Scuba safety basics: buddy checks, equalising, safety stops and flying after diving
TUREFF• •0
Recreational diving has a good safety record when divers follow a handful of rules that are taught on every course and forgotten surprisingly quickly afterwards. These are the basics worth revisiting before every trip. They do not replace training; if anything here is unfamiliar, take a course or a refresher with an instructor.
Plan the dive and dive the plan
Before you get in, agree with your buddy on the maximum depth, the time, the route, the air or gas level at which you turn back and what you will do if you get separated. A common separation rule is to search for up to a minute, then ascend slowly and meet at the surface.
The buddy system
- Pre-dive check: inflate and deflate each other's BCD, confirm the air is fully on, check weights, releases and that both regulators breathe properly.
- Stay close: close enough to reach your buddy's alternate air source within a few seconds.
- Agree signals: run through the hand signals for "OK", "problem", "low on air" and "out of air" before the dive.
Never hold your breath
This is the first rule of scuba. Air in your lungs expands as you rise, and holding your breath while ascending, even a short distance, can injure your lungs. Breathe slowly and continuously throughout the dive.
Equalising
Pressure builds quickly in your ears and sinuses on the way down. Equalise early and often, before you feel discomfort, by gently pinching your nose and blowing or by swallowing and moving your jaw. If it will not clear, rise a little and try again. Never force it, and do not dive with a cold or congestion: blocked ears are one of the most common causes of diving injuries.
Equalise your mask, too, by breathing a little air out of your nose into it.
Ascend slowly
Rise slowly, at the rate your training and dive computer give you. A figure of around 9 to 10 metres per minute is commonly taught for recreational diving; many computers warn you if you go faster. Watch your computer rather than your bubbles.
The safety stop
At the end of most dives, recreational divers make a safety stop of three minutes at about 5 metres (15 feet). Training agencies and dive computers differ on exactly when it is required, so follow your own training and computer; many divers make one on every dive. It costs three minutes and reduces risk, so treat it as part of the dive.
Flying after diving
The reduced pressure in an aeroplane cabin can trigger decompression sickness in a diver who has recently been underwater. Guidance from a DAN workshop sets these minimum surface intervals for recreational divers:
- 12 hours after a single no-decompression dive
- 18 hours after multiple dives a day or multiple days of diving
- substantially longer after dives that required decompression stops
Many divers and dive centres simply leave 24 hours, and PADI advises waiting longer whenever possible. None of these intervals guarantees freedom from decompression sickness. Plan your last dive around your flight, not the other way round, and check your computer's no-fly time.
Signs of decompression sickness
Symptoms can appear soon after surfacing or many hours later, sometimes up to a day. Watch for:
- unusual tiredness
- joint or muscle pain
- itchy skin or a rash
- dizziness, numbness or tingling
- weakness, confusion, difficulty breathing or collapse
Do not dismiss symptoms as a pulled muscle. The first aid is oxygen at the highest concentration available, then urgent medical help: call local emergency services, then a diving emergency line such as DAN's for your region, and get the diver to a doctor experienced in diving medicine. Save the emergency numbers for where you dive before the trip.
Other habits worth keeping
- Dive within your training and experience.
- Do not dive while unwell, hungover or exhausted.
- Ask the dive guide about currents and entry and exit points.
- Look after your health: if you have a medical condition, get clearance from a doctor before diving.
What safety habit do you never skip, or what are you unsure about? Share it in the comments below.