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PIANC Report 120

Report n° 121 - 2014

Harbour approacH cHannels

Design guiDelines

PIANC

‘Setting the Course’

The World association for Waterborne Transport infrastructure

in co-operation with

A

B

PIANC Report 120

Harbour approacH cHannels

Design guiDelines

pianc reporT n° 121

MariTiMe naVigaTion coMMission

pianc ‘setting the course’

Table of Contents

• 1 General Aspects
  • 1.1 Scope...................................................................................................................
  • 1.2 Introduction - 1.2.1 Terms of Reference...................................................................................... - 1.2.1.1 Objective - 1.2.1.2 Matters Investigated......................................................................... - 1.2.2 Structure of Report - 1.2.3 Related PIANC Reports - 1.2.4 Members of the Working Group.................................................................... - 1.2.5 Meetings - 1.2.6 Acknowledgements
  • 1.3 General Aspects of Channel Design - 1.3.1 Maritime Configuration of Ports..................................................................... - 1.3.2 Approach Channel Design Considerations - 1.3.3 Basic Definitions - 1.3.4 General Project Criteria - 1.3.4.1 Basic Criteria - 1.3.4.2 Elements Defining a Channel - 1.3.4.3 Types of Ships and Characteristics - 1.3.4.4 Limiting Operational Conditions........................................................ - 1.3.4.5 Human Error and Project Uncertainties - 1.3.5 Physical Environment Data - 1.3.5.1 Data Requirements - 1.3.5.2 Physical Environment Issues.......................................................... - 1.3.5.3 Data Analysis and Modelling - 1.3.6 Elements of Channel Dimensions - 1.3.6.1 Channel Depth - 1.3.6.2 Channel Width - 1.3.6.3 Links between Vertical and Horizontal Dimensioning
    • 1.3.7 Design Verification Procedures
      • 1.3.7.1 Deterministic Verification
      • 1.3.7.2 Probabilistic Verification.............................................................................
    • 1.3.8 Safety Factors.....................................................................................................
  • 1.4 Processes in Channel Design and Design Philosophy
    • 1.4.1 Design Process...................................................................................................
      • 1.4.1.1 Concept Design
      • 1.4.1.2 Detailed Design
    • 1.4.2 Design Methodology
      • 1.4.2.1 The ‘Design Ship’ Concept
      • 1.4.2.2 Channel Depth, Width and Alignment
      • 1.4.2.3 Aids to Navigation......................................................................................
    • 1.4.3 Probability Aspects in the Design Process
      • 1.4.3.1 Marine Traffic and Risk Analysis
      • 1.4.3.2 Vertical Channel Dimensions
      • 1.4.3.3 Horizontal Channel Dimensions
    • 1.4.4 Risk Assessment
    • 1.4.5 Upgrading Existing Channels
• 2 Design of Vertical Channel Dimensions
  • 2.1 Channel Depth Factors
    • 2.1.1 Water Level Factors
      • 2.1.1.1 Reference Level (Datum)
      • 2.1.1.2 Design Water Level
      • 2.1.1.3 Tidal and Meteorological Effects
    • 2.1.2 Ship-Related Factors
      • 2.1.2.1 Static Draught............................................................................................
      • 2.1.2.2 Allowance for Static Draught Uncertainties.................................................
      • 2.1.2.3 Change in Water Density
    • 2.1.2.4 Ship Squat.................................................................................................
    • 2.1.2.5 Dynamic Heel
    • 2.1.2.6 Wave Response Allowance
    • 2.1.2.7 Net UKC ( UKCNet )......................................................................................
    • 2.1.2.8 Manoeuvrability Margin (MM).....................................................................
  • 2.1.3 Bottom-Related Factors
    • 2.1.3.1 Allowance for Bed Level Uncertainties
    • 2.1.3.2 Allowance for Bottom Changes between Dredging
    • 2.1.3.3 Dredging Execution Tolerance
    • 2.1.3.4 Muddy Channel Beds
• 2.2 Air Draught Clearance ( ADC )............................................................................
• 2.3 Concept Design – Vertical Dimensions
  • 2.3.1 Design Water Level.............................................................................................
  • 2.3.2 Ship-Related Factors ( Fs )
  • 2.3.3 Air Draught Clearance ( ADC )
  • 2.3.4 Concept Design Example Problems
    • 2.3.4.1 Example 1: Finland, General Cargo Ship
    • 2.3.4.2 Example 2: Richards Bay, South Africa, Coal Bunker.................................
    • 2.3.4.3 Example 3: Zeebrugge, Belgium, Container Ship
    • 2.3.4.4 Example 4: Panama Canal, Tanker............................................................
• 2.4 Detailed Design – Vertical Dimensions
  • 2.4.1 Water Level Factors
  • 2.4.2 Ship Factors
    • 2.4.2.1 Squat ( SMax )...............................................................................................
    • 2.4.2.2 Dynamic Heel ( ZWR )
