Surface-supplied Diving - Variations

Variations

Several different arrangements exist for supplying breathing gas to divers from the surface:

• Standard or Heavy gear – The historical copper helmet, canvas suit and weighted boots is still used for commercial work in some parts of the world.
• Scuba replacement – A surface supplied arrangement where both the primary and reserve air supplies are from high pressure cylinders. The rest of the system is identical to the standard surface supply configuration, and the full umbilical system, communications and surface air panel are used. This is more portable than most compressors and is used by commercial diving contractors as a substitute for scuba with most of the advantages and disadvantages of a regular compressor fed surface supply.
• Hookah – A basic form of surface supplied diving in which the air supply is via a single hose is often referred to as airline or Hookah (occasionally Hooka) diving. This often uses a standard scuba second stage as the delivery unit, but is also used with light full-face masks. Bailout gas may be carried, but this is not always the case. Commercial diamond divers working in the shallow zone off the west coast of South Africa under the codes of practice of the Department of Minerals and Energy use half mask and demand valve hookah, and no bailout as standard practice. Their safety record is relatively poor.
• Snuba – A system used to supply air from a cylinder mounted on a float to a recreational diver tethered by a short (approximately 6m) hose through a scuba regulator.
• Compressor diving – An even more basic system is the "Compressor diving" arrangement used in the Philippines for fishing. This rudimentary and highly hazardous system uses a large number of small bore plastic tubes connected to a single compressor to supply a large number of divers simultaneously. The delivery end of the hose is unencumbered by any mechanism or mouthpiece, and is simply held by the divers' teeth. Air supply is free flow and often unfiltered.