42 SAFETY ONARCHAEOLOGICAL SITES UNDERWATER AND ON THE FORESHORE
The most effective communication system is a hard-wire
telephone via an umbilical between the diver and the sur-
face (plate 6.2), but rope signals are reasonably efficient
if the team is experienced in their use. Through-water com-
munication systems are improving and are less restrictive
than an umbilical, but they can be affected if the diver
is in the shadow of rocks or similar upstanding features.
In addition it is advisable to equip the lone diver using
through-water communications with a surface marker-buoy
or lifeline, so that s/he can be located if there is a prob-
lem. Alternatively, in some very benign diving situations
it may be possible to allow divers to dive alone. However,
this should be incorporated within the risk assessment and
there must be adequate safeguards.
It is important that divers are not pressurized into
adopting any practice they are not comfortable with.
Equally, divers should not feel worried about refusing
to adopt procedures that they consider unsatisfactory.
Some very experienced diving archaeologists prefer not
to work alone unless they are connected directly with the
surface, while others are happy to consider it if there are
other divers on site. It is also vital to remember that
any diving procedure adopted conforms to the code of
practice in use on the project, and that the procedure
also complies with any local or national legislation that
might apply. The following basic points are suggested as
being the minimum necessary for safe diving operations
involving lone divers:
- Divers operating alone must have an effective
method of alerting the diving supervisor if they get
into trouble. - There must be a standby diver in full equipment on
the surface ready to give assistance. - There must be an effective way of locating the lone
diver in distress. - Divers operating alone must have an adequate
and separate reserve of breathing-gas for use only
in emergencies.
SAFETY DURING EXCAVATION
If the work of the project involves excavation, there are
additional safety factors that must be considered. An
excavation site can be a daunting and unfamiliar place
for the inexperienced worker. The site is likely to have
air, water or other power supplies for the airlift, water-
dredge or other tools. In poor visibility these can be
potentially treacherous and divers must have a clear
understanding of where these hazards are in relation to
the route to their place of work. Project diving super-
visors or those responsible for safety should rationalize
the way that equipment lines and hoses are placed on the
site to reduce the potential dangers associated with snags.
Likewise, the process of excavation can concentrate a
diver’s mind to the point where the contents gauge and
dive timer are not given due attention. Complacency is
just as problematic as anxiety and neither contributes to
a high standard of work. It therefore makes sense to
introduce less-experienced team members in a progres-
sive way rather than to simply hope that they will cope.
As with many working situations, it is very useful to
establish a shot- or down-line, which is used for all ascents
and descents. By establishing a fixed route to the site
divers can get to work with minimum fuss.
During an excavation, care must be taken to ensure that
no items of equipment or large objects capable of caus-
ing blockages are sucked into the mouth of an airlift or
dredge. When the lower end of an airlift becomes blocked
it rapidly becomes buoyant and will suddenly rush to the
surface if not tethered. Less-experienced divers should be
trained to ensure familiarity with the safety procedures.
A means of shutting off the supply to the excavation
equipment quickly must be within easy reach of the diver
operating the equipment. It is worth considering having
a wire-cross over the suction end to help prevent block-
ages. For safety, many divers have an alternative air
supply as a secondary breathing source, but these can
be dangerous, particularly when used with an airlift. If
the secondary source gets sucked into the airlift, the
breathing supply will be rapidly emptied. Incidents of this
nature have led to fatalities. To reduce this danger, it is
important to consider the position of an alternative breath-
ing source and other extraneous pieces of equipment.
There is no archaeological investigation in the world that
is worth the health or lives of those involved in it. Those
responsible for a project must avoid generating an atmo-
sphere where people become willing to take risks and push
their luck ‘for the sake of the project’. Get the job done,
but do it competently, professionally and safely, even if
that means taking a little longer.
The following is a list of top tips for safety (best practice):- Ensure that participants fully understand the aims
and objectives of the project. - Make sure participants are sufficiently competent to
carry out their tasks. - Complete a comprehensive written risk assessment
that covers all aspects of the project. - Provide additional training if required.
- Keep written dive-plans.
- Keep records of diving times.
- Conduct daily equipment checks.
- Keep a daily project-log that includes details of
team members, diving supervisors and individuals