613
1 INTRODUCTION
In modern ports due to the economic reasons port
manoeuvresoflargevesselsarecommonlyperformed
in conditions closed to the limits related to ship
dimensions,underkeelclearance,weatherconditions
and towing assistance. This is mainly caused by the
introduction of ultra large container ships (ULCS)
over8,000TEU(t
wenty‐footequivalentunit),of300ξˆ±β€“ξˆ±
400mlength,equippedwith2000‐3500kWthrusters
and 60 β€“ξˆ± 80 MW propulsion systems (Hermans &
Degens,2011,Willemsetal,2013)operatedi.a.inthe
direct services Europe β€“ξˆ± Asia.are Post Panamax
Plus of 6000 β€“ξˆ± 8000 TEU capacity, New Panamax of
11000ξˆ±β€“ξˆ±13000TEUcapacityandPostNewPanamax
(Suezm
ax) of 15000 β€“ξˆ± 19000 TEU capacity, single or
twinpropellervessels.Theycanperformmanoeuvres
inverytightareasandstrongweatherconditions,up
to port operational limits, using their thrusters and
propellers to increase efficiency of manoeuvres
assistedbytugboa
ts.
Thebottlenecksofshipsaccessibilityinmostports
are the narrow port entrances and small turning
basins (PIANC, 2014). There are several phenomena
whichshouldbeconsideredintheriskassessmentof
error during manoeuvring in restricted waters
(Abramowicz‐Gerigk&Burciu, 2012; Abramowicz‐
Gerigk&Burciu;2014,Gerigk,2012;Elootetal.,2010).
Shipmotionsimulationcanbeusedtodeterminethe
riskofapa
rticularmanoeuvre(Alfredinietal.,2011;
Gucma, 2009), safe manoeuvring area  and limiting
weather conditions combined with experts opinion
(
Abramowicz‐Gerigk &Hejmlich, 2015; Hejmlich, 2014).
Theaction reliabilitycanbeincluded inaccessibility
studytodetermine thebestofthepossiblesolutions
with respect to the manoeuvring  tactics of the ship
entranceintoaharbour.
Application of Ship Motion Simulation in Reliability
Assessment of Ship Entrance into the Port
T.Abramowicz‐Gerigk&Z.Burciu
GdyniaMaritimeUniversity,Gdynia,Poland
ABSTRACT:Thegrowingnumberoflargecontainervesselsisthereasonofportinfrastructuremodernization
necessityandchangesoflocalbylawsinports.Theaccessibilitystudiesbasedonshipmotionsimulationallow
fortheassessmentofmanoeuvringoperationssafetyforthenewportdesignsandreconstructionsoftheexisted
i
nfrastructure.Severalfactorscanbeusedtodeterminesafetyofmanoeuvringoperations.Thepaperpresents
an approach to determine the operational reliability which can be included in an accessibility study to
determine thebestof the possible solutions withrespect to the ship entrance into the harbour. The general
reliabilit
ymodelhasbeenproposedandanexampleofreliabilityofshipentranceintothePortofGdyniais
presented.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 10
Number 4
December 2016
DOI:10.12716/1001.10.04.10
614
2 RELIABILITYOFSHIPMANOEUVRING
OPERATIONS
Operationalsafetyisrelatedtobothpotentialandreal
hazards of manoeuvring operations performed by a
ship master during ship approach and entry into a
harbour. The risk management on ship arrival in a
portis adecision makingprocess inthearea of
risk
consisting of making optimal decisions with respect
totheexistedhazardsandacceptedrisklevel(Burciu,
2012).
Theriskrelatedtomanoeuvringoperationscanbe
comparedto the operational riskξˆ±β€“ξˆ± the risk of losses
due to incorrect and malfunction internal processes,
personnel, technical systems and external events
(Hetherington
etal.,2006;Mokhtarietal.,2013).This
ismainlyduetothemaininfluenceofhumanfactor
on the losses which the operational risk level is
dependent on. They are mostly not repeatable and
difficulttopredict.
The voyage of a vessel which is a transportation
taskcanbe considered as
 animplementation of risk
management procedure. Under this assumption the
ship entry into a port is the implementation of risk
control and monitoring –  the last stage of risk
management of PMIξˆ±β€ξˆ±Project Management Institute
(www.projectinsight).
The operational reliability of ship entering a
harbour is the probability of failure‐free
ship
performance during sailing along the approach
channel,passing theport entrances,inner portcanal
and docs, ship turning and berthing manoeuvres. It
canbeexpressedasfollows(2.1)and(2.2):

