6.2 Narrow Channels & Traffic Separation Schemes (Rules 9 & 10)

6.2 Narrow Channels & Traffic Separation Schemes (Rules 9 & 10)

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Rule 9: Narrow Channels & Fairways

A narrow channel or fairway is any navigable waterway where navigable water is confined laterally by shallows, banks, breakwaters, or buoyage. Whether a waterway is legally a "narrow channel" depends on the physical dimensions of the channel relative to the draught, beam, and manoeuvring room of the vessels using it.

1. The Starboard-Hand Rule (Rule 9(a))

"A vessel proceeding along the course of a narrow channel or fairway shall keep as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable."

Similar to vehicular traffic keeping to the right, keep near the starboard outer limit as is safe and practicable, allowing for depth, hazards and other traffic. This ensures meeting vessels naturally pass port-to-port without ambiguity.

2. Obligations of Small Craft & Sailing Vessels (Rule 9(b) & 9(c))

• Rule 9(b): A vessel of less than 20 metres in length or a sailing vessel shall not impede the passage of a vessel which can safely navigate only within a narrow channel or fairway.
• Rule 9(c): A vessel engaged in fishing shall not impede the passage of any other vessel navigating within a narrow channel or fairway.

3. Crossing Narrow Channels (Rule 9(d))

A vessel shall not cross if doing so impedes a vessel that can safely navigate only within the channel or fairway. That vessel may use the Rule 34(d) signal—at least five short and rapid blasts—if in doubt about the crossing vessel's intention.

4. Overtaking in a Narrow Channel (Rule 9(e))

When an overtaking vessel can pass only if the vessel being overtaken takes action to permit safe passage, the overtaking vessel must sound the whistle signals under Rule 34(c):

• Two prolonged blasts followed by one short blast (-- •): "I intend to overtake you on your starboard side."
• Two prolonged blasts followed by two short blasts (-- ••): "I intend to overtake you on your port side."

The vessel being overtaken, if in agreement, must sound the confirmation signal under Rule 34(c)(ii):

• One prolonged, one short, one prolonged, and one short blast (- • - •, Morse "C" for confirm).

If the overtaken vessel doubts the safety of the manoeuvre, she sounds at least five short and rapid blasts (•••••). The overtaking vessel must not attempt to pass until the agreement signal has been sounded.

5. Approaching Obscured Bends (Rule 9(f))

A vessel nearing a bend where other vessels may be obscured by headlands or banks must navigate with caution and sound one prolonged blast (4 to 6 seconds). Any approaching vessel within hearing around the bend must reply with one prolonged blast.

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Rule 10: Traffic Separation Schemes (TSS)

Traffic Separation Schemes (e.g., Dover Strait, Ushant, Casquets) are adopted by the IMO to separate opposing streams of commercial shipping traffic in congested waters.

1. Navigating Within Lanes (Rule 10(b))

Vessels using a TSS must:

• Proceed in the general direction of traffic flow for that specific lane.
• Keep clear of the traffic separation line or separation zone.
• Join or leave traffic lanes at lane terminations. When joining or leaving from either side, do so at as small an angle to the general direction of traffic flow as practicable.

2. Crossing Traffic Lanes: Heading vs. Ground Track (Rule 10(c))

Rule 10(c) contains one of the most critical principles in Yachtmaster theory: "A vessel shall, so far as practicable, avoid crossing traffic lanes, but if obliged to do so shall cross on a heading as nearly as practicable at right angles to the general direction of traffic flow."

Why Heading and Not Ground Track?

1. Clear Crossing Aspect: A heading as nearly perpendicular to traffic flow as practicable makes the crossing vessel's aspect easier for lane traffic to interpret.
2. Crossing Time: The rule standardises the crossing heading; it does not guarantee the shortest crossing time under every wind and tidal condition.
3. Effect of Tidal Streams: When crossing a TSS with a strong cross-tide (for example,3knots along an eastbound lane), the heading must be as nearly perpendicular to the traffic flow as practicable; this is a relative angle, not necessarily090°T. The tide will sweep the vessel sideways, causing her Course Over Ground (COG) to crab across the seabed at an oblique angle. This is completely legal and correct. Do not sacrifice the required crossing heading merely to make the ground track perpendicular. Check the resulting drift and continue applying the other collision-avoidance rules.

3. Inshore Traffic Zones (ITZ) (Rule 10(d))

Inshore Traffic Zones lie between the landward boundary of a TSS and the adjacent coast:

• Through-traffic shall not use an ITZ when it can safely use the appropriate traffic lane within the adjacent TSS.
• Exceptions: Vessels of less than 20 metres in length, sailing vessels, and vessels engaged in fishing may use the inshore traffic zone at all times.
• Any vessel may use an ITZ when en route to or from a port, offshore installation, pilot station or other place within that ITZ, or to avoid immediate danger.

4. Small Craft Obligations in a TSS (Rule 10(j) & 10(g))

• Rule 10(j): A vessel of less than 20 metres in length or a sailing vessel shall not impede the safe passage of a power-driven vessel following a traffic lane.
• Rule 10(g): A vessel shall, so far as practicable, avoid anchoring in a TSS or near its terminations.