam is hitting.

3. The "Repeat" Trick: Most Impulse models allow you to store the last 3 measures. Measure the first bowl, hit the button to save, then measure the second. Showing your opponent both numbers on one screen is the best way to end an argument.