What did we know and when did we know it?
In Part 3, I’ll discuss the discovery of Seam-Shifted Wake.
I began trying to explain how sinkers work in earnest in early 2019. Initially, led by the ideas of Driveline and their athletes, I worked on the idea that seams where causing transition to turbulence on one side of the ball and not the other. The sketch below is one that I published on baseballaero. I’m showing it here so you can see how diabolical that notion is. Since for a 2S pitch viewed from above the seams are 90º apart, having a seam positioned on the front of the ball in a place to cause transition means there’s one on the opposite side that actually causes separation. Not to mention that the sketch below predicts deflection in the wrong direction.
On February 1, 2019, I first proposed that it was seams, not smooth parts of the ball, that caused sinkers to move as they do. Two weeks later I suggested that “laminar express” was an incorrect term and started searching for a new one. My attempt was “seam controlled wakes” which did not catch on for obvious reasons.
On Feb 2019, Alan Nathan introduced me to Mike Fast. We discussed an outing from Eric O’Flaherty of the Braves where he claimed unusual movement due to a bench pressing contest with Brian McCann prior to the game. I thought Eric’s gyro must have ticked up leading to extra SSW. Mike (who is a healthy skeptic) said he saw nothing unusual in the data that day. Anyway, here’s Eric’s inning. Facing the Phillies, men on 2nd and 3rd with no one out and he struck out the side.
https://photos.app.goo.gl/VudAp6Ui3hCuLyFu9
It was around this time that we started using the term “Seam Shifted Wake” (SSW). I can’t pin down when we adopted it but I can vividly recall Andrew Smith suggesting it.
August 2019, at the invitation of Alan Nathan, I attended Saber Seminar in Boston. It was absolutely fantastic. I met Dan Brooks, Harry Kaplan, and Glenn Healey. I bought The MVP Machine and Ben Lindbergh signed it. I presented our findings to date on SSW. Here’s my favorite slide from my presentation, which indicates my confidence level at the time.
Andrew Smith rebuilt our measurement system and began using the cannon from WSU, which was a huge advancement. Furthermore, we acquired a cache of MLB baseballs. Mike Fast of the Atlanta Braves sent us a case (72) 2019 balls. Lloyd Smith of WSU and the Sean Ahmed of the Pirates each contributed another box of 12 (We later received some 2020 baseballs from Alex Wood). With real baseballs and a means to propel them that didn’t alter the ball, we were now making measurements that were useful.
Ironically, by the time we had the system rolling, the WSU group had already tied the low drag on 2019 balls to seam height, so our mission was complete before we started. Lloyd generously suggested we find something else to do with the equipment and money. So it all became about SSW.
I continued to write about our findings at baseballaero. Up to this point, the only evidence I had that SSW existed in MLB was MLB vertical acceleration data on changeups that spun close to 3:00. Stephan Strasburg was my favorite example. About 10% of his changeups accelerated downward faster than gravity. Since these pitches had a vertical component of Magnus force, they should have downward acceleration less than gravity. Having no idea at the time how MLB produced those acceleration values, I was convinced this was proof. I recall Alan Nathan was skeptical (but interested) and knowing what I know now, I can see why. But I was correct.
In November 2019, we published our second Gallery of Fluid Motion entry, this time with Rob Friedman as a collaborator. I chose for music the “Gathering Clouds” closing theme from This Week in Baseball. Baseball fans over 50 thought it that was awesome. Others asked “What’s up with that music?”
Dec 31, 2019 (New Year’s Eve), David Kagan lays this on me: Magnus and SSW have a lot in common. In fact he goes as far as to say they are the same. I push back noting Magnus depends on spin and SSW does not. But in both cases, the pressure force is due to a change in the separation points on one side of the ball versus the other side. If I show you a picture of a shifted wake, you’d be hard pressed to tell me if it was from spin or seams.
I begin trying to demonstrate that seams alter the path of a ball by firing baseballs with the WSU cannon across our high bay. I had borrowed a Rapsodo V1 from Ricky Norton (thanks, Ricky!). Since the cannon could repeat the initial trajectory as well as RPM and velocity, differences in arrival location could be interpreted as differences in break. Not a lot happened, and now we know that is because these were zero-gyro pitches.
On January 17, 2020, in an act of desperation, I scuffed a baseball to show we could get it to move counter to Magnus. This was such a spectacular success and in the direction opposite predicted by a famous baseball physics book. We hit the overhead door on our first attempt. And we proved that John Smoltz does know more about pitching than some scientists (the ball moved toward the scuff).
Two weeks later, John Garret (who had recently started working with us) ran a test on a “scuff ball”, or a pitch that spins around a seam generating a scuff-like effect. It was much more subtle than an actual scuffed ball, but it showed seams mattered. We did not spend enough time on this test to be sure what the results meant.
February 10, 2020 I visited the Sports Science lab at WSU to try their new cannon that could add gyro to a pitch. After a lot of trial and error, I managed to produce a 2-Seamer with a lot of extra run. I still have the baseball I used that day. For my money, it was the first time anyone had demonstrated conclusively that seam orientation mattered.
In mid February, 2020, we found a better zero-gyro orientation that we called “Looper”. Andrew Smith ran this test. We threw 3:00 CH-like pitches in two orientations that were 180º from each other and saw about 8″ of break difference.
The results formed the basis of our first journal paper on SSW.
I was convinced that SSW was a thing and that seams altered the direction of pitched baseballs. What remained was to convince the game that SSW was real and was important.
Link to Part 4.