Two tankers met at a specified ship-to-ship transfer (STS) area, and were secured together as shown in the diagram. Despite calm weather, one of the spring lines broke as a result of chafing damage.

The Nautical Institute gathers reports of maritime accidents and near-misses. It then publishes these so-called Mars Reports (anonymously) to prevent other accidents from happening. A summary of this incident:

Seas were smooth with a one-metre swell and wind was very light (5 knots). Moderate rolling and pitching was noted. Loading commenced, but at one point during loading the deck watch reported that a spring line had broken. The crew took immediate action and the failed line was replaced. Transfers continued without further incident.

Also read: Ship-to-ship transfer ends with a touch of bows

Investigation findings

The company investigation found that the vessel was equipped with two mooring systems – mooring wires fitted with tails, and mooring ropes. In this case, the vessel used mooring ropes. All were reported to be in excellent condition with a rating 10 on a scale of 1 to 10 where 10 is new, 9 excellent and 1 is for scrap.

The investigation found that excessive movement of the vessels in combination with a less than adequate arrangement of protective sleeves caused chafing damage on the mooring lines.

Also read: Terminal pressures vessel crew to resume transfer despite safety issues

Advice from The Nautical Institute

  • If wire ropes are available for such mooring arrangements they would be preferable to fibre ropes.
  • A thorough mooring analysis and compatibility check should be performed before every STS operation.

Also read: ‘Questionable decisions’ during ship-to-ship transfer end in tragedy

Mars Reports

This accident was covered in the Mars Reports, originally published as Mars 202220, that are part of Report Number 355. A selection of this Report was also published in SWZ|Maritime’s June 2022 issue. The Nautical Institute compiles these reports to help prevent maritime accidents. That is why they are also published on SWZ|Maritime’s website.

More reports are needed to keep the scheme interesting and informative. All reports are read only by the Mars coordinator and are treated in the strictest confidence. To submit a report, please use the Mars report form.