SCUBA Diving near Vessels
When divers are required to dive on or in the vicinity of a vessel the protections outlined are to be taken.
Crossing the Keel: A marked swimmer or attended diver in self-contained equipment (SCUBA) should not normally cross the keel from the side on which entry is made. However, should the task dictate that the diver is required to cross the keel, the diver may do so providing a risk assessment is conducted. Particular deliberation is to be given to environmental conditions, individual diver’s experience, training, and safe outlet for the diver on each side of the vessel.
Surface-supplied divers may cross the keel should the task dictate providing a risk assessment is
conducted. A marked swimmer or attended diver should not normally pass between the shaft and the hull of a vessel or through the shaft brackets as the risk of predicament is significantly increased. Should the task dictate that the diver is required to do so however he may provide a risk assessment is conducted?
Diving from vessels using Dynamic Positioning: (DP) (Maintaining station over the seabed by use of computer controlled thrusters) poses considerable hazards to surface-deployed divers because thrusters may stop, start or change the direction of thrust at any time.
Accordingly, such diving should be undertaken only if the vessel conforms to the International Maritime Organization’s “Guidelines for Vessels with DP Systems” and if the vessel and equipment fall into the classification of “Class 3 – redundancy and physical separation of all components”, and when no alternative method of carrying out the task is possible.
Alternatives include the vessel breaking DP to anchor or moor, or carrying out the dive using a suitable boat. If there is no alternative, or the vessel’s equipment class is less than level 3 then a full risk assessment must take place and control measures imposed so that the risk
to the diver is as low as reasonably possible. These risks must be balanced against the operational imperative of the task.
If divers have to be deployed from a vessel using DP the following precautions must be observed:
The Diver’s Team Leader must be fully aware of the hazard areas into which neither the diver nor their lifeline or umbilical must be allowed to enter.
Direct, continuous communications (open line) must be established between the Diver’s Team Leader and the ship control position. Any system alarms should be passed to the Diver’s Team Leader immediately (using the traffic light system, if fitted, as an alerting device).
The maximum length of the lifeline or umbilical from the attendant to the diver must be 5 m less than the distance to the nearest thruster or other physical hazard identified in the risk assessment. The umbilical should be physically controlled to prevent it from becoming within 5 m of such a hazard.
The standby diver’s umbilical should be 2 m longer than the working diver’s umbilical and also suitably restrained. If the task cannot be carried out within this restriction, then any thrusters within the range of the lifeline/umbilical must be stopped and measures are taken to prevent their unintentional re-starting during the dive.
On mono-hull vessels, all diving in depths from the surface to 10 m below the operating draught of the vessel should be carried out over the side and NOT through the moon pool unless it is conducted from the Submersible Compression Chamber (SCC) or a wet bell.
Conclusion:
Safety precautions are crucial when diving near vessels. Crossing the keel should be avoided unless necessary and accompanied by a risk assessment. Diving from vessels with Dynamic positioning requires adherence to guidelines, thorough risk assessment, and communication protocols. Safety measures should be prioritized to minimize risks to divers in all situations.