1ο€½ο€½ ZPK  (2.1)


r
KXZP ο€½ο€½ο€½ 11
 (2.2)
where:
K β€“ξˆ± is an operational reliability, probability of
failure‐freetaskperformance,
K
rξˆ±ξˆ±β€“ξˆ± is a  probability of task performance by a
manoeuvringvessel,
Zξˆ±ξˆ±β€“ξˆ± the characteristic parameter of the state of the
object reliability (1 β€“ξˆ± operationally reliable (task
performed), 0 β€“ξˆ± operationally unreliable (task not
performed),
X β€“ξˆ± the characteristic parameter of the object
reliability(1ξˆ±β€“ξˆ±therearenoinfecting
factorsasfailures,
hydrometeorological conditions, ship movement,
towingoperations,humanfactor;0ξˆ±β€“ξˆ±thereareexiting
infectingfactors).
3 EXAMPLEOFRELIABILITYASSESSMENTOF
SHIPENTRYINTOTHEPORTOFGDYNIA
PortofGdyniaisauniversalmodernportspecializing
in handling unitized cargo transported in the lo‐lo
and
ro‐ro systems, based on the network of
multimodal connections including hinterland, Short
Sea Shipping Lines and ferry connections. It is an
important link in the Corridor VI of the Trans‐
EuropeanTransportNetwork(www.port.gdynia.pl).
The previously performed accessibility study of
ULCSbasedonshipmotionsimulationcarriedoutin
the
 environment of an interactive Full Mission
Simulator SimFlex Navigator 4.6 confirmed the port
accessibilityfortheultralargecontainershipsunder
particular conditions. The numerical model of
navigational area of Port of Gdynia has been
developedbyShipOperationDepartmentofGdynia
Maritime University in two variants of port
infrastructureξˆ±β€ξˆ±
the existed and after a possible
reconstruction. The data bases of the terrain were
developed using specialized programming tools
compatiblewithSimflexNavigatorArea Engineerfor
Full Mission Ship Handling Simulator SimFlex
Navigatorversion4.6basedonNebulaDevice2.
ThemainbridgeofFullMissionSimulatorSimFlex
Navigator 4.6 and
 Port of Gdynia visualization is
presentedinfigure1.

Figure1.PortofGdyniavisualizationintheenvironmentof
main bridge of Full Mission Simulator SimFlex Navigator
4.6
Fullmissionsimulationcreatestheenvironmentof
real navigational and working conditions including
collaboration between ship master, pilot, tug master
andvesseltrafficservicesandisthebesttoolforthe
operational safety and reliability studies of ship
manoeuvringinrestrictedwaters(Gongetal.,2006).
The reliability assessment of ship
 entry into the
porthasbeenperformedtakingintoaccount3stages
ofshipentry:A,B,C,Drelatedtothepa rticularareas
andnecessarycoursechanges:
A. Navigationalongtheapproachchannel:
ο€­ approachchannelwidthattheseabed:150m,
minimumwaterdepth:14.1m,
ο€­
maximumshipdraft 13m atmedium or high
waters,
ο€­ distance between β€žG1‐G2β€ξˆ± buoys β€“ξˆ± the
approach channel gate to the main entrance
2780m=1.5Nm,
ο€­ widthoftheξˆ±β€žG1‐G2β€ξˆ±gate:185m.
B. Passingthemainentrance:
ο€­ widthofthemainentrance:150
m,
ο€­ maximumshipdraft13m.
C. Passingtheinnerentrance:
ο€­ distance between main entrance and internal
entrance:980m,
ο€­ widthoftheinternalentrance100m,
615
ο€­ maximumshipdraft13m.
D. Navigationalongtheinnerportcanal.
Every stage of ship entry (A,B,C,D) requires 3
coursechangesinleadinglinesintherestrictedarea.
Therequiredcoursechangesarepresentedinfigures
2and3ξˆ±β€ξˆ±fora shipnotturnedonarrival andfor
the
ship turned on arrival in Turning Basin No. 2ξˆ±β€ξˆ±
respectively.

Figure2.ShipentranceintothePortofGdyniawithoutturn
onarrival.

Figure3. Ship entrance into the Port of Gdynia β€“ξˆ± ship
turnedintheturningbasinonarrival
Fortheshipfollowingthesequentialleadinglines
during entry into the port the risk R of the
manoeuvringerror duringshipentryisafunctionof
the events related to the ship courses KR
i, i=1, 2, 3
corresponding to the leading lines and can be
presentedasfollows(3.1):

,KR,KR,KRRR
321
ο€½  (3.1)
Fortheassumedminorfaultsincoursekeepingof
thei
th
courseKRi, i=1,2,3 whichcanbe correctedin
thenextstageoftheshipentry,thetotalprobabilityof
afailureduringthesequenceoffoureventsA,B,C,
D:
ο€­ KR
A=KRB=Kr1,
ο€­ KR
C=Kr2,
ο€­ KR
D=Kr3
can be determined using the chain ruleξˆ±β€ξˆ±equation
(3.2).

