I recently decided to test a widely held philosophy that mudballs curve a certain direction - if the mud is on the left, it is believed that the ball will curve to the right. Essentially the ball will curve away from the mud....
As you might imagine it is quite difficult to purposely attach mud to a golf ball. In order to keep things fairly consistent I rolled a small strip of duct tape into a ball and then taped over it to keep it in place with additional duct tape. I primarily wanted to create a scenario where the ball carried additional weight along with increased friction on one side.
All shots were hit with a seven iron and I selected the three 'best' swings for each of the options (mud on the left or right). Here are the Trackman dispersion charts and average numbers for the shots that I measured: (yellow is mud/tape on the left and white is mud/tape on the right)
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The mud/tape on the left is the top line and vice versa:
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The averages for the shots actually showed that the ball could curve either right or left when mud is present - regardless of which side it is located. The results were inconclusive, but I can say this - the spin rate seemed to be decreased and there were a few shots that seemed to actually curve both ways.
The coolest thing about the test was how clearly you could see the ball rotating around a fairly horizontal spin axis. With the black tape contrasting the white of the ball it was amazing how you could see the black side remaining on the side it started for the entire flight of the shot. So much for side spin!
The next time you have a mudball all you can really do is aim for the center of the green and hope for the best.