Why Can’t Scuba Divers Surface Quickly?
If scuba divers ascend to quickly Nitrogen that has been absorbed in their bodies tissues at depth will not have enough time to safely be expelled from the body. This can cause serious implications for scuba divers such as Decompression sickness (DCS or “the bends”), Nitrogen Saturation, Reverse Squeeze & Barotrauma and even Boat Strikes.
Scuba diving is an exciting sport, but it comes with potential dangers such as rough water conditions and marine life, but the more serious dangers are ones we often cannot see – the ones from surfacing quickly!
Scuba divers stay clear from surfacing quickly to avoid scuba diving accidents such as decompression illness. When we take the plunge, our bodies absorb nitrogen gas. The deeper we go, the more nitrogen we absorb which is why some people feel ‘narked’ at deeper depths. This is also known as nitrogen narcosis where you get a similar feeling to being drunk.
Do you remember the scuba hand signal used before you surface?
This signal is used to indicate a safety stop. A safety stop is required to allow nitrogen to be released from our bodies. Surfacing quickly does not allow time for our bodies to do this.
This article is not to scare you but inform you why you cannot surface too quickly – a topic that isn’t often spoken about after getting scuba certified, yet one that is super important to know, because it can be life or death.
In this article, you will learn why scuba divers cannot surface quickly and what steps you can do to make your ascent safer!
What Happens When Scuba Divers Surface Too Quickly?
As divers ascend the pressure increases and nitrogen is absorbed in their bodies tissues. Ascending quickly does not allow the nitrogen to be expelled from the body, causing serious implications for scuba divers such as decompression sickness, also known as “the bends”.
The first 12ft (4m) of a dive has the greatest pressure difference and therefore puts more strain on our bodies.
Issues Scuba Divers Face if they too Surface Quickly.
- Decompression Illness
- Nitrogen Saturation
- Reverse Squeeze & Barotrauma
- Boat Strikes
Also known as “the bends”, decompression sickness is a very serious diving injury. To understand decompression sickness, we need to touch base on some simple physics…Boyle’s Law!
Boyle’s Law & How It Relates to Scuba Diving
Boyle’s Law relates to the volume of gas compared to the pressure in the surrounding environment.
Boyle’s Law: PV = C
P = Pressure
V = Volume
c = Constant number
Now, maths isn’t everyone’s forte, so all you need to remember is that if the pressure (P) increases, the volume (V) of gas will get smaller, and vice versa!
NOTE: For Boyle’s Law to work, the temperature must remain constant (c).
So, what is all this sciency-stuff got to do with scuba diving?
When scuba divers descend, the pressure in the surrounding water environment increases which causes the volume of the air in the diver’s body and equipment to decrease, therefore compressing.
When scuba divers ascend, the pressure in the surrounding water environment decreases. Using Boyle’s Law tells us that the volume of air in the diver’s body and scuba gear will increase, occupying a much larger volume.
The above is why scuba divers perform safety stops, adjust their BCD throughout the dive, and must equalize air spaces in the body.
Ok, so now we have Boyle’s Law out the way, let’s get onto what decompression sickness is, and what divers can do to prevent it from happening.
Decompression Sickness (DCS) & Arterial Gas Embolism (AGE)
Decompression sickness is a serious scuba diving injury. It can be extremely painful, cause severe tissue loss, and even be life-threatening.
If scuba divers surface quickly, they could rupture the alveoli in the lungs causing the lungs to collapse (pneumothorax).
This allows bubbles to enter the diver’s arterial blood circulation. This is serious as the bubbles can travel throughout the bodies blood vessels, restricting or completely blocking the blood flow to vital organs such as the brain and heart.
When gas bubbles travel around the body, this is known as an arterial gas embolism (AGE). I’m not here to scare you, but if you get AGE, it is very very serious! That is why scuba divers perform slow and gradual ascends and make safety and deep stops to reduce the chances of this happening.
If you ever suspect yourself or another scuba diver having decompression sickness or AGE, immediately provide emergency oxygen and seek the nearest hyperbaric/decompression chamber for treatment.
If you are a safe and responsible scuba diver, you have probably heard of “DAN” – not your diving buddy, but the Diver’s Alert Network where most divers get their insurance.
DAN did a little experiment on nitrogen saturation of tissues in ascending scuba divers at a rate of 30ft (9m) per minute. They found that divers that didn’t perform a safety stop suffered from a fast saturation rate (60%), while scuba divers that stopped for a safety stop (3 minutes at 16ft (5m)) had a slower saturation rate of 25%.
This little experiment by DAN proves that taking 3 minutes from your dive time (to do a safety stop) significantly reduces the saturation rate of tissues and reduces the chances of decompression sickness and AGE. This applies to deep stops too.
With advances in technology, we are gifted with dive computers that do all the hard work.
