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Why ships collide?


A bulk carrier named “A” while navigating in a two-way water route had a crossing course with another ship called “B”. The route was monitored by a VTS and outside its limits there are shallows. In contrary to Rule 15 the navigation officers agreed to pass starboard to starboard. To achieve this manoeuvring, the Ship “A” had to turn its course on the left passing from ship “B” to a distance of 0.5 nautical miles. As it is shown in the picture, the ship “A” could remain at its initial course and have a clear port to port pass from ship “B”.


‘Conflicting actions may occur in head-on or near head-on encounters where one ship takes avoiding action by turning to port and the other ship by turning to starboard. Rule 8 (a)


See footage of near-miss ship collision


With the use of ECDIS the incident was examined by the DPA who made the following observations:



  1. Ship “A” changed course to port side against Rule 15 which states to avoid crossing ahead of the other vessel. In a crossing situation, a ship is required to avoid crossing ahead of a ship on its starboard side, if there is a risk of collision.
  2. A VHF agreement cannot be made against a COLREG for any reason.
  3. Safe distance from another ship cannot be less than 1 nautical mile at open sea. Otherwise, speed should be reduced Rule 8(d).
  4. Rule 17(ii) (referred to the ‘stand-on vessel) should be read together with 17(c) that does not allow a ship to alter its course to port side to avoid collision with another ship crossing from its port side