    • 2.4.2.3 Wave Response Allowance ( ZMax )..............................................................
  • 2.4.3 Bottom Factors
    • 2.4.3.1 Allowance for Bed Level Uncertainties
    • 2.4.3.2 Allowance for Bottom Changes between Dredging
    • 2.4.3.3 Dredging Execution Tolerance
    • 2.4.3.4 Muddy Channel Beds
  • 2.4.4 Air Draught and ADC
• 2.5 Probabilistic Design Considerations
  • 2.5.1 Criteria for Probability of Exceedance..................................................................
  • 2.5.2 Risk
  • 2.5.3 Long-Term Probability Criterion
  • 2.5.4 Probabilistic Design
    • 2.5.4.1 Monte Carlo Simulation Technique
    • 2.5.4.2 Probabilistic Design Tools..........................................................................
  • 2.5.5 Operational Channel Allowance
  • 2.5.6 Tidal Window Design
• AREAS.............................................................................................................................. 3 CHANNEL WIDTH, HARBOUR ENTRANCES, MANOEUVRING AND ANCHORAGE
• 3.1 Concept Design - Horizontal Dimensions
  • 3.1.1 Channel Width
    • 3.1.1.1 Introduction to the Concept Design Method................................................
  • 3.1.2 Channel Alignment and Width Consideration.......................................................
    • 3.1.2.1 General
    • 3.1.2.2 Bend Configuration
    • 3.1.2.3 Basic Manoeuvrability
    • 3.1.2.4 Environmental Forces
    • 3.1.2.5 Visibility
    • 3.1.2.6 Bank Clearance and Ship-Ship Interactions
    • 3.1.2.7 Fairway Marking and Positioning Systems
  • 3.1.3 Outer Exposed Channel and Inner Protected Channel.........................................
  • 3.1.4 One- or Two-way Channels
    • 3.1.4.1 Example
    • 3.1.4.2 Example
  • 3.1.5 Concept Design Methods for Straight Channels
    • 3.1.5.1 Basic Manoeuvring Lane WBM
      • 3.1.5.2 Environmental and Other Factors Wi
      • 3.1.5.3 Additional Width for Bank Clearance
      • 3.1.5.4 Additional Width for Passing Distance in Two-Way Traffic
      • 3.1.5.5 Additional Width for Large Tidal Range
    • 3.1.6 Concept Design Methods for Curved Channels and Bends
      • 3.1.6.1 Turning Radius and Swept Path.................................................................
      • 3.1.6.2 Additional Widths in Bends
        • Width 3.1.7 Introduction to Spanish and Japanese Concept Design Standards for Channel
      • 3.1.7.1 Spanish Recommendation for Maritime Works...........................................
      • 3.1.7.2 Japanese Design Method
    • 3.1.8 Harbour Entrances and Manoeuvring Areas
      • 3.1.8.1 Introduction
      • 3.1.8.2 Stopping Procedure and estimation of stopping distance
      • 3.1.8.3 Harbour Entrance
      • 3.1.8.4 Turning Basin
      • 3.1.8.5 Clearance for Moored Ships
    • 3.1.9 Anchorage Areas
      • 3.1.9.1 Introduction
      • 3.1.9.2 Design Factors
      • 3.1.9.3 Anchorage Design for a Vessel with One Anchor Ahead
    • 3.1.10 Pilot Boarding and Landing Areas
  • 3.2 Detailed Design – Horizontal Dimensions
    • 3.2.1 Motivation
    • 3.2.2 Tools and Methods
      • 3.2.2.1 Detailed Parametric Design and Special Formulae...................................
      • 3.2.2.2 Simulation Models
    • 3.2.3 Ship Manoeuvring Simulation Models................................................................
      • 3.2.3.1 Introduction
      • 3.2.3.2 Fast-Time Simulation
      • 3.2.3.3 Real-Time Simulation
    • 3.2.4 Traffic Flow Simulation Models
      • 3.2.4.1 System Boundaries
      • 3.2.4.2 Model Description
      • 3.2.4.3 Simulation Language
      • 3.2.4.4 Verification and Validation
      • 3.2.4.5 Capacity Estimation
    • 3.2.5 Traffic Flow Simulation Model to Determine Capacity
      • 3.2.5.1 Generator Component Process
      • 3.2.5.2 Ship Class
      • 3.2.5.3 Ship Length
      • 3.2.5.4 Draught and Tidal Window.......................................................................
      • 3.2.5.5 Destination in the Port and Incoming and Outgoing Routes
      • 3.2.5.6 Separation Times
      • 3.2.5.7 Inter-Arrival Time and Service Time Distribution.......................................
      • 3.2.5.8 Ship Component Process
      • 3.2.5.9 VTS Components Process.......................................................................
    • 3.2.6 Traffic Flow Model to Determine Safety Levels
      • 3.2.6.1 Introduction
      • 3.2.6.2 Safety Domain
      • 3.2.6.3 Vessel Paths
      • 3.2.6.4 Evaluation of Simulation Results..............................................................
• 4 OTHER ASPECTS
  • 4.1 Risk Management and Analysis
    • 4.1.1 General.............................................................................................................
    • 4.1.2 Maritime Incidents
    • 4.1.3 Types of Incidents
    • 4.1.4 Risk Analysis Methodologies
    • 4.1.5 Simplified Qualitative Matrix Method..................................................................
  • 4.2 Training
  • 4.3 Operational Rules and Environmental Limits
    • 4.3.1 General.............................................................................................................
    • 4.3.2 Channels
    • 4.3.3 Harbour Entrances
