Seasoned travelers realize quickly that the more travel they enjoy, the more places that they have left to see. It is the same Sisyphean task that befalls the lover and student of literature, and perhaps many other disciplines, interests and obsessions.

I have done respectably as a traveler, but until recently three-fourths of the planet was not on my agenda and was essentially lost to me: The deep blue, the sea, that which is under the waves. There is approximately 225,000 square miles of the briny, and plenty of it can and should be seen close to shore. And perhaps the more people that know of what is to be seen under the sea’s surface, the more of us there will be who will care for it. Much is spoken of global warming and the rise of sea levels, but less known is that the greater part of all carbon dioxide produced—and almost all of it is produced on land—ends up in the oceans.

Scuba-diving is a fantastic way of seeing this new world. It is not a cheap hobby, but one that I saw gave great satisfaction to a wide cross-section of people. I learned this on the Cayman Islands (www.caymanislands.ky) island of Grand Cayman, where my fellow divers spanned all ages, sizes and athletic abilities. It is an inclusive sport, but it also is one that requires maturity and in-depth instruction. I was told that asthma was the only condition that would have the dive instructors asking you to sign multiple waivers.

Grand Cayman is a perfect place to learn for two main reasons: The water is as warm as a baby’s bath, and it is also very clear. I signed on with the Professional Association of Dive Instructors (PADI), which has its American headquarters in Rancho Santa Margarita, Calif., and oversees some 5,300 PADI-certified dive outfits around the world. Every diver I met emphasized the importance of safety and proper certification (click on this link for separate, short articles that explain the ins and outs of scuba safety, the PADI open-water certification process and the scuba gear that you can buy or rent; also, keep an eye out for the January 2010 story in Car & Travel on the Cayman Islands.

The Joy of the Seven Seas
So, let’s assume we’re PADI certified (and there is a national database of PADI members that every dive outfit checks before handing you an air tank) and that we’re just about to take a gigantic step off the boat and into the glorious unknown.

Splash! With your dive buddy (and as Ivan, a diving specialist with Sunset Divers in Grand Cayman, says, “If you’re more than 20 feet from your buddy, you don’t have a buddy. You’re solo-diving”), you jump in above a reef previously selected by your boat captain. Slowly you sink down, equalizing your ears, and then, suddenly before you, is a wealth of multicolored fish, coral, sponges, Green moray eels, Hawksbill turtles, Southern stingrays, octopi and a glorious assortment of things you’ll have to research to name.

From Sunset House (www.sunsethouse.com), from where I dived, there are 70 dive sites within a 20-minute boat ride, but you also can dive straight from their rocky shore. Indeed, two of my most wonderful finds were an octopus—a sucker-laced arm poking out of a crevice—and two juvenile Spotted drums (Equetus punctatus), a black-and-white fish with a beautiful, long dorsal fin (adult specimens lack this), and both were seen right against the resort’s harbor wall.

My first reaction on finishing my first post-certification dive is that I have received a real and special privilege. I was allowed to venture somewhere that we humans perhaps should not be visiting. The next morning I was on a boat with 16 other divers. The captain, Mike Sutton-Brown, originally from Blackpool in England, steered us to a site called Ghost Mountain, which features a sizeable pinnacle clustered with coral and sponges. As a rookie, two experienced divers from PADI, accompanied me, one of which was my designated “buddy.”

You need a buddy. In fact, you must have a buddy, for your safety and his or hers. Faulty air tanks are extremely rare, but if your air supply does for some reason stop, your buddy is where you can get some more. All divers wear what is called an Alternate Air Supply, aka an octopus, which allows you both to breathe if this unlikely scenario occurs. A buddy also is necessary to make sure that you safely get back to the boat.

