Thailand has numerous world-class sites for divers of all standards, making it an underwater adventure paradise. While advanced divers are not restricted to normal recreational depth limits and many other constraints, they can only operate safely with professional support both onshore and offshore.

People have been paddling around Thailand’s numerous shallow coral sites with goggles and snorkels for decades, but it was not until about fifteen years ago that more serious diving with proper underwater breathing apparatus really began to take off. At that time, the majority of dive shops in the kingdom ran businesses teaching basic ‘discover scuba’ and open-water courses.

As time passed, word spread of Thailand’s superb dive sites, and dive shops became increasingly competitive in the support they were able to offer advanced divers. This included offering specialized mixed breathing gases, larger volume diving tanks, double tanks, auxiliary tanks and underwater scooters. As these resources have become more readily available, seasoned divers have been able to open the door on a whole new world of exploration. An intrepid breed, they are often referred to as ‘technical divers.’

Respiration is the over-riding concern in diving. The human body is profoundly affected by the compressed gases breathed underwater. Air normally contains about one-fifth oxygen to four-fifths nitrogen — gases which when breathed at surface level are perfectly normal. But once a diver passes beyond normal recreational dive limits, they become potential killers.

A diver who descends to 100 metres may be breathing in compressed form ten times as much nitrogen and oxygen as normal. Too much nitrogen at depth can cause narcosis — with similar results to drinking alcohol in excess. If a diver comes up too fast, there is the risk of decompression sickness — popularly known as “the bends” — which occurs when the body is not given enough time for the gas to dissipate. This can be extremely painful and result in paralysis or even death.

Oxygen, which is essential for sustaining life, meanwhile becomes toxic beyond 60 metres and this can induce convulsions — and drowning if the regulator used for breathing through the mouth falls out.

Mixed gases are essential to extending the depth and duration of dives. Ordinary recreational divers breathe compressed air, and do not have to stop to allow for decompression on the way up. Technical divers use nitrox and tri-mix gases instead. Nitrox has extra oxygen added to the air during compression, and reduced nitrogen, which helps extend dive times and mitigate the risk of decompression sickness.

Tri-mix incorporates helium into the mix, an inert gas that reduces the risk of both nitrogen narcosis and oxygen toxicity. For deep dives of more than 60 metres, technical divers use tri-mix to go down, and nitrox for decompression when they come back up.

Two of the most popular new activities in Thailand are wreck diving, mostly in the Gulf of Thailand, and cave diving, mostly along the Andaman Sea coastline. The Gulf of Thailand falls well short of being an Asian Bermuda Triangle, but is rich in sunken wrecks resulting from misadventures in trading, piracy and war. Many stories have been lost in the mists of time but, according to one list, there are at least 179 sunken Japanese ships — or marus, as some divers prefer to call them.

Some of the biggest recent discoveries date from the Second World War. In mid-2005, a group of technical divers from Koh Tao came across a US submarine that had been sunk in 72 metres of water by the IJN Hatsutaka, a Japanese minelayer that recorded an anti-submarine action with depth charges at the time.


Bruce Konefe works for American Nitrox Divers International (ANDI), and has lived in Thailand for more than 14 years. He is an instructor trainer who now teaches at only the highest levels of technical diving, and has helped design both cave diving courses and hyperbaric chamber medical courses for the agency. His career has taken him around the world, including to Australia, Canada, Dubai and the United States. He has trained military divers in both the Thailand and the Philippines, and was on the team which first dived on the IJN Yamashiro, a 39,000-ton Japanese battleship sunk on 25 October 1944 in the Second World War battle of Surigao Strait.

Images © Bruce Konefe

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