    • 4.3.4 Stopping Areas
    • 4.3.5 Turning Areas
    • 4.3.6 Anchorage Areas
    • 4.3.7 Moorings Areas and Buoy Systems
    • 4.3.8 Basins and Quays
  • 4.4 Winter Navigation and Channel Design
    • 4.4.1 General.............................................................................................................
    • 4.4.2 Factors Affecting the Design of a Channel for Winter Navigation
      • 4.4.2.1 General Conditions
      • 4.4.2.2 Alignment and Geometry
      • 4.4.2.3 Channel Width
      • 4.4.2.4 Channel Depth, Gross Underkeel Clearance............................................
      • 4.4.2.5 Channel Markings/Aaids to Navigation.....................................................
      • 4.4.2.6 Harbour Basin
      • 4.4.2.7 Pilotage
  • 4.5 Environmental Issues
    • 4.5.1 Regulations and Sustainability
    • 4.5.2 Work on Channels and Dredged Materials Management
      • 4.5.2.1 Dredge Planning Activities
      • 4.5.2.2 Dredging
    • 4.5.2.3 Disposal of Dredged Material
    • 4.5.3 Biodiversity
  • 4.6 Aids to Navigation (AtoN)
    • 4.6.1 Channel Markings
    • 4.6.2 On-Board Navigation Systems
      • 4.6.2.1 Visual Navigation.....................................................................................
      • 4.6.2.2 Electronic Aids.........................................................................................
    • 4.6.3 VTS/VTMS Systems and Impact
    • 4.6.4 Future Development of AtoN
• 5 REFERENCES
• APPENDIX A: TERMS OF REFERENCE List of Appendices
• APPENDIX B: GLOSSARY, ABBREVIATIONS AND SYMBOLS
  • B.1 GLOSSARY
  • B.2 ABBREVIATIONS.....................................................................................................
  • B.3 SYMBOLS
• APPENDIX C: TYPICAL SHIP DIMENSIONS
  • C.1 Typical Ship Dimensions from ROM 3.1
  • C.2 Japanese Statistical Analysis of Ship Dimensions................................................
  • C.3 Relationship Between DWT and Hkt
  • C.4 Relationship Between CB , Δ, Δm and 
  • C.5 Relationship Between Ship’s Draught and Water Density
  • C.6 Japanese Metacentric Height Estimates
  • C.7 References...............................................................................................................
• APPENDIX D: PREDICTION OF SHIP SQUAT
  • D.1 Ship Characteristics
    • D.1.1 Dimensionless Parameters
    • D.1.2 Block Coefficient
    • D.1.3 Water Plane Cross-Sectional Area
    • D.1.4 Ship Speed
    • D.1.5 Calculated Ship Parameters.................................................................................
  • D.2 Channel Characteristics..........................................................................................
    • D.2.1 Channel Types
    • D.2.2 Channel Parameters
  • D.3 Combined Ship and Channel Parameters
    • D.3.1 Relative Depth Ratio h / T
    • D.3.2 Blockage Factor S
    • D.3.3 Velocity Return Factor S
    • D.3.4 Depth Froude Number Fnh
    • D.3.5. Critical Speed in Canals VCr
  • D.4 Empirical Squat Formulas.......................................................................................
    • D.4.1 Tuck (T)
    • D.4.2 Huuska/Guliev (H)
    • D.4.3 ICORELS (I)
    • D.4.4 Barrass3 (B3)
    • D.4.5 Eryuzlu2 (E2)
    • D.4.6 Römisch (R)
    • D.4.7 Yoshimura (Y)......................................................................................................
  • D.5 Example Problems
    • D.5.1 BAW Model Container Ship in Unrestricted Channel
    • D.5.2 SR108 Container Ship in Unrestricted Channel
    • D.5.3 FHR Model Container Ship in Restricted Channel
    • D.5.4 BAW Model Container Ship in Restricted Channel
    • D.5.5 Esso France Model Tanker in Suez Canal............................................................
    • D.5.6 Global Challenger Bulk Carrier in Panama Canal
  • D.6. Special Effects on Squat
    • D.6.1 Passing and Overtaking Ships
      • D.6.1.1 Head-On Passing Encounters
      • D.6.1.2 Overtaking Manoeuvres
    • D.6.2 Proximity of Channel Banks
    • D.6.3 Channel Bottom Configurations............................................................................
    • D.6.4 Muddy Bottoms....................................................................................................
    • D.6.5 Ship Stern Transoms
  • D.7 Numerical Modelling of Squat.................................................................................
    • D.7.1 Numerical Methods
      • D.7.1.1 Slender-Body Models
      • D.7.1.2 Boundary Element Models
      • D.7.1.3 Computational Fluid Dynamic (CFD) Models...............................................
    • D.7.2 Modelling System to Predict Ship Squat
    • D.7.3 Numerical Modelling Examples
      • D.7.3.1 BAW Model Container Ship in Unrestricted Channel
      • D.7.3.2 SR108 Container Ship in Unrestricted Channel
      • D.7.3.3 FHR Container Ship in Restricted Channel
      • D.7.3.4 Esso France Tanker in Suez Canal
      • D.7.3.5 Global Challenger Bulk Carrier in Canal
  • D.8 Future of Squat Research
• APPENDIX E: WATER DEPTHS IN MUDDY AREAS-THE NAUTICAL BOTTOM APPROACH
  • E.1 Introduction
  • E.2 Mud Characteristics
    • E.2.1 Rheology
