Ball impact speed on drop shots

[Ed Brzezowski]

Recently played and rated a course where one par three green was 100 feet below the surface of the tee. We had our physics teacher do the math and a seven iron hit to this green impacted the surface at approx 117 MPH. 195 yard hole laser said it played 150, which it did thankfully. He used an LPGA players swing speed and ball flight for calculations.
 
So supers how do you maintain a green that takes a beating like this? Is it built differently from the beginning? Another teacher thinks the ball hits with five pounds of pressure in the 1.68 area of impact upon the green. The math is beyond me on this.
 
How do you keep it from looking like the moon and constantly being bumpy?

[Jeff_Brauer]

Ed,

Not much you can do on a drop shot, design wise.  A few years back, when the Buy.com tour was at my design in Omaha, the agronomist told me that they prefer the front of greens, where most shots hit, to be flatter than the back to reduce ball marks.

That course was designed in the 2-2.5% green slope era, but now, I keep most front slopes slightly below 2% to reduce the impact of ball marks.

[JESII]

Ed,


Can you ask the physicist how many people hit the green from that tee?


Betting under 20%...

[Ed Brzezowski]

Well we had eight raters play it, handicaps from 2 to 20. We were at 75% but I believe that was because we had the laser with slope, which was a big help.

[Matt_Cohn]

A few different sources put a golf ball's terminal velocity at around 72mph, so not that it makes a difference to this question, but it's unlikely that it would be going 117mph when it hit the green! The issue would be the straight-on nature of the impact rather than the speed specifically. I would think a flat 3-wood shot impacts a green with more speed, but just at a glancing angle.

[Dan Delaney 🐮]

Ed, you ignorant slut

What whack job scientist calculated 117mph? Let alone with you or the GAP rating team swing speed?!?!?

Noteven close!!! I'd explain it to you, but fear you'd get lost.  Quickly...

You and your boys were landing with butterfly feet at a relatively benign 47-56 mph, depending mostly on trajectory. Fix yer ball mark properly and move on.

Tell the crew I send regards from Shanghai.

[Ed Brzezowski]

Well hello Dan, I see you are well from your first line.
 
The calculations were done by a physics teacher and the crew at Astra Zeneca, so they are questionable at best. The ball marks were massive, Top Flites will do that I guess. And you leave GAP alone, they put me on the EC so be nice.
 
Hope all is well.
 
breeze

[A.G._Crockett]

The biggest such drop I've seen is at Waterfall in N. Georgia.  The second hole is 187 yds, with a 210' drop; it plays about 120.   The drop is so severe that you get a touch of vertigo even looking at the green.  The entire course is bent grass and some spots stay very soft, so they have a local rule on that hole, at least for casual play, that if all members of a group agree on where the ball landed and it can't be found there is a no-penalty drop at that spot. 

It's the signature hole of the course, and features (you guessed it!) a waterfall from the tee down to the green level; spectacular!  But the punch line is, of course, that the waterfall is artificial and is shut off each day after the last group goes out; then the water is pumped back up to the top to a pond only to be part of a waterfall again the next day.