DP Alert Responses
If diving is to be carried out from a vessel operating on DP, then an audio/visual alarm activated by the DP operator must be fitted in dive control to inform the diving supervisor of the DP status. It must be tested before each dive when operating on DP. On a diving support vessel, DP status lights are provided for the safe conduct of diving operations and are to be used only for this purpose. On initiation of alert levels by the DP operator, diving operational responses should be carried out as defined in this section.
DP Status
A system of lights and audible alarms should indicate the DP system status at the appropriate operational/control locations. The required responses to a change in alert level should be determined by risk assessment and documented in tabular format in the ASOG.
The red alert, accompanied by a distinctive alarm, should additionally sound in the master/OIM’s cabin, operations superintendent’s cabin (if applicable) and the senior diving supervisor’s cabin (if applicable). A local means of acknowledging and silencing these alarms and flashing lights should be provided.
Guidance on DP status and responses is given below.
-
Normal status – GREEN light. Full DP diving operations can be undertaken.
- The DP system is operating as intended;
- Operational, environmental and equipment performance criteria as defined within the ASOG are all categorised as normal;
- The vessel could maintain position in the prevailing environmental conditions after the WCF.
-
Degraded status – YELLOW light. The diving supervisor should instruct the divers to suspend operations and move to a safe location1. The DPO, after consulting the diving supervisor, should decide if further action is necessary. If the diving supervisor is unable to get clear advice from the DPO then the divers should be instructed to return to the bell or deployment device and obtain a seal or to return to the surface as appropriate.
A failure in the DP system has occurred leaving the DP system in an operational state but with its DP redundancy compromised. An additional failure in that system may result in an inability to maintain the vessel’s position:
- The vessel’s position keeping performance is deteriorating or unstable;
- The vessel would be unable to maintain position in the prevailing environmental conditions after the WCF;
- A ‘yellow’ condition exists as defined in the ASOG for abnormal operational, environmental and equipment performance conditions;
- Any other condition exists which may lead to a suspension of diving activities.
-
Emergency status – RED light with accompanying distinctive alarm. The diving supervisor should instruct the divers to return immediately to the bell (or deployment device as appropriate) and obtain a seal. The deployment device should be recovered as soon as possible after due consideration of hazards involved in the recovery. The DPO(s) should use all available means to limit the inability to maintain position while the divers are being recovered.
- A system failure or other condition has occurred resulting in an inability to maintain position or heading control or to safely conduct diving operations;
- A ‘red’ condition exists as defined in the ASOG for hazardous operational, environmental and equipment performance criteria;
- Any other emergency situation which warrants immediate recovery of divers to a safe position.
