What is a hook ball?
A hook ball instead of going dead straight, produces a curve or an arc after delivery.
At the point of release, the bowlers hand comes from behind the ball to round the side which causes the ball to rotate sideways rather than end over end like a straight bowler. This sideways rotation is what makes the ball hook left for a right-hander and right for a left-hander.
Coming in from the side increases the area a bowler can hit to get a strike (the pocket) meaning absolute consistency is less important. In addition, the ball will have started to roll in order to turn which allows it to create plenty of impact.
There are generally two different styles of hook bowler. There are crankers and strokers. In Asia they have a variation to a hook bowler, which is called a spinner or a helicopter bowler. These three types of bowler are detailed below.
The Stroker
This is the classic style of hook bowler. The Stroker's sliding foot stops just before the ball gets to the bottom of the swing, creating moderate leverage for a good, controllable ball reaction.
The shoulders are very square at the point of release. The Stroker generally plays straighter up the outside of the lane allowing the ball to gently hook up into the pocket.
The Cranker
This is the classic style of hook bowler. The Stroker's sliding foot stops just before the ball gets to the bottom of the swing, creating moderate leverage for a good, controllable ball reaction.
The Cranker gets maximum revolutions on the ball, producing more power than any other type of bowler.
Generally the Cranker will stand with their feet to the left hand side of the approach, and swing their ball out to the edge of the lane.
In order to create this, the Cranker uses "late" timing (getting to the foul line before the ball). They plant their foot and pull their arm through, bending the elbow to keep the hand behind and under the ball and leaving the shoulders open for maximum leverage.
A Cranker is prone to injury due to the amount of "muscle" they put into each shot.
The Spinner/Helicopter
This style of bowling is not seen very often, but is very popular in Asia. It was developed in Taiwan to combat brutally hard lane conditions.
Spinners use lightweight balls (usually 10-12lb). The technique is one that leaves people asking the question "How?". The bowler deliberately brings the fingers all the way round the top of the ball, as opposed to the hook bowler who brings the fingers round the side.
The ball travels straight down the lane (regardless of the oiling pattern) but is rotating in a similar way to helicopter blades, hence the name "helicopter bowling.
On impact with the pins, this technique mixes the pins like no other style of bowling. Very effective if you can master it.