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View Full Version : Double hit question - Dr. Dave?



killerstroke
09-24-2005, 07:13 PM
It is still a mystery to me how average/knowledgeable players still don't believe how a double hit occurs when two balls are close together. It would help us all for these non-believers to check out Dr. Dave's videos of a double hit. A few months ago, BD ran an article explaining how a double hit occurs when two balls are close together and cutting them while using outside draw. Dr. Dave is this a video I missed on your web site or is this something we could see. I do agree with theory. Thanks

Ronoh
09-24-2005, 10:42 PM
I think this is what you're looking for.

High Speed double hit (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-10.htm)

And this one (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-12.htm)

pooltchr
09-25-2005, 05:16 AM
<blockquote><font class="small">Quote killerstroke:</font><hr> It is still a mystery to me how average/knowledgeable players still don't believe how a double hit occurs when two balls are close together. <hr /></blockquote>

It is quite possible to shoot straight into a cue ball that is less than the width of a piece of chalk from the object ball without making a double hit. If you ever get the chance to work with a good instructor, they can show you how. I forget whether it was Randy or Doc who showed me.
Steve

killerstroke
09-25-2005, 06:39 AM
Yes I agree, BD had a good article a while back on ways to hit it if you are close together and close to a rail. My favorite is hitting off the top of the ball with an upstroke.

killerstroke
09-25-2005, 06:47 AM
I believe these videos are showing the shots straight on. My shot is if the OB was being cut in at a 45deg angle with about a chalk width between them and using outside english. I believe there is a fine line between high, middle ball, and draw if it does double hit. Probably most definate if using draw. Because of the outside english and the short distance between them, the follow through hits the CB as it caroms off to the left also. I did watch these, I think, I couldn't get them to load up right now. Thanks!

Fran Crimi
09-25-2005, 08:17 AM
<blockquote><font class="small">Quote killerstroke:</font><hr> Yes I agree, BD had a good article a while back on ways to hit it if you are close together and close to a rail. My favorite is hitting off the top of the ball with an upstroke. <hr /></blockquote>

There was a controversy about that at the BCA pro event in Vegas a few years ago. At the players' meeting we were told by BCA officials that if the balls were within a chalk-width of each other, we either had to shoot away from the ob, or if we shot directly into the ob, it would be an automatic double-hit foul if the cb moved past the spot where the center of the ob stood. In other words, we were being limited to shooting down on the ball but were not being allowed to shoot up over the top of the cb. We argued and argued but were flat out refused. BCA officials argued back that it would be impossible to tell with any certainty if a double hit had occurred if the cue stick was angled up at the cb. Not true. We lost the battle that year, but won it the following year, and have been allowed to shoot up at the cb ever since.

Fran

Sid_Vicious
09-25-2005, 10:19 AM
Hi Fran. I had gone years here in Dallas believing the BCA's rule was just as you described them to portray it to be during y'alls conflicts. Then I was enlightened one night a couple of years ago when one of the locals who happened to be one of the refs at Vegas ruled on a hit and went against me, the guy topped the ball but shot in line, I just knew I had that call coming my way, nope. I respectfully agree that there is certainly techniques to use and miss the double hit, and yet wouldn't it be simpler to just keep the rule as BCA wanted it to be? The guy who topped the CB on me, in my observation, double hit, but it happens so fast that the human judge is going to more times than not, call it for the shooter just out of not being certain he heard or saw the DBL hit. Just me maybe but it seems like asking for friction to let shooters jack up or jack down(top CB where the CB actually rolling forward as it did in my lost call.) We just do not have the expertise in judges IMO to adequately make the right calls in a high percentage of the times. I am sure the professional classed events does have such judging depth, but overall, these BCA trained judges can't get that call correct when indeed there is a double hit. It makes sense to me to use the BCA's off angle requirement and disallow the finesse abilities of those who can successfully manufacture a clean hit. Like I said, years went by before I was even aware that the BCA's "if it rolls foreward beyond the resting point of the OB" stipulation, and in my call' it did roll several inches forward. That rule limitation would keep it equally and simply regulating on both opponents and relieve the judge of an inability(IMSO) that many just do not have in the first place...sid

Fran Crimi
09-25-2005, 10:59 AM
BCA RULE BOOK: INSTRUCTIONS FOR REFEREES: Section 2.20


"When the distance between the cue ball and the object ball is less than the width of a chalk cube, special attention from the referee is required. In such a situation, unless the referee can positively determine a legal shot has been performed, the following guidance may apply: if the cue ball follows through the object ball more than 1/2 ball, it is a foul."


Clearly, this is a guideline and not a rule. Unfortunately, the guideline falls short in that it doesn't describe an acceptable cue stick position for using topspin. Once the referee has been taught to recognize that cue stick position, the referee can easily recognize it and could, with more than reasonable certainty, call a good hit.

