201927 Swinging at anchor – close call

24 Apr 2019 MARS 2019

Swinging at anchor – close call

When another large tanker anchored about 0.3nm away at the same anchorage. Some time later, the vessels began to swing about their respective anchors due to the shifting tidal stream, but the effects on each ship were slightly different. The vessel’s sterns began to approach one another. Concerned about a possible collision, the OOW on vessel


A repeatedly attempted to communicate with vessel B but received no response.


The Master was called to the bridge. With the vessel still receiving no response on VHF from vessel B, the anchor party was made ready and the main engine brought on line for manoeuvring. Only 25 minutes had transpired since the vessels began to swing from their initial positions, but they were now less than 0.15nm apart. Dead slow ahead was ordered and the anchor was heaved up simultaneously, increasing the distance between the vessels.



Lessons learned

  • When going to anchor, place your vessel in a position that allows for a 360° swing on the anchor chain and still provides a safety margin with other anchored vessels that may also swing 360°.
  • At anchor, just as when underway, it is important to maintain close monitoring of your position and of those vessels around you.
  • If you have concerns about traffic, weather etc while at anchorage, keep your main engine available at short notice to help prevent any risk of collision.