Another site, Oro Verde, features a sunken wreck of the same name. It was here that I saw a huge turtle float by. We were told the story of the Oro Verde, which is very much the stuff of local legend. Apparently, its captain wanted to retire, and he thought retirement might be made easier if he conducted some illegal activity just before giving up work. A certain white powder was secretly stored on board, but very soon the crew discovered the contraband and approached the captain to ask for a share of the proceeds. The captain refused, so the crew “dispatched” him. It was then that things went very wrong for them. They wanted to put the boat somewhere safe to dwell on their next move, but they lacked the captain’s knowledge of the local reefs. The boat grounded, and the panicked crew all drowned. Rumors start to spread on the island that there was an interesting cargo still aboard, and all boats turned towards the Oro Verde. Fortunately, the police reached the site first and confiscated the drugs. This is when the police made its big mistake of the whole error-prone tale. They took the cargo to the more desolate East End of Grand Cayman, wanting to get rid of the drugs before the weekend started. So they burned them, but just as they began to do this, the wind changed direction. Locals joke that still to this day, residents of George Town and Seven Mile Beach, to the west, stand outside their houses and shops every Friday night and wistfully stare eastwards with their nostrils dilated.

It was a great story that gave an extra dimension to the dive.

Other dive sites near to Sunset House featured short tunnels, different depths and large sandy expanses over which glided rays. The fish I saw in the Cayman Islands included Fairy basslets (purple front halves, yellow back halves); Trunk fish (white with black spots and a bright orange mouth that looks as though it is pouting); Stoplight parrotfish (there is a green, amber and red striped area at the base of its tail); Red hinds (red dots and a bright blue eye); Peacock flounders (blue rings in a flat fish that changes color and lies flat on the sandy bottom); Foureye butterflyfish (with large black spots on their latter halves that look like a second set of eyes and probably confuses predators) and Hogfish (huge and orange). Some lucky divers even saw a shark, but as divers usually dive in small groups, in order to give everyone space, not everyone sees the same things. Missing out on seeing a beautiful animal is not cause for disappointment, but an excuse for another dive later on.

Most divers engage in what are called no-decompression dives, meaning that they stay within safe nitrogen-eliminating depths. When you get progressively deeper, the body produces more nitrogen. This nitrogen builds up, but it is not dangerous if you rise up to the surface at no speed faster than 60 feet a minute and take the obligatory three-minute safety stop 15 feet beneath the surface. This is not something to worry about and the reason divers are put through a strict and thorough training course. When no-decompression diving, scuba-divers ensure that decompression sickness, aka the bends, does not happen and that the three-minute safety stop is merely made part and parcel of your dive for added conservatism, not because you are on your way to being ill. Your dive computer also helps you (see the attached (URL – TK Why You Wear What You Wear section of these notes).

Divers quickly graduate to wanting to take photographs of what they see. Cameras have been built for this task and are protected against water and pressure by specially constructed cases, known as “housing.” Some caution is needed, as it is not unknown for novice divers, excited at photographing sea life, to not pay as much attention as they should do to their dive computers. Nevertheless, it is a glorious thing to be able, as I did, to follow a turtle swimming gracefully along the seabed, to see large shrimp and lobsters moving along crevices, to see a gigantic moray eel stick its head out of one hole and its tail out of another and to see light beam in through holes in the rock and illuminate a diver who has just emerged from a passage, among other pleasures of the deep.

I once saw the smiles of a group of very experienced divers who had just seen a seahorse. Surely they had seen many of these before?

Yes, they had, but the spark in their eyes showed you that the pleasure of their favorite world had in no way diminished. It shouldn’t, as it is vast.

Some of the World’s Top Dive Sites
Not surprisingly, divers love diving in warm water in tropical climes. Not only is the water nicer, the scenery is probably superb for those few periods of rest taken between dives.

According to PADI, the following is the Top 10 dive sites around our beautiful planet. There are PADI-certified establishments in all of them:

1. Great Barrier Reef, Australia
This is the largest barrier reef in the world, so not surprisingly it offers a tremendous array of diving and tops the list as every diver’s must-go location. Stretching for approximately 1,875 miles and including 900 islands, this chain consists of almost 3,000 individual reefs. All of it is an UNESCO World Heritage Site, and it stretches up to the neighboring country of Papua New Guinea, which is itself a major new diving location.

