Narrow Channels and Traffic Separation Schemes (Rules 9-10)

Introduction

Rules 9 and 10 govern navigation in special, restricted waters where normal vessel hierarchy and encounter rules may not provide adequate safety. These rules are paramount and, when applicable, their provisions take precedence over Rule 18 (vessel hierarchy) and modify the standard encounter rules.

Rule 9: Narrow Channels

Rule 9 - Narrow Channels provides a specific set of required actions for navigating in confined waterways.

Rule 9(a)(i) - The "Rule of the Road"

"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."

This is the maritime equivalent of "stay in your lane." Just like driving on the right side of the road, vessels must keep to the starboard (right) side of the channel.

Rule 9(d) - Crossing

"A vessel shall not cross a narrow channel or fairway if such crossing impedes the passage of a vessel which can safely navigate only within such channel..."

A crossing vessel must wait for a safe gap in traffic. It cannot force a channel-bound vessel to slow down or alter course.

Rule 9(f) - Bends

"A vessel nearing a bend... where other vessels may be obscured... shall navigate with particular alertness and caution and shall sound the appropriate signal prescribed in Rule 34(e)."

The signal is one prolonged blast (-). Any vessel approaching from the other side shall answer with one prolonged blast.

This is critical for safety around blind bends where vessels cannot see each other approaching.

Rule 9(g) - Anchoring

"Any vessel shall, if the circumstances of the case admit, avoid anchoring in a narrow channel."

Anchoring in a channel creates a critical obstruction and is a serious violation. Vessels should anchor outside the channel boundaries whenever possible.

The "Shall Not Impede" Mandate (Rule 9(b) & (c))

This is the most critical safety component of Rule 9.

Rule 9(b)

"A vessel of less than 20 meters in length or a sailing vessel shall not impede the passage of a vessel that 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."

Critical Legal Distinction

The legal distinction between "shall not impede" and "shall keep out of the way" (give-way) is vast:

"Give-Way" (Rule 16) is a reactive duty that applies once "risk of collision" (Rule 7) has already been established.

"Shall Not Impede" (Rule 9) is a proactive duty. The smaller vessel has the obligation to monitor channel traffic and take early action to "keep well clear".

What "Shall Not Impede" Means in Practice

The goal is to ensure that the large, constrained vessel never has to question the small vessel's intentions or slow down.

The small vessel must:

• Stay well to the side of the channel
• Typically position outside the main channel boundaries if water depth allows
• Take action early, before any risk of collision develops
• Monitor radio communications for large vessel movements
• Never assume the large vessel can maneuver to avoid them

Rule 10: Traffic Separation Schemes (TSS)

A Traffic Separation Scheme (TSS) is a maritime "highway" system established by the IMO to manage traffic in busy, congested areas like the English Channel or the approaches to major ports.

Components of a TSS

A TSS consists of several parts:

1. Traffic Lanes: Designated lanes for one-way traffic
2. Separation Zones/Lines: The "median strip" that separates opposing lanes. Vessels are forbidden from entering the separation zone except in emergencies or to fish
3. Inshore Traffic Zones (ITZ): The "service road" area between the outer edge of a traffic lane and the adjacent coastline

The Golden Rule of TSS (Rule 10(a))

"This Rule... does not relieve any vessel of her obligation under any other Rule."

This is the most violated and misunderstood part of Rule 10. A vessel transiting properly within a traffic lane does not automatically have right-of-way over other vessels.

Critical Example: The "TSS is Not a Shield"

Situation: A container ship (Vessel A) is proceeding correctly in a traffic lane. A ferry (Vessel B) is crossing the TSS. The ferry is on the container ship's starboard side.

Rule: This is a standard crossing situation (Rule 15).

Result: The container ship (Vessel A), despite being "in the lane," is the Give-Way vessel and must take action to avoid the ferry.

The TSS is a traffic management tool, not a right-of-way allocator.

Transiting a TSS (Rule 10(b))

A vessel using a TSS shall:

1. (i) Proceed in the appropriate traffic lane in the general direction of traffic flow
2. (ii) So far as practicable keep clear of the separation line/zone
3. (iii) Normally join or leave a traffic lane at the ends. If joining or leaving from the side, do so at "as small an angle... as practicable" (i.e., merge like on a highway)

Crossing a TSS (Rule 10(c))

A vessel "shall, so far as practicable, avoid crossing traffic lanes." If obliged to cross, she "shall cross on a heading as nearly as practicable at right angles to the general direction of traffic flow".

Critical Distinction: "Heading" vs. "Track"

The rule explicitly says heading. The mariner must not apply a correction for current or tide.

Why This Matters

The purpose is to present a clear 90-degree aspect (profile) to the vessels in the lane. This:

• Makes the crossing vessel's intentions "readily apparent" (Rule 8)
• Allows them to cross the lane as quickly as possible
• Prevents confusion about the crossing vessel's course

A vessel that "crabs" across the lane to achieve a 90-degree track over the ground will present a confusing, angled heading to oncoming traffic and will be in violation of the rule.

Example

Traffic lane flows at 090° True. A strong current is setting south at 3 knots.

Incorrect: Steer 180° heading (to account for current and achieve 090° track) Correct: Steer 180° heading (90° to the 090° traffic flow)

The current will push you south, but your bow will be pointed at 90° to the traffic, making your intentions clear.

Inshore Traffic Zones (Rule 10(d))

This rule separates "through" traffic from "coastal" traffic.

Large Vessels

"A vessel shall not use an inshore traffic zone when she can safely use the appropriate traffic lane..."

Who CAN Use the ITZ

Exceptions for vessels that are exempt:

1. Vessels of less than 20 meters in length
2. Sailing vessels
3. Vessels engaged in fishing

Universal Exception

Any vessel "may use an inshore traffic zone when en route to or from a port, offshore installation... or to avoid immediate danger".

Key Takeaways

Narrow Channels (Rule 9):

• Keep to starboard side of channel (9a-i)
• Do not cross if it impedes channel-bound traffic (9d)
• Sound one prolonged blast around blind bends (9f)
• Avoid anchoring in channels (9g)
• "Shall not impede" (9b/c): Proactive duty for vessels <20m, sailing vessels, and fishing vessels
• "Shall not impede" ≠ "give way" - action required BEFORE risk develops

Traffic Separation Schemes (Rule 10):

• TSS does NOT grant automatic right-of-way (10a) - other rules still apply
• Transit in appropriate lane in direction of traffic flow (10b-i)
• Keep clear of separation zone/line (10b-ii)
• Join/leave at ends or at small angle from sides (10b-iii)
• Cross at right angles using HEADING not TRACK (10c)
• Critical: Heading = direction bow points, Track = path over ground
• Do not correct for current when crossing - maintain 90° heading to traffic flow
• ITZ restricted to vessels <20m, sailing, fishing, or vessels accessing ports (10d)

Common Violations:

• Small vessels assuming channel-bound vessels will maneuver for them
• Vessels in TSS lane assuming they have automatic right-of-way
• Crossing TSS at angle other than 90° heading
• Large vessels inappropriately using ITZ