Throughout maritime history, thousands upon thousands of vessels have been lost at sea due to fierce storms and collisions with floating and underwater objects. The oceans of the world are literally littered with the remains of not only small craft, but are the resting place of passenger liners, freighters, warships and a vast collection of boats of all sizes and purposes.
For the scuba diver, these vessels lost in a liquid nether-world have become an attraction that draws them as does the mystery of a haunted house. Divers descend to view a piece of history that is gone but not forgotten and to collect priceless artifacts. Shipwrecks can be found at all different depths and many are well within reach of recreational divers. In many areas vessels have been sunk on purpose and form artificial reefs that attract a multitude of marine life and over the years will be adorned with corals, seafans sponge, barnacles, oysters and other colorful invertebrate life.
Although dive guides in many resort areas will routinely lead their charges to view ‘safe’ wrecks lying in shallow water, the exploration of most shipwrecks requires specialized training and strict procedures. Shipwrecks can be very dangerous places, they can deteriorate rapidly making them unstable structures, they are a draw to fish, hence a target for sport and commercial fishermen and can be a host to snags of fishing nets and monofilament line just waiting to trap unsuspecting divers.
Wreck diving can be divided into three main categories and a highly contested fourth. Non penetration diving involves swimming over and around wrecks and although this is the safest form of wreck diving, there is still the hazard of fishing line, nets and the possibility of jagged, sharp, objects.
Penetrating the interior of wrecks is a dangerous undertaking and many divers go no further than within the light zone where the exit point is always in sight. Even so, silt forms quickly in shipwrecks and all it takes are a few fin kicks to dislodge a blinding cloud that places the diver in a zero visibility situation that can disorient them and make finding their exit point impossible.
Full penetration wreck diving is accomplished with the use of reels carrying hundreds of feet of line. The line is tied off to the outside of the entrance, tied again just inside and at points along the penetration path giving the divers a guide line to the exit point. Even with this seemingly foolproof method, divers become lost and continue to perish in the bowels of the wrecks.
Another technique utilized by many experienced wreck divers is progressive penetration. Each foray into the wreck goes a little farther with the diver familiarizing themselves with the layout of the wreck on each successive dive. As this technique obviates the use of reels, it is not taught by any mainstream training agencies.
Many well trained and highly experienced divers descend well beyond the limits of recreational diving, often utilizing exotic blends of mixed gasses. Side-mounted tanks are carried to carry out their staged decompression stops and the divers pay for short duration explorations of the wrecks with hours of decompression stops on their way back to the surface.
The Andrea Doria, an Italian liner that sank after a collision with another ship off the east coast of the United States is said to be the ‘Mount Everest of shipwreck diving’. The liner rests in 250 feet of water with the top at 190 feet and over the years has claimed the lives of 16 divers from disorientation, entanglement, embolisms and decompression sickness.
With proper training and equipment, wreck diving can be an exciting undertaking and to visit these once proud ocean going vessels in their watery graves is a passion for those that wish to take their diving to an extreme level.