A tool used to determine the no-decompression limits for scuba dives based on depth and time, facilitating safe diving practices. These tools can be physical, like the classic wheel-based device, or digital, often integrated into dive computers or available as standalone software applications. An example of a practical application would be a diver using this tool to plan a 30-meter dive and ascertain the maximum allowable time underwater without requiring decompression stops.
Prior to the widespread availability of dive computers, these instruments were essential for preventing decompression sickness, a potentially life-threatening condition. They provided a systematic method for calculating safe dive profiles, reducing reliance on estimations and increasing the safety margins for divers. Their historical development mirrored the evolution of diving itself, from basic depth and time calculations to incorporating factors like repetitive dives and altitude.