COLREGS Rule 3 - General Definitions and Interpretations from the Main Text

Rule 3

General Definitions — International 

For the purpose of these Rules, except where the context otherwise requires: 

(a) The word “vessel” includes every description of water craft, including non-displacement craft, WIG craft and seaplanes, used or capable of being used as a means of transportation on water. [There is a Canadian modification about this definition.]

(b) The term power-driven vessel means any vessel propelled by machinery. 

(c) The term sailing vessel means any vessel under sail provided that propelling machinery, if fitted, is not being used. 

(d) The term vessel engaged in fishing means any vessel fishing with nets, lines, trawls or other fishing apparatus which restrict manoeuvrability, but does not include a vessel fishing with trolling lines or other fishing apparatus which do not restrict manoeuvrability. 

(e) The word “seaplane” includes any aircraft designed to manoeuvre on the water. 

(f) The term vessel not under command means a vessel which through some exceptional circumstance is unable to manoeuvre as required by these Rules and is therefore unable to keep out of the way of another vessel. 

(g) The term vessel restricted in her ability to manoeuvre means a vessel which from the nature of her work is restricted in her ability to manoeuvre as required by these Rules and is therefore unable to keep out of the way of another vessel. The term “vessels restricted in their ability to manoeuvre” shall include but not be limited to: 

(h ) The term vessel constrained by her draught means a power-driven vessel that, because of the vessel’s draught in relation to the available depth and width of navigable water, is severely restricted in the vessel’s ability to deviate from the course the vessel is following. 

(i) The word underway means that a vessel is not at anchor, or made fast to the shore, or aground. 

(j) The words length and breadth of a vessel mean her length overall and greatest breadth. 

(k) Vessels shall be deemed to be in sight of one another only when one can be observed visually from the other. 

(l) The term restricted visibility means any condition in which visibility is restricted by fog, mist, falling snow, heavy rainstorms, sandstorms or any other similar causes. 

(m) The term Wing-in-Ground (WIG) craft means a multimodal craft which, in its main operational mode, flies in close proximity to the surface by utilizing surface-effect action. 

From the main text of the Canadian regulations there are additional terms that may be required in interpreting the Collision Regulations:

Interpretation 

air cushion vessel means a vessel designed so that the whole or a significant part of its weight can be supported, whether at rest or in motion, by a continuously generated cushion of air dependent for its effectiveness on the proximity of the vessel to the surface over which it operates.   

barge means a non-self-propelled barge, scow, dredge, pile-driver, hopper, pontoon or houseboat.   

composite unit means a pushing vessel and an associated pushed vessel that are rigidly connected and that are designed as a dedicated and integrated tug and barge combination.

direction of traffic flow means the direction for traffic on a route that is indicated by arrows on a reference chart.   

give-way vessel means a vessel that is required by these Regulations to keep out of the way of another vessel.  

inconspicuous, partly submerged vessel or object means a raft or vessel or any other floating object that is low in the water and is generally difficult to see.   

inshore traffic zone means a routing measure that is a designated area between the landward boundary of a traffic separation scheme and the adjacent coast that is intended for local traffic.  

Notice to Mariners means the monthly and annual publication by the Department of Fisheries and Oceans to provide marine information.  

Notice to Shipping means an urgent release by the Department of Fisheries and Oceans to provide marine information. [Replaced by Navigation Warnings]  

ODAS means an ocean data acquisition system that consists of any object on or in the water and is designed to collect, store or transmit samples or data relating to the marine environment or the atmosphere or to the uses thereof.   

raft includes a boom.   

route means an area within which there are, at any point, one or two directions of traffic flow and that is delineated on two sides by separation lines, separation zones, natural obstacles or dashed tinted lines except that the continuity of such lines or zones may be interrupted where the route merges with, diverges from or crosses another route.   

routing system means any system of one or more routes or routing measures which systems may include traffic separation schemes, two-way routes, recommended tracks, areas to be avoided, inshore traffic zones, roundabouts, precautionary areas and deep water routes.   

seaplane includes any aircraft designed to manoeuvre on the water.   

separation zone or separation line means a zone or line separating routes in which vessels are proceeding in opposite or nearly opposite directions or separating a route from the adjacent inshore traffic zone.  

traffic lane means a route within which there is one direction of traffic flow.   

traffic separation scheme means a routing measure that provides for the separation of opposing streams of traffic by appropriate means and by the establishment of traffic lanes.  

trawling means fishing by dragging through the water a dredge net or other fishing apparatus.    

vessel shall ... be read to include a reference to a seaplane when it is on or over the water

Arguments over Definitions

The term making way is used in the COLREGS but never defined. A similar term underway "means that a vessel is not at anchor, or made fast to the shore, or aground" (Rule 3(i)). The general understanding of "making way" is that a vessel is being propelled through the water (by machinery or by sail); that is a vessel that is drifting is not making way. So, a vessel that has just slipped its mooring may be underway, but it may not yet be making way (until it starts to manoeuvre). 

The distinction is important for certain rules. Some classes of vessels show certain lights when making way, but not when underway. For example, vessels that are engaged in fishing, or are not under command, or are restricted in their ability to manoeuvre will display sidelights and a stern light when making way (e.g., being propelled), but not when they are underway and not making way (e.g., drifting). (Power-driven and sailing vessels are to show sidelights and a stern light whenever they are underway, even if not making way.) See Rules 26(b)(iii) and 26(c)(iii) for fishing vessels and Rules 27 (a)(iii) and 27(b)(iii) for vessels not under command and restricted in ability to manoeuvre. 

A power-driven vessel that has its engines idling or switched off might try to claim it is not under command (NUC) or restricted in its ability to manoeuvre (RAM). However, to be considered not under command, there must be exceptional circumstances limiting the vessel's compliance with COLREGS; setting engines to idle or to off is not an exceptional circumstance. A vessel that is restricted in the ability to manoeuvre can claim this privilege only if the restrictions are a consequence of "the nature of her work"; thus a simple self-imposed restriction from switching engines to idle or to off is not sufficient to qualify as restricted in ability to manoeuvre under the COLREGS. The understanding is that a power vessel can easily engage engines when needed, so is still under command and is not restricted from moving if she wants to. 

The definition "engaged in fishing" is worded to exclude vessels that are fishing by trolling (Rule 3(d)). The historical argument was that, when trolling, a vessel can still manoeuvre so as to comply with the COLREGS just as they are meant to apply to normal power-driven vessels. Salmon fishermen and others have tried for many years to point out that vessels that are trolling can sometimes be as hampered in manoeuvrability as much other fishing vessels; however they have not been successful in having the exclusion in the definition of "engaged in fishing" changed to treat trolling the same as other methods.