Yachtmaster revision module 5 of 20

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COLREGs

International Regulations for Preventing Collisions at Sea — steering rules, lights, and shapes.

Steering and sailing rules (Rules 5, 7, 8, 9, 10, 12–19)General rules including Rule 2 (Responsibility)

14 guided lessons · 20 practice questions · 21 flashcards

3 outcomes · self-guided revision
  • Explain international Regulations for Preventing Collisions at Sea — steering rules, lights, and shapes.
  • Apply Steering and sailing rules (Rules 5, 7, 8, 9, 10, 12–19) to a realistic onboard situation.
  • Recall the core check: cOLREGs apply to ALL vessels on navigable waters.

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Lesson summaries

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What Are the COLREGs?

The International Regulations for Preventing Collisions at Sea (COLREGs, also known as IRPCS) are the 'rules of the road' at sea. They apply to all vessels on the high seas and connected...

  • COLREGs apply to ALL vessels on navigable waters
  • Part B (Steering and Sailing Rules) requires full knowledge
Read the full lesson: What Are the COLREGs?

Rule 2 — Responsibility

Rule 2 underpins every other rule. It states that nothing in the COLREGs shall exonerate any vessel, owner, master, or crew from the consequences of neglecting the rules, or neglecting an...

  • No vessel is exempt from the consequences of neglecting the rules
  • Ordinary practice of seamen must always be followed
Read the full lesson: Rule 2 — Responsibility

Rule 5 — Look-out

Every vessel shall at all times maintain a proper look-out by sight AND hearing, as well as by all available means (including radar), so as to make a full appraisal of the situation and t...

  • Look-out by sight AND hearing at all times
  • Use all available means appropriate to the circumstances; radar where fitted and operational, with AIS only as a supplement
Read the full lesson: Rule 5 — Look-out

Rule 7 — Risk of Collision

You must use all available means to determine if a risk of collision exists. If there is any doubt, assume it does exist.

  • If in doubt, risk of collision EXISTS
  • Constant bearing + decreasing range = collision risk
Read the full lesson: Rule 7 — Risk of Collision

Rule 8 — Action to Avoid Collision

Any action taken to avoid collision must be positive, made in ample time, and large enough to be readily apparent to the other vessel. Small, indecisive course changes are dangerous — the...

  • Action must be POSITIVE and EARLY
  • Course changes must be LARGE enough to be obvious
Read the full lesson: Rule 8 — Action to Avoid Collision

Rules 12–18 — Who Gives Way?

Rule 12 (Sailing vessels): When two sailing vessels meet, the vessel on port tack gives way to the vessel on starboard tack. If both are on the same tack, the windward vessel gives way. I...

  • Sailing vessels: port tack gives way to starboard tack
  • Overtaking vessel ALWAYS gives way (overrides other rules)
Read the full lesson: Rules 12–18 — Who Gives Way?

Rule 18 — Responsibilities Between Vessels

Rule 18 sets responsibilities between vessel types and statuses. It is a practical guide to who should keep clear in normal sighted encounters, not an absolute right-of-way ladder.

  • Rule 18 sets keep-clear duties by vessel status and manoeuvrability
  • Avoid impeding vessels limited by channel, fairway, or draught constraints
Read the full lesson: Rule 18 — Responsibilities Between Vessels

Rules 9 & 10 — Narrow Channels and TSS

Rule 9 (Narrow Channels): Keep to the starboard side. Vessels under 20m or sailing vessels must not impede vessels that can only navigate within the channel. Do not cross a narrow channel...

  • Narrow channels: keep to starboard side
  • Small vessels must not impede vessels confined to the channel
Read the full lesson: Rules 9 & 10 — Narrow Channels and TSS

Navigation Lights

Power-driven vessels display: masthead light(s) (white, 225°), sidelights (red port, green starboard, each 112.5°), and a stern light (white, 135°). Vessels 50m or more show two masthead...

  • Power-driven: masthead (white 225°) + sidelights + stern
  • Sailing: sidelights + stern; Rule 25 permits specified combined or red-over-green alternatives
Read the full lesson: Navigation Lights

Day Shapes

Day shapes are black shapes hoisted where they can best be seen during daylight to indicate a vessel's status or activity. They supplement or replace lights during the day and are require...

  • Ball — vessel at anchor
  • Cone apex down — motor-sailing (engine + sails)
Read the full lesson: Day Shapes

Rule 19 — Restricted Visibility

Rule 19 applies to vessels not in sight of one another when navigating in or near an area of restricted visibility (fog, heavy rain, snow, etc.). It replaces Rules 12–18 when vessels cann...

  • Applies when vessels are NOT in sight of one another
  • Proceed at a safe speed adapted to visibility
Read the full lesson: Rule 19 — Restricted Visibility

Yachtmaster Offshore Standard

COLREGs at Yachtmaster level is not just recall. The answer has to show command judgement, evidence quality, margin, and a fallback if the first plan stops being safe.

  • State the evidence you trust and the evidence you distrust.
  • Name the margin that makes the plan defensible.
Read the full lesson: Yachtmaster Offshore Standard

Advanced Scenario Check

Decision pressure: A small course alteration may look neat on paper but be invisible to the other vessel.

  • Apply Steering and sailing rules (Rules 5, 7, 8, 9, 10, 12–19) to a changed real-world situation.
  • Separate fact, estimate, and assumption.
Read the full lesson: Advanced Scenario Check

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