GREENS SPEED MEASUREMENT TOOL
The uniformity of the greens on a golf course is most significant. Variations in speed, whether from one green to the next or on different parts of the same green, can do more to negate a player’s skill than can ragged fairways or unkept bunkers.
Greenkeepers are well aware of this, and are always seeking better ways to establish consistent speeds on all of their greens. The problem they face is complicated. Numerous variables affect the speed with which a ball will roll on a putting surface and calculating the speed of one green compared to another can be most frustrating.
The Stimpmeter is a simple yet accurate device to make a standard measurement of, and place a numerical figure on the speed of a green.
GREENS SPEED DATA LOG SHEETS
What is a Stimpmeter?
The device is an extruded aluminium bar, with a V-shaped groove extending along its entire length. It has a precisely machined ball-release notch at a specific distance from the tapered end (the end which rests on the ground). The underside of the tapered end is machined away to reduce bounce, as a rolling ball in contact with the ground is required.
The V-shaped groove has angle which suitably supports a golf ball two points ½” (12.7mm) apart. A ball rolling down the groove has a slight over spin, which is thoroughly consistent and has no deleterious effect on the ensuring measurements.
The ball-release notch is so designed that a ball will always be released and start to roll when the Stimpmeter is raised to approximately 20 degrees. This ensures that the velocity of the ball will always be the same when it reaches the tapered end.
Although the Stimpmeter is sturdily built, it should be taken care of as one does with any precision instrument. When not in use, it should be stored in a plastic tube or case. Even relatively slight damage to the release notch or groove may cause errors.
How to use the Stimpmeter.
Equipment needed: Stimpmeter, 3 tees/markers, 3 golf balls, Measuring Tape, Data Sheet (included).
Select a level area on the green, approx. 10ft x 10ft (3m x 3m). To check the level, lay the Stimpmeter flat on the green and place the ball in the V-shaped groove, the movement of the ball will indicate whether or not the area is reasonably level.
Insert a tee or some other form of marker in the green, near the edge of the selected area to serve as a starting point. Holding the Stimpmeter by the notched end, rest the tapered end on the ground besides the tee and aim it in the direction you intend to roll the ball. Put the ball in the notch and slowly raise that end until the ball starts to roll down the groove. Repeat the same procedure with two more balls, keeping the tapered end on exactly the same spot.
All 3 balls should come to rest not more thian 8 inches (203mm) apart. Should they be farther apart than that, the Stimpmeter may have been been moved too much during the series, the balls may be damaged or of inferior quality or unusual conditions may exist. In any event a pattern larger than 8 inches is of dubious accuracy, and the three-roll series should be repeated. Assuming the balls stop within the 8 inch limit, insert a second tee in the green at their average stopping point. The distance between the two tees is the length of the first series of rolls.
Repeat step 2, using the second tee as a starting point and the first tee as an aiming point; in other words, roll a series of three balls along the same line but in the opposite direction.
Second tee indicates average position of the first three rolls and acts as the starting point for the second three rolls.
Repeat step 3, thereby establishing the length of the second series of rolls. Then using the two measurements, calculate:- First distance + Second distance divided by 2 = Greens Speed!
Note: Should the difference in length between the first and second series be greater than 18 inches (457mm) the accuracy of the resulting average may be questionable. The area selected for the test may not have been sufficiently level, or sufficiently representative of the green, in which case it is advisable to select another area and repeat the test. Sometimes a green may be so severely undulating or sloping that a level area is simply not available, in which case the data record should so indicate.
Key Points to Remember:
Selecting a reasonable level test area is important. Measurements taken up or down a slope, over mounds etc. will result in misleading data.
Conditions during a test are important. Initially, test your greens under optimum conditions, a cleanly mowed, dry, smooth surface on a calm day. Once this basic speed has been established, you can then document speeds as they vary under unusual conditions: windy days, wet surfaces, non-mowed, recently top dressed, time of day, before and after fertiliser application, etc. The data thus accumulated will lead to a better understanding of how different management practices affect the speed and consistency of each green on your golf course.
Practice makes perfect. A relatively small amount of practice in using the Stimpmeter will increase the accuracy and consistency of each green on your golf course.
Keep thorough records. Obviously, complex and accurate records, maintained over extended periods, are essential.
The Potential of the Stimpmeter.
Once the Stimpmeter has been put into use at your course, the resulting data can be analysed and acted upon, the possibilities for improved playing conditions are virtually endless.
Preliminary speed charts have been developed, based on data from tests performed by recognised Green Section Agronomists. The charts presented are for general information purposes only.
Speeds for Regular Play
8’ 6” Fast
7’ 6” Medium - Fast
6’ 6” Medium
5’ 6” Medium - Slow
4’ 6” Slow
Speeds for Tournament Play
10’ 6” Fast
9’ 6” Medium - Fast
8’ 6” Medium
7’ 6” Medium - Slow
6’ 6” Slow
The Effects of Management Practices.
The way putting greens are managed has tremendous influence on their speed consistency. Most of these factors are known to some degree, but almost all are worthy of research.k
Some of the major variables which using the Stimpmeter will help us to manipulate more effectively are:
Height and frequency of cut are extremely important considerations. The mowers bench setting is no guarantee that greens are being cut at a prescribed height. Moreover, the conditions of the mowers, the type of mowers, (floating or rigid cutting unites) attachments such as Wiehle rollers, groomers, brushes, combs, etc. all can make a difference in cut and in green speeds, so does double cutting. The precise effect of each of these factors can be measured with the Stimpmeter.
Watering practices and surface moisture (dew) are crucial to green speeds, moist grasses will be slower than dry turf at any height. Again the effects of such variables can be studied and used to benefit of any club.
Fertilizing practices can be studied: the effects of rate and frequency of application, nitrogen source and nutrient balance.
Grain is one of the most common deterrents to uniformity of speed. How grain is affected by changes in direct of cut, use of vertical mowing equipment, riding versus single unit mowers, etc can be studied as they relate to green speed.
The effects of weeds, clover, chickweed, crabgrass, pearlwort etc on green speed can be measured.
The effects of aeration, spiking and topdressing can be measured, both before and after treatments are made.
Speed differences among the different grasses presently used for putting greens can be documented.
By keeping records you will be better able to observe, determine and explain variants in green speed throughout the year, and to compensate for them. For example, in spring, when Poa annua produces excessive seed heads, greens can be much slower and bumpy, thus inconsistent. Your records will serve as a reminder to top dress, begin vertical mowing or invoke other practices calculated to help maintain the desired green speed and consistency.
General Comments: Knowing the speed of the greens may assist in determining whether a pin setting is fair or unfair. A green so fast (or hole cut in such a position) that a ball cannot be stopped within approx. 2ft (0.6m) of the hole from any point on the green, for example, is probably an unfair challenge.
Championship greens should be fast and uniformly placed, firm but resilient, they should place a premium on well executed shots, while exacting a penalty for less precise shots. Close daily mowing, a light nutrient program, minimal amounts of water, a good topdressing schedule and a minimum of thatch are the means of achieving excellence. The test for a properly ‘firm but resilient’ surface is the type of ball mark that results from a distance shot on the green. If turf within the ball mark depression holds together, if it is more a bruise than a scar, the green has the firmness required of a championship green.