Webbing strop failure during transponder recovery

A DSV was conducting diving operations recovering a previously installed transponder array. During the transponder recovery the diver connected the transponder beacon’s webbing strop (supplied with the transponder) and a separate vessel strop on the tripod stand to the crane hook.

The load was lifted off the bottom and the divers moved clear under the vessel. The crane lifted the load 10m then slewed to stern and carried on coming up. Upon arrival at surface the transponder beacon was found to be missing. Due to compliance with safe crane and diving operations, there was no personal injury or subsea asset damage. The transponder beacon was subsequently located close to original lifting position.

In the resulting investigation, the stitching on the webbing strop on the transponder beacon was found to have failed. The webbing strop had not been subjected to certification or maintenance. In communication with the supplier, the hire company stated that the webbing strop was not supplied for lifting purposes but only for general handling.

The company’s immediate actions were:

• Issue of a safety alert;
• Removal of any hire company supplied webbing strops from all transponder beacons;
• All future transponder deployment and recovery operations are to be carried out with strict adherence to company procedure;
• All sites are to carry out a safety brief to make personnel aware of this incident;
• Site management are to reiterate with personnel the requirement to carry out pre-use visual inspection of lifting equipment;

The company has also noted the following longer term actions:

• Discussion with transponder supplier of suitable lifting equipment arrangements;
• Issue of a company work instruction to identify suitable lifting arrangements for transponders;
• Sharing of lessons learned with industry, through IMCA.