TYPES OF WRECK DIVING
In his classical work on the subject, The Advanced Wreck Diving Handbook, Gary Gentile sub-divides wreck diving into three categories:
- Non-penetration diving (i.e. swimming over the wreck)
- Limited penetration diving, within the “light zone”
- Full penetration diving, beyond the “light zone”
Each succeeding level involves greater risk, and will normally require greater levels of training, experience and equipment.
Non-penetration wreck diving is the least hazardous form of wreck diving, although divers still need to be aware of the entanglement risks presented by fishing nets and fishing lines which may be snagged to the wreck (wrecks are often popular fishing sites), and the underlying terrain may present greater risk of sharp edges.
Penetration within the light zone presents greater hazards due to overhead and greater proximity of the wreck’s structure, but because of the proximity of a visible exit point, and some amount of external light, those hazards are more manageable. However, there is clearly a greater risk of entanglement and silt-out inside of the structure, as well as the requirement to move laterally to a defined exit point before one can surface in the event of an emergency.
Full penetration involves the greatest level of risks, including the risk of getting lost within the structure, the risk of complete darkness in the event of multiple light failures, and the inability to escape unassisted in the event of a disruption to air supply.
These categorisations broadly coincide with the traditional division between “recreational” wreck diving (taught as a specialty course by recreational diver training agencies and normally limited to the “light zone” and/or 100-130 cumulative feet of depth plus penetration) and “technical” wreck diving (taught as a stand-alone course by technical diver training agencies).