Rules 16 & 17 — Steering & Sailing
Give-Way vs Stand-On
Once you have classified the encounter (crossing, overtaking, or head-on), the rules assign one vessel as give-way and one as stand-on. But the stand-on vessel's privilege to hold course is not absolute — Rules 16 and 17 together define a two-stage system that requires action from both vessels when the situation deteriorates.
The two-vessel framework
Give-Way Vessel
Rule 16
- →Take early and substantial action to keep well clear
- →Action must be obvious to the other vessel — not a last-second twitch
- →Avoid crossing ahead of the stand-on vessel when possible (crossing situations)
- →If in doubt, take more action sooner — do not wait
Stand-On Vessel
Rule 17
- →Keep course and speed — initially (Rule 17(a)(i))
- →May take avoiding action when give-way vessel is not acting (Rule 17(a)(ii))
- →Must take action when collision cannot be avoided by give-way vessel alone (Rule 17(b))
- →Shall not alter to port when give-way vessel is on her port side (Rule 17(c))
Rule 16 — Action by the Give-Way Vessel
“Every vessel which is directed to keep out of the way of another vessel shall, so far as possible, take early and substantial action to keep well clear.”
- →Three requirements in one sentence: early, substantial, and well clear. Doing one out of three fails the rule.
- →'Early' means before close-quarters develops — not after you can see whites of the other captain's eyes.
- →'Substantial' means a large, obvious course or speed change. A 10° turn at normal speed may be invisible to the other vessel at distance.
- →'Well clear' means not just technically not colliding — it means a comfortable margin, obvious to the other vessel.
- →Rule 8(a) reinforces this: any action to avoid collision must be positive and made in ample time.
Rule 17 — The Three Stages of the Stand-On Vessel
“(a)(i) Shall keep her course and speed. (a)(ii) May take action to avoid collision as soon as it becomes apparent that the vessel required to keep out of the way is not taking appropriate action. (b) When a collision cannot be avoided by the action of the give-way vessel alone, the stand-on vessel shall take such action as will best aid to avoid collision. (c) A power-driven vessel shall not alter course to port for a vessel on her own port side.”
Keep your course and speed. The give-way vessel needs a predictable target to maneuver around. Altering course or slowing unpredictably at this stage can worsen the situation.
If it becomes apparent the give-way vessel is not taking appropriate action, the stand-on vessel may take avoiding action. This is a permission, not yet a requirement. Acting early in this stage is seamanship.
When collision cannot be avoided by the give-way vessel alone, the stand-on vessel shall take action. This is mandatory. At this point holding course and speed is no longer an option — it is a failure to comply with the Rules.
A power-driven stand-on vessel shall not alter course to port when the give-way vessel is on her own port side. Turning to port in a crossing situation where the give-way vessel is approaching from port shortens the passing distance and removes any margin. Alter to starboard, or reduce speed, or stop.
Common exam mistakes
- ✗Thinking the stand-on vessel never has to act. Rule 17(b) is a 'shall' — when collision cannot be avoided by give-way alone, the stand-on vessel must act. Holding course into a collision is not compliance.
- ✗Forgetting Rule 17(c). The no-port-alteration rule applies when the give-way vessel is on your port side. The exam will ask about starboard alteration scenarios precisely to catch this.
- ✗Applying give-way/stand-on in restricted visibility. Rules 16 and 17 apply only when vessels are in sight of one another. In restricted visibility, Rule 19 replaces them entirely.
- ✗Calling Rule 16 a one-time action. 'Take action to keep well clear' is a continuous obligation. If the first action is insufficient, take more.
- ✗Describing the give-way vessel as having 'right of way' or the stand-on vessel as having 'no obligation.' Both descriptions are wrong. The give-way vessel has an obligation to maneuver; the stand-on vessel has an obligation to help when give-way fails.
USCG exam questions — Rules 16 & 17
Drawn from the same pool used in real USCG licensing exams. Answers and explanations are shown.
1. Two sailing vessels are approaching one another so as to involve risk of collision. Vessel A has the wind on her port side. Vessel B has the wind on her starboard side. Which vessel is the give-way vessel?
- A.Vessel A, because she has the wind on the port side✓
- B.Vessel B, because she has the wind on the starboard side
- C.The vessel that is more close-hauled
- D.The vessel to leeward
Why: Rule 12(a)(i) states that when each sailing vessel has the wind on a different side, the vessel with the wind on the port side shall keep out of the way. Vessel A has the wind on port; she gives way. The close-hauled state and leeward position are irrelevant to this specific sub-rule.
2. Rule 14(c) states that if a vessel is in any doubt as to whether a head-on situation exists, she shall:
- A.Stand on and wait for the other vessel to take action
- B.Sound the doubt signal of five short blasts
- C.Assume a head-on situation exists and act accordingly✓
- D.Contact the other vessel on VHF to clarify the situation
Why: Rule 14(c) resolves ambiguity with a safety default: assume it is head-on and apply Rule 14 — alter to starboard. This prevents a vessel from standing on a potentially fatal course while waiting for certainty. The doubt signal is a general safety signal but is not the Rule 14(c) directive.