    • E.2.2 Density
    • E.2.3 Density-Rheology Relationship
  • E.3 Criteria for Determining the Nautical Bottom
    • E.3.1 Echo-Sounding Criteria
    • E.3.2 Rheology-Related Criteria
    • E.3.3 Ship Behaviour Criteria
    • E.3.4 Mud Density Level Criteria
    • E.3.5 Actual Practice
      • E.3.5.1 Belgium
      • E.3.5.2 France
      • E.3.5.3 Germany.....................................................................................................
      • E.3.5.4 The Netherlands
      • E.3.5.5 United States
  • E.4 Behaviour of Ships in Muddy Areas
    • E.4.1 Causes of Changed Behaviour
    • E.4.2 Internal Undulations at the Interface (Internal Waves)...........................................
    • E.4.3 Resistance and Propulsion...................................................................................
    • E.4.4 Manoeuvrability....................................................................................................
• APPENDIX F: AIR DRAUGHT
  • F.1 Introduction
  • F.2 Air Draught Clearance (ADC)
  • F.3 Concept Design
  • F.4 Detailed Design
  • F.4.1 Japanese Statistical Analysis of Air Draught Hst
  • F.4.2 Detailed Design of ADC
  • F.4.3 Comparison Ballast Draught with Appendix C
    • F.4.3.1 Oil Tanker, 300,000 DWT
    • F.4.3.2 Container Ship, 100,000 DWT
• APPENDIX G: SPANISH AND JAPANESE METHODS FOR DESIGN OF CHANNEL WIDTH
• G1: SPANISH RECOMMENDATIONS FOR CONCEPT DESIGN WIDTH
  • G1.1 General Design Criteria.........................................................................................
    • G1.1.1 Design Lifetime..................................................................................................
    • G1.1.2 Elements Defining a Navigation Channel and Harbour Basin
    • G1.1.3 Design Criteria...................................................................................................
  • G1.2 Horizontal Dimensioning of Channels and Harbour Basins................................
    • G1.2.1 Introduction........................................................................................................
    • G1.2.2 General Criteria
    • G1.2.3 General Layout Recommendations
    • G1.2.4 Fairway Width....................................................................................................
      • G1.2.4.1 General Criteria
      • G1.2.4.2 Determining Nominal Width Bn by the Deterministic Method
      • G1.2.4.3 Determining Nominal Width Bn by the Semi-Probabilistic Method
    • G1.2.5 Point of No Return
  • CONCEPT DESIGN G2: JAPANESE NEW DESIGN METHOD OF FAIRWAY WIDTH DETERMINATION AT
  • G2.1 Basic Formulae of Fairway Width Determination
  • G2.2 Ship Types.............................................................................................................
  • G2.3 Estimation of Fundamental Manoeuvring Lane
    • G2.3.1 Width Requisite against Wind and Current Forces
      • G2.3.1.1 Drift Angle due to Wind Forces
      • G2.3.1.2 Drift Angle due to Current Forces..............................................................
    • G2.3.2 Width Requisite against Yawing Motion
    • G2.3.3 Width Requisite for Drift Detection
      • G2.3.3.1 Drift Detection by Observing Light Buoys with Naked Eye
      • G2.3.1.2 Drift Detection by Observing Light Buoys with RADAR
      • G2.3.1.3 Drift Detection by GPS..............................................................................
  • G2.4 Estimation of Additional Width for Interaction Forces
    • G2.4.1 Width Requisite against Bank Effect Forces
    • G2.4.2 Width Requisite against Two-Ship Interaction in Passing
    • G2.4.3 Width Requisite against Two-Ship Interaction in Overtaking
  • G2.5 Safety Factor Based on Risk Level
  • G2.6 Fairway Width Determination
    • G2.6.1 Determination Procedures
    • G2.6.2 Design Examples...............................................................................................
  • G2.7 Bend Curvature Determination
  • G2.8 Calculation of Drift Angle due to Wind Forces (Addendum)
    • G2.8.1 Drift Angle and Check Helm
    • G2.8.2 Linear Derivatives of Hull Forces and Rudder Forces
    • G2.8.3 Wind Force Coefficients
  • G2.9 Calculation of Check Helm against Interaction Forces (Addendum)
    • G2.9.1 Check Helm against Bank Effect Forces
    • G2.9.2 Check Helm against Two-Ship Interaction
  • TYPE-SIZES G3: DETAILED JAPANESE FORMULAE ON WIND-WAVE-CURRENT EFFECTS VERSUS SHIP
• G3.1 Equations of Ship Manoeuvring Motion
• G3.2 Wind Forces
  • G3.2.1 Representations of Wind Forces
  • G3.2.2 Estimations of Wind Force Coefficients
• G3.3 Wave Forces
  • G3.3.1 Lateral Deviation due to Yawing Motion
  • G3.3.2 Representations of Wave Drifting Forces
• G3.4 Current Forces
• G3.5 Hull Forces and Rudder Forces
  • G3.5.1 Hull Forces
  • G3.5.2 Rudder Forces
• G3.6 Linearised Motion Equations
  • G3.6.1 Linearisation of Hydrodynamic Forces
  • G3.6.2 Linearised Sway and Yaw Equations
  • G3.6.3 Estimation of Linear Hull Force Derivatives
• G3.7 Drift Angle and Check Helm in Course Keeping Motion under Wind Forces
  • G3.7.1 Equilibrium Equations
  • G3.7.2 Drift Angle and Check Helm

