Neither power-driven vessel A nor power-driven vessel B gives way or stands on in a head-on encounter. Therefore, some communication is needed between vessels A and B. The most common response in a head-on meeting between power-driven vessels is to signal an intention to pass port-to-port. This action is initiated by one of the vessels sounding one short blast.
In short, vessel A must blow one short blast, indicating its intention to pass port-to-port, and then alters its course to starboardright hand side of a vessel.. Vessel B must return one short blast—to indicate agreement and understanding—and alter its course to starboard, thereby, leaving room on each vessel's portleft hand side of a vessel. side for passing.
If it is not possible to pass port-to-port due to an obstruction or shoreline, a starboard-to-starboard pass should be signaled with two short blasts.
In short, vessel A must blow two short blasts, indicating its intention to pass starboard-to-starboard, and alter its course to port. Vessel B must return two short blasts to indicate agreement and understanding and alter its course to port, thereby, leaving room on each vessel's starboard side for passing.