Leave the Flagstick In (and Tend it Too)

[saevel25]

38 minutes ago, iacas said:

Your eyes are lying to you. That ball is moving pretty fast. I believe it would have missed.

I think the ball would have slammed the lip of the cup on the far end of the hole and went a good ways past the hole. Probably less if the ball missed the hole entirely, but still way more than where it ended up after hitting the flagstick.  

[iacas]

The hole is 4.25" wide. The ball takes - 14/30th of a second to travel from point A to a point just inside the hole.

Doing some measuring, the hole is 212.46 pixels wide. The ball covers a distance of 1274.7 pixels. That's about 25.5" (to the edge of the hole - the ball covers some of the distance over the hole, too).

25.5" in 14/30th of a second, or 2.125 feet per 0.466666667 seconds. That's 4.55 feet per second.

The diameter of a golf ball is 1.68" and thus the circumference is about 5.28". 4.55 feet is over 10 revolutions per second.

So, the ball most likely doesn't drop. And… the limit for a ball dropping into the hole is 10 revolutions per second, and that's only if the ball hits the exact center of the hole (and the hole is level; this hole is situated on a downslope, which is probably why the ball rebounded UP slightly - the flagstick was likely leaning slightly away from the incoming ball).

Conclusive? No. But the only chances that realistically exist are if the ball slowed down from 10.35 revolutions per second to below 10, and that's highly unlikely. Most likely the ball hits the back edge of the cup, pops up, and rolls about a foot past.

10 is the limit, and that's with a firm, crisp, even-height far edge with a ball striking the exact middle of the hole on the near and far sides. This hole is on a downslope. And look at the frame on the right: the ball doesn't appear to have gone down at all. (We don't know if the ball is before or just after impact.)

1 hour ago, onthehunt526 said:

So @iacas, I am assuming you are okay with leaving the flagstick in under the 2019 rules for say a 30' putt.

I wouldn't say I'm "okay" with it. I hate the rule.

But if you want to shoot the lowest score, and one of the two conditions aren't met (lean, wind), yeah, leave it in from 30'. Hell, leave it in from 20' if your distance control isn't awesome.

1 hour ago, onthehunt526 said:

It grinds my gears when I am on the fringe in a tournament and everyone else is on the green, and I have a putter in my hand, auto pull the flagstick. I politely ask them to return the flagstick because I'm off the green. If I'm 1 inch off of the green, I don't care if I'm 12 feet from the hole, or 60 feet from the hole, the pin stays in. I've rattled a couple off of the flagstick. "Oh, you should've taken it out, the flagstick got in the way." I reply. "No, it didn't, I hit it too hard." If you hit a putt with the proper capture speed at the hole even with the flagstick in, the ball will still go in the hole.

Yep.

1 hour ago, billchao said:

That putt looked like it was going to roll 6' past the hole IMO. I don't know what it would have done had the stick not been in, but it looks faster to me than it does to you, I think.

Probably more than that. Tiger said he "hammered" it IIRC. It's on a little downslope, too, which is why the ball barely slows down during the last half of its roll.

1 hour ago, Golfingdad said:

You mean 6' past the hole IF he missed the hole.  Surely, you don't think that it would have gone 6' past the hole on the line it was on?

Factoring the hole in, it most likely hits the back lip and rolls out a foot or two.

[rehmwa]

17 hours ago, iacas said:

Your eyes are lying to you. That ball is moving pretty fast. I believe it would have missed.

I was thinking it would have fallen.  But if we think 4.55 fps is a decent calc, easy enough to calculate how deep it gets before hitting the far edge of the cup..... good stuff

 

" And… the limit for a ball dropping into the hole is 10 revolutions per second "  where did you get that one?  inquiring minds....

 

edited

Edited March 21, 2018 by rehmwa

[iacas]

8 minutes ago, rehmwa said:

I was thinking it would have fallen.  But if we think 4.55 fps is a decent calc, easy enough to calculate how deep it gets before hitting the far edge of the cup..... good stuff

10 revolutions per second is about the max speed (with a level cup, hitting the exact middle), for a ball to fall 0.84" over 3.41" (center of the ball to the outside edge of the ball across the cup).

10 revolutions per second is just under 4.4 fps.

[rehmwa]

1 hour ago, iacas said:

10 revolutions per second is about the max speed (with a level cup, hitting the exact middle), for a ball to fall 0.84" over 3.41" (center of the ball to the outside edge of the ball across the cup).

10 revolutions per second is just under 4.4 fps.

ah, half a golf ball descent.  Good enough assumption, though I'd think the cut off would be a little less than that:  the ball is descending when it hits that 'corner'; it's a soft lip,,,mostly: even a rebound that's slightly up would still hole out.

but as good an assumption one should make on the first pass as one can ask for

thanks, if I wasn't at work, I'd have sussed this out already, but your thought process is the same as what I had in mind...

[iacas]

20 minutes ago, rehmwa said:

ah, half a golf ball descent.  Good enough assumption, though I'd think the cut off would be a little less than that:  the ball is descending when it hits that 'corner'; it's a soft lip,,,mostly: even a rebound that's slightly up would still hole out.

but as good an assumption one should make on the first pass as one can ask for

You're ignoring the effects that a ball's topspin (from rolling) can have on the putt climbing out slightly.

