The other vessel is coming directly toward the observer, so both the port and starboard running lights are visible.
You are approaching the stern of another vessel
A vessel displaying a visible white light signifies that it is a power-driven vessel. Observing this light helps determine the vessel's status and potential course of action to avoid a collision.
You are approaching the starboard side of another vessel
The other vessel is coming directly toward the observer, so both the port and starboard running lights are visible.
You are approaching the stern of another vessel and may be overtaking it
Give-way to starboard side
3 seconds of rapid bell ringing
You are approaching the port side of another vessel
It depends on the configuration seen. There are different lights visible depending on the relative headings of the vessels and relative sizes etc.
Encountering or meeting unexpectedly
How the two vessels are propelled
Different societies encountering one another.