Diving Down Under: Australia’s Coral Sea

David Prichard

There aren’t too many places in the world where one can almost travel back in time and experience an abundance of endemic life both above and below the water’s surface like when visiting Australia’s northeastern coastal region of Queensland. Bordering the Great Barrier Reef and the Coral Sea, the area is a haven for divers and naturalists.

A quirk of nature kept Australia — the only country that is also a continent — isolated from the rest of the world to develop many creatures and plants not found anywhere else on Earth.

After stepping from a rain forest land of predinosaur life, visitors can explore the Great Barrier Reef — the world’s largest living organism — and then the fascinating underwater realm of the Coral Sea.

A Captive History

While the continent has been inhabited by the aboriginal people for possibly 65,000 years, explorers from other countries didn’t discover this southern landmass until nearly the 17th century when the Dutch and Portuguese made brief stops along the western and northern coastlines. Unimpressed with what they found, the Dutch named the land New Holland and went off to settle more profitable lands farther north.

A few English explorers made note of the land, too, but it wasn’t until Capt. James Cook’s 1770 voyage of discovery that the more inviting eastern coast was discovered. Cook’s survey of the new region aboard the Endeavour turned up many new species of plants and animals during his land excursions, including one six-week stint forced upon him and his group when they discovered that the Great Barrier Reef can put a hole in the hull of a ship.

After the American Revolutionary War, Great Britain found itself without a convenient place to dump unwanted prisoners, so Cook’s report of this new land seemed to offer a good solution to England’s overcrowded jail problem. In 1788, a fleet of 11 ships with about 1,100 people (of which more than 700 were convicts) arrived in what is now Sydney Harbor to start a new settlement. The penal colony eventually grew as additional fleets arrived with more “captive settlers” and new cities began appearing from the expansion.

A gold rush that started in 1851 and lasted several decades helped expand the country’s exploration, immigration and settlement. Further immigration swings occurred after both world wars with about 96 percent of the estimated current population of 19.2 million being of European decent, mainly British and Irish. About 20 percent of today’s Australians were born in other countries.

The aboriginal population has dwindled over the past two centuries and now accounts for less than 1 percent of Australia’s total population with many living in tribal communities in remote areas.

While Australia is the sixth-largest country (about the same size as the continental United States) it has a sparse population (6 people per square mile [2 per sq km]). Nearly 80 percent of Australia’s population lives along the southeastern coast with Sydney and Melbourne each containing more than 3 million residents. In fact, about two-thirds of all Australians live in cities with populations of more than 100,000.

The Commonwealth of Australia, the country’s official title, is divided into six states and two territories. Good early planning placed the capitals of each of the states and territories along the coastline near protected harbors and major rivers. Only the country’s capital, Canberra, is inland, but even it is only 80 miles away from the coast.

Like Canada, Australia is a constitutional monarchy with Queen Elizabeth II of England serving as the ceremonial head of state, but with little to no power. Instead, the country is ruled by a parliamentary system of government with a prime minister acting as the head of the ruling coalition or political party.

Like No Other Place on Earth

When Australia separated from the southern supercontinent of Gondwanaland (which also included Antarctica, South America, Africa, India and New Zealand) more than 50 million years ago, its lack of destructive forces allowed its rain forest inhabitants to evolve in isolation to their current form. Angiosperms, the most primitive of flowering plants, can only be found here in the oldest rain forest on Earth (the Amazon is just a tyke compared with this one). The King Fern, with fronds up to 20 feet (6 m), is basically the same plant as it was 325 million years ago.

Queensland’s rain forest, filled with 60 percent of the continent’s butterfly species and such marsupials as the cuscus, sugar gliders and tree kangaroos, is part of the United Nations’ World Heritage Area, along with the Great Barrier Reef. Surprisingly, one of the most feared land animals in this region is the cassowary, a large flightless bird related to the emu. This bird’s aggressive nature, coupled with sharp talons on powerful legs, can make it a dangerous encounter in the bush.

