April 16, 2019
Mars Report: Hydrodynamic Interaction Close-call

Leaving from and mooring into a berth can cause hydrodynamic interactions. All the more reason to make one's intentions clear and to maintain good situational awareness.

A cruise ship (CS Orange in the diagram) was moored starboard side to, bow out. Another cruise ship (CS Black) turned on arrival and was backing into its berth, going port side to. While CS Black was nearing its final position, the bridge officer on the starboard wing reported that CS Orange had begun to let go lines and was departing. Yet, the bridge team of CS Orange had not announced their intention to depart the berth on VHF 16 or the port working frequency. Several of CS Black’s lines were now ashore when CS Orange departed its berth and rapidly increased its speed.

Lessons Learned

  • The surging of CS Black during mooring could have caused the spring line to part had it been secured, which in turn could have caused serious injury or even death.
  • During a mooring operation, it is important to maintain broad situational awareness. One cannot always count on the bridge teams of nearby vessels to exercise good and safe seamanship.

Editor’s note: For more hydrodynamic interactions see Mars 201703 and 201704 among others.

Mars Reports

This is one of the March Mars Reports (number 201916) that are part of Report Number 317. A selection of this Report has also been published in SWZ|Maritime’s April issue.


Through the kind intermediary of The Nautical Institute we gratefully acknowledge sponsorship provided by:
American Bureau of Shipping, AR Brink & Associates, Britannia P&I Club, Cargill, Class NK, DNV, Gard, IHS Fairplay Safety at Sea International, International Institute of Marine Surveying, Lairdside Maritime Centre, London Offshore Consultants, MOL Tankship Management (Europe) Ltd, Noble Denton, North of England P&I Club, Sail Training International, Shipowners Club, The Marine Society and Sea Cadets, The Swedish Club, UK Hydrographic Office, West of England P&I Club

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