There is an internationally recognized flag that tells all other boats in the vicinity that there is a diver underwater.

When the flag is displayed all boats should stay clear and proceed very slowly.

Divers should always work in pairs, within easy view of another diver. This allows one's partner to help in freeing one from obstructions or in sharing air if a hose or a mask is lost or ruptured.

In a diving emergency when the air supplying hose or mask is lost or ruptured, divers can share air at depth.

The diver must always breath normally.

Before diving, between dives and after diving, divers should drink large amounts of water to prevent dehydration which increases the risk of decompression sickness.

By making a safety stop at 5 metres for 3 to 5 minutes, nitrogen in the divers' body has more time to turn into gas and escape through breathing.

A good practice is for the boat crew to hang a line with a weight from the boat with a flag or a marker at a depth of five metres. The divers then find the marker and hold onto the rope for three to five minutes.

A diver with a watch or someone on the boat should keep the time and tell the divers when the five minutes has passed.

For long, deep dives one or more decompression stops may be necessary.

While resting on the surface the body is able to get rid of nitrogen simply through breathing.

The longer the diver is able to rest between dives the more nitrogen the diver will be able to get rid of.

The traditional dive boat can be modified to reduce the possibility of carbon monoxide gas entering the air supply.

The air intake for the compressor needs to be moved well away from the exhaust gases of both the compressor and the boats engine.

Diver, pearl diver, sponge diver, oyster diver, diving fisherman.

Using surface supplied compressed air or air from self-contained breathing apparatus (SCUBA), dives in waters up to 60 metres depth to hunt for fish using spears; to gather shell fish; to gather marine life for aquaria or to harvest fish traps. On rotation (while not diving) may be called to monitor the compressor, tend to diving air hoses, operate the boat, prepare the catch for storage and transportation. Prior to departure from village will inspect the diving equipment and may be called upon to inspect and maintain the boat and compressor motors. On shore may be called upon to build and repair fish traps as well as diving boats. May also engage in diving salvage operations. Catching fish and other forms of aquatic life, selling some produce at local markets.

Commercial diver, boat operator, diving tender, fisherman, coastal waters, subsistence agricultural and fishery workers.

Anchoring; attaching; boat operating; building (boats); building (traps); checking; cooking; diving; fueling; handling (lines); handling (hoses); handling (marine products); harvesting; inspecting; lifting; loading; lubricating; maintaining; navigating; observing; operating; positioning; repairing; sorting; storing; transporting; trapping; unloading

Air Hose; anchors; boats; compressor; depth gauge; dive flag; diving mask; fins; fish trap; gloves; nets; shirts (long sleave with roll collar); spear; spear gun; shoes; ropes; SCUBA equipment; watch; weight belt

Basically operates in tropical, shallow waters from open dive boats. May travel several days from home base depending on season, weather and target catch.

According to research carried out and in Thailand by Indigenous Fishermen Diver Project and in the Philippines by the Diving Diseases Research Centre (DDRC), there is a high incidence of decompression sickness (DCS) among the diving population. (As much as 85% of the diving population in Thailand suffers from type I DCS). There are also large numbers of fisherman divers with DON as evidenced by recent research by DDRC in the Philippines.

Both the Thai and Philippines projects have reported a considerably elevated mortality rate due to diving related injury and illness.

Home made, poor and deficient equipment has not been designed for safe diving and carries no provisions for secondary air sources.

No or limited access to first aid, medical care nor recompression facilities.

Work is often carried out at long distances from any form of assistance and there is no means of communications from the boat to sources of assistance.

Gold, D: The Sea Gypsies of Thailand. Asian Diver Magazine. 12/97. Vol 6 No 4

Gold, D: Indigenous Divers, in Stellman, J. (Ed) The ILO Encyclopaedia of Occupational Health and Safety, 4th Edition, ILO Geneva, 1998. Vol 3. pp 66.3-4.

McDonald, K. Bends in the Philippines. Diver. 7/95. Vol 40 No 7.