Yet, nothing strikes fear into the locals more than having a “saltie” surprise them along the side of a river. Another relic from ages past, the saltwater crocodile can grow to 20 feet (6 m) in length and humans are not excluded from its diet. They prefer the brackish waters of tidal rivers, but can go far inland and out into the ocean. The crocs prefer to lie in wait underwater and then propel themselves at missile speed with their powerful tails to snatch unsuspecting prey along the river edge.

Another hazard that swimmers face at certain times of the year is the box jellyfish, or “stingers.” At times from October to March (usually the wet summer season) many beaches are closed as these jellyfish with tentacles as long as 9 feet (3 m) inhabit the coastline and can deliver fatal injuries.

The Greatest Reef

About 500,000 years ago, coral polyps began congregating off Queensland’s coast in great quantities. Now billions of these tiny organisms have formed the world’s largest chain of reefs (more than 2,500) and islands that extend about 1,250 miles (2,000 km). The Great Barrier Reef is as close as 10 miles (16 km) from Queensland’s coast in some areas and as far out as 100 miles (160 km). Divers can explore this chain’s 400-plus species of coral and 1,500 fish species in tropical waters that range from the mid-70s Fahrenheit (23-25 degrees Celsius) in the winter to lower 80s F (27-28 C) in the summer.

Beyond this barrier reef system and the normal range of day boats lies the Coral Sea, our destination for a week’s worth of live-aboard diving on the Mike Ball Expedition’s Spoilsport live-aboard that departed from Townsville. Other boats that offer Coral Sea trips from Queensland include the MV Nimrod Explorer and Spirit of Freedom. The Coral Sea is part of the South Pacific Ocean, but is an area that contains an unusually large number of coral atolls, submerged seamounts and bank reefs.

One of the first stops on the way to the Coral Sea is the shipwreck of the SS Yongala, which is within the Great Barrier Reef system but beyond the range of most day boats (48 miles from Townsville). This 394-foot (120-m) steel passenger and freight steamer sank without a trace in March 1911 during a storm. All 122 passengers and crew perished and the wreck remained undiscovered until 1958.

Since its sinking, the Yongala has become a haven for marine life with the ship resting at a starboard list in a depth of 100 feet (30 m) on a sandy bottom while the upper structure sits at 52 feet (16 m). Hard and soft corals cover the ship’s surface for a colorful landscape with schools of trevally, kingfish, grunts, silversides, barracuda and batfish making their rounds over and under the site. Sharks lurk around the wreck while hawksbill and loggerhead turtles graze off the abundant food supply. Curious olive sea snakes wind through the ship’s outcroppings while lionfish stay tucked away in recesses of the wreck. Numerous cleaning stations attract a wide variety of customers, including huge stingrays that are not shy around divers.

The Flinders Reef complex of the Coral Sea includes walls, seamounts and lively reefs ranging from depths more than 100 feet (30 m) to relatively moderate depths of 50 feet (15 m). Swim-through canyons can be explored at sites called Anemone City, Berlin Wall, Trigger Happy and Cod Wall. Currents are generally light in most areas and the 75-F (24-C) water temperature during the early spring season (end of August) invites the use of light hoods and gloves while diving. A 3-mm or 5-mm wet suit is recommended. Coral polyps spawn around October or November.

Since most of the diving in the Coral Sea is based from a boat at anchor, divers normally exit the stern and follow a descent line to the dive site. Occasionally, some sites require the crew to use inflatable boats to ferry divers back and forth and eliminate long surface swims. Nitrox and E-6 processing are generally available.

Purplish football anemones are common throughout the Flinders Reef complex, with their clownfish partners either hiding in their tentacles or boldly attempting to drive divers away. At depth, gorgonian sea fans grow to great size, some as wide as 15 feet (4.5 m).

One of the highlights of the Spoilsport trip was a visit to the boat’s private Scuba Zoo. The only creatures that you concentrate on at this site are the 30 or more sharks that come to put on a show. Four large shark cages in a V-shape permanently sit 50 feet (15 m) down on a sandy bottom at this site where divers are invited to kneel on top of the cages for an unexposed view of the pregame show. Between the cages is a large, secured barrel filled with fish pieces that are hooked to a chain with an attached float.

