At regional, national and world level events, games are timed by officials using an official clock selected for the event by the Chief Umpire. The clocks are sometimes large format mechanical clocks or computer programs running on Apple's OS X or Windows.
The details of the timing requirements for an event is described in the USCA's 2009-2010 Championships Rules Booklet (currently under Section III -- Event Procedures, M. Game Timing). Since the most up to date information can be obtained by reading the USCA's document, exacting details from it will not be documented here as they are subject to change over time. An athlete should prepare themselves for an event by reviewing the rules. If they have questions, they should contact the Chief Umpire.
Timing and Timers
The management of the amount of time a team (particularly your team) has during a game can be imperative to the success of your game. For example, if your team runs out of time before your last rock crosses the T-line at the delivering end, your game is an automatic forfeit. When this occurs, the points are not considered in determining the winner. Be careful to note that the clock may run out while your team's last rock is being delivered as long as the deliverer has crossed the T-line at the delivering end with the rock prior to the clock reaching zero. In other words, it's not an issue that a slower draw may take more time to come to a stop than remains on the clock.
The timers may not know the players on each team, so it's imperative that they can easily tell which team you are on when they are trying to determine if your team has "yielded the ice." The official is trying to determine if all players on your team have stepped to the side or are out of the way such that a reasonable curler could deliver the next rock. It can be very difficult for timers to recognize you and your team mates if they are not visibly identifiable. Imagine a game where eight players are all dressed in black or each player is wearing a unique individual color. How can a timer tell if the person with the green shirt is playing on team A or team B when the other players are wearing red, blue, yellow, white, black and brown shirts/jackets?
Having matching jackets is very helpful and will allow the timers to clearly identify your team when they are wearing their jackets, but what happens when they take their jackets off? If their shirts match those of their team, the players are giving a clear signal to the timers -- "Hey, I'm on team A!" Can they take this a step further to guarantee that the timers can recognize them? Certainly! If the team matches their shirts with their rocks, an even clearer signal will be given. If a team is assigned to throw light colored rocks in a game, their shirts should be light in color. If they are assigned dark rocks, they could wear a dark colored shirt.
In the end, the decision of what clothes to wear is up to the athlete. However, an athlete must recognize that they are running a risk if they don't help their timers to clearly recognize them.
Practice with Clocks
Teams that have not had a chance to work within a game time may be able to get some practice using one of the free curling clocks available for download. Both of the following programs were developed by officials at the Granite Curling Club in Seattle, Wa.
Teams wishing to gain practice under the watchful eye of a timer may download these programs to their laptops and use them during practice or league games.