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- I shoot upward and cannot hold a safety stop
What is happening
Near the surface, gas in the BCD and suit expands, and a small buoyancy error can accelerate your ascent. The problem is clear when you rise through the safety-stop depth without being able to remain there.
Why it happens
Ordered from the most common cause down. Open one to see the mechanism behind it.
As you ascend, gas volume and buoyant force increase. This is the most common trigger in reported buoyancy problems and can turn a slight rise into a rapid ascent.
- late venting
- too much gas in the BCD
- inappropriate weighting
In reported buoyancy problems, running out of air is the most frequent trigger. When gas is running low, stress pushes the slow-ascent plan and safety stop into the background.
- checking the gauge too late
- underestimated consumption
- no reserve for the stop
Panic narrows attention and can lead to an uncontrolled ascent. In a DAN study, some divers with a first panic episode reported a rapid or uncontrolled ascent.
- breathlessness
- loss of orientation
- task loading
A stuck inflator, unintentionally dropped weights or an inappropriate drysuit can add buoyancy that you cannot compensate for in time. You need to know and practise the emergency response in advance.
- a stuck inflator
- lost weights
- a drysuit that is too large
An SMB line can entangle and pull you upward, while upwelling can carry you involuntarily toward the surface. In both cases, slow and control the ascent rather than completing the task at any cost.
- SMB line
- upwelling
- downwelling
What to try on your next dive
One thing, not ten. Give it a full dive before you judge it.
A stable safety stop
- Plan enough gas for the ascent and stop. Before ascending, check depth, gas and the direction to the exit with your buddy.
- Ascend slowly, venting expanding gas from the BCD before you begin to accelerate.
- At 5 m, take a horizontal position, breathe normally and use small BCD adjustments rather than your hands.
- Hold the safety stop in the 5–6 m range and monitor your computer until the stop is complete.
- Do a weight check and confirm that you can hover near the end of the dive with an empty BCD.
- Practise oral inflation and disconnecting an inflator hose only with an instructor or in a controlled environment.
How you will know it is working
| Published reference | Value | Source |
|---|---|---|
| Conservative reference | 9 m/min | DAN — Ascent Rates |
| PADI maximum | no more than 18 m/min | PADI — Standard Safe Diving Practices |
| PADI safety stop | normally 5 m for 3 minutes or more | PADI — Standard Safe Diving Practices |
After the dive, review your computer log for the maximum ascent rate and note whether you held the full safety stop.
- Never hold your breath during ascent; exhale continuously and inhale as needed.
- Do not descend again to make up a missed safety stop.
- After a rapid ascent or missed stop, stop diving for the day, monitor for signs of DCI and seek medical help if symptoms occur.
- Do not use your last gas to complete a safety stop.
- After an uncontrolled ascent, end the dive and have your equipment serviced if there was an inflator or BCD problem.