With cameras snapping away, sharks begin circling the barrel for nearly 20 minutes as they wait for the contents to be released. Save some film for the main show because the crew will usher you into the cages while a divemaster manipulates a series of ropes that releases the barrel’s lid. Up goes the float and in come the sharks into a massive feeding frenzy. It lasts only a minute or so before the sharks quickly disappear and divers can pour out of the cages in search of shark’s teeth on the sandy bottom.

In addition to live-aboard diving there are many dive operators that run day boats to the reef from Cairns, Townsville and Port Douglas.

Australia Walkabout

Accommodations in Queensland range from simple bed-and-breakfast homes to elaborate coastal resorts. Camping is also quite popular.

A broad range of international restaurant fare can be found across the country, albeit with an Aussie flair. A well-decked out hamburger usually includes a beet slice and probably a fried egg. Ice-cold beer is a popular beverage, usually sold in “slabs” (cases) of 24 “tinnies” (cans). Native wines are gaining in popularity both locally and internationally.

In many restaurants, you grab a table and then go up to one counter to order your food and over to the bar to order your drink. The food will come out to your table while you’re enjoying your drink. Perhaps this is why tipping isn’t customary in Australia except at upscale restaurants, where 10 percent is acceptable.

Cairns is a central location for many activities. Trips to the rain forest jungles of the Daintree and Cape Tribulation national parks generally include an hour-long boat ride up the Daintree River to spot some “salties” and other exotic creatures. Another popular tour includes a scenic train ride up into the Atherton Tablelands to the tourist village of Kuranda. After shopping and lunch there, you hop on a Skyrail gondola and ride the cableway nearly five miles over the rain forest canopy back to the suburbs of Cairns. Next to the cable station is the Tjapukai aboriginal cultural park where you can get a lesson on native culture, arts and even instruction on how to throw boomerangs, spears or make music on the didgeridoo.

Rental cars are available for those who wish to strike out on their own. Driving is on the left side of the road. The interiors of automobiles are reversed to accommodate this so many of the controls are on the opposite side of the wheel. (This explains why the windshield wiper comes on when you think you’re activating your turn signal.)

White-water rafting, kayaking and canoeing are also big outdoor adventures to be experienced, along with sailing along the coast. Spectator sports include Australian-rules football (which from what we observed means no rules at all), rugby, cricket and soccer. You can take a short flight or long drive down to Brisbane and stay out on Fraser Island, the world’s largest sand island. Nearby Hervey Bay usually has about 3,000 humpback whales visit each year during their migrations. September is peak whale-watching time. A little way up the coast is the Mon Repos Turtle Rookery with a variety of turtles nesting there from early November through the end of March. Turtles come ashore to lay eggs around midnight when the tide is high. From mid-January to March, the young hatch and scamper to the water.

If you do plan a visit to Australia’s tropical vacation state, then allow plenty of time to experience the world’s oldest continually surviving rain forest as well as the diverse underwater ecosystems of the Great Barrier Reef and the Coral Sea. In either setting, you can kick back and enjoy the land of, “No worries, mate!”

This article was orignally published in “Dive Training Magazine“.

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The Maldives: Jewels of The Indian Ocean

This describes the Republic of Maldives, a haven for divers half a world away, with more than a thousand coral reefs and white-sand beaches on hundreds of uninhabited islands. The clear tropical waters and abundance of marine life around the atolls of the Maldives make an attractive setting for those who want to get away from it all on a dive holiday.

Earth-moving Origins

Many millions of years ago most of the Earth’s landmass was composed of the “supercontinent” of Pangaea, which during the Jurassic period broke into two large landmasses, Laurasia and Gondwanaland. To the north, Laurasia contained North America, Europe and Asia. To the south, Gondwanaland included South America, Antarctica, Australia, India and Africa.

