PART A (General)
Application.
(a) These Rules shall apply to ALL vessels upon the high seas and in all waters connected therewith navigable by seagoing vessels.
(b) Nothing in these Rules shall interfere with the operations of special rules made by an appropriate authority for roadsteads, harbours, rivers, lakes or inland waterways connected with the high seas and navigable by seagoing vessels. Such special rules shall conform as closely as possible to these Rules.
(c) Nothing in these Rules shall interfere with the operation of any special rules made by the Government of any state with respect to additional station or signal lights, shapes or whistle signals for ships of war and vessels proceeding under convoy, or with respect to additional station or signal lights or shapes for fishing vessels engaged in fishing as a fleet. These additional station or signal lights, shapes or whistle signals, shall, so far as possible, be such that they cannot be mistaken for any light, shape or signal authorised elsewhere under these Rules.
(d) Traffic separation schemes may be adopted by the Organization for the purpose of these Rules.
(e) Whenever the Government concerned shall have determined that a vessel of special construction or purpose cannot comply fully with the provisions of any of these Rules with respect to the number, position, range or arc of visibility of lights or shapes, as well as to the disposition and characteristics of sound-signalling appliances, such vessel shall comply with such other provisions in regard to the number, position, range or arc of visibility of lights or shapes, as well as to the disposition and characteristics of sound-signalling appliances, as her Government shall have determined to be the closest possible compliance with these Rules in respect of that vessel.
The important part for us, is that the Regulations apply to all vessels on the sea and also in their connected waters, which are capable of being navigated by seagoing vessels.
Note that, in addition to the Rules, extra regulations might also apply, when navigating in harbours, rivers and other inland waterways. These might relate to the imposition of specific speed limits and steering directions in restricted waters, though other special conditions may also apply.
For instance, in river Thames Region byelaws require a full set of navigation lights for powered craft under 7m (23ft), even though the Regulations call for an all-round white light only, provided the boat cannot exceed 7 knots. Another example can be found on the Rhine, where German authorities insist on, where practicable, the masthead lights being on the same level as the sidelights, rather than at least 1m (3ft 3in) above them. This is to assist in avoiding confusion with bridge signals.
Clearly, when operating in areas under the jurisdiction of a specific navigation authority, one has to be sure of compliance with local rules. But the basic principles of collision-avoidance remain the same in almost all situations.
You will come across above mentioned variations in coastal waters, mainly in harbours.
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