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Ensuring the continued safety andefficiency of ships transiting channelsrequires designers and naval architectsto better understand the handling andmanoeuvrability of both existing and newgeneration ships in shallow and restricted

 waters. In particular, PIANC, the World Association for Waterborne TransportInfrastructure, wishes to provide the best

possible advice on the issues of horizontaland vertical dimensions relating toshipping channels and manoeuvring areas.

Consequent ly , PIANC recent lypublished ‘Harbour Approach Channels– Design guidelines’, a report from its

 Working Group 121 (previously MarCom Working Group 49). This report providesguidelines and recommendations for

the design of vertical and horizontaldimensions of harbour approach channels,manoeuvring and anchorage areas withinharbours, along with defining restrictionsto operations within a channel. It includesguidelines for establishing depth and

 width requirements in addition to verticalbridge clearances.

 The report supercedes and replaces the

Harbour approachchannels – designguidelines

Dr Mark McBride , Manager,

Ships Group, HR Wallingford, UK 

Figure 1. Complex channel design requires robust design techniques.

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 joint PIANC-IAPH report ‘ApproachChannels – A Guide for Design’, which waspublished in 1997 (from PIANC MarCom

 Working Group 30). This report was widelyaccepted worldwide by port designers.

 The new report has been compiledonce more in close cooperation with

IAPH (International Association ofPorts and Harbours), but also withIMPA (International Maritime Pilots

 Association) and IALA (Internationa l Association of Marine Aids to Navigationand Lighthouse Authorities).

Historical context  The design of approach channels andfairways was first considered by PIANCin a report published by Working Group 2of the PIANC International Oil TankersCommission (IOTC) in 1972. Some yearslater, this work was reviewed by WorkingGroup 4 of the PIANC InternationalCommission for the Reception of LargeShips (ICORELS) in a report publishedin 1980. The subject was most recentlyconsidered by the joint PIANC-IAPH

 Working Group PTC II-30 in co-operation with IMPA and IALA. Their findings were published, first as a preliminary setof concept design guidelines in 1995,followed by the 1997 final report ‘ApproachChannels – A guide for design’. Thisquickly became the world’s definitivereference for maritime channel design.

Updated guidelinesIn 2005, Working Group 121 (WG121)

 was created with 20 members from 12

countries, including three membersfrom the previous Working Group30 (WG30). It was to review, updateand, where appropriate, expand on thedesign recommendations as presentedin the WG30 report of 1997. In doingso, the Working Group considered

recent developments in simulation andother design tools, along with the sizesand handling characteristics of newgeneration vessels. In addition, furtherattention was given to the design of the

 vertical dimensions of channels than hadpreviously been provided.

 The over al l report was complete lyrestructured to present the verticaland horizontal aspects separately, withconceptual and detailed design techniquespresented in each main chapter.

 The new report ca n be purcha sedfrom the PIANC website or for PIANCMembers, it can be downloaded free ofcharge at http://www.pianc.org/edits/articleshop.php?id=2014121.

Methodology Aims and objectives The aim of the updated guidelines wasto provide the best international practicefor the design of approach channels that

 was avai lable to the por t engineeringcommunity. The goal was to produce apractical set of guidelines, which are easy tounderstand and apply. However, as with the

previous version of the guidelines, their usestill requires proper engineering judgement. The main object ives of WG121 were

to review, update and, where appropriate,

expand on the design recommendationson vertical and horizontal dimensioningas presented in the WG30 report of 1997.Recent developments in ship design, betterunderstanding of ship manoeuvrability andbehaviour in waves, and further research inship simulation and modelling required a

comprehensive update to the 1997 report. The Working Group paid par ticul ar

attention to:• Vertical motions of ships in approach

channels (due to squat, wave-inducedmotions, dynamic effects, etc.);

•  Air draught for ver tical clearancesunder bridges, overhead cables etc;

• Horizontal dimensions of channelsand manoeuvring areas;

• Simulation of ships in channels;• New and fu tur e generat ion

ship dimens ions/manoeuvr ingcharacteristics;

•  Wind effect on ship navigation andmanoeuvring;

• H u m an e r r o r s an d p r o j e c tuncertainties;

• Environmental issues, and• Safety criteria, assessment of levels of

risk and appropriate clearance margins. Al l si zes of ap proach ch an ne l fo r

commercial shipping were considered, asthe problems of catering for small coastersin a small port may be as great as those fora large tanker at an oil terminal.

Revised report  The new WG121 guidelines update theconceptual design techniques presentedin the previous WG30 work for both

Figure 2. Channel depth design components.