These two chunks of land began breaking up even further about 130 million years ago during the Cretaceous period into the smaller portions that comprise our existing continents. The “continental drift” theory (plate tectonics) suggests that portions of the Earth’s crust (continental plates) float on top of a liquid core and are ever so slowly in motion.
The Maldives were created from a geological “traffic accident” between India and Africa.
India floated up and banged into Asia, resulting in their current alignment. Africa’s plate followed too closely and didn’t stop in time after the India/Asia pileup. This ramming of submerged plates caused a major “fender bender” that resulted in the formation of a long mountain range of volcanoes (1,250 miles [2,000 km]) rising out of the Indian Ocean. It is called the Laccadives-Chagos Ridge.

After a long period, the cones of volcanoes collapsed back into themselves, leaving a ring of small islands, each called an “atoll.” This is the only English language word that has been derived from the Maldivian language of “Dhivehi” from the word “atholhu.”
The Maldives is made up of 26 of these atolls, stretching 550 miles (880 km) north and south of the equator. These atolls contain 1,196 small, flat islands with no isle covering more than five square miles (13 sq km) or averaging a height greater than six feet (1.8 m) above sea level.

A Wealth of Cowries

It is unclear as to the origins of the first settlers of the Maldives. Legend states a mysterious group of explorers called the “Redin” were the first to visit the islands, but the first immigrants appear to have been of Hindu and Buddhist heritages from southern India, 275 miles (440 km) to the north, and from Sri Lanka, 440 miles (704 km) to the northeast. Ruins of Buddhist buildings from the second or third century B.C. have been found on the islands, including a stone head of Buddha on Thoddoo Island.

Local folklore says a Sinhalese prince, named KoiMale, became the first sultan of the islands after being shipwrecked there with his wife, the daughter of the king of Sri Lanka. Archaeologist Thor Heyerdahl noted that some figures discovered in the Maldives resemble items unearthed on Easter Island in the Pacific Ocean.

The Maldives later became an important stopover for sailors along the trade route from Rome to China. The Greek astronomer Ptolemy noted the existence of “1,378 little islands west of Taproban (Sri Lanka). Records from the Ming dynasty of China tell about the submerged mountain chain called Liu Shan and noted the customs of the people who lived there. The ninth century Persian merchant/explorer Suliman wrote, “in the Sea of Herkend there lies 1,900 islands and the ruler is a woman and their wealth consists of cowries.”
Cowry shells (cyprea moneta) were an important form of currency in many areas of the Middle East and in regions of India. The Maldives was the “mint” of the region where most of the “money” shells were gathered. The islands were also famous for producing the Maldive Fish. A delicacy in India, this dried and smoked tuna was an important source of food for long sea voyages because the ebony-colored filet remained edible for a long time.
Arab Muslim traders began calling on the Maldives in the eighth century and proved to have the most influence on its people. By 1153, Islam was adopted in the islands and it was ruled by sultans for about 800 years until 1968 when it became a republic.

The Portuguese military captured the Maldives in 1558 and ruled it for 15 years. A mixture of early guerilla tactics by the islanders and logistical supply problems by the occupational force helped the Maldivians overthrow the Portuguese in 1573. The islands later became a protectorate of the Dutch when they ruled Sri Lanka (Ceylon). The British then took over the region from the Dutch and the Maldives became a British protectorate from 1796 to 1965. The Maldivian Independence Day is July 26.

The people of the Maldives are a mix of ethnic backgrounds but mainly all Sunni Muslims. Many come from Indian and Sri Lankan heritage, but there are many also descended from Arab traders and black slaves imported from Africa. The main language is Dhivehi, which is a dialect of Sinhala but with a script resembling Arabic. English is widely spoken along with Arabic and Hindi.

Unlike other Muslim countries, women play a prominent function in the Maldivian society with many in civic and business leadership roles. Women often retain their maiden names and can obtain and keep personal property and business holdings when married. This freedom of women in an Islamic state has been a tradition throughout Maldivian history.
Only a little more than 200 of the islands are populated with villages. Nearly a third of the nation’s population lives on Male, an island that measures only 1 mile by 1.5 miles (1.6 km by 2.4 km) in size. Yet already more than 80 islands are home to resorts, which bring in about 300,000 tourists a year — roughly equal to the entire population of the Maldives. Tourism is vital to the economy of the Maldives.

