1.2 General Definitions (Rules 1–3)

Rule 1 — Application

Rule 1 states that the Rules apply to all vessels upon the high seas and in all waters connected therewith navigable by seagoing vessels. That is the legal hook that puts COLREGS on coastal approaches and, through U.S. adoption and the Inland Navigational Rules Act, puts a parallel code on inland waters. Rule 1 also authorizes special rules made by an appropriate authority for roadsteads, harbors, rivers, lakes, or inland waterways — provided those special rules conform as closely as possible to the international rules. That is how Inland Rules, pilot rules, and certain local regulations lawfully sit beside the general text rather than replacing the duty to avoid collision.

For Master 100 practice: every vessel you meet is bound — kayaks, sailing dinghies, dredges, seaplanes on the water, and 900-foot tankers. Size does not exempt anyone from lookout, safe speed, or risk assessment. Local rules may add requirements (VTS call-in, speed limits, one-way traffic) but they do not license a Master to ignore Rule 2 when danger is immediate.

Rule 2 — Responsibility (highest-yield short rule)

Rule 2 is short and repeatedly tested because it undercuts the excuse "I followed the letter of Rule 15."

Rule 2(a) — Rule of Good Seamanship

Nothing in the Rules shall exonerate any vessel, or the owner, master, or crew thereof, from the consequences of any neglect to comply with these Rules or of the neglect of any precaution which may be required by the ordinary practice of seamen, or by the special circumstances of the case.

In Master language: compliance with a single rule is not a free pass. If a prudent Master of a passenger vessel would have slowed earlier, posted a bow lookout, or refused to pass close ahead of a ferry, Rule 2(a) still holds you accountable for that omission. Courts and investigations lean heavily on this clause after collisions involving passenger-carrying Masters.

Rule 2(b) — General Prudential Rule (departure clause)

In construing and complying with these Rules, due regard shall be had to all dangers of navigation and collision and to any special circumstances, including the limitations of the vessels involved, which may make a departure from these Rules necessary to avoid immediate danger.

This is the legal basis for breaking the normal give-way/stand-on assignment in extremis. If standing on would cause the collision, Rule 2(b) not only permits but requires you to depart from the Rules to avoid immediate danger. Exam items often pair a rigid "always stand on" option against the correct answer that special circumstances / immediate danger justify departure. On a crowded passenger deck with limited sea room, that clause is not theory — it is the last-second legal and moral duty.

Rule 3 — General Definitions

Rule 3 is the dictionary for everything that follows. Misclassify the vessel and every later steering or light answer fails.

Vessel types and categories

RAM examples named in the Rules (high yield): laying or servicing a navigation mark, submarine cable, or pipeline; dredging, surveying, or underwater operations; transferring persons, provisions, or cargo while underway; launching or recovering aircraft; mine clearance operations; a towing operation that severely restricts the towing vessel and her tow in their ability to deviate from their course.

NUC vs RAM trap: NUC is about an exceptional circumstance (engine failure, lost steering, major casualty). RAM is about the nature of the work while still operational. A dredge pumping spoil is typically RAM; a freighter with a failed main engine is NUC. A Master passenger vessel with a broken rudder is NUC, not "restricted by work."

Movement and condition terms

A vessel drifting with engines secured, neither anchored nor aground, is underway. If she is not moving through the water she is underway but not making way — a distinction that later controls certain lights and sound signals. "In sight" means eyes, not radar paint: if you only have the other vessel on radar in fog, Rule 19 (restricted visibility) governs, not the Section II crossing/head-on rules.

Sail under power, fishing without privilege

Two classic Master 100 traps:

1. Auxiliary sailboat with engine on — even with sails set, she is a power-driven vessel once propelling machinery is being used.
2. Sportfisher trolling — trolling lines do not qualify as "engaged in fishing" under Rule 3. She remains an ordinary power-driven vessel with no fishing privilege over you.

Seaplanes and WIG craft

A seaplane taxiing on the surface is a vessel under Rule 3 and must keep clear of all vessels in general terms under later rules; WIG craft get specific treatment when taking off, landing, or in flight near the surface. For Q100, the takeaway is breadth of "vessel" — do not exclude aircraft on the water from collision duties.

Why classification wins the module

Rule 18's responsibilities between vessels (covered in a later chapter) is just a sorted list of these categories: power-driven keeps clear of sailing; sailing keeps clear of fishing; fishing keeps clear of NUC/RAM; and so on. Every geometry question (head-on, crossing, overtaking) assumes you first named the vessels correctly. On a Master passenger boat, also remember your own status: if you are power-driven underway with passengers, you are not "special" merely because you carry people — unless you fit a defined category (for example, RAM while engaged in a listed work operation, which ordinary passenger carriage is not).

Master Exam Framing

Expect items that (1) redefine a motoring sailboat as power-driven, (2) deny fishing privilege to trollers, (3) distinguish underway from making way, (4) invoke Rule 2(b) departure for immediate danger, and (5) mark CBD as International-only. Answer from the definition table, not from "what feels fair" on the water.