Lesson 1: Application, Responsibility and Definitions

Rules 1–3

Start every encounter by establishing which rules apply and what each vessel is actually doing.

The working method

Rule 1 sets the scope. Rule 2 preserves the responsibility to use ordinary seamanship and allows departure from a rule only when necessary to avoid immediate danger. Rule 3 supplies the definitions used throughout the Rules.

Underway means not at anchor, made fast to shore or aground. It does not necessarily mean making way.
A vessel using sails and machinery is treated as power-driven.
Fishing status applies only when fishing gear restricts manoeuvrability.
Not under command and restricted in ability to manoeuvre describe specific operational conditions, not convenience.

Decision sequence

Confirm location, visibility and any local special rules.
Identify propulsion, activity and displayed lights or shapes.
Ask whether special circumstances make strict application unsafe.
Keep monitoring: status and risk can change.

Scenario check

Scenario: A yacht has sails set but is also using its engine. How should you classify it for the steering and sailing rules?

Show the recommended decision

Treat it as a power-driven vessel. It should also display the prescribed cone by day.

Rule link: Rules 3 and 25(e).

Source: USCG Navigation Rules.

Educational material only. It does not replace the current official rules, notices, local regulations, proper training or prudent seamanship.