Wreck Diving

Why divers love wrecks

A wreck on the sea floor soon becomes an artificial reef. Corals and sponges settle on its surfaces, and fish shelter in its holds and around its hull. Many wrecks are also historic sites, from merchant ships to warships and aircraft lost in battle. Some of the world's best-known wreck dives include the SS Thistlegorm in the Red Sea, the SS Yongala off Queensland in Australia and the Second World War fleet in Chuuk Lagoon (Truk) in Micronesia. Other wrecks are sunk on purpose as artificial reefs and dive sites, such as the USS Kittiwake off Grand Cayman.

Outside and inside

Non-penetration wreck diving means staying outside the wreck, or within the "light zone" near an opening where you can see daylight and swim straight out. It's open-water diving with extra care, and many recreational divers enjoy it with ordinary training and a careful guide.

Penetration diving means going inside, beyond the light zone. Inside a wreck there's an overhead: you can't swim straight up to the surface. Passages may be narrow, collapsed or full of fine silt that can drop visibility to zero with one careless kick. Penetration diving needs specialist training, a guideline from the entrance, at least one backup light and a gas plan with a large reserve, as in cave diving.

Hazards

• Entanglement in fishing line, nets, cables and wiring.
• Sharp edges of torn and corroded metal.
• Silt-outs that wipe out visibility, especially inside.
• Disorientation, because a ship lying on its side turns floors into walls.
• Collapse of decaying structures.
• Depth. Many wrecks lie deep enough that nitrogen narcosis and short no-decompression limits come into play.
• Currents around the hull, and boat traffic above.

Skills and gear

Excellent neutral buoyancy and a gentle frog kick protect the wreck and keep silt down. A cutting tool helps if you snag on line. A reliable light brings out color in dark holds and shadows. Agree the plan with your buddy, including where you'll go and when you'll turn back.

Laws and respect

Many wrecks are protected. Some are war graves, where people died, and are treated as memorials. Others are protected as historic or archaeological sites, and taking anything from them can be a crime. Even where it isn't illegal, removing items takes the history away from the next diver. The common rule is to look and photograph, but not touch or take.

Training

Most agencies offer a wreck diving specialty course covering wreck mapping, hazards, line use and limited penetration within the light zone. Full penetration, beyond the light zone or into deep wrecks, belongs to technical training. Never go inside a wreck beyond your training, however inviting the opening looks.

Frequently asked questions