CBAD
BACAB
ADCBA
KRKRKRKRP
)KRKRKR(P)KRKR(P
)KR(P)KRKRKRKR(P



 (3.2)
Theriskoffailureduringshipentryintotheportis
dynamic in nature as it is the result of fast
organizationalchangesinshipcommand‐controland
environment (Khakzad et a., 2012). It can be
determinedapplyingtheconsequencesofshipfailure,
expressed in qualitative or semi‐quantitative
values
related to i.e. the safe distances from the port
infrastructure(Abramowicz‐Gerigk,2012).
The counteraction to the hazards existed during
sequentialstagesofshipentryintotheport(A,B,C,
D) in the particular time and at absolute level of
acceptableriskcanbecalledriskmanagementofship

entrance manoeuvresξˆ±β€ξˆ±the system of methods and
actions(throttlesettings,coursecorrections)aimingto
keeptheaxis of a fairway to keep the vessel on the
designatedcourseduringA,B,C,Devents.
The operational reliability of ship manoeuvring
during taking andkeeping the course in A, B, C,
D
eventsiscalledthecoursereliability.
It is defined as an operational characteristic of a
shipdeterminingthattheshipcansafelyperformthe
task of entry into the port on K
A,B,C,D courses in
particular weather conditions. The course reliability
canbeexpressedintheformofequation(3.3).




 APR
R
o
 (3.3)
where:
R(
o
)ξˆ±β€“ξˆ±iscoursereliabilityduringtheshipentrystages
A,…,D;
ο„ο‘ξˆ±β€ξˆ±isasectorofthesafeshipcoursesinaparticular
shipentrystage,
Ξ”A β€“ξˆ± is a sector of safe courses for keeping in the
headingline.
For example the course reliability for KR
A the
assumed sector 5
o
 (+/‐2.5
o
) can be determined as
follows:
 
o
52A . 





o
R
o
52PR .

Course reliability enhancement options for ship
entranceintotheharbour
The course reliability enhancement can be
obtainedbytheimplementationofseveraloptions:
ο€­ decisionsupportsystems,
ο€­ changesoftheportinfrastructurelayout:
ο€­ wideningofinnerentrance,
ο€­ buildinganouterport.
Anexampleofa decision support
system for the
ship entry into the port called Ship Virtual Mask
(VSM) has been introduced in (Abramowicz‐
Gerigk&Burciu, 2010). VSM allows determining a
complex safety measure for the manoeuvring
operationsalongtheapproachchannel.
It is based on the real time information about
weatherandtrafficalongwiththeprediction
models.
Statistical emulator provides the necessary estimates
determining the most probable circulation patterns
fromtheactualatmosphericforcingfield.
Themodelsofshipmotionofhigheraccuracythan
the generally accepted models used in applications
dedicated for design and training include stochastic
transfer functions for wind and current forces
generated
onahull.
ShipentryintoPortofGdyniaξˆ±β€ξˆ±navigationalong
the approach channel under the wind and
unexpected, wind generated, transverse surface
current in front of main entrance is presented in
figure4.
616

Figure4.ShipentryintoPortofGdyniaξˆ±β€“ξˆ±navigationalong
the approach channel under the wind and unexpected,
windgenerated,transversesurfacecurrentinfrontofmain
entrance
ShipentryintoPortofGdyniaξˆ±β€“ξˆ±navigationalong
the approach channel under the wind and
unexpected, wind generated, transverse surface
current in front of main entranceξˆ±β€ξˆ±allision with the
entranceheadispresentedinfigure5.

Figure5.ShipentryintoPortofGdyniaξˆ±β€“ξˆ±navigationalong
the approach channel under the wind and unexpected,
windgenerated,transversesurfacecurrentinfrontofmain
entranceξˆ±β€ξˆ±allisionwiththeentrancehead
The safe ship entry into Port of Gdynia β€“ξˆ±
navigation along the approach channel under the
wind and unexpected, wind generated, transverse
surface current in front of main entrance β€“ξˆ± using
Virtual Ship Mask System (VSM) is presented in
figure6.

Figure6. Ship entrance into Port of Gdynia β€“ξˆ± navigation
along the approach channel under the wind and
unexpected, wind generated, transverse surface current in
front of main entrance β€“ξˆ± safe entrance using Virtual Ship
MaskSystem(VSM)
The ship entry into Port of Gdynia after the
widening of the internal entrance needs only a 1‐2
o
changeofshipheading.Thenavigationlightsectorof
anewleadinglineispresentedinfigure8.

Figure8. Ship entrance into Port of Gdynia β€“ξˆ± widened
internalentrance,navigationlightsectorsofanewleading
line
A concept design of outer port in Gdynia is
presented in figure 8. The new solution allows safe
shipentryusingonlyoneleadingline.

Figure7.ConceptdesignofouterportinGdynia
PrΔ…d
przypowierzchniowy
A
B
surfacecurrent
PrΔ…d
przypowierzchniowy
surfacecurrent
PrΔ…d
przypowierzchniowy
A
B
VSM
surfacecurrent
617
4 CONCLUSIONS
Operational reliability usually defined as the
probabilityoffailure‐freeperformanceofataskovera
specified time frame, under specified environmental
conditions e.g. quality over the time with respect to
the ship course reliability has been expressed in the
paperasaqualityoverthecoursechange,
relatedto
the ship course stability and layout of the port
infrastructure. The course reliability determined for
thesuccessivestagesofshipentryintotheportallows
forthe quantitativeassessment ofdifferent solutions
ofmanoeuvringtacticsrelatedtotheoutlineofthea
infrastructure.
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