Discussion of Rule 14
Rule 14 applies to power-driven vessels when in sight of one another. It does not, for example, apply to sailing vessels, or to other vessels in special categories. It is unique among the Rules in that it mandates a particular steering maneuver (turn right to pass port to port) — most rules give more generic instructions such as "stay clear," "do not impede," "avoid turning... in a particular direction," etc. It also covers the unique situation where neither of the two meeting vessels has right of way. There is no stand-on vessel when two power-driven vessels meet head to head. Whenever there is risk of collision, both must turn. You cannot note that the other vessel turned, therefore you are OK and carry on. In this situation, both must turn right.
It determining whether the situation is a meeting or crossing one, it is generally considered that if both sidelights of each vessel are visible to the other vessel, then the situation is a meeting one. Both sidelights may show over an arc of as much as 6º on either side of the bow, so a similar aspect of the vessels in daytime would indicate a head-on situation.
The phrase ”so as to involve risk of collision” in this rule has been held to apply to any situation that may develop now or in the future should proper maneuvers not be made and not just to the situation as it exists upon first sighting. Rule 8 requires that any course change made be large enough to effect a safe passage.
If there is any doubt about the situation, then power-driven vessels are required to assume that the situation does exist and to make appropriate maneuvers. However, if there is no risk of collision, then neither vessel is required to turn to starboard. Further, if there is no risk of collision then the vessels may pass starboard to starboard. But, a power-driven vessel approaching another in a head-on situation that proposes a starboard to starboard passage assumes the entire risk of the maneuver, including any misunderstanding of signals.
It is valuable to remember that this Rule applies to vessels in visual sight of one another, within risk of collision. When viewing meeting vessels by radar, on the other hand, all targets approaching from dead ahead will look like meeting vessels at a long distance off. It would be imprudent and indeed contrary to the Rules to maneuver before you are certain of the approaching vessel's true course relative to yours. If you turn without knowing the risk of collision, you could turn to the right and increase the risk of collision. Rule 7 addresses more specifically the cautions to be taken when observing vessels by radar.
Under the US Inland Rules, a power-driven downbound vessel with a following current on the Western Rivers or other specific waters has the ”right-of-way” over upbound vessels, shall propose the manner of passage, and shall initiate maneuvering signals. The phrase ”right-of-way” does not mean that the downbound vessel is relieved of any liability for resulting collisions. The requirements of the Rules follow long-standing customs on the Mississippi and other rivers. They are intended to give less maneuverable vessels, which may be required to venture into the port side waters of tortuous channels, the opportunity to safely transit those waters without the additional burden of maneuvering around vessels proceeding upstream. This privilege is only available to vessels that positively require it. See Inland Rule 9 (a) (ii) Discussion for further information.