Rings of Coral

All of the islands of the Maldives are circled by protective coral reefs that defend the white sandy shores against wave erosion. Its reef system is the largest in the Indian Ocean with an area exceeding 2,174 square miles (5,652 sq km).
Because of its proximity to the equator, water around the Maldives generally stays between a comfortable 80 and 85 degrees Fahrenheit (27 and 30 degrees Celsius). A light wet suit is recommended. In these tropical waters you can find about 187 types of coral and nearly 1,100 species of marine life. Underwater visibility ranges from 60 to 100 feet (18 to 33 m).

Plankton blooming begins in May at the start of the rainy season, which lasts through August. This reduces visibility, especially on the eastern sides of the atolls, but the trade-off is worth it — whale sharks and manta rays can be found here in large numbers, attracted by the plankton.

We toured the northern atolls on the Manthiri live-aboard after the rainy season and saw several remaining manta rays, but missed the whale sharks. Other dive boats offering excursions through the atolls include the MV Nasruali and the Isis motor cruiser. Many resorts have dive centers that offer land-based dive trips.

Sloping reefs and walls are adorned with colorful soft corals. Every nook and cranny hosts inhabitants such as lobsters, transparent “ghost” cleaner shrimp, or brightly marked moray eels. Anemonefish dart in and out of large anemones, immune to their stinging tentacles. Fish life abounds here, including majestic Moorish idols, stately emperor butterflyfish, and a variety of parrots, triggers and trumpets.

Even seemingly barren sand flats will reveal small creatures such as nudibranchs, mantis shrimp and our favorite, the ghost pipefish, an elongated cousin of the sea horse.
The “big stuff” — including a variety of sharks and rays, moves in the swift currents atop seamounts and in channels carved between the islands. Here, thousands of schooling fusiliers, silversides or jacks may pass in front of you on a single dive.
There are a few shipwrecks to explore throughout the atolls. We investigated a large Japanese fishing trawler, called the Varu, which had sunk off the coast of the capital island of Male. This unusual wreck was sitting nearly vertical, with its stern resting at about 100 feet (30 m) and its bow sticking about 33 feet (10 m) above the water’s surface. A nice array of soft corals grew on the belly of the ship, while schools of fish darted in and out of its many openings.

Getting Around the Dhoni Way

A nation of islands means that the general mode of transportation is by boat and the Maldives has its own style of sailing vessel — the “dhoni.” Skilled carpenters using few tools and no plans make traditional versions of these hand-crafted ships of coconut palm wood. The skills of shipbuilding are passed from one generation to the next. Tall, curved bows, like scimitars raised in the air, decorate the front of the boat while the ornate hand-held rudder distinguishes the stern.

Dhonis range in size from large cargo ships, called “buggalows,” which export fish and import most of the Maldives’ staple food items and general goods, to small water taxis. The Male International Airport is on its own island so tourists need to be transported to the island of Male by a dhoni taxi. Visitors to remote resorts are often transported by seaplane or helicopter.

The Manthiri is actually a two-boat operation. The large live-aboard houses the guest and crew, but divers transfer to a dhoni that takes them to the actual dive sites.
The main use for a dhoni on the islands is as a fishing vessel since the majority of Maldivians are employed as fishermen.

Island Touring

The Maldives are home to many posh tropical resorts that mostly cater to Europeans. Some have international telephone and Internet service, as well as satellite television service for those that don’t want to be too far out of contact with the world.
On a typical Maldivian island, a “Katheeb” or island chief is in charge of the day-to-day affairs of the island. This chief then reports to the “atholhuverin” or atoll chief who acts as the governor of that atoll’s islands. The nation’s government appoints both chiefs. The republic is composed of a 50-member Citizens Council that has two representatives from each populated atoll, two from Male and eight appointed by the president. The president is nominated by the council and is elected by a popular vote to a five-year term.