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horizontal and vertical dimensions. Thehorizontal dimension guidelines include

revised and updated allowances for channel wi dt h de si gn, al on g wi th provi dingmention of Spanish ROM and JapaneseMLIT standards, which need to be appliedin those particular countries. The verticaldimension sections were also revised andupdated with additional methods andexamples to illustrate the techniques. Thenew guidelines provide:• Conceptual design empirical

methods:o Channel width – sum of shipbeams, modified version of previous

 WG30 method;

o Chanel depth – new initialestimate method and ‘intermediate’calculation methods;

• Guidance on detai led des ignmethods;

• Emphasise that results of conceptualdesign empirical methods are not afinal design;

• Expect conceptual design to beconservative, and

• Optimise using detailed designmethods described in the guidelines.

Much of the effort of WG121 wasfocused on detailed design guidelines, andin particular, probabilistic design and riskaspects, reflecting the requirements ofmodern engineering design principles.

 Th e ve rt ic al dimens ion gu id el inesinclude further discussion and examplesfor predicting vertical ship motions dueto waves that include deterministic,statistical and probabilistic methods. Theyalso include sections on squat and muddychannel beds, which have been updatedbased on recent research and developments.In addition, with recent accurate (PDGPS)measurements of ship squat and calibrated

theories, squat can now be predicted withmore accuracy and this information isincorporated in the new guidelines.

 Another aspect was the recent

development of Post and Ultra-Post-Panamax container vessels (with capacities

of up to 18,000 TEU), large car carriers,and QFlex- and QMax-size LNG carriers.

 These vessels have specific characteristics(high windage, larger bulbous bows,

 wider transom sterns , minimal parall elmid body/flat of side, etc.), which mayrequire specific risk mitigation measuresthat can have an impact on access channeldesign and operation. The new guidelinestake these new design changes intoconsideration.

Furthermore, the use of advancednumerical models of wave propagationand ship response to waves, along

 wi th ev er real is ti c sh ip manoeuvr ingsimulation, have become commonpractice in port engineering design. Thenew guidance includes more details andexamples of their use.

Capacity simulation models can alsobe used to evaluate the safety of portinfrastructure and are described with anexample. Today, there is a more continuousrange of tools available, so that each typeof simulator/simulation can be used indifferent stages and detail of channel design.

Recent developments have led to a moreintegrated approach for environmentalaspects for channel design. In the previousapproach, the conceptual design wasfirst completed and was then used asthe basis for the Environmental Impact

 Assessment (EIA). After completion ofthe EIA, detailed design was undertaken,

 which led to long and interrupted designperiods. Now, the EIA study is integrated

 with both the conceptual and detaileddesign stages, which leads to a fasterdesign process, with environmental aspectsbeing taking into account throughout theengineering design process.

Conclusion The ne w WG12 1 ha rbo ur cha nn eldesign guidelines provide best practice

recommendat ions for the des ignof horizontal and vertical channeldimensions, and for manoeuvring areadimensions within harbours. Theseinclude consideration of many factors,including design vessels, operationallimits, risk, economic and environmental

considerations, support craft requirements,and aids to navigation.

Figure 3. Channel width design components.

 About the author 

Dr Mark McBride is the managerof the Ships Group at UK-based HR

 Wallingford and has over 25 years ofexperience in port and maritime designrelated work. He has been involved innumerous projects regarding the designof approach channels, turning circleand manoeuvring areas, berth locations,

ship mooring analysis, and operationals imulat ion s tudies examiningoptimisation of transportation networks,berths and storage facilities. He wasthe Chairman of PIANC WorkingGroup 121 which produced the reportdescribed in this paper. In addition, heis the author of many technical paperson port operations, ship navigation andmooring-related topics.

 About the organisation

PIANC is the World Association for

 Waterborne Transport Infrastructure.It provides a forum where professionalsaround the world join forces to provideexpert advice on cost-effective, reliableand sustainable infrastructures tofacilitate the growth of waterbornetransport. Established in 1885,PIANC continues to be the leadingpartner for government and the privatesector in the design, developmentand maintenance of ports, waterwaysand coastal areas. As a non-politicaland non-profit organisation, PIANCbrings together the best internationalexperts on technical, economic andenvironmental issues pertaining to

 waterborne transport infrastructures.M e m b e r s i n c l u d e n a t i o n a lgovernments and public authorities,corporations and interested individuals.

Enquiries

HR Wallingford,Howbery Park,

 Wallingford,Oxfordshire,

OX10 8BA, UK  Tel: +44 (0)1491 835381 Web: www.hrwallingford.com

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