The word in the guidelines that scares the referees is "positively." That word is unrealistic with these types of hits. Reasonable certainty is all we can ask for when judging something like this.

The pros straightened out the situation with the referees with regard to their events. If the amateurs wish to do the same, they should contact the referee program administration.

randyg
09-25-2005, 12:37 PM
A truly believe that 90% of the BCA Referees understand the Double Hit. It's too bad the other 10% can't get their stuff together.

The Rule is solid. Understanding and enforcement in that 10% is a little shaky.......SPF-randyg

pooltchr
09-25-2005, 03:52 PM
Sid,
Help me understand your position. Are you saying the rules should outlaw a perfectly legal hit, simply because there may not be many players who know how to execute it properly, or some officials may not know how to make the correct call?
Steve

Sid_Vicious
09-25-2005, 09:03 PM
What I am saying is this. If the width is less than a cube of chalk, it is simply a better hard and fast rule IMO to say that one should be required to hit off center, right or left. If that simplistic approach threatens someone with the ability to finesse the shot by jacking up and nipping the CB, well...tough. It is again IMO, that the bulk of the rulings when hit directly in line and called good in local league play, is indeed a bad call, but that it happens faster than the ref can POSITIVELY say was good, hence the shooter gets the call. Keep it simple and force everyone to hit off center. This game has enough hangups with rules already, remedy this one with a concrete verdict beforehand...sid

woody_968
09-26-2005, 03:10 AM
<blockquote><font class="small">Quote Sid_Vicious:</font><hr> It is again IMO, that the bulk of the rulings when hit directly in line and called good in local league play, is indeed a bad call, but that it happens faster than the ref can POSITIVELY say was good, hence the shooter gets the call. <hr /></blockquote>

Changing a rule based on how most league players call that rule would be a bad idea, most of them dont know the rule or how to apply it.

Proof being in what you just said, if the ref (or who ever they have chosen to watch the hit) cant say for sure that it was a good hit then in this case the call is supposed to go to the other player. Im assuming we are still talking about CB and OB less than a chalk width apart and the CB goes forward more than half the distance of the OB.

Instead of changing the rules I think getting leagues to teach and inforce the rules would be much better.

JMO.

Woody

Sid_Vicious
09-26-2005, 05:58 AM
"Instead of changing the rules I think getting leagues to teach and inforce the rules would be much better."

That task alone adds to my opinion that the BCA's idea of enforcing it like I THOUGHT it to be over the years is a good one. Can you imagine the job it would be to revamp refs down to the local levels with just this one rule? My guess is that it will remain a half understood rule, but hey, I just have an opinion. The impact of simplifying the issue still seems the best avenue. sid~~~has no problem in playing the shot cleanly if need be, with either rule interpretation

Fran Crimi
09-26-2005, 08:16 AM
I think you're right, Randy. BCA referee training is very rigerous and has become even moreso over the past couple of years. The standards have been getting higher and higher. I think that over time that stubborn 10% will eventually be weeded out.

I think the problem is more on local levels where people designated as referees are not BCA referees and haven't received the proper training. If league operators don't want to bother to send someone to BCA ref school then they'll continue to have problems. The rule shouldn't be changed just because they don't want to take the trouble to make that happen.

Fran

SPetty
09-26-2005, 08:23 AM
I still like the idea, I think it was Fred that I heard it from, of simply doing away with the double hit foul.

dr_dave
09-26-2005, 08:25 AM
<blockquote><font class="small">Quote killerstroke:</font><hr> It is still a mystery to me how average/knowledgeable players still don't believe how a double hit occurs when two balls are close together. It would help us all for these non-believers to check out Dr. Dave's videos of a double hit. A few months ago, BD ran an article explaining how a double hit occurs when two balls are close together and cutting them while using outside draw. Dr. Dave is this a video I missed on your web site or is this something we could see. I do agree with theory. Thanks <hr /></blockquote>
FYI, the only clips I have of double hits are HSV A.9-A.12 and A.110-A.115. They can be viewed from the high-speed video section of my website (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/index.html). A brief description of the latter clips can also be found in another thread (http://www.billiardsdigest.com/ccboard/showthreaded.php?Cat=&amp;Board=ccb&amp;Number=201675&amp;page =0&amp;view=collapsed&amp;sb=5&amp;o=&amp;vc=1). Sorry, but I don't have the exact shot you are looking for.

Regards,
Dave

Bob_Jewett
09-26-2005, 11:22 AM
<blockquote><font class="small">Quote SPetty:</font><hr> I still like the idea, I think it was Fred that I heard it from, of simply doing away with the double hit foul. <hr /></blockquote>
The problem is what the rule will become. Here is one possibility:

It is permitted for the tip to strike the cue ball more than one time provided that is it done with a single forward stroke of the cue stick.

