Lesson 3: Selecting the right Bowl

 Bowls Characteristics

Bowlers can ascertain a suitable bowl size by encircling a bowl so that the tips of middle fingers and thumbs can just touch. Alternatively by placing the thumb against the stop on a card indicator, they can read the required size from the scale against the tip of the extended middle finger. In most instances, bowls that are too large cause greater difficulty than bowls that are slightly smaller than the measured size. Heavyweight bowls are about 4% heavier than medium weights of the same size. Extra-heavyweights are about 3½% heavier than heavyweights of the same size.

Bowls have bias because of their asymmetric shape. The side of a bowl identified by the smaller engraved ring is slightly heavier than the opposite side as a result of factory machining. This causes a bowl to follow a path that curves inward towards the biased side. This characteristic provides a bowler with a multiplicity of tactical options. It provides separate forehand and backhand approaches into a head, according to which side the bias faces when the bowl begins its run. Furthermore, by varying the delivery line and delivery speed combination, the bowl will turn to a greater or lesser extent in course to the head.

If a bowl is to come to rest in the head a bowler must deliver it at an angle that counteracts the effect of bias. The shoulder is the segment where the bowl stops diverging from the centre line and runs parallel to it before converging on the head. Depending on the profile of the bowl, the shoulder is 55% to 70% of the distance to the head. Note that by the time a bowl reaches the shoulder, it will have undergone at 1/5th of its ultimate draw, or turn. Therefore a bowler must aim wider than the shoulder to avoid a narrow delivery

 Bowl Grips

The force applied to a jack or bowl is most efficient when acting through the centre of gravity. A bowler achieves this by positioning the tip of the middle finger, the last point of contact during delivery, under the running circumference. To ensure that a bowl will run free of wobble, a bowler should avoid a grip that causes its engraved rings to cock or tilt. The main differences are the positioning of the thumb and the separation of the fingers. The finger grip provides good 'touch' for play on medium or fast greens. A claw is a secure grip for fast shots and for play on slow greens. The cradle grip suits players with small or weak hands.

 Pace of Green

The pace of green is the time in course of a bowl that comes to rest 27 metres from the delivery point. Many Australians bowlers would regard greens producing times below about 12 seconds as 'slow', and above about 14 seconds as 'fast'. Grass surfaces that are green, damp, and leafy are commonly slow. Those that are brownish, dry, mown and rolled are commonly fast. The faster the green, the slower is the required delivery speed of jacks and bowls to run a given distance. The faster the green, the greater is the required aiming angle to offset the bias. However, the wider line of bowls on faster greens does not greatly increase run distance. For example, the curved path of a bowl to a jack 30 metres away on a 17-second green is only 31 metres.