Vessels in Sight of One another, Crossing
When two ships meet, and if risk of collision exists (see previous article in series), the Collision rules specify that unless one is overtaking the other, they are ‘crossing’. If they are crossing, the ship that has the other on her starboard side (right side, and this ship is the ‘give way’ vessel) will keep out of the way of the other vessel, which is the ‘stand on’ vessel, which must maintain its course and speed.
The give way vessel can alter speed or alter course, or indeed, a combination of the above. Usually in the open sea, an alteration of course is sufficient, as can be seen in the diagram.
If required, stipulated signals or sounds (foghorn) will be made by the vessels. For example, one short blast on the foghorn (or one flash of a light at night) will indicate “I am altering course to starboard" )
In any case, the give way vessel will avoid crossing ahead of the other vessel. At sea, a starboard alteration of course is invariably made in such situations.
If both vessels are head on (on reciprocal courses) each will alter course to starboard and keep out of the way of the other.