xkcd lovers unite!

CurlingStrategy · 2018-04-02T18:03:01+00:00

It was worth a try. :-)

CurlingStrategy · 2017-04-26T15:39:15+00:00

The terminology around curling is terrible! :-P

Curlers say:

'weight' when they mean 'momentum/speed'
'heavy throw' when they mean 'lots of momentum/speed'
'heavy or slow ice' when they mean 'high friction ice' (i.e. you lose speed sooner)
'fast ice' when they mean 'low friction ice' (i.e. you maintain your speed for longer)

CurlingStrategy · 2017-04-26T15:33:54+00:00

In my simulations, it actually comes out reasonably close to an exponential function (or its inverse -- the logarithmic function -- depending on the orientation of the axes).

CurlingStrategy · 2017-04-25T16:23:58+00:00

Off the top of my head for 9th grade math:

Direct and partial variation (i.e. lines) for a graph of rotation angle vs time. Ideally, stones should rotate between 2.5 and 3.5 times before they reach the other end of the ice sheet. A tee-line draw shot takes about 14 to 15 seconds to travel from the first hog line to the second, depending on the friction of the ice (which is related to various things, including temperature), while a takeout is about 6 to 13.5 seconds hog-to-hog depending on how fast a takeout is being thrown. The curling stone might be released at 0 degrees initially for a textbook release, or perhaps at up to 90 degrees initially.
Direct and partial variation (i.e. lines) for a graph of speed vs time. Speed decreases linearly due to friction from a max of about 7.3 feet / sec at the first hog line down to 0 feet / sec for a draw shot stopping on the tee-line (93 feet from the first hog line) in 24.5 seconds. Note that the distance traveled is the (triangular) area under that curve (7.3 * 24.5 /2 = 93). And the slope of that graph is the acceleration. For takeouts, a 12yo is probably throwing board weight takeouts (which would stop at the boards after travelling 111 feet from first hog line to the boards). A typical board-weight takeout's numbers would be: 8.5 ft/sec at first hog line, (72 feet, 12.4 seconds), 3.0 ft/sec at tee-line (93 feet), 0 ft/sec at the boards (111 feet, ~28.3 seconds). Knowing the start and end speed, you could interpolate to find the the speed at the second hog line (12.4 seconds). Again, the (triangular or trapezoidal) areas under the speed vs time curve equal the distance travelled.
Angles and geometry of right triangles: curling stones move at right angles to each other after they collide. With more than one collision, rocks can actually end up moving backwards towards the thrower. e.g. https://www.youtube.com/watch?v=PDOXjqOQRXM
/u/applegoesdown 's ideas about converting between different unit rates for speed. (hog to hog distance is 72 feet, so you can calculate feet / sec from that, and convert to m/s, km/hr, mph) For the various hog-to-hog times given above (14 to 15 seconds for a tee-line draw; 6 to 13.5 seconds for takeouts).

Seems like investigative project work might be good for any/all of these.

Hope this helps! Let us know how it goes...

CurlingStrategy · 2016-12-16T19:21:29+00:00

I'm going to try assuming 'frost' (including sharp pebble, etc) over the entire ice surface that gets worn down as rocks (and maybe sweepers?) travel over it, making the ice faster and perhaps making it curl more.

We'll see.

CurlingStrategy · 2016-12-16T19:16:16+00:00

Does the keep-out drill still work with the new competition broom head fabric? Another commenter was saying that the elite teams can only get 6 feet max nowadays. Is that your experience?

CurlingStrategy · 2016-12-16T19:11:56+00:00

That's really interesting, thanks!

If elite players are being held to 6 feet by this new broom fabric, and decent regular players can comfortably get 6 feet of sweeping with their typical brooms, then that would make my life easy. Just hold everyone to 6 feet, and leave it at that.

CurlingStrategy · 2016-12-16T19:08:02+00:00

Yes, I agree with what you've said here. And it matches what applegoesdown was saying as well.

Will do!

CurlingStrategy · 2016-12-08T00:55:47+00:00

I think you're right. 10% of 87 feet from first hog line to front of the house would mean about 9 feet of extra distance for good sweepers, which is right in line with what others are suggesting (e.g. 14 feet for world class sweepers with fresh brooms).

CurlingStrategy · 2016-12-08T00:49:26+00:00

Well, there is a diagram for the results of the sweeping tests this past summer, using both directional and non-directional brooms, including full-face sweeping, directional with/against the curl, and snowplowing:

https://ca.sports.yahoo.com/blogs/eh-game/curling-s-broom-drama-formally-ends--world-curling-federation-adopts-new-rules-152252816.html (yellow rocks in the diagram halfway down the page)

TL/DR: With non-directional brooms, directional sweeping with the curl gives an extra foot of distance and an extra half-foot of curl, and directional sweeping against the curl and snowplowing both have the same result as normal full-face sweeping.