Does that sound about right? If so, I'll explain some other problems that such a rule implies.

Fred Agnir
09-26-2005, 11:27 AM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr> <blockquote><font class="small">Quote SPetty:</font><hr> I still like the idea, I think it was Fred that I heard it from, of simply doing away with the double hit foul. <hr /></blockquote>
The problem is what the rule will become. Here is one possibility:

It is permitted for the tip to strike the cue ball more than one time provided that is it done with a single forward stroke of the cue stick.

Does that sound about right? If so, I'll explain some other problems that such a rule implies. <hr /></blockquote> That's about what I've proposed. If they can control the double hit, more power to 'em, I say.

I guess I'd like to hear the downside.

Fred

Fran Crimi
09-26-2005, 12:01 PM
I'd be interested in hearing the reasons why as well.

Maybe if there's a slight angle to the shot, I'd guess that it's conceivable that the cue tip could actually hit the ob, like that trick shot where the ob is pocketed, not by the cb but by the cue tip. Cautioning the shooter away from shooting straight through balls that are close would seem to prevent that.

Fran

Bob_Jewett
09-26-2005, 03:05 PM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr>... If so, I'll explain some other problems that such a rule implies. <hr /></blockquote>
One minor problem that most pool players will feel is not a problem is that in the other disciplines it is forbidden to hit the cue ball more than once. A similar rule is the one that governs whether you can play into an object ball that's frozen to the cue ball, and neither the French nor the English games permit this. Given that pool permits shooting into a frozen ball, extending that to multiple tip-to-ball contacts when the balls are not frozen is not much of a stretch.

Ronoh
09-26-2005, 09:21 PM
Quote Bob_Jewett:
--------------------------------------------------------------------------------

Quote SPetty:
--------------------------------------------------------------------------------
I still like the idea, I think it was Fred that I heard it from, of simply doing away with the double hit foul.
--------------------------------------------------------------------------------


The problem is what the rule will become. Here is one possibility:

It is permitted for the tip to strike the cue ball more than one time provided that is it done with a single forward stroke of the cue stick.

Does that sound about right? If so, I'll explain some other problems that such a rule implies.
--------------------------------------------------------------------------------

That's about what I've proposed. If they can control the double hit, more power to 'em, I say.

I guess I'd like to hear the downside.

Fred

You cannot create experience. You must undergo it.

---------------------------------------------------------

Here's my take on it.

Rules of pool is like a Country's constitution.

First rule, never hit the cue ball twice during the same stroke to make an object ball. (it's what keeps everyone on the same playing field, and is fair)

Most people with a HINT of integrity (http://www.yourdictionary.com/ahd/i/i0177000.html) know this unwritten rule. It's what pool is, and has been for centuries.

It's allowed in trick shot tourneys, but should not be allowed in "true shot" tourneys.

As the game of billiards romps forward, high speed cameras will be on hand to refut if a shot is leagal or not. Count on it.

Rule of Thumb: If you can't do it legally, learn how.

Fred Agnir
09-27-2005, 05:39 AM
[ QUOTE ]

Most people with a HINT of integrity know this unwritten rule. It's what pool is, and has been for centuries.<hr /></blockquote> This has been a written rule, not unwritten.

[ QUOTE ]
As the game of billiards romps forward, high speed cameras will be on hand to refut if a shot is leagal or not. Count on it.

Rule of Thumb: If you can't do it legally, learn how<hr /></blockquote> I think you're missing some essentials in the conversation.

Fred

Ronoh
09-27-2005, 08:45 PM
::: Not trying to hijack this thread :::

Fred, you're a good joe.

I thought I understood the tread in the fullest. I was only trying help the OP to point out that if you do a double hit, at least be an upstanding pool player and admit you did it.

I gave links to videos that shows how a double hit happens. Most people that are new to the game don't even know they are doing it, becuase they don't understand the feeling (response)of the stick during their stroke when it happens.

Integrity while playing pool is the only thing that matters. I felt that that's what the OP was trying to convey.

My apologies if I offended anyone, wasn't my intention.

poolboy
09-29-2005, 10:39 AM
I absolutely agree. Most refs do have a complete understanding of the shot. What is the BCA 45 degree rule? There isn't one! The only rule is that you can't double hit the ball. IMHO there is a huge difference between a referee who is nationally certified and one who is only locally certified.

