Some scuba diving techniques taught in the Open Water Diver course are intended for emergency situations only, and some should be used each time you hit the water. A safety stop should be a crucial part of every safe scuba diver’s routine. They are a proactive way to ensure our bodies have properly decompressed as we make our way to the surface.
As integral as safety stops are, they are often forgotten, overlooked, or not fully understood by divers despite the fact that they are one of the first things taught in a course. Since your safety is so important, in this article, we’ll provide a refresher course on why safety stops are so important and how to perform them.
What are safety stops and when are they required?
A safety stop is a recommended dive procedure that is done by divers when they have descended to depths of 10 meters (33 feet) or below. On their ascent, once they have reached a depth of 5-6 meters (15-20 feet), they pause for 3-5 minutes. This gives their body time to decompress after the time they spent at depth, and is highly recommended to decrease the chances of getting decompression sickness.
Why make a safety stop?
As you may have or will learn in your Open Water diving course, inhaling compressed air underwater results in an accumulation of nitrogen gas in our tissue and bloodstream. As you begin your ascent, the drop in pressure releases the nitrogen gas, and this process is known as off-gassing.
When a diver ascends too quickly, the rapid drop in pressure causes the nitrogen to release too quickly. Think of what happens when you shake a bottle of Coke or Pepsi. You’ll notice bubbles will rise to the surface, and now imagine this process happening inside your body. These nitrogen bubbles can get into all sorts of places in your body, and this is what ultimately causes the dangerous effects of decompression sickness.
By performing a safety stop at the end of each dive, you give your body time to safely release the excess nitrogen that has accumulated in the blood and tissues. Now technically the process of off-gassing continues for several hours after a dive. However, the safety stop makes the ascent much safer.
Now if you performed a shallow dive (<10 meters) then you may be tempted to skip the safety stop. After all, they aren’t mandatory like decompression stops are. However, regardless of how deep you dive, there is always a miniscule chance that decompression illness can occur, so why risk it? It’s just a good habit to perform a safety stop for each dive.
There are more reasons to perform a safety stop other than to prevent decompression sickness. First, stopping to take a breath can give you time to assess the surface conditions and spot any ascent hazards (e.g. a boat). Second, it gives you time to ensure your gear is strapped in. It would be a shame if you suddenly dropped an expensive flashlight or camera as you were getting on the boat.
How to perform a safety stop
With how important safety stops are, it’s crucial that divers do it correctly. Beginners or infrequent divers may find themselves forgetting to perform a safety stop or doing it incorrectly. With proper technique and practice, you can get it done right every time. Here are our tips to help you perform the perfect safety stop.
Maintain Neutral Buoyancy
First, remember back to your lessons that you should be deflating your BCD as you ascend. This is because you don’t want to go up too quickly to give your body time to decompress. You should aim to establish neutral buoyancy as you exhale to make the safety stop easier.
As you head closer to the surface, the decreasing water pressure will cause the air to expand making you more positively buoyant. You must frequently make tweaks to your BCD so that the ascent is slow and controlled. Ideally, you should be neutrally buoyant so that you don’t have to waste any energy remaining in place as you wait out the 3-5 minutes for the safety stop.
Time Your Stop
Even if you’re diving with a group or a trusted dive buddy, you are ultimately responsible for your own safety. As a certified diver, you should be in charge of timing your own safety stop. Thankfully, a dive computer can handle this for you; it will let you know when you should perform a safety stop and for how long.
Even after you’ve completed your safety stop, you must be careful to surface slowly. The last 5 meters (15 feet) are notoriously dangerous for all divers. This is where the greatest change in pressure occurs and is where the majority of lung overexpansion injuries and decompression sickness occurs.
When the 3-5 minutes have elapsed, make your way slowly to the surface as you did before, making sure to stay below the maximum ascent rate of 9 meters/30 feet per minute. If you aren’t sure what your ascent rate is, a dive computer is excellent for monitoring this and alerting you when you exceed this ascent rate.
Safety Stop Position
It doesn’t matter whether you prefer to wait out the safety stop in a vertical or horizontal position. What is important is if the position is advantageous for the situation you’re in. Otherwise, just go with whatever your personal preference is.
No matter what position you’re in, you must remain neutrally buoyant. Keep a close eye on your computer to ensure that you’re not actually ascending. Keep your dive computer at around chest level so your torso is at the right depth.