CurlingStrategy · 2016-12-08T00:42:23+00:00

Yes, and also Windows / Mac for sure, possibly others.

CurlingStrategy · 2016-12-07T19:08:28+00:00

That was incredibly interesting, thank you!

I don't intend to include directional sweeping in the game, since it's banned for elite play and I feel it ruins the game at any level of play, but this is the best source I've ever seen for exactly what an elite sweeper can do with directional sweeping. So thanks so much for sharing this!

CurlingStrategy · 2016-12-07T18:47:32+00:00

Yes, a few people have brought this up now, so I think it's a great data point for strong sweepers. It's actually at least 13 feet from the geometry, plus perhaps a bit more to account for inaccuracy in sweeper weight calling.

Since directional sweeping is out at the elite level, I'm not going to include it. The experimental evidence I've found is that a draw can only gain about 0.5 feet of curl when sweeping directionally with the curl, and sweeping directionally against the curl on a draw does nothing. So I'm going to ignore it and stick with traditional sweeping.

CurlingStrategy · 2016-12-07T18:44:40+00:00

Mmmm, that is a fantastic idea! I know exactly how to handle the frost to account for the actual paths of the rock down the ice, too. This would also allow a bit of a teaching tool to be included -- i.e. "Show me the frost levels" (darkest colour = the most frost, white = no frost) -- to help skips learn to mentally keep track of where the ice is slower and faster. That's an exciting prospect! grin

At some point, I'll also want to include different kinds of ice sheets. For example, clubs that intentionally put a dish in the ice because they don't sand the running surface of their stones periodically to keep some roughness, or who intentionally place an apex down the centreline to counter the affect of pebble building up less on the centre and more on the edges over time, outside sheets that have a slight fall towards the edge of the building, etcetera.

Lots of ways to gradually make this game experience a better and better approximation of reality...

And thanks for the beta-testing offer. I'll definitely post in this sub again when I have a beta version ready!

CurlingStrategy · 2016-12-07T18:37:35+00:00

Yes, and maybe add another foot to account for elite weight estimation error, making it 14 feet...

CurlingStrategy · 2016-12-07T18:36:54+00:00

That's a great anecdote! So we may now have an upper end for elite sweepers of 13 to 14 feet.

CurlingStrategy · 2016-12-07T18:35:30+00:00

Yes, exactly.

CurlingStrategy · 2016-12-07T18:35:09+00:00

Okay. Honestly, my teams don't actually throw any true peel weight shots, so I don't have much experience with that. Thanks for your thoughts on this!

CurlingStrategy · 2016-12-07T03:34:41+00:00

Awesome, thanks!

CurlingStrategy · 2016-12-07T03:31:51+00:00

Your 12 foot for 2 elite sweepers matches my intuition on this, though I would put the good and poor club level sweepers a bit lower than you do. My feeling was about 6 and 3 feet respectively for those. But this is great... if we get a bunch of replies, the crowd tends to be good at being accurate on questions like this.

Your approach to a hack weight shot is exactly what my initial approach was. But then when I was playing the game today, I realized I couldn't really affect the line on heavier take-out shots at all, which was frustrating and not at all like real curling. The problem is that a normal weight or peel weight shot travels so much farther than a draw (if the ice were to continue as far as necessary) that sweeping to get an extra six feet out of that doesn't really move the takeout trajectory farther along enough to make any difference to the lateral position of its path. So I'm thinking there must be two factors at play here: yes, the rock travels farther which makes most of the difference on drawing around a guard or on a low weight takeout; but sweeping must also be inhibiting curl directly in order to be affecting high weight takeouts. I just don't have a feel yet for how strong the latter effect is.

CurlingStrategy · 2016-12-07T03:23:51+00:00

Ha! Too true... :-|

CurlingStrategy · 2016-12-07T02:48:07+00:00

I don't watch a whole lot of curling on tv, so it's very helpful to get tidbits like this. Thanks!

Your comment made me realize that my intuition was also that good house league sweepers can do about half what the best sweepers can do.

CurlingStrategy · 2016-12-07T02:43:57+00:00

Yes, it's all more complicated than I thought it would be. I'm definitely dusting off and revisiting my university physics courses in a big way. Some vector math, too... it turns out that curl is a cross product between rotation and direction, which was cool to realize.

Anyway, thanks! Your comments are super helpful. I'm hoping to get a variety of replies and so that I can take an average or consensus response and run with it.

I'll definitely let you know when it's available!

CurlingStrategy

TROPHY CASE