Rule 3 — General definitions
A wrong definition leads to wrong answers about the steering rules and lights: a yacht motor-sailing called a sailing vessel, a drifting ship called not underway, a radar contact treated as in sight. All thirteen definitions in Rule 3, grouped, with what each one decides elsewhere in the rules.
It gives the meanings of thirteen terms, (a) to (m), that apply throughout the rules 'except where the context otherwise requires'. Together they decide which other rules apply to a vessel — her lights, her sound signals, and who keeps out of whose way.
It covers 'every description of water craft' used or capable of being used as a means of transportation on water, expressly including non-displacement craft, WIG craft and seaplanes. Rule 3(e) adds that a seaplane includes any aircraft designed to manoeuvre on the water.
The definition is deliberately wide: a ship's tender, a rowing boat and a seaplane on the water are all vessels. Each kind has provisions of its own — Rule 23(b) sets an extra light for an air cushion vessel operating in the non-displacement mode, and Rule 18(e) requires a seaplane on the water, in general, to keep well clear of all vessels and avoid impeding their navigation.
A Wing-in-Ground craft: a multimodal craft which, in its main operational mode, 'flies in close proximity to the surface' using surface-effect action. Rule 18(f) requires a WIG craft taking off, landing or in flight near the surface to keep well clear of all other vessels and avoid impeding their navigation; on the water surface she complies with the steering and sailing rules as a power-driven vessel.
Rule 3(b): a power-driven vessel is any vessel 'propelled by machinery'. Rule 3(c): a sailing vessel is any vessel under sail, provided that 'propelling machinery, if fitted, is not being used'.
So a sailing yacht with her engine running and in gear is a power-driven vessel, sails up or not. She has the duties of a power-driven vessel in the steering rules, shows the lights of a power-driven vessel underway (Rule 23), and Rule 25(e) requires a vessel proceeding under sail while also propelled by machinery to show a cone, apex downwards, forward — a shape, so shown by day (Rule 20(d)). In fog she gives the power-driven signal of Rule 35(a) or (b), not the sailing vessel's signal in 35(c).
A vessel fishing with nets, lines, trawls or other fishing apparatus 'which restrict manoeuvrability'. It does not include a vessel fishing with trolling lines, or with other apparatus that does not restrict manoeuvrability.
The test is the gear and what it does to her manoeuvrability, not the type of vessel. As we read it, a fishing vessel on passage with her gear stowed is not engaged in fishing, and a yacht towing a mackerel line is not either.
Neither can manoeuvre as the rules require — a vessel not under command is 'unable to', a vessel restricted in her ability to manoeuvre is restricted in her ability to — and both are 'therefore unable to keep out of the way of another vessel'. The difference is the cause.
Not under command, Rule 3(f): the cause is 'some exceptional circumstance' — in practice, something like a main engine or steering gear failure. Restricted in her ability to manoeuvre, Rule 3(g): the cause is 'the nature of her work'.
Rule 3(g) says the term shall 'include but not be limited to' — so the list is not exhaustive: (i) a vessel laying, servicing or picking up a navigation mark, submarine cable or pipeline; (ii) one dredging, surveying or engaged in underwater operations; (iii) one replenishing or transferring persons, provisions or cargo while underway; (iv) one launching or recovering aircraft; (v) one engaged in mineclearance operations; (vi) one engaged in a towing operation that 'severely restricts' the towing vessel and her tow in their ability to deviate from their course.
Item (vi) is not every tow. A towing vessel is restricted in her ability to manoeuvre only when the towing operation severely restricts her and her tow in their ability to deviate from their course.
A power-driven vessel that, because of her draught in relation to the available depth and width of navigable water, is 'severely restricted' in her ability to deviate from the course she is following. Only a power-driven vessel can be one.
Because Rule 18 builds its order of responsibility on them, except where Rules 9, 10 and 13 otherwise require. A power-driven vessel underway keeps out of the way of a vessel not under command, a vessel restricted in her ability to manoeuvre, a vessel engaged in fishing and a sailing vessel (18(a)). A sailing vessel underway keeps out of the way of the first three (18(b)). A vessel engaged in fishing when underway, so far as possible, keeps out of the way of the first two (18(c)).
A vessel constrained by her draught is protected differently: under 18(d), any vessel other than one not under command or restricted in her ability to manoeuvre must, if the circumstances of the case admit, avoid impeding her safe passage — when she is exhibiting the signals in Rule 28.
At any time she is not anchored, not made fast to the shore and not aground. A vessel drifting with her engines stopped is underway.
'Making way' is not defined in Rule 3. The rules use 'making way through the water' for a vessel actually moving through the water, and they treat the two states differently: Rule 35(a) gives a power-driven vessel making way through the water one fog signal, and Rule 35(b) gives one underway but stopped and making no way through the water another.
The length and breadth of a vessel mean her 'length overall and greatest breadth'. So a length threshold in the rules — the 20 metres in Rules 9(b) and 10(j), for example — refers to length overall.
Only when one can be 'observed visually' from the other. A contact on radar, on AIS or heard on VHF is not in sight.
This decides which section of Part B applies. Section II — Rules 11 to 18: sailing vessels, overtaking, head-on, crossing, give-way and stand-on action, and the order of responsibilities in Rule 18 — applies to vessels in sight of one another (Rule 11). Rule 19 applies to vessels not in sight of one another when navigating in or near an area of restricted visibility.
Any condition in which visibility is restricted by fog, mist, falling snow, heavy rainstorms, sandstorms 'or any other similar causes'. The rules give no distance.
It triggers Rule 19 and the fog signals of Rule 35, both of which apply in or near an area of restricted visibility — so clear weather alongside a fog bank still counts.
It may come up as a definition, then straight into what it means for you. Examples of the kind of question to be ready for:
“Define a sailing vessel. Your yacht is motor-sailing — what are you, and what do you show by day?”
“What is the difference between not under command and restricted in her ability to manoeuvre?”
“Give me some examples of vessels restricted in their ability to manoeuvre. Is every tug with a tow one of them?”
“Is a vessel trolling a vessel engaged in fishing?”
“Your engines are stopped and you're drifting. Are you underway?”
“When are two vessels in sight of one another?”
“What is restricted visibility? Give me a distance.”
The common slips: calling a yacht under sail and engine a sailing vessel; confusing not under command with restricted in her ability to manoeuvre, or treating every tow as restricted; counting any boat with fishing gear aboard as engaged in fishing; saying a drifting vessel is not underway; treating a radar contact as in sight; and giving a distance for restricted visibility.
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