Several years ago, practicing at James Gardens LBC, I confirmed that if I maintained a consistent ditch weight in my delivery when I cut my aim angle by half I would pass through a head situated halfway between the hog line and the forward T line. Furthermore, if still delivering ditch weight, I cut my normal delivery angle to one-fourth, my bowl would pass across the centerline at around the hog line (as would be required to hit near a short jack).
A concrete example may clarify this. At James Gardens LBC on rink 4, playing in the North/South direction, bowling from a mat position at the two-meter mark, the correct aim line for my Aero 3.5 H Z-Groove Sonic bowls runs straight at the front ditch number on rink 3. This draw shot would return to center rink. If I want to disturb a head situated halfway between the hog line and the forward T, I deliver a ditch-weight (full-length) bowl along an aim line targeting the boundary marker between rinks 4 and 3. This is one-half the normal draw angle.
If instead, I wish to disturb a head located at about the hog line, I would bowl with ditch weight along an aim line targeting a point on the forward bank midway between the aforementioned boundary marker and the rink 4 rink number. This would be just one-quarter of the normal draw angle.
Further testing has shown that this procedure is transferable from one green to another. Of course, on heavy grass greens, the initial aim angle for drawing is much smaller. But note the important thing that does change from one rink to another—the precise weight you must give a bowl to travel from ditch to ditch.
Remember, however, these rules assume a nearly level green without ruts. I would expect that the rules work better, the slower/heavier the green since the chance for error becomes larger as the aim angle becomes smaller. I would also expect that you will get better results if you drive on the narrower side of the rink.
Note that this approach will more violently disrupt shorter jacks because your weight will be ditch-weight throughout.
I appreciate the notion of coming up with a heuristic process for determining target lines on running shots. As a keen novice it's useful to have this sort of calculation (as opposed to leaving it to 'feel'). However, it would be more useful if we could adapt the process for different weights. I find that the situation in the head often dictates the necessary weight. So a narrow high port may dictate a full on drive - whereas a partial blocker may dictate less than ditch weight.
ReplyDeleteOne approach might be to determine appropriate lines/weight for a constant distance (since you can control the distance when you have the mat).