Sweeping to Victory!
Our club alternates between Leagues and Events. During League, we're concentrating on playing. Once the league ends, we concentrate on bringing new people into the Roaring Game.
We normally get a few hours of ice-time on Saturday nights, and we've done three Learn-to-Curl nights, some drop-in games, our first "Beginner's Drop-in" and last week, our first 4 week Beginners' League.
I like teaching during the breaks, because I always learn something.
Ryan and I coached during the Beginner's Drop-In, and he did a short sweeping clinic. I stood there nodding as he did it, but I also paid close attention. Ryan has curled for decades. He's also a mechanical engineer, and while he didn't exactly discuss the physics of sweeping, he was talking about the physics of sweeping.
A curling stone is a shade under 12 inches across, but the shape of the stone gives us a roughly 5 1/2" running surface.
Ryan's discussion was about getting the maximum effort into an area just slightly wider than the running surface.
Less expensive (and less sophisticated) brooms have a fixed angle between the handle and the head. When sweeping, the long side of the head is roughly parallel to the path down the ice.
Fancier brooms have a swivel, so the head may be at any angle, from exactly parallel, to exactly perpendicular to the direction of travel. If you turn the head perpendicular to the travel, you can get really, really close to the rock, which I thought was a good idea.
What it means is that your broom is sweeping across an area less than 2" across. There isn't a lot of time to alter the surface of the ice.
Turning the broom 90 degrees means you are sweeping an area 8" along the stone's path.
What do the best-of-the-best do? I pulled out my video from the 2011 Brier, and while they aren't sweeping 100% perpendicular to the line of travel, the broom head is 90 degrees to the handle. This is something I'll be sharing with my rink-mates.
Ryan also noted that ideally the pressure should be straight along the handle, with the handle as near vertical as is comfortable. As the handle becomes more horizontal, the stress on the swivel at the broom head is increased, and may break.
On an unrelated topic: a Towel can be massively useful.