1 GENERAL ASPECTS

1.1 Scope

This report provides guidelines and recommendations for the design of vertical and

horizontal dimensions of harbour approach channels and the manoeuvring and

anchorage areas within harbours, along with defining restrictions to operations within a

channel. It includes guidelines for establishing depth and width requirements, along with

vertical bridge clearances.

The report supersedes and replaces the joint PIANC-IAPH report ‘Approach Channels –

A Guide for Design’ published in 1997 (PIANC MarCom Working Group 30) in

cooperation with IAPH, IMPA and IALA. This report has been widely accepted worldwide

by port designers. This new report has again been compiled in close co-operation with

IAPH (International Association of Ports & Harbours), IMPA (International Maritime Pilots

Association) and IALA (International Association of Marine Aids to Navigation and

Lighthouse Authorities).

1.2 Introduction

1.2.1 Terms of Reference

The Terms of Reference set by the Maritime Commission of PIANC (MarCom) for

Working Group 49 (WG 49) are given in Appendix A of this report and are summarised

below.

1.2.1.1 Objective

The objectives of the Working Group were to review, update and, where appropriate,

expand on the design recommendations on vertical and horizontal dimensioning as

presented in the Working Group 30 report of 1997 on approach channels. Recent

developments in ship design, better understanding of ship manoeuvrability and behaviour

in waves and further research in ship simulation and modelling required a comprehensive

update to the 1997 report.

1.2.1.2 Matters Investigated

The Working Group has paid particular attention to:

 Vertical motions of ships in approach channels (due to squat, wave-induced motions,

dynamic effects, etc.)

 Air draught for vertical clearances under bridges, overhead cables, etc.

 Horizontal dimensions of channels and manoeuvring areas

 Simulation of ships in channels

 New and future generation ship dimensions/manoeuvring characteristics

 Wind effect on ship navigation and manoeuvring

 Human errors and project uncertainties

 Environmental issues

 Safety criteria, assessment of levels of risk and appropriate clearance margins

 Dr. Michael J. Briggs, WG 49 Vertical Subgroup Leader, USACE Coastal and

Hydraulics Laboratory, USA

 Larry Cao, Canadian Coast Guard, Canada

 Capt. Don Cockrill, IMPA and Port of London Authority (PLA), UK

 Dr. Pierre Debaillon, CETMEF/DRIM/LHN, France

 Werner Dietze (former Member of WG 30), formerly WSV, Germany

 Rink Groenveld (former Member of WG 30), WG 49 Horizontal Subgroup Leader, TU

Delft, The Netherlands

 Jarmo Hartikainen, Finnish Transport Agency, Finland

 Jose Ramon Iribarren, Siport21, Spain

 Hans Moes, CSIR, South Africa

 Dr. Terry O’Brien, OMC International, Australia

 Dr. Kohei Otsu, Tokyo University of Marine Science & Technology, Japan

 Sahil Patel (Corresponding member), Prestedge Retief Dresner Wijnberg (Pty) Ltd.,