The half ball thing is only a guideline. If someone understands the rule and has a true grasp of the physics...I'd feel confident they'd make the right call.

killerstroke
09-29-2005, 02:35 PM
I would like to thank everyone for there opinions. There is one thing that was only mentioned once, thanks poolboy, please forgive me if I missed anyone. The important part of knowing if its a bad hit or not is the physics of ball direction after contact. What line did the CB or OB take after contact. The same concept applies when watching for a bad hit in any game.

randyg
09-30-2005, 04:23 AM
HUH????Same thing....SPF-randyg

dr_dave
10-03-2005, 09:07 AM
<blockquote><font class="small">Quote Ronoh:</font><hr>As the game of billiards romps forward, high speed cameras will be on hand to refut if a shot is leagal or not. Count on it.<hr /></blockquote>
I don't think high-speed video is the answer here; although it would be fun to see on TV. The equipment is very expensive, usually requires extremely bright lighting, requires lots of setup and equipment positioning, etc. (for more info, see my August'05 instructional article (http://www.engr.colostate.edu/~dga/pool/bd_articles/index.html)). Also, as I describe and illustrate in another thread (http://www.billiardsdigest.com/ccboard/showthreaded.php?Cat=&amp;Board=ccb&amp;Number=201675&amp;page =0&amp;view=collapsed&amp;sb=5&amp;o=&amp;vc=1), even high-speed video can't always provide conclusive proof. To me, the proof is in how the cue ball and object ball react (see the clips mentioned here (http://www.billiardsdigest.com/ccboard/showthreaded.php?Cat=&amp;Board=ccb&amp;Number=206064&amp;page =0&amp;view=collapsed&amp;sb=5&amp;o=&amp;vc=1) for examples). If it is difficult to decide if there is a double hit or not based on this reaction, then the judgment should go in favor of the shooter (just like baseball or the legal system ... innocent until proven guilty).

Regards,
Dave

Bob_Jewett
10-08-2005, 03:27 PM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr> ... The problem is what the rule will become. Here is one possibility:

It is permitted for the tip to strike the cue ball more than one time provided that is it done with a single forward stroke of the cue stick.

Does that sound about right? If so, I'll explain some other problems that such a rule implies. <hr /></blockquote>
Here is a situation at nine ball. Your opponent scratches on the break, and you have ball in hand on the one ball. The 5-9 is dead, but the 7 is between the 1 and the 5, and the distances are too large to hope to play the 1-7-5-9. Place the cue ball 1/16-inch from the one ball pointed directly at the 5-9. Shoot hard with a little draw. The 1 will take out the 7, and the cue ball will go through to hit the 5-9 combo.

Here is a situation at one pocket. Your opponent has stuck you on the wrong side of a nearly intact rack, 1/16th of an inch from a ball. You notice that the corner ball on your side of the rack is dead to your pocket, but you aren't going to get much power into it, because it's a 5-ball combo. Simply shoot the cue ball directly towards the rack as hard as you can, perhaps hitting the cue ball five or six times. Be careful not to touch any object balls with your stick, as that would be a foul. You might make three or four balls in your pocket, and will almost certainly improve your position.

Here is a situation at straight pool. The 15th ball of the rack is just barely over the line, and you leave the cue ball in the rack. The cue ball now goes behind the line. Place it very, very close to the object ball with the shot pointed straight into the side pocket. Angle your cue a little -- there is a system for this -- to make the cue ball go straight to the 14-ball rack.

It should also be noted that when I said the cue ball was close to the object ball, that it doesn't really have to be. On a nearly straight shot, it's OK to hit the cue ball a second time even if the balls are six inches apart.

Another example is when you have to cut a ball thinly along the end cushion when the cue ball is close to the object ball. Often you don't want the cue ball to travel to the other end of the table. Just let the cue ball come off the cushion and hit the tip a second time to stop it.

Do you really want these shots to be legal?

Colin
10-31-2005, 12:43 AM
Bob, and to others interested.

Here is how the English Pool rules define it.

I prefer this method and have played a lot under these rules in Australia. The only change I would make is to allow hitting into a touching ball.
-----------------

O. Push Shots and Double Hits
Definitions: Most shots commonly known as "Push Shots" in the game of "Snooker" are allowed in the game of Eight-Ball Pool. Generally, any shot played with speed will not be deemed to be a Push Shot regardless of the fact that the cue tip may have come into contact with the Cue Ball more than once.


Exceptions that are Standard Fouls:-


When, during the playing of a shot, the tip of the cue strikes the Cue Ball twice and the referee is able to actually see each contact.


When, during the playing of a shot, a player plays the cue so slowly through the Cue Ball that the cue tip remains in contact with the Cue Ball so as to be visibly pushing it along.


When the Cue Ball is played into a touching Object Ball.

<blockquote><font class="small">Quote Bob_Jewett:</font><hr> <blockquote><font class="small">Quote SPetty:</font><hr> I still like the idea, I think it was Fred that I heard it from, of simply doing away with the double hit foul. <hr /></blockquote>
The problem is what the rule will become. Here is one possibility:

It is permitted for the tip to strike the cue ball more than one time provided that is it done with a single forward stroke of the cue stick.

Does that sound about right? If so, I'll explain some other problems that such a rule implies. <hr /></blockquote>