Improper scuba diving can kill you. Proper scuba diving opens up 75 percent of the Earth's surface otherwise hidden to man. Ace the skill set, and you can chase dolphins and angel fish; muck it, and your lungs can explode.

Improper scuba diving can kill you. Proper scuba diving opens up 75 percent of the Earth's surface otherwise hidden to man. Ace the skill set, and you can chase dolphins and angel fish; muck it, and your lungs can explode.

This lingers in the back of my mind as I stand near the heated indoor pool at the Underwater Connection in Grandview and begin to strap on gear: a metal tank of compressed air, buoyancy vest with weights and inflatable bladders, flippers, mask and three-millimeter wetsuit.

The human body isn't built to hang out in pressurized ocean depths with some college buddies and a $5 waterproof camera. You need, all told, enough gear to make you walk on land like a giant, drunken penguin. Waddling for the first time to the edge of a pool - basic underwater tactics swirling through your head - seems like a leap of faith.

Step forward. Secure your mask and vest. Take the plunge.

Don't worry: You float.

Thanks to the laws of buoyancy, your clumsy gear is an afterthought and you're bubbling down into the eight-foot water in no time. Breathing easy is actually required.

"I get a lot of people who have a genuine fear of water and a feeling of claustrophobia with all the stuff," said Jane Margiotta, who's owned the school and dive shop on West Third Avenue with husband Bill since 1988. "But scuba diving is like being in your own room underwater."

For centuries, navy officers, salvage specialists and inventors toyed with various ways to survive underwater, starting first with crude metal diving bells and re-breathers. The modern recreational scuba set is one triumph of their sometimes deadly trial-and-error: an outfit of rubber, metal, plastic and nylon that can transport even casual divers comfortably into the depths.

"It helps to be in shape, but anyone can do it," said Bill Margiotta, who learned to dive in New England and worked as a guide in the Bahamas and Florida Keys.

Prospective scuba divers can choose from a handful of accredited courses, but the Professional Association of Diving Instructors, which the Margiottas prefer, is the most popular. More than 5,300 global dive shops and resorts accept PADI students.

For basic certification, all courses cover three areas: knowledge development, pool training and open-water diving.

By attending classes or using an interactive CD-ROM, you'll learn about gear assembly, buoyancy, dive charts, underwater pressure and how the body functions when submerged. The course seems daunting at first, but it's nothing you can't handle with professional help.

As you're hitting the books, you'll also practice basic skills in the pool - things like breathing through a demand regulator, clearing a leaky mask and what to do if you run out of air. Anyone who can swim 200 yards (and breathe properly) will be reluctant to surface from the bottom of the pool.

Once you've mastered these, you're ready to test the open waters.

A common track for those who want to explore the Caribbean is to knock out the first two requisites here in Columbus and get a referral, a certificate signed by an instructor saying you're ready to complete the open-water dives. That way, you can finish training in the tropics without wasting vacation time studying.

"I was a little apprehensive at first, but it's a cool feeling," said Downtown resident Evan Wilcox, who will complete his open-water training next month in the Dominican Republic. "I'm not the type of person who just sits on the beach and drinks all week. I'd rather go out and do something."

Others in my class were traveling to the tropics - and two to the Red Sea - but you don't need an exotic locale to practice the sport. Expensive trips don't always produce the best dives.

One of Bill Margiotta's favorite spots is a wreck beneath the St. Clair River, and he claims the Great Lakes offer the world's best wreck diving. His enthusiasm for relaxing underwater excursions - non-technical dives rarely deeper than 80 feet - is infectious.

"You don't have to go on vacation - you can dive right here," he said. "There's another whole world right in our backyard."

Come springtime, his students not traveling abroad will complete their open-water dives at the Circleville Quarry.

Yep, pumpkin land. It's even got a dive shop.