CA Hoop Tests – March 2013
Note: this is a DRAFT report, prepared by Martin French. From these tests reported here, it was felt:
Hence, these tests were not considered conclusive and have only served to inform our next round of testing. The following draft report is offered in case it is of interest, but should not be regarded as the last word on any of the points considered.
In recent years, there has been a growing desire for hoops that present a greater challenge for Association Croquet Championship (and A Class) play, even in our wettest UK summers. To many, the easy hoops and slow lawns after a period of rain remove the advantage that accurate break play should bring in top class Association Croquet – if we could restore that premium, it would be of great benefit to the sport. This report describes some tests conducted by the CA Equipment Committee on a number of novel or prototype hoops, all hoping to produce more demanding hoops in "easy" conditions.
The results were less clear cut than would be liked – it seems in typical damp loamy soil, nothing so far trialled makes a large difference in the challenge provided by a hoop. However three factors seem to help with increasing the challenge:
Two factors that didn't seem to help:
It seems nothing found so far is as good as a prolonged dry spell (with no lawn watering) if you want challenging hoops.
Narrow hoops set in firm, dry ground provide a good challenge for top players. But after periods of rain, even hoops set to 1/32" gap can seem "trivial". An ideal new hoop type, even when set in soft ground, should present a proper challenge and reward the more accurate play of the best players, while penalising inaccurate approaches and poor hoop strokes. It is not the intention to make an "impossible" hoop, just to restore the premium for accurate break play that can be lost when the conditions are "easy". By creating just a couple more 'opportunities to break down' per game for an inaccurate player, would help restore the premium for good play.
The hoops tested all contained ideas aimed at providing this ideal:
The objectives of the tests were to tease apart which of these innovations were actually making the hoop more difficult to run, and which seemed to make little difference.
See the table in Appendix 1 for details.
Note about settings
While each hoop's "free air width" just below the crown and at half-ball height was measured, in practice, every hoop was set using an Oakley hoop clamp (as sold by the CA Shop) in new holes to the same setting of 1/16" (except where noted otherwise), with a tolerance of 1/64". Hoops were moved to new holes for subsequent batches of tests.
While the width at the top of the uprights of the Quadway may be adjusted with the aid of an Allen key, this on its own makes precious little difference to the width in the ground, but could allow a consistent width to be created all the way up to the crown that might affect jump shots.
Note about the Superhoop
This hoop seems unsuitable for typical UK loamy and stony soils. It took 6 minutes of continuous pounding with a heavy mallet to get the Superhoop in the ground. It was noticeably less firm than all the other hoops, perhaps because the integrity of the turf had been broken by the fins. It is not practical to adjust the width in the normal ways – the width is whatever it ends up when you remove the clamp.
Removing the Superhoop is very difficult indeed. An accurate template must be constructed and a car jack used to pull the hoop up away from the template – whose purpose is to hold the surface of the ground together during extraction. Removing the hoop took several minutes and despite the template, a chunk of turf about 9cm x 7cm x 6cm came out stuck between the bottom of the fins. It left significant damage to the court.
Two test rigs were used:
1. A 2m Ramp, raised by around 40cm, such that a ball would travel around 6m across a typical lawn. The design of the ramp meant that the balls were delivered with a degree of top spin – something some players strive for in hoop strokes. (The ramp was in fact two rails, around 45mm apart, so that as the ball ran down these rails, its angular velocity at its periphery was greater than its forward motion.) All the tests with the ramp were on straight hoop shots, but with various offsets from the hoop centre-line.
2. the Pidcock Peeling Plank was used (PPP) to shoot balls at angled hoops, and at various offsets to the near wire (-1/8" through to +3/16").
All the tests with the PPP were at angled hoops of between 25° and 50°. The angles quoted are measured with respect to the 'normal' to the hoop – so a straight hoop would have an angle of 0°.
With the Ramp, batches of ten tests were conducted from each position; with the PPP, five peels were conducted from each angle.
Critique of techniques
After 30 or 40 shots, the balls created a very small dent at the foot of the Ramp and also a rabbit run in the jaws. This dent was perhaps throwing balls off-target. Out of a batch of shots, there would be a wide variety of distances travelled. It was also observed that a 'track' developed after a few shots, which reduced the resistance to subsequent balls – in several batches of tests, there were some of the longest outcomes late in the batch.
The tests with the PPP suffered a different problem – that having lined up the two balls for the peel, it had to be struck with a mallet manually. So there was a large variation in force of stroke. Slower strokes seemed more likely to drift off target and into one or other wire, compared to firm strokes.
The consequence for both test rigs was the variations in outcomes across the batch of shots (5 or 10) was large, and may mask any real differences between one hoop and the next. Perhaps the most fundamental problem is that it isn't feasible to test the range of typical hoop strokes in such rigs: the strength, spin, follow-through, real-world inaccuracies in aim, and so on.
Unless stated otherwise, all tests were conducted with the hoop set in new holes and with a gap between ball and hoop of 1/16".
Balls were Dawson 2000.
The ground was damp but not saturated – it seemed firm but plastic, and typical of a summer lawn in the UK except during a prolonged dry spell.
The soil was a typical UK loam. The top 1" was quite sandy due to repeated top-dressing. Below that, the soil was a reasonably sticky loam with occasional stones.
Lawn speed was judged to be medium, though was not measured in Plummers. The lawns had been double-cut the day before and had been in play throughout the previous winter months.