South Africa

 Carlos Sanchidrian Fernandez, PROES Consultores S.A., Spain

 Paul Scherrer, IAPH and Port of Le Havre, France

 Esa Sirkiä, Finnish Transport Agency, Finland

 Capt. Masanori Tsugane, Tokai University, School of Marine Science & Technology,

Japan

 Dr. Wim van der Molen, CSIR, South Africa

 Jos van Doorn, Marin, The Netherlands

 Prof. Marc Vantorre (former Member of WG 30), Ghent University, Belgium (in

co-operation with Flanders Hydraulics Research, Flemish Government – Department

Mobility and Public Works, Belgium)

1.2.5 Meetings

A total of 14 meetings of the WG were held during the course of the project in Madrid,

Brussels, Lisbon, Wallingford, Vicksburg, Antwerp, Wageningen, Le Havre, London

(IMPA), Elsfleth, Stellenbosch, Wageningen, Brussels and London (IMPA and IALA).

1.2.6 Acknowledgements

We would like to acknowledge Peter Hunter, HR Wallingford, UK, our MarCom Contact,

for his support and assistance in compiling and publishing this report.

The following individuals and organisations also contributed substantially to the

successful completion of this report:

 Nick Dodson, IALA, UK

 Roger Barker, IALA, UK

 Hendrick Eusterbarkey, IALA, Germany

 Dr Masayoshi Hirano, Akishima Laboratories (Mitsui Zosen) Inc., Japan

 Teruhiko Kohama, Coastal Development Institute of Technology, Japan

 Takemasa Minemoto, Coastal Development Institute of Technology, Japan

 Stephen Cork, former Chairman of the PIANC UK Section, UK

 Ian A. Mathis, Institute for Water Resources (IWR), USA

1.3 General Aspects of Channel Design

1.3.1 Maritime Configuration of Ports

The maritime port configuration includes water areas that are part of the channel and its

related navigational areas and must all be considered together to achieve a harmonised

overall design. They can be classified into two groups:

 Moving vessel areas: those principally assigned to navigation of vessels (e.g.

channels, harbour entrances, manoeuvring areas)

 Stationary vessel areas: those principally assigned to stationary vessels (e.g.

anchorages, mooring areas, quays, berths, terminals)

Some element descriptions are as follows:

 Channels: clearly defined route within which vessel traffic is established

 Harbour entrances: the entry and exit zone to a port or terminal

 Manoeuvring areas: zones where a vessel stops or turns, or manoeuvres to berth

 Anchorages: areas with sufficient depth and conditions for a ship to be able to anchor

safely

1.3.2 Approach Channel Design Considerations

Port planners generally seek to optimise the economics of the overall transport chain,

including an acceptable return on investment in port infrastructure and equipment and

compliance with any environmental criteria.

The pressure on port authorities to provide approach channels for larger ships, or to allow

larger ships to use existing channels, is a result of the economics of shipping. The costs

per tonne-km of cargo, with respect to fuel, crew, and capital value for a ship at sea,

decrease as ship size increases.

Increases in ship size, once accepted, puts a premium on minimising time in port, which

leads to further pressures on the approach channel design:

 To minimise ship transit time in the approach channel

 To provide accessibility at all stages of tide in all weathers, or at least to minimise

restrictions

The development of a successful port is an on-going process, dependent on variations in

both world trade and markets and on trends in shipping and cargo-handling practice. It is

necessary for the port authority, therefore, to anticipate demand and trends, and to

forecast the quantities of goods likely to pass through the port, and the ships that will be

used in years to come. Combining the forecasts, quantities of goods may be translated

into numbers of ships of various types, all of which must be accommodated by the marine

side of the port operation.

From these forecasts, the design ship size will be derived, but the increase in numbers of

ships also imposes pressures on the approach channel design as it increases the

frequency of ship to ship encounters.

1.3.4 General Project Criteria

1.3.4.1 Basic Criteria

The basic criteria for defining a channel and its related navigation areas are safety of

manoeuvres and operations. The government, port authority or terminal owner/operator

defines the desired cargo throughput which in turn enables the type and size of the

design ship(s) to be identified, along with other conditions. The task of the designer is to

convert these basic criteria into a finalised design that is usually the result of several

iterations, in agreement with the owner/port authority/engineers. Once safety criteria are

set, alternatives may be examined to determine the most suitable solution for the case

under consideration, with the understanding that any alternative must respect the

previously defined safety factors. Also at this point, it is necessary to assess the criteria

for the channel with respect to potential ship size changes and cargo types in the future.

