Having the only criterion for winning be a stopwatch will likely encourage reckless and unsafe practices.
If you're trying to organize a "rope skills" competition, you might take inspiration from the industrial rope access world, e.g., Grimpday (youtube vlog from The Rope Access Channel, CMC GRIMP 2022 held on the USS Iowa). It consists of multiple rope team rescue scenarios, requiring ascending/abseiling, raising/lowering victims, confined space rescues, water hazards, and so forth. Each scenario is judged with time as only a secondary/tertiary factor---main judging criteria include General Safety, Appropriate Rope Techniques, Victim Comfort, Team Management/Dynamics/Communication, Team Conduct & Respect towards organizers/volunteers/other teams, and so forth.
While the rules are written for the industrial rope access world, they give inspiration for a recreational scenario. Here are some paraphrased examples along with suggestions of how they might look for you:
- Saftey Practices and PPE (helmets etc) required at all times; unsafe practices lead to immediate disqualification.
- While systems are being rigged, the stopwatch is running. However, once any system is rigged, a safety observer will call a
SAFETY CHECK. During this period, the clock is STOPPED while knots/anchors/carabiners/mechanical devices are inspected. The team is informed of any deficiencies, which they must correct after the stopwatch is restarted. Consider adopting this verbatim---participants are timed while they rig their rappel system, but timing is halted while it is inspected by a qualified supervisor. Even automobile racing has a separate vehicle safety inspection that is untimed.
- All participants require certification (e.g., IRATA, SPRAT, NFPA, ...). Have an certification/qualification mandated for all participants. Having someone who has never rappelled/ascended before being involved in a timed competition is a horrible idea. Similarly, have minimum rigging standards for participants: acceptable ascending/abseiling systems & devices and so forth.
- Industrial Rope Access mandates redundancy---completely redundant anchors and connections, never being connected to only a single rope or tether, etc. Consider adding redundancy to the ascending/abseilling events by, e.g., tying participants into a completely separate rope system during the time-stopped safety check and having them belayed by a qualified organizer. Or even an independently rigged auto-belay that is connected during the safety check.
- All systems must be capable of passing the “whistle test” (meaning if the person in control of the lowering or descent operation lets go, the system(s) default to stopping). Mandate assisted braking devices, "third hand" backups, etc.
My local climbing coalition organizes an annual event that you might also take inspiration from. It consists of a timed 14mi (3,500' vert) trail run combined with a climbing competition (untimed) at a local crag. Each route has a pre-rigged toprope with a dedicated belayer; redpointing any given route awards a certain time deduction. The winner is whoever has the lowest net time at the end of the day. By organizing the event in this way, observe how everything related to safety in the vertical world is decoupled from racing & rushing.