2. Sulawesi Island, Indonesia
On my childhood maps, this island chain was known as the Celebes. The island sort of looks—well, at least to me—like a dancing seahorse, and it is, surprisingly, the world’s 11th largest island. Even experienced travelers might not have heard of Bangka, Bunaken, Lembeh Strait and Wakatobi, but divers have, and they glorify in their clear waters and abundance and sheer numbers of fish. There are direct flights to these dive sites from Indonesia’s capital, Jakarta, as well as from Singapore and Malaysia, but once there, you’ll feel alone—along with millions of fish, that is.

3. Little Cayman, British West Indies
Little Cayman is one of the three Caribbean Cayman Islands, the other two being Grand Cayman and Cayman Brac. If you think life is slow in Grand Cayman, the largest of the three, take the short flight here, where the fastest things are the fish and marine animals you’ve come to see. The Caymans are thought to be the only sizeable Caribbean islands not to have a population before the arrival of Europeans. This might be because they lack rivers, and it is this lack of ground water that keeps the reefs crystal clear.

4. Bikini Atoll, Marshall Islands
This is the atoll famous for giving the world the name for a popular design of swimwear. It was also—less advertised—the site of U.S. nuclear testing, but that is all over, and in the mid-90s, the Bikinians decided to open up their home to upscale tourism, including diving. Divers have been raving about them ever since, knowing that the reefs they’re seeing have been untouched for almost 50 years. A word of caution: the fragility of this place often leads local tourism officials to close down tourism operations to all but a select group, which could include divers. Check any tourism plans, and check again and often. Also, several dives down to the wrecked hulls of ships (some are American battleships sunk in World War II) require training beyond the introductory Open-water Diving certification.

5. Sharm El-Sheikh, Egypt
On the tip of the Sinai Peninsula, this Red Sea spot offers warm-water diving. Notable is Ras Mohammed, a national marine park where the reef is protected. So important is diving to the local economy, the local coast guard act as security guards, too, and recently opened was a specialized hospital for diving illnesses. The reef starts almost at the beach, and when you’re tired of diving (is it possible?), then the Pyramids are a short flight away.

6. Cocos Island, Costa Rica
Three wonderful Costa Ricans I met in Grand Cayman—Juan Carlos, Juan Carlos and Karla—love it here, and that is enough of an endorsement for me. It is also isolated and the haunt only of divers and a few obsessed birdwatchers. A 36-hour boat trip is needed to reach them, and once there it might not be everyone’s cup of tea. As one of the Juan Carloses told me, “you just dive down, sit on a ledge and watch hundreds and hundreds and hundreds of Hammerhead and White-tip sharks swim by.” Sounds like fun?

7. The Maldives
Some know these islands for being the Poster Child of attempts to reverse global warming and rising sea levels and because recently its president. Mohamed Nasheed, proposed setting up a fund so as to buy a new homeland for his people should the oceans rise even farther. The Maldives’ 1,192 islands—many uninhabited and many more off limits to tourists—have an average height of approximately five feet, but such is the range of coastline, the diving is superb, and there is almost nothing else to disturb the diver from his marine pursuits.

8. Belize
This small Central American country has long been known as a diver’s paradise. Such islands as Ambergris Caye and Caulker Caye attract many Americans, somewhat because of the short flying time, especially from Miami. The Belizean reef pretty much exists in a curved line all the way from the Honduran islands of Roatán and Utila (perhaps soon to make this Top 10) to the Florida Keys.

9. Turks & Caicos
The second British colony to make the list, but it uses the U.S. dollar as currency (so does the Cayman Islands, even if its official currency is the Cayman Islands dollar). Divers particularly favor one of its islands, Salt Cay, in late winter, as Humpback whales come here to breed, but diving is great everywhere. What do you expect from a place whose flag depicts a conch and a lobster?