For example, deciding the depth to which a channel is dredged, as a function of local

tides and waves, can be based on economic and environmental considerations, but the

consequences of the decision should be variations in the time when the channel can be

used safely, and not variations in levels of safety. The economic analysis therefore is a

trade-off between investment, port availability and efficiency, but not between investment

and risk, since recommended safety requirements must always be maintained.

1.3.4.2 Elements Defining a Channel

Design and definition of a channel and its related navigation areas requires determination

of the following elements:

 Geometric configuration of the water and above-water spaces from plans and

sections that define all dimensions including axes, alignments, curves, heights and

levels and datums

 Aids to navigation to identify and mark such spaces

 Maritime and atmospheric limiting conditions which will allow the channel and its

related navigation areas to be used under normal operating conditions. These

conditions may be different according to vessel type and dimensions, or other defined

conditions

 Required pilotage, escorting and towing requirements for certain types of vessels to

ensure safe navigation under normal operating conditions

A channel is therefore defined not only by its geometric characteristics but also by its aids

to navigation, its limiting operating conditions and by any need to use pilots, tugs or patrol

vessels.

1.3.4.3 Types of Ships and Characteristics

Ship Classification

Ships may be broadly classified by their cargoes as high density and heavy (‘weight’

carriers) or low density (‘volume’ carriers). The ’weight’ class includes cargo ships

(general cargo ships, break bulk and dry bulk carriers) and oil tankers (crude oil and

chemical product carriers). The ’volume’ class includes container ships, RoRo (Roll

on/Roll off) ships, Pure Car Carriers (PCC, only cars), LPG (Liquefied Petroleum Gas),

CNG (Compressed Natural Gas), LNG (Liquefied Natural Gas), Passenger cruise ships,

and Ferries (conventional and single hull, catamaran or hydrofoil fast ferries). Specialised

ship types include warships, fishing boats and pleasure craft (power boats and sailboats).

Load Capacity

The most often used parameters for defining a ship according to its size and load

capacity are:

 Deadweight Tonnage (DWT) – Maximum load plus fuel, lubricating oil, water, stores,

crew and supplies in tonnes (t). This parameter is often used to define ‘weight’

carriers

 Gross Tonnage (GT) – Although expressed as a ’tonnage’, this is actually a complex

measure of the overall internal volume of the ship’s enclosed spaces according to the

IMO’s (International Maritime Organisation) 1969 International Convention on

Tonnage Measurement of Ships. There are no units associated with GT as it is a non-

dimensional quantity. This parameter is often used to define ’volume’ carriers.

Specialised parameters are often used to express load capacity for specific ship types.

For instance, the TEU (twenty foot equivalent unit) is used to define the capacity of

container ships, cargo volume (m³) for LNG, CNG and LPG gas carriers, Car Units for

Car Carriers, lane-metres for RoRo vessels and Pax (number of passengers) for

passenger vessels.

Load factors come into play if the ship is less than fully-loaded since this affects its

manoeuvrability and response to environmental factors. The ship’s displacement or

weight displacement (∆) is equivalent to the weight of water displaced in tonnes. Usually,

∆ is listed for the fully-loaded ship. The ‘Light Displacement’ (LD) description corresponds

to the basic weight of the ship as it comes out of the shipyard with no cargo, fuel, or

ballast. Typically, LD is the difference between the fully-loaded ∆ and the DWT, or

approximately 15 % to 25 % of the full-load ∆. The minimum displacement at which a ship

can safely sail is known as the ’Light Load’ or ’Ballast Displacement’ (BD) condition. It is

equal to the LD condition plus the minimum ballast to ensure safe navigation in terms of

stability and propeller submergence and is typically 20 % to 40 % of full-load ∆, or 30 % to

50 % of DWT.

Ship Dimensions

Principal ship dimensions, as illustrated in Figure 1.2, include the length overall ( Loa ),

length between perpendiculars ( Lpp ), beam ( B ), and full-load draught ( TFL ). In addition,

because a ship is restricted by the height of bridges or cables over fairways, total height

(ship height from keel to top of ship, Hkt , or from water surface to top of ship, Hst ) is also a

principal dimension. The principal dimensions and above-water shape (and hence windage)

are determined by whether the ship is a ‘weight’ or ’volume’ carrier. The former are

characterised by a deep draught and relatively low windage, the latter by a light draught and

higher windage. Note that the fresh water draught Tfw is greater than the draught in

seawater Tsw since the density of fresh water,  fw is smaller than  sw. Some example ship

parameters are listed in Table 1-1. Additional details are contained in Appendix C.

Figure 1. 2 : Typical ship dimensions

Specific Waterway Capacity

Ship design is often constrained by the boundary conditions required by the dimensions

of important waterways and harbours, such as the Panama Canal and the Suez Canal.