Tourists arriving by boat need to first get permission from the Katheeb to look around the village. Often visitors are welcomed to be guests that evening of the “boduberu,” a traditional community gathering of music and dance with African influences.
Dress in the Maldives is casual with T-shirts and cotton clothing the most suitable for the climate. Since the country is an Islamic state, women should wear modest clothing without baring too much skin.

An Eye on the Climate

Even though the Maldives are situated away from typhoon or cyclone areas the threat of the entire landmass of the nation disappearing below the waves is increasing. Most of the islands are only 5-6 feet (1.5-1.8 m) above sea level with 80 percent being only about 3 feet (1 m). The highest point is on Wilingili Island in the Addu Atoll with a height of only 8 feet (2.4 m).

The threat of global warming raising sea levels would be catastrophic for the islands and force its residents to become refugees. Coral mining (for building materials and souvenirs), sand dredging and solid waste pollution have also taken a toll on the islands’ ability to defend itself from the elements. In April 1987, high tides swept over Male and nearby islands after much of the natural reef was removed.
Already the increase in surface temperatures from El Niño has resulted in large-scale coral bleaching in shallow areas that used to be vibrant and healthy. The government has now taken a keen interest in monitoring climate changes.
The world will keep changing, but for now the Maldives offers a diverse underwater world for divers to explore and many island retreats where you can truly get away from it all and enjoy a bit of paradise.

This article was originally published in “Dive Training Magazine“.

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Cavern Diving: A Beginner’s Guide

David Prichard and Cathryn Castle

Photos By Lily Mak

You’re gliding into a vast underwater cavern. In the crystal-clear water all around you majestic stalactites hang down from the cavern ceiling like icicles. Cone-shaped stalagmites rise up to meet them. Gnarled tree roots snake through the cavern’s roof to get a drink of water. But wait…you must be dreaming, because you’re only an Open Water-certified diver. You can’t possibly be exploring the inner sanctum of an underwater cavern, because this type of diving is suited for only those expert divers who’ve had a lot of advanced training, right?

Well, yes. And no.

While cavern exploration shouldn’t be attempted without proper training, there are places where divers can enjoy the cavern diving experience without specialized training. In some areas cavern interiors have been made safe for novice divers. In other areas, professionally trained guides lead divers through caverns on introductory tours. These advances have opened the world of cavern diving to divers of various experience levels. Many who complete the cavern diving experience go on to acquire the training necessary to become full-fledged cavern explorers.

Caverns and Caves Defined

What’s the difference between cavern diving and diving in a lake, quarry or ocean? Caverns and caves, like shipwrecks, are called overhead environments, because a physical barrier exists between the diver and the surface. This barrier prevents a diver’s direct ascent to the surface and is one of the main reasons why cavern divers must receive training beyond that which is offered in Open Water class.

What’s the difference between a cavern and a cave? The National Speleological Society’s Cave Diving Section (NSS-CDS) defines a cavern as the opening area of a cave that receives direct sunlight, goes no deeper than 70 feet (21 m) and is within 130 linear feet (39 m) of the cave entrance. Basically, if you don’t see natural light, you’re in a cave. And since a cavern is defined by natural light — sunlight, caverns do not exist at night. Cavern diving is strictly a daytime endeavor.

There are four different types of caves: littoral (sea), coral, solution and lava tubes.

Sea caves are usually formed by wave action and are not extensive. They are generally chamberlike in shape and can be found in coastal areas, including the Great Lakes, New England, the Sea of Cortez and California.

Coral caves are formed when corals grow together to form arches that create tunnels and passageways. They’re often draped with colorful marine life and may provide a home to fishes like copper sweepers or a sleeping nurse shark.

Lava tubes are formed by volcanic action; as lava flows from a volcano into the sea, the surface of the flow cools and hardens while the molten inner core keeps flowing, eventually creating a hollow tube. Lava tubes are most common in Hawaii and the Northwest Pacific coast.