10. Cozumel, Mexico
After partying in Cancún, come to this neighboring island for some rest, relaxation and scuba-diving. Accessible by direct planes from the United States, or a ferry from the Riviera Maya town of Playa del Carmen, Cozumel still has great diving, although some of the reefs were damaged by hurricanes Emily and Wilma, which both struck in 2005. A wonderful, and relatively local, trip is to Holbox island, where the world’s largest fish, the Whale shark, comes to breed.

TRAINING
I am not an instructor. I’m a novice scuba-diver. PADI (www.padi.com) are the experts, and nothing I write below should be constructed as any form of instruction. Your PADI dive shop’s instructors are trained to a very high degree.

As I researched and did my online study, my eyes often became misty as I tried to absorb everything I needed to know, but I soon saw that once you are in the water with your instructor and your scuba gear, everything quickly makes sense.

How to Start
Upon payment of an introductory fee, leaner scuba-divers get access to an online PADI training manual that takes you step by step through everything you need to know. At the end of each section is a preparation test, followed by an actual test. If you get 75 percent of the answers correct in the actual test, you move on to the next step.

Take notes. Study them. Watch the online videos. When you have passed the complete course, print out your results. This is the form that you must bring to your PADI dive shop, at the PADI center of your choice around the world, so as to do your swimming-pool and open-water segments of your training. Many learner scuba-divers complete their online and pool training in their hometown and then do their open-water segment somewhere warm and sunny. I recommend this course of action.

Places such as New York City and Long Island are perfect for pool training, but the waters around them usually are cooler and have less visibility than, say, the Cayman Islands. Even experienced divers say that once they’ve dived in warm, clear waters, they feel little desire to “go back.” I met in the Caymans divers who learned in PADI-assigned quarries and pools in places such as Iowa. That’s fine. Diving in such a place is not without its own joys, but hey, it’s not a reef in the Caribbean or an atoll in Tahiti.

The pool segment initially consists of a swim of 650 feet (no time limit) and the treading water for 10 minutes. Then you put on your scuba gear and go through a range of exercises that prepare you for the open water. These exercises are designed to make you comfortable breathing under water and competent in terms of both your scuba gear and your relationship with your dive buddy.

I was told that some people get uncomfortable when they have to take out the regulator (the apparatus that allows you to breathe) from their mouth, slowly blow bubbles from the side of their mouth and then replace the regulator and purge the water from it. I did not feel this. The surface of the pool was not more than four feet above my head, something that comforted me. Likewise, when you are asked to fill half of your mask with water, and then all of it, and then get rid of that water, I was comforted by the fact that all that mattered was that I was able to breathe. In fact, the golden rule of scuba-diving is Never Stop Breathing. Yeah, I’ll remember that, I thought.

In addition, my instructor was feet from me, as was his alternate air supply. He would complete the assigned task first and then signal to me to do it. When I completed the task successfully, he shook my hand to show me that I had passed.

Other tasks included taking off and putting back on your air tank, which is connected to the jacket you wear when diving that also is known as a buoyancy-control device, or BCD; taking off and putting back on your mask, and getting rid of the water that seeps in; dropping your regulator from your mouth and retrieving it with one front-crawl arm sweep; towing an “injured” diver; using a dive compass; getting rid of a leg cramp; taking off and putting back on your weight belt; buoyancy skills so as to hover over and not damage corals, and inhaling and exhaling so as to also influence buoyancy.

Four open-water dives are required, and all the pool exercises are repeated there. An open-water dive, in terms of certification, is any dive that lasts more than 20 minutes and reaches deeper than 20 feet. On my second open-water certification dive, my right ear would not equalize, so I signaled to my instructor that I wished to abort the dive. This is nothing to be ashamed of. The next day, my ears behaved, and suddenly I was being told that I had certified.

The certification procedure is done at your speed. I realize rookie divers will have different concerns, but personally I felt in very safe hands all the time, and when I had finished I knew that I could both make sensible decisions while under water and be able to help my dive buddy. I was ready.

