Lessons Learnt: Oil Spill due to failure of cargo hose
Vessel Type: Tanker
A tanker was fixed to load a petroleum product cargo at an offshore anchorage by ship to ship transfer (STS). After making fast alongside the storage vessel, cargo tanks were inspected and pre-loading checklists completed which included agreement on the maximum cargo transfer rate. A flexible cargo hose supplied by the STS service provider was connected between the respective vessels manifolds. During transfer operations, the cargo hose ruptured near the receiving vessel's manifold, causing oil to spray on deck and overboard. The crew responded immediately by raising the alarm, instructing the storage vessel to stop the transfer and by taking prompt action to confine and collect oil spillage on deck. After clean-up operations and the subsequent investigation were completed, the hose was replaced and operations resumed.
Only a very small quantity of oil was released into the sea, mainly due to the quick and effective response of the crew. The investigation into the incident concluded that the failure of the hose was related to its condition as there was no evidence that the agreed pumping rate or pressure in the system was exceeded. Markings on the hose indicated that it was last pressure tested more than two years before the incident and no valid certificate of inspection and test could be produced on demand. In this case, responsibility for confirming the hoses were fit for the intended service and properly certificated rested with the STS service provider. However, the crew should carefully inspect transfer hoses as far as safely accessible and request access to the hose documentation, cross checking that identification markings match up and protesting any defects or anomalies. Industry guidelines require that periodic tests of hoses are undertaken at intervals not exceeding 12 months.
- Ship to Ship transfer operations must be performed taking into consideration the requirements of the vessel STS operations plan, MARPOL regulations for the prevention of pollution during transfer of oil at Sea, the Ship to Ship Transfer Guide and the vessel Safety Management System
- Cargo transfer hoses should be fit for purpose and provided with valid records of test and inspection
- Any evidence of deficient or non-compliant transfer hoses should be protested and thereafter investigated / rectified by the responsible party
- This incident demonstrates the vital importance of the crew keeping a vigilant deck watch during transfer operations and in responding rapidly to contain a spill in accordance with drilled procedures