A member has reported an incident in which a low pressure mud hose parted. The incident occurred during the disconnecting and lifting of the mud hose from a vessel to a platform. The mud hose was disconnected from the vessel manifold, and the vessel banksman gave a signal to the crane operator to lower the sling. The hose was attached to the sling and a signal was given to raise the hose. The intent was that the crane should take the weight of the hose and then the securing line from the vessel to the hose could be more easily disconnected. However, the crane operator misunderstood the hand signals and continued to lift whilst the hose was still lashed to the vessel. As a result the coupling and hose parted. As transfer of mud had stopped, there was no spill and there were no injuries.
Our member investigated and noted the following immediate causes of the incident:
- Procedures not understood . the crane operator may not have been aware that the hose was lashed to the vessel;
- There was poor visibility at the time of the incident owing to heavy rain.
The following root causes were identified:
- Communication between workgroups was not effective . poor visibility noted at the time of the incident, and the crane driver may not have seen the stop sign by the banksman. The banksman did not have direct very high frequency (VHF) communication with the crane operator.
The following lessons were learnt:
- There should be clear and continuous radio communication between vessel master and the crane operator and banksman during lifting operations;
- Hand signals can be used provided the banksman can always be clearly seen by the crane operator. In conditions of poor visibility, radio communication between banksman and crane operator should be clear and continuous.