A golf lesson on plumb bob
Putting is not just about feeling. It is also about information processing. In other words, the better you know how to read the greens, the more likely you are to sink a putt. You don’t need a golf tip to tell you that. The plumb line is an old school technique for generating information that is useful for putting. Some players use it. Others ignore it. The question is whether it can help you sink a putt.
The biggest knock against the sinker is that it tells you how much a putt breaks, but not how much. But a computer model developed by Fredrick Haney, Ph.D., a few years ago is changing the way golfers think about plumb bobs. Haney’s model suggests that there is more to it than meets the eye and that with a little effort you can use it to help determine how much to break a putt. Improve your putting and you’ll reduce your golf handicap strokes fast.
The art of the plumb line
Before we get into Haney’s findings, let’s take a look at plumb bob and how to do it correctly. Here are six tips on plumb bob:
1. Stand behind the ball
2. Extend one arm
3. Hold the grip slightly
4. Align your dominant eye
5. Bend your knees
6. Align the longest point of the shaft
Stand behind the ball so that the hole, the ball, and your dominant eye are in line. Keep your eyes parallel to any slopes on the part of the green you are on. Slightly bend your knees. Let your body lean with the slope of the green. Lightly holding the top of the grip between your thumb and forefinger, slightly extend your arm. Let the putter hang freely in your grip.
Then, using your dominant eye, align the putter so that the lowest point of the shaft covers the ball. Without moving his head, he looks down into the hole. If he appears to the right of the well, the hole leans to the left. If it appears to the left, the hole leans to the right. If it is in line with the putter, the hole is flat. That’s all about it. You can learn everything you need to know about plumb in the first 5 minutes of a golf lesson.
Determining the plumb distance
If you plumb correctly, you will notice that the putter makes a point to the left or right of the hole on the surface of the putting green. The distance from that point to the center of the hole, Haney explains, is the plumb bob distance (PBD), a measure of slope and distance on the ball. On a level putt with no break to the right or left, the PBD is zero. But for all other putts, the sinker produces a discrete value. That value is an indicator of how much the ball will react around the hole.
Using PBD, Haney developed a computer model of the plumb bob. It takes into account the different speeds of the greens, the distance of a putt and the amount of slope (both sideways and up or down). He also takes into account the effect of friction on a putt. When you first hit a ball, it first slides and then rolls. Both are considered in the computer model. The force of friction causes the ball to slow down. Haney’s goal was to find out if the plumb bob could be used to determine the actual amount of breakage.
Computer Model Guidelines
After examining many examples and generating numerous graphs, Haney concludes that for typical green speeds (9 on the Stimpmeter) and level putts (no uphill or downhill slope), the amount of break varies from a little more than PDB to gentle slopes up to approximately 1-1/2 times the PBD for steeper slopes.
The above guidelines assume you are following Dave Pelz’s suggestion to leave your missed putts 17 inches beyond the cup. If he likes to die his putts on the hole, then he should allow 2 to 4 times the PBD for steeper slopes.
For similar conditions, moderate uphill putts break as little as half the PBD. Downhill putts can break eight to 10 times the PBD. Obviously, downhill putts break much more than uphill putts. Green speed has the same effect as uphill and downhill putts. The break is greater for the faster greens than for the slower ones.
Putting is about sensation and information processing. The better you feel and the more accurate your information processing, the better your chances of being the kind of low golf handicap putter I talk about in my golf tips. Keep in mind, however, that there is no magic formula for determining the break on a putt. But by experimenting and using PBD as a bit of additional information, you can improve your green reading skills.