Recreational Decompression & Safety Stops
Every Dive is a Decompression Dive
A common misconception in recreational diving is that "no-decompression dives" do not involve decompression. In reality, every dive involves a degree of decompression, as the body absorbs nitrogen under pressure and releases it upon ascent. The term "no-decompression dive" simply means the diver has no decompression obligation—they can ascend to the surface at a controlled rate without stopping beyond recommended safety protocols.
"A no-stop-dive, also known erroneously as a no-decompression dive, is a dive in which no-decompression stops are required. The term no-decompression dive is a misleading name. As we have seen, every dive involves a degree of on-gassing, and every ascent involves a degree of off-gassing, and so decompression of some sort is required on every dive."
— Deco for Divers, Mark Powell (pg. 54)
Recreational Diver Decompression Options
- Do nothing: The dive remained well within the No-Decompression Limit (NDL), and an ascent can be made directly to the surface at a controlled rate.
- Conduct a Safety Stop: The common practice of pausing at 15 feet for 3 minutes to add a margin of safety.
- Ascend using a decompression profile: A gradual staged ascent, sometimes called "flying the curve", which is primarily taught in technical diving and GUE training.
Comparison of Ascent Methods
| Ascent Type | Depths Used | Stops Required | Advantages | Challenges |
|---|---|---|---|---|
| Direct Ascent | Any depth within NDL | None | Simple, fast, no extra gas use | Higher DCS risk if near NDL |
| Safety Stop | 15 ft for 3 min | Recommended | Extra safety margin, habit-forming | May be skipped in emergencies |
| Decompression Ascent | Staged every 10 ft after reaching 1/2 max depth | Required for deco dives | Most effective at off-gassing | Requires training and discipline |
My Approach to Ascent and Safety Stops
- Preferred Ascent Method: I prefer a decompression ascent over a traditional safety stop, as it provides a more gradual reduction in pressure. However, I often dive with people who are more comfortable with a standard safety stop, so I adapt accordingly.
- Safety Stop vs. Decompression Ascent Impact: I haven’t personally encountered a situation where either method made a clear difference in safety, but I still see the decompression ascent as a superior approach.
- Handling Stops in Challenging Conditions: When conditions make holding a stop difficult, my go-to strategy is to launch a dSMB to signal the boat and hold the stop while drifting.
- Adapting to Different Dive Buddies: If diving with a new buddy or a group, I generally follow the standard 3-minute safety stop at 15 feet since it’s the common approach in recreational diving.
Final Thoughts
Every dive is a decompression dive, but recreational divers are not obligated to perform decompression stops. Whether using a safety stop or a decompression ascent, both approaches serve the same goal—reducing DCS risk and improving ascent discipline. While many divers stick with a safety stop, those trained in progressive ascent methods may find staged decompression ascents beneficial.
Ultimately, personal preference, training, and dive conditions will determine which method is best for a given dive. The key takeaway? Slow ascents are always better.