Drift - spin bowling

I've been blogging now for 11 years (2019) and over those years have had conversations on-line with  many people on the subject via forums and my Youtube channel including Australian International Stuart MacGill. At every opportunity I have, I've asked these people to unravel the mysteries of drift and 11 years on I'm still not happy with the answers.

I'm an art person, I paint, draw and take photographs and struggle with physics and maths. There are a handful of books and one in particular that go into Drift in some depth - Brian Wilkins book "The bowler's art" being one of the better ones, but I struggle with getting my head around robins forces and torque and deciphering the diagrams he uses.

If you look around most of the explanations on the internet are extremely vague, this one here from the Quora website where someone has quoted Ravi Ashwin recently...


"You mentioned drift just now. How does one get the ball to drift, is it breeze-related alone?
It is, to some extent. How you call a mirage, drift is also a bit of a mirage. How it leaves your hand and what kind of arc it makes and what kind of parabola it makes is what you think is drift. For a batsman sometimes, you feel it has gone into you, it’s gone late. Most of the time, you are not looking at drift that happens from the hand but drift that happens towards you when it reaches the batsman. When drift happens from the hand, it is more of an angle, it is more of a curvature. What happens is the batsman is looking for it, he is playing for it, he is letting it come in like an inswinger. But when you load the ball differently and put enough revs on it, it starts drifting when it is about to dip. That is when a batsman is committed to a shot and that is something that is not dependent entirely on the breeze. It is dependent on how much revs you put on and how well you loaded and uncocked your wrist. On certain occasions in Indian grounds, it is going to be a bit challenging because all the grounds are almost cocked and fit, so you will not get any assistance from the breeze like there was in Sri Lanka in the first two games. But I think you can get a little bit of curve in terms of shape on the ball when you are bowling to the batsman with your wrist.

Is drift in some way a spinner’s equivalent of swing?
Not necessarily. It’s the amount of revs that you put on the ball that makes the ball behave differently. With the SG ball now, I don’t know. Definitely from the time I started playing first-class cricket and now, the quality of SG balls have differed so much, I don’t know how it is going to be this series (against South Africa). Sometimes, the box of balls that is thrown at you is not great, so it is very imperative for the spinner that the ball is very good. Sometimes in the past, I have overlooked the quality of balls and gone on bowling because I thought it doesn’t really matter. But it does, it does to a certain extent. When you are playing against quality batsmen, you will encounter Hashim Amla, Faf (du Plessis) and AB (de Villiers) in this particular series, it is very important you get all the stocks right".

To me this is as vague as hell and virtually tells us nothing.

The nearest I got to getting my head around it was this here...
http://www.bigcricket.com/community/threads/drift.62786/page-10

My biggest issue with the whole idea was that if it was down to physics alone e.g. if it could repeated and replicated again and again in wind-tunnels as inferred by the likes of Wilkins, a professional bowler would be able to learn how to release the ball consistently and accurately like Jeetan Patel for instance here and then bowl at the appropriate speed and revs and get consistent drift.?

If it was down to those factors alone, my question is/was - can top professionals decide when they want to bowl with drift e.g. turn it off on and on during an over? In conversation with Stuart MacGill, he said no. His answer was pretty much along the lines of when you're bowling well, the combination of revs, seam angle and speed will mean the ball will drift, but you can't just turn up and say. I'll bowl 4 that drift in this next over and then stop bowling drift with the last two. He also mentioned that when the wind is favorable it increases the potential to get the ball to drift, but the thing he felt was most important was the to spin it hard with maximum revs.

It's only in the last few years that I've seen it happening in my own bowling and its sporadic. I seem to see more frequently when I bowl in particular ways - more round arm and the only other time I see it frequently is when the wind is in the right direction. Our home ground, Holy Cross in Basildon during the summer has a relatively consistent wind direction, if I get to bowl from the 'Estate End' the wind is blowing diagonally over my left shoulder as I stand at my mark and the ball drifts there sometimes.

The round arm scenario though is interesting as this is generally in practice. Unlike when I bowl in game situations, practice involves bowling a lot of deliveries and (Too be continued)