3. Rule 17(c) states that a stand-on vessel taking action in accordance with Rule 17(a)(ii):
- A.Becomes the give-way vessel for the remainder of the encounter
- B.Shall not alter course to port for a vessel on her own port side✓
- C.Must first reduce speed before altering course
- D.Must sound the appropriate maneuvering signal before acting
Why: Rule 17(c) prohibits the stand-on vessel from altering course to port for a vessel on her own port side when she decides to act under 17(a)(ii). Turning toward a give-way vessel approaching from the port bow would increase closing rate. Turning to starboard (away from the give-way vessel) is the correct action.
4. Two sailing vessels are approaching one another so as to involve risk of collision. Vessel A has the wind on her port side. Vessel B has the wind on her starboard side. Which vessel is the give-way vessel?
- A.Vessel A, because she has the wind on the port side✓
- B.Vessel B, because she has the wind on the starboard side
- C.The vessel that is more close-hauled
- D.The vessel to leeward
Why: Rule 12(a)(i) states that when each sailing vessel has the wind on a different side, the vessel with the wind on the port side shall keep out of the way. Vessel A has the wind on port; she gives way. The close-hauled state and leeward position are irrelevant to this specific sub-rule.
5. Under Rule 13, a vessel is overtaking another when she is approaching from a direction more than how many degrees abaft the beam of the vessel being overtaken?
- A.30 degrees abaft the beam
- B.45 degrees abaft the beam
- C.22.5 degrees abaft the beam✓
- D.60 degrees abaft the beam
Why: Rule 13(b) defines the overtaking sector as more than 22.5 degrees abaft the beam — the same arc covered by the stern light. If you can see only the stern light of the vessel ahead, you are in the overtaking sector and must keep clear regardless of what other rules might otherwise apply.
6. Rule 14(c) states that if a vessel is in any doubt as to whether a head-on situation exists, she shall:
- A.Stand on and wait for the other vessel to take action
- B.Sound the doubt signal of five short blasts
- C.Assume a head-on situation exists and act accordingly✓
- D.Contact the other vessel on VHF to clarify the situation
Why: Rule 14(c) resolves ambiguity with a safety default: assume it is head-on and apply Rule 14 — alter to starboard. This prevents a vessel from standing on a potentially fatal course while waiting for certainty. The doubt signal is a general safety signal but is not the Rule 14(c) directive.
7. Under Rule 16, the give-way vessel shall:
- A.Sound the appropriate signal and then take action
- B.Take early and substantial action to keep well clear✓
- C.Reduce speed to half ahead and maintain course until the stand-on vessel reacts
- D.Alter course to starboard in all situations
Why: Rule 16 requires the give-way vessel to take early and substantial action to keep well clear. 'Early' prevents last-minute maneuvers; 'substantial' ensures the action is perceptible to the stand-on vessel; 'well clear' sets a high standard that goes beyond merely avoiding collision.
8. Rule 17(c) states that a stand-on vessel taking action in accordance with Rule 17(a)(ii):
- A.Becomes the give-way vessel for the remainder of the encounter
- B.Shall not alter course to port for a vessel on her own port side✓
- C.Must first reduce speed before altering course
- D.Must sound the appropriate maneuvering signal before acting
Why: Rule 17(c) prohibits the stand-on vessel from altering course to port for a vessel on her own port side when she decides to act under 17(a)(ii). Turning toward a give-way vessel approaching from the port bow would increase closing rate. Turning to starboard (away from the give-way vessel) is the correct action.
Frequently asked questions
- What does 'give-way vessel' mean under COLREGS?
- The give-way vessel is the one required to take early and substantial action to keep well clear. Rule 16 says she 'shall take early and substantial action to keep well clear' — not merely avoid collision at the last second. The action must be taken in time to be apparent to the other vessel.
- Can the stand-on vessel ever turn to avoid a collision?
- Yes — and sometimes must. Rule 17(a)(ii) permits the stand-on vessel to take avoiding action on her own when it becomes apparent that the give-way vessel is not taking required action. Rule 17(b) requires the stand-on vessel to take action once a collision cannot be avoided by the give-way vessel alone. The stand-on obligation to hold course is not absolute — it ends when safety demands action.
- Why can't the stand-on vessel alter to port when the give-way vessel is on her port side?
- Rule 17(c) specifies that a power-driven stand-on vessel shall not alter course to port when the vessel required to give way is on her port side. Altering to port brings your bow across the path of the give-way vessel and removes the safety margin. Alter to starboard (or slow/stop) instead.
- Does the give-way/stand-on framework apply in restricted visibility?
- No. Rule 17 and Rule 16 both apply only to vessels 'in sight of one another' (Rule 11). In restricted visibility, Rule 19 governs instead — and there is no give-way or stand-on vessel. Both vessels take independent action per Rule 19.
- What is the Rule 2 exception to give-way obligations?
- Rule 2(b) states that nothing in the Rules exonerates any vessel from the consequences of neglect, and that a departure from the Rules is justified to avoid immediate danger. If rigidly following Rule 17 (holding course) would cause a collision, you are required to act. Rule 2 is the safety escape valve the exam tests with 'you must follow the rules even if' — the correct answer is always that you must act to avoid collision.
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