Solution caves are formed over eons of time by water containing carbonic acid percolating through limestone and dissolving the rock. As the rock dissolves, the cave is formed. Solution caves are a source of fascination for geologists and cavern/cave explorers alike. Divable caverns can be found in Florida, Missouri, Texas, the Yucatan Peninsula and throughout the entire Caribbean region.

The Cavern Diving Experience

Just like any type of dive site, cavern diving amenities and conditions will vary from one location to another. Many areas feature on-site dive centers that offer everything from air fills and equipment to guided tours and complete certification courses.

Divers who visit Florida’s springs enter the water at sites where Spanish moss hangs from magnificent cypress trees. The water is cool and crystal-clear, and suspended platforms are often in place to keep divers from kicking up silt from the bottom. At the mouth of the cavern, an out-flowing current can usually be felt, as the underground river forces its way through the small opening. A large, permanent guide line anchored to the cavern floor marks the exit. Catfish and freshwater eels scurry to escape the glare of divers’ lights. Farther inside, where daylight ends and the cavern walls grow narrower, a sign indicates the transition into a “cave divers only” area — a labyrinth of tunnels that should be entered only by those with full cave certification and proper equipment.

Another popular destination for recreational divers to experience cavern settings is along Mexico’s Yucatan Peninsula in an area known as the Riviera Maya, which extends from Playa del Carmen south to Tulum. Cenotes (see-NO-tays), natural sinkholes, are the entrances into numerous underground solution cave systems.

After a ride through the steamy jungle, divers reach the cenote, which at first glance doesn’t look too appealing — a hole in the ground with a set of stairs that leads to the water below. Trained guides escort divers on a tour that is part geological wonder, part mythical adventure. Besides the numerous sunny openings to the cenote, small holes in the jungle floor/cenote roof allow shards of light to penetrate the water like laser beams. Divers weave in and out of gigantic columns formed by the mating of stalactite and stalagmite. Smaller stalactites the size of soda straws cover the ceilings.

The number of divers visiting the cenotes has been doubling each year, according to Scott Carnahan, who operates a dive center in Playa del Carmen. “It’s the biggest growth area in diving that I have seen in the past 10 years,” he says. He estimates that about 90 percent of the Riviera Maya’s diving customers were first-time cenote divers who participated in cavern tours with professional guides.

Novice divers who engage in recreational cavern diving, whether on their own at specially prepared sites or on guided tours, should not confuse “sport” cavern diving with technical cavern and cave exploration.

The Cavern Diver Course

Many divers who enter a cavern on a guided tour exit mesmerized, eager to learn more about the cavern environment and how to safely explore it on their own. Enrolling in a Cavern Diving specialty course is the next step. Several scuba training agencies offer cavern diving courses. Most agencies have developed programs based on the course standards of the National Speleological Society, founded in 1941. The NSS Cave Diving Section developed the first cave diver training program in the 1950s. Another leading cavern and cave diving organization, the National Association for Cave Diving, was founded in 1968 with the goal of providing safe cave diving through training and education.

Prerequisites for cavern specialty courses vary depending on the training agency, but most include a minimum age of 18, Open Water or Advanced Open Water scuba certification and at least 20 logged dives.

Most cavern diving courses can be conducted in a weekend and usually consist of at least six to eight hours of academic lessons and field exercises, and three or four dives over a two-day period.

When you enroll in a cavern diving course, in addition to learning the basics of cavern geology, you’ll be taught the proper planning, procedures and techniques for — and hazards of — diving in overhead environments within the limits of light penetration.

Equipping for Cavern Diving

Standard scuba gear is reconfigured to reduce the risk of entanglement or stirring up silt that will reduce visibility. Dangling gauge consoles, inflator hoses and octopus regulators are shored up. Snorkels are removed since they prove useless in an overhead environment and present an entanglement risk. Flapping fin straps are taped down and accessory gear is stowed or secured with loops of surgical tubing or other fasteners.

