Types of Diving -- Free (Breath-Hold) Diving
Free diving, or breath-hold diving, is the earliest of all diving techniques, and has played a historic role in the search for food and treasure or in military operations. The ancient Greeks developed underwater military squads, using free divers to ambush enemy ships during the Peloponnesian Wars. Roman divers collected dye-producing Mediterranean snails to color the Emperor's rich purple cloaks. The Ama of Japan and Korea still dive for seafood, such as abalone, as they have done for centuries. Likewise, native people throughout the Caribbean and Polynesia have been diving for oysters, conch, fish and lobster for thousands of years.
What is the advantage of free diving?
The obvious advantage of free diving as a work method and a recreational activity is that it allows maximum freedom for the diver to maneuver. The obvious disadvantage is that the diver's air supply is limited to the amount of air the diver can take in and maintain in a single breath or can obtain using a snorkel-type reed or tube to the surface. The modern snorkel is an aid in breath-hold diving but doesn't supply air continuously unless the diver is very near the surface.