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Bradley Anderson

  • Karma: +0/-0
Tom,

Maybe you can calculate speed from this USGA study that was done in 1933 measuring drift on the vegetative varieties of bent. Judging form the height of cut and the clipping yield that they would have gotten from those first power mowers I would estimate the speed to be around 5.5 - 7.5 depending on moisture.

Note that this is not a Stimpmeter reading because they only measured the distance one direction and not both ways. But if you read closely they did work from various percentage slopes and maybe you can calculate something from the data?















« Last Edit: May 02, 2012, 06:10:13 PM by Bradley Anderson »

Tom_Doak

  • Karma: +3/-1
Tom,
I think the chart you're looking for is in this article, the same one from which I gleaned the speed scale:

http://turf.lib.msu.edu/1990s/1997/970312.pdf

Jim:

Yes, it's there.  I overlooked it the first time, because I remembered it being more nicely presented before, but here are the numbers:

At a Stimpmeter reading of 6:  the ball rolls 6.7 feet on a 1% slope, 7.6 ft @ 2% slope, 8.8 ft @ 3%, 10.5 ft @ 4%, 12.8 ft @ 5% and 16.4 ft @ 6%.

At a Stimpmeter reading of 8.5:  10 ft @ 1%, 12 ft @ 2%, 15.4 ft @ 3%, 22.1 ft @ 4%, 33.9 ft @ 5%, 81.9 ft @ 6%

At a Stimpmeter reading of 11:  13.8 ft @ 1%, 18.2 ft @ 2%, 26.6 ft @ 3%, 51.8 ft @ 4%, and 492 feet @ 5%.  No, I didn't forget the decimal point on that last number.

At a Stimpmeter reading of 12.5:  16 @ 1%, 22 @ 2%, 36 @ 3%, 109 @ 4%, and it doesn't stop rolling at 5%.

Jim_Kennedy

  • Karma: +0/-0
Tom,
Do you (and others) use these numbers when calculating how much level run-out you need after a ball comes off a  spine, tier, etc. on a green that's to be mowed to a ten,? How do you go about making that sort of estimation if the ball is coming off the stimp meter at around a 20 degree angle and rolling off a tier of 5?  Experience, formula, feel, or some combination of them ?

   
"I never beat a well man in my life" - Harry Vardon

Tom_Doak

  • Karma: +3/-1
Tom,
Do you (and others) use these numbers when calculating how much level run-out you need after a ball comes off a  spine, tier, etc. on a green that's to be mowed to a ten,? How do you go about making that sort of estimation if the ball is coming off the stimp meter at around a 20 degree angle and rolling off a tier of 5?  Experience, formula, feel, or some combination of them ?
 

Jim:

It's nice to have seen these numbers years ago and have an idea how they work, but when you are building a green it is really more a matter of feel for making it work.  Being a good putter and having played on most of the great sets of greens in the world is pretty helpful to that sense of feel.

The other thing I have learned, from MacKenzie courses in particular, is that you can sometimes use a counter-roll to make a slope playable that would otherwise be too severe ... it may not let you stop the ball around the hole, but it will let you keep the ball on the right terrace of the green.