Test 1 – initial assessment of maximum running angle (PPP)
A more challenging hoop would give a smaller maximum angle from which it could be run.
* Although in a new hole, this hoop remained wobbly in the ground and was surprisingly easy to run as a result
Potential Finding: surprisingly small differences, especially with the square uprights which looked formidable. Were the parsnips of the Quadway and Hoop 3 "worth" 5° of additional challenge?
Test 2 – effect of offset (PPP)
* At 8mm offset, the ball be bullied through with a forceful shot, but would stop in the jaws with a normal stroke
Potential Finding: it was most surprising how much offset could be applied before balls ceased to run the hoop. This is offset with respect to just clearing the near wire: it seemed to be often possible to run the hoop with an offset from -1.6mm up to +8mm.
Test 3 – initial assessment of maximum offset on straight hoop strokes (Ramp)
The ramp, set up at right angles to the hoop, was moved progressively more and more offset to one side, to find how 'forgiving' the hoop was of poor hoop strokes. The point at which balls either failed to run or only grovelled through was recorded.
* Tests on 2A and 4A were conducted with the hoop in the existing holes (for 2B and 4B) but now from the other side. As there was a slight slope and this was now up-slope rather than down-slope, a check was made on 2B turned around so that was also up-slope: this gave a result of 13mm instead of 14.5mm when down-slope. So the effects of slope were much smaller than the difference between hoops 2A and 4A, and all the other hoops.
Potential Finding: The Quadway seemed slightly more challenging (but see Test 6 later). The square uprights of Hoops 2A and 4A, which differed only from 2B and 4B by the latter having very slight chamfers on the edge between the faces, were considerably less tolerant of off-line hoop strokes.
Test 4 – Subjective assessment of resisting abuse
Hoops 1 and 3 (same round uprights, on either round carrots or square parsnips) were 'hacked at' repeatedly. 20 very hard stokes were played from about 45cm away, at around 30° to the normal. Some strokes ran, some rejected, for both hoops.
Potential Finding: It seems likely the small difference in widening observed was as much due to differences in the 'free air width' of the hoop or to the odd stone below ground, as to the different properties of carrots or parsnips. We did not find the greater resistance to bullying we hoped for from the parsnips.
Test 5 – Further comparison of Quadway and equivalent Aldridge Hoop 3
The Quadway and Hoop 3 appear to be very similar in construction (square parsnips and round uprights of the same diameter), and yet some of the measured results had been quite different. Why? Perhaps it was down to different masses and surface finishes? It was decided to repeat and extend some of the tests on just these two.
Potential Finding: in most regards, the Quadway was a more challenging hoop to run than Hoop 3, and yet they seemed very similar. It was speculated that perhaps the smooth powder coating surface finish on the Aldridge was helping balls through. It was decided to scrape the powder coat off of the running area of hoops 3 and 4 for the remaining tests, to see if this could be confirmed.
Test 6 – Extended offset tests using Ramp: Quadway, Hoop 3 and Hoop 4
With the surface coating removed from Hoops 3 and 4, an extended set of tests running batches of balls down the Ramp and measuring how freely (= far through) they ran.
* note the "tracking" effect, where the longest runs all seem to come later in the batch
Potential Finding: this illustrates the problem with these tests, despite careful execution. All 10 attempts at 15mm offset ran through the hoop – yet in Test 3 we had determined that 12.5mm was the maximum offset that would still run through the Quadway. Perhaps the tracking effect developed by the earlier batches facilitated the later batches running at "impossible" offsets?
This testing approach does however show an increasingly inaccurate hoop stroke results in the ball running decreasingly far through the hoop, despite having the same initial energy.
The other hoops were then tested using just the 15mm offset for comparison, and to reduce the chance for tracking to develop.
A club hammer was taped to the crown of the hoop at the end of the 4B test, to see if the extra mass made any difference, but it didn't appear to.
Potential Finding: With the powder coating removed from the running areas of Hoops 3 and 4, the more challenging results found previously for the Quadway were now over-taken by Hoops 3 and 4. Hoop 4A with no chamfer was particular resistant to balls running at this offset. These results show that the difference observed in earlier tests between the Quadway and the similar Aldridge trial hoops was more to do with the powder coating finish than the underlying construction.
Test 7 – Comparison of Hoop 4A with Hoop1 (Ramp and PPP)
A final comparison was made of the most challenging trial hoop, 4A with the powder coating removed, versus Hoop 1 (a standard Aldridge championship hoop).
When it was realised the 4A batch had been run with a wider hoop setting, they were repeated with the hoop set in new holes to 1/32" – but this made no material difference to the outcome.
Potential Finding: Whereas a standard hoop (Hoop 1) would accept a shot up to 15mm off-target, with the square un-painted uprights and parsnips of Hoop 4A, this reduced to 10mm. So 4A now presented more of a challenge. As suspected, changing the width of the hoop setting from over 1/16" to 1/32" made no material difference.
Potential Finding: So despite square uprights, parsnips and no paint on the uprights, there was no measurable difference between Hoop 4A and the reference Hoop 1. Again, changing the width of the hoop between 1/16" and 1/32" made no measurable difference either.
Martin French comments (Aug 2013):
CA Equipment Committee hoops trials - Spring 2013
* For some later tests, the powder coat was scraped off to reveal a plain steel finish
Empty fields - data still to be collected.
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