Some examples with typical maximum dimensions are listed in Table 1.1. Many of these

classifications are based on particular waterways and harbours.

Future Trends

No-one knows for certain how future ship dimensions will develop, but history suggests

that they may continue to increase. For example, modern container ships continue to

increase in size in all dimensions, especially length and beam. The draught is the last

dimension to increase so as not to restrict entry in shallower channels and harbours.

Channel boundary conditions imposed by waterway and harbour authorities will still affect

future trends. For instance, the dimensions of the new Panama locks have created a new

class of vessels, the ‘New Panamax’. As a consequence the commonly used term Post-

Panamax may change in the future.

Ships are designed to travel as efficiently as possible from port to port, mainly via open

sea and their design focuses on carrying the maximum amount of cargo whilst reducing

drag and lowering fuel consumption, using streamlined underwater forms that include

bulbous bows and stern transoms. However, once they enter shallow, laterally-confined

access channels they begin operating in an environment for which they have not been

optimally designed. This can give rise to problems in ship handling and higher squat

values which can reduce underkeel clearance (UKC) and safety. Channel designers, port

authorities and operators need to decide how to manage these trends to remain

competitive in the global market while still ensuring safe port operations.

1.3.4.4 Limiting Operational Conditions

Handling a ship in all conditions of tide and weather is not always possible in the confined

waters and low speeds associated with port operations. If the UKC is too low, the waves

too high, the current too strong, the wind speed too great, the vessel speed too low or the

visibility too poor, the ship may be endangered. The pilot may not be able to control the

vessel safely, tug operations may be compromised or berthing may not be possible.

There are certain limits beyond which operations become unsafe and it is important that

the designer is able to quantify these limits in the design stage. In addition, the designer

may need to make allowance for any existing operational limits. If operational limits are

particularly restrictive, they may have a significant commercial impact on port operations,

and it may be decided to modify the design to allow greater freedom.

Vessel speed limits, both minimum and maximum, are also regarded as operational

limits. In some cases tidal and speed limits may interact, for example, where a vessel is

passing down a long channel on a falling tide.

Operational limits may also be dependent on ship-based factors, such as the ship type,

its manoeuvrability and navigation equipment and systems, which may have a significant

impact on the evaluation of limiting conditions when the ship can use the channel safely.

Also the type of cargo (especially hazardous cargo) may affect operational limits or

procedures.

Different reaches or stretches of a channel may have different limiting operational

conditions. Depending on these limiting conditions, different horizontal and vertical

dimensions may be obtained for each stretch, with different tug and aids to navigation

requirements. This can adversely affect availability and efficiency of the channel.

1.3.4.5 Human Error and Project Uncertainties

Approximately 70 to 80 % of maritime accidents are caused by human error [Hansa 2006,

2010]. The remainder are caused by mechanical breakdowns of ship or tug equipment

(i.e. engines and steering gear) and a small percentage by the channel itself (i.e. lack of

proper maintenance of channel dimensions). The uncertainties in channel operations can

be classified in four different groups (see Chapter 4.1):

 Uncertainty of the risk event

 Uncertainty of the available data

 Statistical uncertainty

 Uncertainty in any operational model being used

Human factors have a special relevance in the design of channels as each vessel

manoeuvre is a consequence of human decisions, which are made by the mariner (e.g.

ship’s master, pilot and/or helmsman) and carried out by other people (tug crews,

port/terminal operators). This uncertainty derives from human behaviour and affects the

people involved, as well as the risk event itself and the model uncertainty.

Consequently, the design process needs to take into account human factors by using, for

example, more sophisticated design tools (such as real-time simulation). Risk analysis,

which is recommended, should also take into account human factors.

Operational regulations are an essential part of correct channel design. They should be

developed with the active collaboration of the operators and mariners (e.g. pilots) and to

cover all types of predictable events with the objective of managing risks within

acceptable limits.

1.3.5 Physical Environment Data

1.3.5.1 Data Requirements

It is important to obtain as much information as possible about the environment in which

the channel will be placed so its width, depth and alignment may be determined

appropriately. In addition, it is necessary to consider changes which may occur to

environmental conditions as a result of the proposed design of the channel and any

manoeuvring areas and swinging areas (and other associated port structures).

In some cases only sparse information may be available and it is with this that key

decisions relating to the channel design may have to be made. In this case, extrapolation

of existing knowledge and the use of assumed frequencies of occurrence of

environmental effects are required. In general, the designer should err on the side of

conservatism, especially when the environmental situation is not fully known and so

assumptions need to be made. The original design can therefore be refined, and,

possibly, savings made, if the environment is subject to continuous monitoring.

For a channel and navigation area design, physical environment data is required for:

 Wind

 Waves

 Currents and tidal streams

 Tide cycles and elevations