Narrow Channels & TSS Practice Questions

1. Under Rule 9, a vessel proceeding along a narrow channel or fairway shall:

• A.Keep to the center of the channel at all times
• B.Keep as near to the outer limit of the channel on her starboard side as is safe and practicable✓
• C.Give way to all vessels overtaking from astern
• D.Sound one short blast to signal her intention to maintain course

Why: Rule 9(a) requires vessels in a narrow channel to keep to the starboard side of the channel — not the center. This mirrors the road rule and ensures predictable traffic flow, reducing the risk of head-on encounters in confined waterways.

2. Under Rule 9, a vessel less than 20 meters in length or a sailing vessel in a narrow channel:

• A.Has priority over power-driven vessels proceeding along the channel
• B.Shall not impede the passage of a vessel which can safely navigate only within the channel✓
• C.May anchor in the channel if no traffic is visible
• D.Shall keep to the port side of the channel to leave room for larger vessels

Why: Rule 9(b) places a duty on small vessels and sailing vessels not to impede vessels that can only safely use the channel. This is a proactive obligation — the small or sailing vessel must act to stay clear, rather than simply being low in the hierarchy when an encounter develops.

3. Under Rule 9, a vessel shall not cross a narrow channel if such crossing:

• A.Would require more than 5 minutes to complete
• B.Impedes the passage of a vessel which can only safely navigate within that channel✓
• C.Takes place during periods of restricted visibility
• D.Is made at right angles to the channel

Why: Rule 9(d) prohibits crossing a narrow channel if doing so would impede a vessel that can only safely navigate within the channel. The crossing vessel bears the obligation to yield; the channel-bound vessel has right of way in this scenario. Time or angle of crossing are not the legal standard.

4. Under Rule 10, a vessel using a traffic separation scheme shall normally proceed in:

• A.The lane that places her on the starboard side of the traffic flow
• B.The appropriate traffic lane in the general direction of traffic flow for that lane✓
• C.The center of the separation zone to maintain maximum clearance from traffic
• D.Either lane, choosing the lane that offers the greatest underkeel clearance

Why: Rule 10(b)(i) requires a vessel using a TSS to proceed in the appropriate traffic lane in the general direction of traffic flow. The separation zone — not the center — provides the buffer between opposing traffic streams, and vessels must stay within their designated lane.

5. A vessel less than 20 meters or a sailing vessel in a TSS:

• A.Is exempt from the traffic separation rules and may navigate freely within the scheme
• B.Shall not impede the safe passage of a power-driven vessel following a traffic lane✓
• C.Must use the inshore traffic zone if one is provided
• D.Must sound one prolonged blast every 2 minutes while transiting the TSS

Why: Rule 10(j) places an explicit duty on vessels under 20 meters and sailing vessels not to impede power-driven vessels following a traffic lane. This does not exempt them from the TSS rules — they must still comply — but they additionally must not get in the way of lane-following power vessels.