Two problems concerned with the use of radar to reduce the risk of collision are frequently called to mind by reports of casualties and correspondence relating to them. One is that of avoiding the ‘region of collision’ and the other is how best to proceed within such a region when it is unavoidable. The writer's attention was recently drawn to that phrase as it was used in 1932 in the judgment of the Court of Appeal on the collision between Haliotis and Chisone. The phrase caught the eye because of the need (in the writer's view) of a striking term to appeal to the imagination of some incautious mariners and impress them with the undesirability in fog of leaving too much to chance; it seemed to have more significance than the term ‘close-quarter situation’.

In the case in question the Chisone was found partly to blame because she did not stop her engines until five minutes after hearing the fog signal of the Haliotis. Although she was stopped, or nearly so, some minutes before the collision, she had come directly into the path of the Haliotis and so was considered to have committed the breach of Art. 16 (Rule 16 (b)) ‘in the region of the collision.’