page_title: Wreck diving
section_title: Procedures and safety
hierarchical_section_title: Wreck diving / Procedures and safety
caption_attribution_description: Shipwreck porthole
context_page_description: Wreck diving is recreational diving where the wreckage of ships, aircraft and other artificial structures are explored. Although most wreck dive sites are at shipwrecks, there is an increasing trend to scuttle retired ships to create artificial reef sites. Diving to crashed aircraft can also be considered wreck diving. The recreation of wreck diving makes no distinction as to how the vessel ended up on the bottom.
  Some wreck diving involves penetration of the wreckage, making a direct ascent to the surface impossible for a part of the dive.
context_section_description: Wrecks may present a variety of site-specific hazards to divers.  Wrecks are often fouled by fishing lines or nets and the structure may be fragile and break without notice.  Penetration diving, where the diver enters a shipwreck is an activity exposing the diver to hazards of getting lost, entrapment and consequently running out of breathing gas. Management of these risks requires special skills and equipment.  Many attractive or well preserved wrecks are in deeper water requiring deep diving precautions.  Training agencies recommend that at least one cutting device be carried in case the diver is entangled with fishing lines, nets or ropes and to have a spare light source in case the primary light fails.  If penetrating a wreck, a guideline tied off before entering a wreck  and run out inside the wreck is advisable.  A guideline can help a diver to find the way out more easily in case of low visibility.  For penetration diving, a reserve of breathing gas sufficient to allow the diver to exit the wreck and make a safe ascent in the event of any reasonably foreseeable single failure of equipment is required by training agencies' protocols and scientific codes of practice. Most wreck divers use a minimum of the rule-of-thirds for gas management. This allows for 1/3 of the gas down and into the wreck, 1/3 for exit and ascent and 1/3 reserve. In addition, because of the potential fragility of the wreck, the likelihood of disturbing sediments or disturbing the many marine animals that take advantage of the artificial habitat offered by the wreck, extra care is required when moving and finning. Many divers are taught to use alternative finning methods such as frog kick or modified flutter kick which direct the thrust of the fins away from the bottom where most of the silt is likely to deposit. Good buoyancy control is necessary for safe and non-destructive diving in the environment of a wreck.
caption: Diver with porthole recovered from a shipwreck in New York's Wreck Alley
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