But anyway, 10 fps has been fairly well established as the absolute maximum speed. A softer lip generally hurts as it tends to make it easier to get "under" the equator of the ball and for the ball's topspin to carry it forward a bit.

That's why I've suggested that the likely outcome is that the ball hits the back lip, pops up, and rolls forward another foot or two. It has spin on it.

[Zeph]

@iacas are your data based on calculations or did you hit a bunch of balls with flag in and out, recorded the speed and noted the results?

[iacas]

2 minutes ago, Zeph said:

@iacas are your data based on calculations or did you hit a bunch of balls with flag in and out, recorded the speed and noted the results?

They're based on calculations mixed with empirical data.

The calculations have been done by many people, including Mark Sweeney, Geoff Mangum, myself… and some others. They've done some experimental tests here as well.

My experimental data is more about directing balls at the flagstick at various speeds and distances away from center (or on-center) and seeing how many go in or don't go in.

The advantage grows the harder you hit the ball. It's never really better to take the flagstick out unless it meets one of the two conditions above.

I wish the USGA/R&A had actually tested this. Instead, they're seemingly relying on the words of people and the actions of people (in taking the flagstick out) who don't actually know anything more than what they've heard or always done.

[rehmwa]

1 hour ago, iacas said:

You're ignoring the effects that a ball's topspin (from rolling) can have on the putt climbing out slightly.

 

yes I did, darn 3D rotational mechanics, completely killed my air hockey level assumptions......

Quote

10 fps has been fairly well established

Based on the above, I'm sure you meant 10 rot/sec.... (4.4 fps as noted) which is a normal to leisurely walking pace....

Edited March 21, 2018 by rehmwa

[iacas]

9 minutes ago, rehmwa said:

Based on the above, I'm sure you meant 10 rot/sec.... (4.4 fps as noted) which is a normal to leisurely walking pace....

Yeah, sorry, my bad there.

[iacas]

I like to admit when I was wrong, and I'm going to add a fourth item to the list of when you should take the flagstick out. This will join the other three existing times when I recommend or allow it. Those three are:

1. When the flagstick leans so much that a ball won't fit.
2. When the flagstick is rattling back and forth in the cup liner because of high winds and could knock your ball away.
3. When you are absolutely positive that you will be able to control your distance to within about 2-3 feet.

The fourth new reason:

4. When you are going to spin the ball so much that a little kick off the flagstick will push the ball back far enough to grab one blade of grass that the spin grabs so hard the ball is pulled out of the hole.

I will admit to not having conceived of this idea, but there you go: reason #4. 🙂

[billchao]

10 hours ago, iacas said:

4. When you are going to spin the ball so much that a little kick off the flagstick will push the ball back far enough to grab one blade of grass that the spin grabs so hard the ball is pulled out of the hole.

I'll have to remember this and pull the flag out whenever this situation arises 

[mvmac]

15 hours ago, iacas said:

4. When you are going to spin the ball so much that a little kick off the flagstick will push the ball back far enough to grab one blade of grass that the spin grabs so hard the ball is pulled out of the hole.

Noted 🤣

[Vinsk]

Damn. No tellin’ how many strokes that has cost me.

[iacas]

For talking about the 2019 Rules, as this topic was primarily about leaving the flagstick in when hitting from off the green, and tending it when you have a longer putt, please look at this topic:

Thank you!

[iacas]

 

Note: this is the older topic from before 2019. It's mostly about chipping from off the green, and having the flagstick tended under the pre-2019 rules when putting. For the talk of putting with the flagstick in, head here:

[mdl]

On 9/4/2018 at 5:18 AM, iacas said:

I like to admit when I was wrong, and I'm going to add a fourth item to the list of when you should take the flagstick out. This will join the other three existing times when I recommend or allow it. Those three are:

1. When the flagstick leans so much that a ball won't fit.
2. When the flagstick is rattling back and forth in the cup liner because of high winds and could knock your ball away.
3. When you are absolutely positive that you will be able to control your distance to within about 2-3 feet.

 

Maybe I missed this earlier in this very long thread.  But am I right in deducing from #3 that according to your testing while having the flagstick in doesn't hurt if you're stopping the ball within a couple feet of the cup, it also doesn't help?  Intuitively that makes sense if you're only going to run it by ~6".  But I'm surprised if having the stick in doesn't help at least a touch on balls that are going to run 3' by.

[iacas]

16 minutes ago, mdl said:

 

Maybe I missed this earlier in this very long thread.  But am I right in deducing from #3 that according to your testing while having the flagstick in doesn't hurt if you're stopping the ball within a couple feet of the cup, it also doesn't help?  Intuitively that makes sense if you're only going to run it by ~6".  But I'm surprised if having the stick in doesn't help at least a touch on balls that are going to run 3' by.

It doesn’t because the capture size of the hole at that width is wider than the flagstick-touching-ball width. (2.18”)