I wrote this column for another web site but I think everyone might find it of interest.
Why do Golf Shots Curve? (Slice, Hook, Fade or Draw)
Let's start by defining the necessary terms. First let's define Path, Face. Target Line, Inside and Outside. The Target Line is an imaginary line extending through the ball to the target. Note: the "extended target line" is an extension of the target line back away from the ball. The area on the side of the target line closest to you is referred to as the "inside". The area on the "other side" of the target line away from you is called the "outside". Your goal is a swingpath that starts on the inside (moving toward the outside) striking the ball squarely then moving back to the inside. I'm assuming that everyone knows a slice is a shot that curves to the right (for right handed golfers) and a hook is a shot that curves to the left and that a fade is a "little" slice and draw is a "little" hook.
Path refers to your "swing path" which is the angle your club comes at the ball. Path is measured in degrees. You path could be 0 degrees which would be dead square or it could be measured as a certain number of degrees inside. For example, a 5 degree "inside" path means you are coming at the ball on a path of 5 degrees from inside to outside. A path of 3 degrees "outside" would mean you are coming at the ball on a path 3 degrees from outside to inside.
FACE refers to the where your club face is pointing when it strikes the ball (Closed, Square or Open). We also measure that in degrees.
Here's the tricky part. What's important is where the face of the club is pointing relative to your path when you strike the ball. However, and this is the tricky part, your FACE or face angle is usually measured NOT according to your path but it's measured as to how many degrees your club face is open or closed to the "target line".
So here's a trick question:
IF YOUR CLUB FACE WAS OPEN TWO DEGREES TO THE TARGET WHEN YOU HIT THE BALL WHICH WAY WOULD THE BALL CURVE?
Answer: It depends!!! You really don't have enough information to answer that question. It could slice, however it also might be a straight ball or a hook. For example, if your club face is two degrees open and your swing path is two degrees from inside to outside then you will get a straight shot pushed slightly to the right. However, if your swing path was straight at the target with your club face being two degrees open then you'd get a slice although is would be a small one. Finally, if your club face was two degrees open and your swing path was inside to outside four degrees you'd wind up with a hook.
With a two degree open club face the following will happen:
If you path is more than two degrees from the inside to the outside you will get a hook.
If your path is two degrees inside to outside you'll get a straight shot.
If your path is less than two degrees inside to outside you'll get a slice. (If you path is one degree inside to outside you will get a very slight slice (fade). The more outside to inside your swing path becomes the bigger your slice will be. If you had a 3 degree outside to inside swing path you'd have a pretty good banana ball. How much will your ball will slice in each of the above examples can be pretty well estimated with the "Rule of Seven".
The Rule Of Seven
Cochran and Stobbs in The Search for the Perfect Swing (originally published in 1968) found that at 200 yards a drive would slice approximately 7-8 yards for every degree the club face was open to the swing path. This could vary slightly depending on the loft, club head speed and ball type. So the "Rule of Seven" is a quick and dirty way of figuring out how many degrees you shots are off of perfect. It's just an estimate but it's a pretty handy tool.
The direction the ball takes off will tell you which way your club head was traveling at impact. If the ball takes off left of center that means your club head was traveling Outside-To-Inside at impact. If the ball takes off to the right of center that means your swing path was from Inside-To-Outside.
You Can Figure It Out
Look at each shot and you can calculate two things. You can figure out your swing path by looking at the direction the ball takes off. Then look at how much the ball curves and you can figure how many degrees the face was open to the swing path using the "Rule of Seven".
You will slice more with your driver and long irons because you hit them the hardest and they have the least amount of loft. This means they put less backspin on the ball, and more side spin, than any of the other clubs. Because you drive on 12 to 14 holes per round, a slice can get you off to a bad start, on most of holes. Clubs that put more backspin on the ball therefore put less side spin on the ball so they curve (slice or hook) the ball less. That's why you don't tend to slice your short irons as much as your long irons or driver.
Another problem for slicers or hookers is loss of distance. Distance is lost because of the curving flight of the ball. Also, when the club face opens the loft of the club is increased and when it closes the loft decreases. Go get a club and address the ball. Twist the shaft to the right (for a right handed golfer), opening the club face and watch the loft increase. Twist is the left closing the club face and what the loft decrease. Opening the club actually tilts the club face backward increasing the effective loft. The result is weak, high shots landing short of the target. Closing the club face results in a low shot curving the left.
The first step to curing the slice or hooks is to understand the real causes. Sometimes this will contradict long held beliefs which were considered gospel in their day. For example with a slice, your instincts may tell you to help push the ball with the right shoulder and try to pull it over to the left. Or you may aim a little to the left. Unfortunately these remedies result in a pull or an even bigger slice. It seems contradictory, but the only remedy for the slice will be to go against your natural impulses. You have to learn to swing toward the slice (inside-square-inside) while controlling the club face. It won't feel right at first, but the only way to improve is to make that leaf of faith.
No matter what the direction of the swing path, remember the amount of the slice or hook is a function of the angle between the direction the club head is traveling (swing path) and angle of the open club face. We refer to this angle as the curve angle. The greater the curve angle the greater the slice or hook. You must understand that in order to manage the curve of your shots, you will need to control both the swing path and the angle of the club face at impact.