COLREGS Rule 8 — Action to Avoid Collision

Rule Text

What it means on the water

• →Action must be taken in AMPLE TIME — not at the last moment.
• →Action must be LARGE and POSITIVE — small course changes are insufficient and may not be detected.
• →Course alterations are generally preferred to speed reductions when time and sea room allow.
• →After action, monitor until the vessel is finally past and clear.
• →A vessel may stop or reverse if necessary — there is no prohibition on backing down to avoid collision.
• →Avoid impeding the passage of vessels in channels or TSS (a separate duty in Rules 9 and 10).

Common exam mistakes

• ✗Making small, tentative course changes — examiners know that Rule 8 requires action that is readily apparent.
• ✗Assuming that once you alter course the situation is resolved — you must monitor until past and clear.
• ✗Forgetting that slowing, stopping, or reversing is explicitly permitted under Rule 8.

USCG exam questions — Rule 8

These questions are drawn from the same pool used in real USCG licensing exams. Correct answers and explanations are shown.

1. 1. Under Rule 8, any action taken to avoid collision shall be:

   • A.A series of small alterations to clearly communicate intent
   • B.Large enough to be readily apparent to the other vessel and shall not result in another close-quarters situation✓
   • C.Taken at least 10 minutes before a predicted CPA of zero
   • D.Approved by the master before being executed

   Why: Rule 8(b) requires action to be large and bold enough to be readily apparent to another vessel observing visually or by radar. A series of small alterations are explicitly discouraged because they may not be detectable and can create confusion about the vessel's true intentions.

2. 2. A vessel takes action to avoid collision by altering speed. According to Rule 8, such a speed reduction:

   • A.Must reduce speed by at least half to be effective
   • B.Is only permitted when an alteration of course would create a new risk
   • C.Must be substantial enough to be readily apparent to the other vessel✓
   • D.Must be followed by an appropriate sound signal

   Why: Rule 8(b) applies to both course and speed alterations — either must be large enough to be readily apparent. A small speed reduction may be invisible to radar and undetectable visually, and therefore fails the standard. There is no mandatory minimum percentage reduction prescribed.

3. 3. Under Rule 8(e), if necessary to avoid collision or allow more time to assess the situation, a vessel shall:

   • A.Sound five short blasts and maintain course
   • B.Reduce speed, stop, or if necessary take all way off✓
   • C.Immediately transmit a securite call on VHF channel 16
   • D.Alter course to the right if the other vessel is on the port bow

   Why: Rule 8(e) explicitly permits — and requires when necessary — a vessel to slacken speed, stop engines, or even take all way off. Stopping provides maximum time for assessment and avoidance. The VHF call is prudent seamanship but not part of Rule 8's directive.

4. 4. Under Rule 8(d), action taken to avoid collision with another vessel shall be such as to result in passing at a safe distance. Which statement correctly completes the Rule's requirement?

   • A.And shall be accompanied by the appropriate sound signal
   • B.The effectiveness of the action shall be carefully checked until the other vessel is finally past and clear✓
   • C.And shall be taken at least 15 minutes before the predicted time of closest approach
   • D.And shall be confirmed by the other vessel using VHF communication

   Why: Rule 8(d) requires that after action to avoid collision, the effectiveness shall be carefully checked until the other vessel is finally past and clear. A single alteration is not enough — the mariner must monitor the developing situation and take further action if the initial maneuver proves insufficient.

5. 5. Rule 8(d) states that action taken to avoid collision with another vessel shall be such as to result in passing at a safe distance. When shall such action be taken?

   • A.In ample time, with due regard to seamanlike action✓
   • B.Only after the vessels are within visual range of each other
   • C.As soon as the other vessel sounds a signal of intent
   • D.Only if the other vessel fails to take action first

   Why: Rule 8(d) requires that action taken to avoid collision shall result in passing at a safe distance, and that effectiveness shall be carefully checked until the other vessel is finally past and clear. Rule 8(a) further requires that such action be taken in ample time.

6. 6. Under Rule 8, if a vessel finds herself so close to another vessel that collision cannot be avoided by the give-way vessel alone, what must the stand-on vessel do?

   • A.Take such action as will best aid to avoid collision✓
   • B.Sound five short blasts and maintain course and speed
   • C.Reverse engines immediately regardless of other traffic
   • D.Display the not-under-command lights and stop engines

   Why: Under COLREGS/Inland Rule 17(b), when the stand-on (give-way's counterpart) vessel finds herself so close that collision cannot be avoided by the action of the give-way vessel alone, she "shall take such action as will best aid to avoid collision" — matching option 0 exactly. This in-extremis duty overrides the normal Rule 17(a)(i) obligation to keep course and speed; Rule 8(e) (slackening/stopping/reversing) is only a general supporting measure, not the controlling rule here.

7. 7. Which of the following actions complies with Rule 8 when taking action to avoid collision?

   • A.Making a bold alteration of course to starboard away from a crossing vessel✓
   • B.Making a series of small course changes to gradually alter the CPA
   • C.Reducing speed by 10% and maintaining course
   • D.Waiting for the stand-on vessel to sound a signal before altering course

   Why: Rule 8(b) requires that alterations of course or speed be large enough to be readily apparent to the other vessel. A bold, definitive alteration satisfies this requirement, while small incremental changes are specifically discouraged as they may not be detected by the other vessel.

8. 8. Rule 8(e) allows a vessel to take what action if necessary to avoid collision or to allow more time to assess the situation?

   • A.Slacken her speed, stop, or reverse her means of propulsion✓
   • B.Sound five or more short blasts and maintain course
   • C.Request an emergency escort from the nearest coast guard station
   • D.Immediately anchor in the fairway until the danger has passed

   Why: Rule 8(e) explicitly states that if necessary to avoid collision or allow more time to assess the situation, a vessel shall slacken her speed or take all way off by stopping or reversing her means of propulsion. This drastic action is a last resort before collision becomes inevitable.

Frequently asked questions

How should the give-way vessel act under Rule 8?

The give-way vessel must take early and substantial action to keep well clear. The action must be large enough to be readily apparent to the other vessel — small, gradual changes are insufficient. The vessel must then monitor the situation until the other vessel is finally past and clear.

Can a vessel stop or reverse to avoid a collision?

Yes. Rule 8 explicitly states that a vessel may slacken speed, stop, or reverse if that is what is needed to avoid collision or allow more time to assess the situation. There is no prohibition on using astern propulsion to avoid collision.

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