Hold a Line
Trying to perform a safety stop in open water without a line can be challenging. Without a visual reference, it’s hard to tell if you’re bobbing up and down, not quite neutrally buoyant. While off-gassing, you should endeavor to maintain your position at a certain depth. An easy way to ensure this occurs is by holding onto a mooring line or anchor for the duration of your safety stop.
Frequently Asked Questions
What is the difference between a safety stop, decompression stop, and deep stop?
Perhaps you’ve heard of these different types of stops and aren’t sure what they mean.
Deep stops are a 30-60 second stop done at 50% of the maximum depth of your dive. Deep stops are not a substitute for a safety stop; you should do both.
Decompression stops are very similar to safety stops. Divers perform decompression stops when they have exceeded their no stop decompression limit (NDL). Like in a safety stop, divers should remain neutrally buoyant at the prescribed depths (calculated by the dive computer or a dive table) for a few minutes to decompress.
The difference between a safety stop and a decompression stop is that decompression stops are mandatory, safety stops aren’t. Furthermore, divers may need to perform multiple decompression stops in a single dive, and their final stop is a safety stop.
Safety stops are an important procedure to prevent getting bent. In the same way that dive computers handle deco stops, they will also recommend a safety stop at the end of each dive even if you stayed within your decompression limit.
What happens if I miss a safety stop?
For recreational divers, if you’ve missed a safety stop for some reason, it isn’t the end of the world. As long as you were following safe diving practices, you should generally be okay.
However, let’s not take any chances. If you’ve missed a safety stop, do yourself a favor and just take the rest of the day off from diving. As we mentioned, your body will be off-gassing for many hours, so give your body time to release the nitrogen safely. Also, monitor yourself for symptoms of decompression sickness.
Do I need to do a safety stop even if I’m diving with nitrox?
Yes! It doesn’t matter what gas mix you’re using, safety stops should still be an integral part of any dive plan, even if you’re diving with enriched air nitrox. Your body is still inhaling compressed air while under pressure which means nitrogen is still entering your bloodstream and tissues and needs to get released slowly.
Should I still make a safety stop in an emergency?
No, safety stops are highly recommended but they are not strictly necessary. As a recreational diver, as long as you stay within your no-decompression limits, then technically you can head to the surface any time without making a safety stop.
With that said, there may be a time when you encounter an emergency that is so critical that a safety stop will actually worsen the situation. For instance, if your dive buddy is suffering a medical emergency or there is a serious equipment malfunction with the scuba tank or regulator, then stopping for 3-5 minutes can be more dangerous than heading straight to the surface.
What if I don’t have enough air for a safety stop?
Well this would certainly qualify as an emergency as mentioned above. You lost track of your pressure gauge reading and now you may not have enough air to perform a safety stop. As scary as this is, we’ve all been there.
In this situation, though it’s not ideal, you can skip the safety stop. However, if you still have some air left, then perhaps you can stop for a little while to decompress as much as you can before surfacing, because getting bent is no joke.
How should I position my body during a safety stop?
When it comes to body positioning, there have been no conclusive studies indicating that a horizontal or vertical position is better. In a prone (horizontal) position, your entire body will be exposed to equal ambient pressure, which hypothetically would help you decompress evenly.
In a vertical position, the diver’s head and legs are exposed to different ambient pressures, however this difference is small and ultimately negligible. So at the end of the day, it doesn’t really matter and the body positioning can be adjusted based on the diver’s preference.
Depending on the situation, divers may prefer one type over another. For instance, if there are strong currents, then it will make more sense for a diver to remain horizontal with their head facing into the current while holding onto the dive line. Alternatively, if you have deployed your own surface marker buoy (SMB), then it may be easier to have your body be in a vertical position.
Scuba Diving Safety Stops: Recap
Safety stops are a crucial part of avoiding decompression sickness. Though it’s not considered mandatory the way decompression stops are, any safe scuba diver should be doing it every dive if possible. Why bother with safety stops?
Our bodies experience the greatest change in pressure when ascending the final 5-6 meters (15-20 feet) of the dive. This is when excess nitrogen will be rapidly released if the ascent is too quick. Waiting 3-5 minutes allows time for excess nitrogen to safely dissolve from the blood and tissues and decrease the likelihood of getting bent.
Even if you performed a shallow dive that never exceeded 10 meters (33 feet), there’s no reason not to perform a safety stop. After all, why risk experiencing the symptoms of decompression sickness? All it takes is 3-5 minutes of your time, and the benefits are enormous. Safety stops are a proactive way for divers to protect themselves, and we highly recommend performing a safety stop for each dive.
If you found this article helpful, then we recommend you also read our article on scuba diving safety tips.