All dive computers have a safety stop warning that starts ticking down when you reach 16ft (5m). If you have reached 16ft (5m) and your dive computer has not displayed the safety stop function, that is because you have either ascended very very slowly or have been at a shallow depth for long enough for nitrogen to be released.
If you have ignored your computer at deeper depths, don’t be surprised if you get more than 3 minutes on your safety stop – that is because you have reached “DECO” during the dive.
Your computer is smart, it is telling you to allow a little extra time for nitrogen to be released. Always follow your dive computer if it tells you this – it is keeping you safe!
If no one in your group has a dive computer, ascend at a rate no faster than 30ft (9m) per minute.
You may have been told to ascend at a rate no faster than the slowest bubbles from your regulator, this is not an accurate or safe way to control your ascent. So many factors can affect your bubble speed such as how fast and hard you breathe, and which way the current is travelling.
You will be stuck under the surface all day if there is a strong down-current waiting for those bubbles to reach the surface!
Reverse Squeeze & Barotrauma
Also known as a “reverse block”, a reverse squeeze can happen to scuba divers that surface quickly. As you ascend, pressure in the middle ear can cause the eardrum to rupture – which can be extremely painful, plus you will probably have to sit out the next dives!
Barotrauma occurs in the soft tissues from pressure differences between airspaces in our bodies and the ambient pressure (surrounding pressure). The pressure expands or contracts causing an injury in the airspaces.
Ear barotrauma is very common among scuba divers. Failure to equalize properly allows the pressure to build up inside the middle ear creating pressure in the eardrum. The tissues in the middle ear swell from increased pressure and cause the middle ear to bleed, often rupturing.
Ear barotrauma can also occur from forcefully equalizing causing a round window rupture with perilymph leakage, damaging the inner ear – which is extremely painful to experience.
The main sign is bubbles being expelled from the ears.
You are more prone to an ear and sinus barotrauma if you use solid earplugs, are on prolonged decongestants, had an ear or sinus injury, have a nasal deformity or polyps, and if you have chronic nasal and sinus disease.
If you ever suffer from barotrauma, always seek medical attention.
Remember the first rule in scuba diving? – Continuously breathe.
By continuously breathing, you reduce the risk of lung overexpansion or overpressure accidents.
If you shoot up to the surface then you risk getting pulmonary barotrauma as the gas trapped in the lungs increases causing gas bubbles to escape in your pleural space (causing pneumothorax), mediastinum (causing emphysema), and pulmonary vasculature (causing AGE).
Barotrauma injuries can be anything from a mild accident to a fatal one.
At dive sites where there is lots of boat traffic, surfacing quickly can lead to boat strikes. Most dive sites that are known to be busier than others, require scuba divers to deploy a DSMB/SMB to warn captains that divers will be surfacing soon.
I have unfortunately heard of some horror stories where SMB’s have not been deployed and divers have surfaced quickly, getting hit by the boat, not ending well for the diver…
5 Tips for Divers to Avoid a Quick Ascent
Every scuba diver should follow the correct protocol to ascending to prevent problems from surfacing quickly.
- Ensure you have enough air for safety and decompression stops.
- Keep a close eye on your SPG.
- Be prepared to release some air from your BCD – remember Boyle’s Law? Your BCD air pressure will increase the closer you get to the surface.
- Try not to become disorientated – focus on your dive buddy or DSMB/SMB line.
- Breathe normally and relax!
10 Tips for Divers to Perform a Safe Ascent
- Always signal first.
- Perform a safety stop.
- Perform decompression stops if you are on a decompression-stop dive.
- Use a dive computer – if you do not have one, they are probably the best piece of scuba equipment you can invest in. Some diving computers are super affordable, you check some out here!
- Ascend at a rate no faster than 30ft (9m) per minute.
- Use a DSMB/SMB, a vital diving accessory!
- Always look up and listen for boat traffic.
- Listen to instructions from your instructor or dive guide.
- Equalise your ears if needed.
- Finally, protect your head by stretching one arm out before poking your head out of the water.
Don’t Forget Your Dive Insurance!
Before you go out on any dive trip or holiday, it is essential to make sure you have insurance that covers you if something goes wrong. Check out our dive insurance article for more information.
Or go straight to these dive insurance company websites:
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Scuba divers must not surface quickly to reduce the chances of serious issues such as decompression sickness, AGE and even boat strikes. Remember to always watch your dive computer, or the most conservative one in the group if you have not got one.
If you take one thing from today’s article it should be: never to surface faster than 30ft (9m) per minute.
Make sure you always protect yourself diving with a good scuba diving insurance company like DAN so you are covered if you do surface too quickly and need medical assistance.
To find out more information on scuba diving accidents and how common they are, you can click here.
Thank you for reading, we hope to see you again soon. We hope you always make safe ascents, happy bubbles!
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