One of the most important equipment items used by cavern divers is the reel, which is used to lay down a guide line from the cavern entrance. The guide line marks the entry/exit point and may be the diver’s only means of finding the way out if visibility becomes reduced. Divers who enter caverns without a guide line risk becoming lost and drowning.

Even though cavern divers are taught to remain within the area of natural light, each diver is equipped with one primary dive light and at least one backup light.

Because water temperatures in most caverns average in the mid-60s to mid-70s Fahrenheit (low-30s to low-40s Celsius) a wet suit is recommended, even in tropical locations like Florida and Mexico. Gloves are not recommended, as they may reduce a diver’s sense of touch, which is important when using a guide line in limited visibility.

Additional cavern diving accessories include a knife or line-cutting device and an underwater slate.

Skills and Drills

Participants start out performing a series of land drills that teach basic reel and guide line use. Training then moves to a shallow open-water site, with more emphasis on laying and following a guide line, and a host of other skills, including emergency procedures such as out-of-air situations and responding to a silt-out. Problem solving and confidence building are emphasized.

Communications skills are sharpened. In addition to hand and light signals, and message writing on slates, cavern divers learn “touch” signals that allow them to communicate in zero-visibility conditions.

Buoyancy control and underwater propulsion skills are introduced, with variations from the way these skills are usually presented in Open Water class. Cavern divers are taught to position their weights slightly forward of the waist area for better horizontal trim. Neutral buoyancy is practiced to perfection. Long, fluid fin kicks with almost no bend at the knee give way to the bent-kneed “cave diver’s kick” that helps minimize silting when moving through caverns.

Cavern divers don’t operate merely as buddies, but as teammates. Participants in a cavern diving course learn to operate as a unit and be able to assist each other in an emergency. When entering a cavern, the leader lays down a guide line and others follow; each maintains contact with the guide line by making an “OK” sign loop around it with a thumb and forefinger.

Air supply management is another important skill, because a direct ascent to the surface isn’t possible in the event of an out-of-air emergency. This is where the “rule of thirds” comes in. A diver uses one third of his or her air supply to enter a cavern, and one third to exit. One third remains in reserve in an emergency.

Team members are taught to routinely monitor and communicate their air supplies. The first diver in a team to reach one third of his air supply signals that it’s time to turn around and begin exiting the cavern.

All training dives are conducted under the supervision of a qualified cavern diving instructor.

Accident Analysis

Cavern diving is not without risk, and has claimed the lives of many divers over the years. Accidents involving fatalities are carefully analyzed to determine the direct and indirect causes. Virtually every cavern and/or cave fatality has been linked to one or more of the following factors:

  • Failure to run a continuous guide line to open water.
  • Failure to adhere to the “rule of thirds.”
  • Lack of proper training or exceeding the limits of training.
  • Inadequate number of lights.

Despite its inherent risks, cavern diving is clearly gaining in popularity in both the recreational and technical diving communities. It’s also clear that the risks can be mitigated with proper training and equipment. Even if you don’t plan to become a frequent cavern or cave explorer, the skills and drills taught in a cavern diving specialty course can help you become a better diver.

Cavern Diving

For more information on cavern diving, contact one of the following agencies:

  • International Association of Nitrox and Technical Divers (IANTD),, (305) 751-4873
  • National Association of Cave Diving (NACD),, (888) 565-6223
  • National Association of Underwater Instructors (NAUI),, (800) 553-6284
  • National Speleological Society’s Cave Diving Section (NSS-CDS),, (570) 223-1732
  • Professional Association of Diving Instructors (PADI),, (800) 729-7234
  • Scuba Schools International (SSI),, (800) 892-2702
  • Technical Diving International (TDI),, (207) 729-4201

Recommended Reading

“The Cenotes of the Riviera Maya” by Steve Gerrard

“NSS Cavern Diving Manual” by Zumrick, Prosser & Grey

“Cave Diving Communications” by Joe Prosser & H.V. Grey

“The Cave Divers” by Robert Burgess

This article was originally published in “Dive Training Magazine“.

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