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Technical
Double Hits in Pass Rolls

John Riches writes:

I have recently been performing some tests with carbon paper taped to the mallet face in order to find out the extent to which the ball slides or rolls across the mallet face, or contacts it more than once, in various strokes.  [I am aware that others have performed similar tests and published results on the net.]

I have been concentrating on pass rolls, especially the one which can be part of a triple, where the peelee was left in 4-back after hoop 3, and after hoop 4 you rush (or roquet) it through 4-back and then pass roll it to penultimate while going to a ball at hoop 5.

This stroke can be played in various ways, and the carbon paper tests reveal some interesting results which I will probably share with those interested at a later date, after further testing and when I have been able to give more thought to the interpretation of the results.

Three methods of playing the long pass roll can be roughly explained as follows:

1.  With only a short backswing (or else none at all, starting the forward swing from a stationary position a foot or less behind the ball), use a flat, rapidly accelerating "short-arm jab" through the top half of the striker's ball with the mallet handle more or less vertical.

2.  Tilt the mallet handle sharply forward (at 45 degrees or more from vertical) and use a fairly flat swing through the ball.  Again you need to accelerate the mallet head through the ball, but much of the desired forward momentum of the striker's ball is achieved by "squeezing" the ball between the ground and the sloping mallet face.  This method works best when the ground is hard (as it almost always is here), and does not work on a soft, spongey or sandy surface.

3.  Play what we refer to as a "clonk" roll (because you just go "clonk!"). This involves playing the pass roll as you would a jump shot through a hoop, hitting down sharply on the striker's ball with the mallet handle sloping well forward; except that you may want to have one hand closer to the mallet head than you would when jumping through a hoop.  The striker's ball actually does jump, though not as much as if the croqueted ball were removed, and this helps it to get past (or over) the croqueted ball.  This method seems to require an angle of 20 degrees or more between the directions of the two balls, as in the shot I have described above.

I would be interested in any ideas readers may have on the likely or possible legality of pass rolls using any of these methods, and in any other methods I could try and test.

The main reason for writing this email, however, is to ask whether anyone -  perhaps one of our experts in physics and mechanics  -  can answer the following more basic questions:

  1. In theory, is a double hit or multiple contact (which would of course be a fault) more likely to occur with a light mallet than with a noticeably heavier mallet?
  2. Would a flexible shaft be more likely to result in a double hit than a rigid shaft?
  3. Would it depend on which method is used to play the stroke?

John Riches
Email: jriches@adelaide.on.net
 

imprint - pass roll
1). Long pass roll from behind 4-back to penultimate and hoop 5
imprint - pass roll
2). Same as 1. 
imprint - jump
3). Jump through a sidey hoop
imprint - split roll
4). Right angle split from around hoop 3 to hoops 2 and 4
imprint - pass roll
5). Flat pass roll
imprint - full roll
6). Long equal roll from near hoop 3 sending both alls to hoop 4
imprint - angle stop shot
7). Wide angle stop shot
imprint - pirie poke
8). "Pirie Poke"

MAX HOOPER WROTE:

I interpret John's Pictures 1 and 2 differently from Martin. I think there were two separate hits. The first one caused the round image. The mallet and ball then separated for a short moment and the smear shows the ball rolling along the mallet head. I cannot conceive how a single contact could produce the two overlapping images.

Max may well be correct in this iterpretation, but to me it would seem strange that the "tail" which indicates that the ball rolled across the mallet face is obviously continuous with the larger and lighter impression, suggesting that the small dark circle must have been caused by the first contact of mallet with ball. Why would the first impact, when the mallet was presumably moving fastest, result in so much less flattening of ball against mallet than the second impact which was presumably a rebound, with the ball and mallet parting company between the two impacts? It seems more likely to me that there was only one impact, with most of the force being absorbed into a small area of the ball's surface (the dark part) as the ball then flattened against the mallet face so that a larger area came into contact with it.

Since the mallet was being rapidly accelerated through the ball, I would have expected two separate contacts to show more evidence of movement between the two, with the milling lines more obscured as happened in some of the other shots where multiple contacts did definitely occur.

AND NIGEL GARDNER WROTE, inter alia: (my responses are introduced by arrows)

it would seem from JR's carbons that a pass-roll executed as a jump shot >seems the > nearest thing to legality.

---> I agree, as least temporarily until we have conducted further tests. It is likely that the jump-pass will become our favoured coaching method; but unfortunately it does not work (or does it - perhaps I am not playing it the right way?) when the angle between the directions of the two balls is noticeably less than 20 degrees. This means that for pass rolls in which the balls travel in more or less the same direction we are faced with the necessity of teaching a method which, when I use it myself at any rate, produces carbon images that reveal clear evidence of multiple contacts.

As an aside re. the test results, No6 is remarkably similar to No1 in that the player is tending to come aross the ball and the ball is rolling down the face of the mallet, the discontinuities possibly being caused by small irregularities in the ground rather than true double taps.

---> That is an interesting suggestion, particularly in view of the fact that our ground is very dry and hard.

I was surprised that the ball rolled down the mallet face at such an oblique angle, since I tried to play the equal roll stroke with the handle vertical (as I tell those I coach to do) and swinging straight through the centres of the two balls.

I have long believed that in such strokes the ball remains in contact with the mallet face until it has moved (in most cases) right across the face (this fact was first pointed out to me many years ago by Tom Armstrong, and in fact it almost inevitably turns out that everything 'new idea' I have about croquet was first thought of by Tom many years ago); but I thought there would have been more evidence of sliding rather than rolling. For this reason I have always insisted on having the corners of my mallet face well rounded (much more so than in the illustrations) because I convinced myself that with a sharp corner it would make a difference in some strokes (mainly long split-rolls) exactly which side of the corner the ball rolled off as it left the mallet face, thus making them more difficult to control accurately. Of course a round mallet face, or (as I have used for many years) an oval-shaped one - actually, a "super-egg" for those mathematically inclined, would overcome the problem; but these can have disadvantages for other shots.

John Riches

Author: John Riches
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Updated 28.i.16
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