How to Talk Under Water
Hand signals are something that are also taught. The key lesson is to remember that the thumbs-up sign is not a signal to say that you’re okay, but a sign that says, I’m not okay, and I want to go up to the surface. The correct sign for okay is the okay sign, thumb and fore finger together so as to make a circle, with the rest of the fingers spread upwards.  Other signals signify that you have run out of air (I never saw this used at all, expect during training), that you need to start your safety stop, that it’s time to go to the surface, that your buddy wants you to look at him and the instructions he is giving and that you have stepped off the boat and everything is in order.

On all my dives, I happily saw that all my new, experienced friends were almost stepping over themselves to help and encourage me. There is camaraderie beneath the waves that comes, I think, from understanding the privilege of being part of the sport, as I alluded to above, and, I know, from the need to be safe, secure, mature and sensible.

Every minute look at your dive computer. What is it telling you? The boat captain and lead diver will explain what any particular dive’s profile is. How deep are you allowed to go? Say, 80 feet. How long can you dive for? Say, 50 minutes. Each dive will be different. Listen to the instructions, and never exceed them. If the profile is, say, 80 feet for 50 minutes, that does not mean you can sprint down to that depth (your ears will probably not let you anyway) and stay down there for 50 minutes. The deeper you are the less air you will have, because of water density. Look at your dive computer. It will tell you how long you can stay at any depth, and it will beep if you are ignoring the rules of no-decompression diving. Your dive master will have selected that dive site because it will have a range of great things to see at several depths. There will be no reason to push the dive profile.

The second dive of a two-tank trip will always be at a shallower depth. Again, this is designed to be a commonsense issue of safety. Between the two dives, there will be what is called a Surface Interval Time that is based on the first and second dive profiles. A dive computer also never stops working, so if you go and have lunch, you will know when it is you can dive again and at what profile. Some divers dive five or six times a day, all within the safety rules.

I should repeat again that I never felt in danger and that the underwater world is an incredibly beautiful and wonderful one to be in.

Why You Wear What You Wear
Scuba-divers need equipment, mainly as they, like all of us, cannot breathe naturally under water. Here is what they have:

Fins: If you want to see eyebrows rise on dive instructors’ foreheads, then the best way to do that is to call what you wear on your feet while diving “flippers.” Flippers, they’ll explain, are what dolphins have. You, then they’ll say, have fins. Fins come in three main styles, and there are various lengths.

Buoyancy Control Device: This is also known as a BCD. You wear it like a life jacket, and attached to it is every other piece of equipment, except for your fins and your mask and snorkel. Air from your tank allows the BCD to inflate and deflate, depending on your needs. Velcro flaps on the BCD secure the regulator’s tubes.

Regulator: Collectively, the four tubes that connect to your air tank, and then are secured to your BCD, are known as the regulator. Specifically, the regulator is your principal air source. An alternative air supply, also known as an octopus, is for your dive buddy to use if the very unlikely situation occurs in which his air ceases, and it is recognizable by usually being a bright color; it is connected to your buddy’s BCD by a plastic ring, thus making it easy to be pulled down and used. The third tube allows the BCD to be inflated/deflated, and the last tube is your submersible gauge or dive computer, which shows you how much air you have left, your depth, the time of your dive and other information that the dive instructor will explain.

Mask and snorkel: Masks allow the eyes to see under water. Men are often told that being clean-shaven helps the mask’s seal to be perfect. The snorkel—completely useless under water—is used on the surface of the water instead of the regulator.

Suit: In warm water, a wet suit is used. A thin film of water will coat your skin beneath the suit, and that film soon warms up, thus keeping the diver warm. A suit also protects the diver from grazes. In colder waters, a dry suit might be worn, which does not permit a film of water.

Weights: Depending on your own weight and the temperature of the water, divers might wear less or more weight in order to sink beneath the waves. Knowing what weight you need, and when you need less or more, comes with experience. Divers will tell you that the hardest stretch of water to sink through is usually the first 30 feet because there the density of water is at its lowest.

Scuba tank: Divers most usually will rent tanks from certified PADI dive shops. In this way you can be assured that the air is good and that the tank has been serviced.