Stimpmeter

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The Stimpmeter is a device used to measure the speed of a golf course putting green by applying a known force to a golf ball and measuring the distance traveled in feet.

It was designed by golfer Edward Stimpson, Sr. in 1935.[1] The Massachusetts state amateur champion, Stimpson was a spectator at that year's U.S. Open at Oakmont. After watching a putt by a top professional (Gene Sarazen) roll off a green, Stimpson was convinced the greens were unreasonably fast, but wondered how he could prove it. He developed a device, now known as the Stimpmeter, which is an angled track that releases a ball at a known velocity so that the distance it rolls on a green's surface can be measured. Although the original device was made of wood, in 1976 it was redesigned from aluminum by the Frank Thomas of the United States Golf Association (USGA). It was first used by the USGA during the 1976 U.S. Open at Atlanta and made available to golf course superintendents in 1978. The official USGA stimpmeter (painted green) is not sold to the public.[1]

The device is an extruded aluminum bar, 36 in (91 cm) long and 1.75 in (4.45 cm) wide, with a 145° V-shaped groove extending along its entire length, supporting the ball at two points, half an inch apart. It is tapered at one end by removing metal from its underside to reduce the bounce of the ball as it rolls onto the green. It has a slot at a right angle to the length of the bar 30 in (76 cm) from the lower tapered end where the ball is placed. The ball is pulled out of the slot by gravity when the device is slowly raised to an angle of about 20°, rolling onto the green at a repeatable velocity of 6.00 ft/s (1.83 m/s). The distance traveled by the ball in feet is the 'speed' of the putting green. Six distances, three in each of two opposite directions, should be averaged on a flat section of the putting green.[2][3]

One problem on modern greens is finding a near level surface as required in the USGA handbook. Many greens cannot be correctly measured as you cannot find an area where the measured distance or green speed in opposing directions is less than a foot, particularly when they are very fast requiring a very long level surface. A. Douglas Brede was able to devise a formula to solve that problem. His formula:

\frac{2\times S\uparrow \times\ S\downarrow}{S\uparrow +\ S\downarrow}

(where S↑ is speed up the slope and S↓ is speed down the slope) eliminates the effect of the slope and provides a true green speed even on severely sloped greens.[4]

The USGA stimpmetered putting greens across the country to produce the following recommendations:[1]

  • Slow greens: 4.5 feet
  • Medium greens: 6.5 feet
  • Fast greens: 8.5 feet

For the U.S. Open, they recommend:[1]

  • Slow greens: 6.5 feet
  • Medium greens: 8.5 feet
  • Fast greens: 10.5 feet

The greens at Oakmont Country Club (where the device was conceived) are some of the fastest in the world, with readings of 13–15 feet.[5]

[edit] References

  1. ^ a b c d Frank Thomas (October, 2001). "Equipment Extra: Eddie Stimpson's slant on putting". Golf Digest. 
  2. ^ USGA Stimpmeter Instruction Booklet
  3. ^ Stimpmeter — Measure putting green speed
  4. ^ A. Douglas Brede, Measuring green speed on sloped putting greensPDF (675KB)
  5. ^ "Oakmont: Rock & roll (& roll & roll & roll) nightmare", Pittsburgh Post-Gazette, 2007-06-10. Retrieved on 2007-06-10. 
  • Brian W. Holmes, "Dialogue concerning the Stimpmeter", The Physics Teacher 24/7 (1986) 401-404.

[edit] External links