Anchor brake maintenance is a crucial element in safe operations. The Nautical Institute gives this advice in its latest Mars Report in which a tanker’s port anchor brake malfunctioned, eventually resulting in it becoming entangles with the starboard anchor chain.

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:

A tanker arrived at a busy anchorage for bunkering and provisions. With pilot on board, they prepared to drop the port anchor at the designated anchorage. After preparations were completed, the port anchor was let go on the brake, with instructions to secure it with seven shackles in the water. During the operation, the anchor and chain took on too much momentum and the brake could not stop the outflow of chain. The anchor was presumed lost.

Having consulted with the pilot, and in view of the surrounding traffic, the master instructed the anchoring team to prepare and lower the starboard anchor with the windlass in gear in order to safely complete the anchoring operation.

The port anchor chain was then heaved up. It was found that the anchor was not, in fact, lost; the bitter end had remained secured. However, when the port anchor was heaved up, it could not be secured because it had become entangled with the starboard anchor chain.

Anchor chain

Investigation findings

The company investigation found that the port anchor brake was not working properly; it did not move before the brake reached the ninety per cent open position. If the equipment had been in good condition, the anchor chain could have been controlled.

Also, the investigation found that after the port anchor chain paid out uncontrollably, the actual condition of the port anchor was not correctly assessed/communicated to the bridge. Had this been done, the starboard anchor would not have been deployed and the incident would have been avoided.

Also read: ‘Wind direction shifts in a crowded anchorage can change the risk scenario’

Advice from The Nautical Institute

  • Anchor brake maintenance is a crucial element in safe operations. The uncontrolled descent of an anchor chain can not only pose a significant risk of losing an anchor, but also poses a lethal hazard to crew.
  • During and after an incident it is sometimes difficult to assess and communicate the state of affairs – yet this is what is needed for ships’ leaders to make the right decisions going forward.

Also read: Covid cruise pause leads to lost anchors

Mars Reports

This accident was covered in the Mars Reports, originally published as Mars 202230, that are part of Report Number 357. Selections of Mars Reports are also published in the SWZ|Maritime magazine. The Nautical Institute compiles these reports to help prevent maritime accidents. That is why they are also published (in full) 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.

Also read: Poor risk analysis for stuck anchor results in fatality