NSS-CDS CCR Trimix Cave Diver

CCR Trimix Cave Training

NSS-CDS CCR Trimix Cave Diver is the closed-circuit rebreather equivalent of the open-circuit Trimix Cave Diver course. The official NSS-CDS page states that it covers the same knowledge and skills, but in the manner required for safe CCR trimix cave diving. This means the course combines deep cave trimix planning with CCR-specific equipment, monitoring, bailout, decompression, and failure-management decisions inside an overhead environment.

This course is for divers who already meet both CCR Cave Diver and Trimix Cave Diver prerequisites. NSS-CDS states that students must meet all prerequisites for both courses, and must have all equipment required for both CCR Cave and Trimix Cave. The size, capacity, number, and content of open-circuit bailout cylinders are dictated by the depths and times of the dives made during training. Candidates should already be disciplined, experienced, and realistic about CCR trimix cave risk.

Training generally takes two days and at least three dives. In High Springs, Florida, CCR Trimix Cave Diver is for advanced rebreather cave divers preparing for deeper cave objectives where helium, decompression, bailout, and exit distance must be planned together. The expected outcome is a diver who can integrate CCR procedures with trimix cave planning, evaluate bailout needs honestly, and keep deep cave decisions conservative from pre-dive planning through exit.