Safety Culture - diving in the zone
“Thank [beep] for that! How lucky were we? We better not do that again.
Don’t tell anyone though, we don’t want to look like amateurs...”
Technical Diving & Training
Checking your air a few times during a dive and coming up as the gauge nears zero is not dive planning. Before you hit the water this summer, brush up on the basics of gas management — this will help keep you safe and might even extend your bottom time.
Sources of contamination include hydrocarbons from compressor lubricants, carbon monoxide (CO) from engine exhaust (or overheated compressor oil) and impurities from the surrounding environment such as methane and carbon dioxide (CO2). Dust particles in breathing gas can also be hazardous, potentially impairing respiratory function or damaging diving equipment. Excessive moisture can cause corrosion in scuba cylinders and other dive gear and may cause regulators to freeze due to adiabatic cooling (heat loss following increased gas volume).
Following training guidelines and conservatively planning our dives can reduce our risk somewhat, but learning how oxygen toxicity affects us and how we can prevent it can mean the difference between a fun dive and one that ends in injury. Push back against complacency and unquestioning acceptance of common practices—understand the effect of oxygen on your body before you plan your next dive.
IPE is the abnormal leakage of fluid from the bloodstream into the alveoli, the microscopic air sacs in the lungs. Symptoms include shortness of breath, coughing up bloody sputum, and respiratory distress. Leakage into the alveoli results in fluid buildup in the lungs, and interrupts gas exchange, similar to drowning. It is important to note that fluid resulting from IPE comes from within the body, rather than from inhalation of surrounding water.
However you define your expedition it is important to recognize that once you begin planning it you have crossed out of the realm of normal recreational or technical and entered a world that requires serious oversight, preparation, and risk mitigation. Expedition diving does not have to be technical or extreme – a recreational diving trip to a destination like Truk Lagoon could put you hours or days away from the nearest medical help and require expedition level preparations for medical treatment and evacuation.
Hold the regulator second stage loosely in your mouth, allowing excess air to escape. If possible, angle your head slightly to avoid bubbles in front of your eyes.
Oxygen sensors, or "cells," which are used in rebreathers have a limited shelf life and need to be replaced every 12 to 18 months. However, new ones are currently not available to the dive community.
In the United Kingdom, oxygen cell manufacturers have been mandated by the UK government to supply cells to the medical industry, leaving the dive community with back orders.
I started cave diving in Italy in 1990. At that time, the rules were very clear, codified and related to the kind of caves that were encountered in my region. Very often, they were resurgences with current (sometimes strong) or sumps inside caves, with water ranging from crystal clear to the color of coffee and variable visibility, depending on the rains.
In September 2014, Egyptian national and technical diver Ahmed Gabr performed a deep dive off Dahab in the Egyptian Red Sea under the auspices and observation of adjudicators from The Guinness Book of Records. After the dive, Gabr was acknowledged for having reached the record depth of 332m, surpassing South African Nuno Gomes who made it to 318m in 2005, also off Dahab.
The beginnings of cave diving can be traced to the Wookey Hole Caves in England. And 85 years later, divers like Matt Jevon are still doing their part to discover this cavern’s full potential.