357
1 INTRODUCTION
TheQuaidesTroisFontainesisaberthingareanear
thetownofGivet inthe Ardennes region of France,
which was designed for 80 m long vessels (CEMT
ClassIV)plyingtheRiverMeuse.Aturningbasinis
located in front of the Quai des Trois Fontaines
to
allow vessels to turn before loading at the quay, as
indicatedinFigure1.
Thequayishardlyusedatpresent.Strongcurrents
canbepresentinthisareaandsomeskippersdonot
feelconfidentaboutthesafetyoftheturn,especially
becausethereisa shallowzone
presentontheright
bank(see Figure 1).Inaddition,it isthoughtbythe
localauthoritiesthatmoretrafficwouldbegenerated
ifthequaywouldbeabletoreceivelargervessels[1].
A study was therefore commissioned by the
waterway authority, Voies Navigables de France, to
studyhowthe
safetyoftheturningmanoeuvrecould
be improved and which measures are required for
safemanoeuvreswithlargervessels,i.e.vesselsof85
and90minlength.Tothisend,theenvironmentof
the Quai des Trois Fontaines was modelled in a
dedicated inland ship manoeuvring simulator and
real
time simulations were carried out with
experiencedskippers.
Optimization of a Ship Turning Basin Using Real Time
Simulations – A Case Study for the Quai Des Trois
Fontaines (Chooz, France)
M.Mansuy&M.Candries
GhentUniversity,Ghent,Belgium
K.Eloot
FlandersHydraulicsResearch,Antwerp,Belgium
B.Wéry
IMDC,Antwerp,Belgium
ABSTRACT:TheQuaidesTroisFontainesisaberthingareainChooz,France,whichwasdesignedfor80m
longvessels(CEMTClassIV)plyingtheRiverMeuse.AturningbasinislocatedinfrontoftheQuaidesTrois
Fontainestoallowvesselstoturnbeforeloading
atthequay.Realtimesimulationsonadedicatedinlandship
manoeuvringsimulatoratFlandersHydraulicsResearchwerecarriedoutwithexperiencedskipperstostudy
how the safety of the turning manoeuvre could be improved and which measures are required for safe
manoeuvreswithlongervessels,i.e.vesselsof85
and90minlength.
Inthefirstphaseofthestudy,turningmanoeuvresofCEMTClassIVvesselsof80m,85mand90mlongwere
studiedintheexistingenvironment.Themanoeuvreswereevaluatedbasedondifferentsafetycriteriaandon
thefeedbackofthepilots.The
realtimesimulationshaveshownthattheactualdesignoftheturningbasinis
suitableforthe80mlongvesselsinanyhydro‐meteorologicalcondition.However,themanoeuvresbecome
riskywith85mlongvesselsundercertainconditionsandimpossiblewithlongerships.Althoughthecurrent
canbevery
strongontheriverMeuse,thelocalwidthturnedouttobethemostcriticalparameter.
Inthesecondphaseofthestudy,measureswereproposedtoallowthesafeturningof85mand90mlong
vessels. Local widening of the river to 100 m and to 105 m
were proposed for 85 m and 90 m long ships
respectively. A third proposed measure is to provide a fixed point near the end of the quay, to which the
vesselscanattachandaroundwhichtheycanthenturn.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 13
Number 2
June 2019
DOI:10.12716/1001.13.02.12
358
Figure1. Turning basin geometry near the Quai des Trois
FontainesinChooz(France).
Table1. Lengths of turning basins as a factor of ship
dimensionfromexistingguidelines[2]
_______________________________________________
RiverCanal
_______________________________________________
China2.5L(4.0L)* 2.0L
Dutchcasebycase 1.2L
Germany casebycase 1.2L
US1.5L**1.2‐1.5L**
PIANC[2] 1.5L1.2L
_______________________________________________
*VFlow>1.5m/s
**FormaritimeportsandV
Flow<0.8m/s
Withadiameterof95mfor80mlongvessels,the
turningbasinalmostcomplieswith1.2∙Lasdescribed
bythedesignguidelinesforfreeturningmanoeuvres
[2].Strictlyspeaking,however,theturningbasindoes
notcomplywithanyoftheguidelines,asindicatedin
Table1.Becauseof
safetyreasonsandtoallowforan
easy turn without being forced to use additional
thrusters, the guidelines indicate that a turning
diametershouldbelargerthanL[2].
Inseverehydro‐meteorologicalconditions,afixed
point(i.e.adolphin)towhichtheshipcanattachand
aroundwhichit
canthen turn,can alsobeused to
reduce the required width of the turning basin.
However, a disadvantage is the necessary length of
the semi‐circular turning area, which should be at
least2∙L,withsomeextraallowanceincasemooring
linesareused[2].
In case of free
‐flowing rivers, high currents can
causedriftandsedimentation,whicharemajorissues
and deserve particular attention when designing
turning basins. In reality, due to environmental,
economic or geotechnical restrictions, the
recommended dimensions can often not be met. In
thosecases,realtimesimulationsbecomeausefultool
to determine
less conservative designs, which are
more adapted to the actual situation. The use of
manoeuvringsimulationstostudythedetaileddesign
of a turning basin is an established practice and
severalexamplescanbefoundinliterature,e.g.[3‐7].
This paper illustrates the use of real time
simulations to optimize
the existing turning basin
located at the Quai des Trois Fontaines in Chooz
(France) and to make it accessible to larger vessels.
Section 2 explains how these real time simulations
were set up and which criteria are used to evaluate
the manoeuvres. Section 3 discusses the simulations
thatwerecarried
outinthe environment as itexists
today, whereas Section 4 discusses the simulations
that were carried out in an environment which was
modifiedinordertobeabletoturnwithvesselsthat
are 85 m and 90 m long. In Section 5, finally, the
conclusionsaregiven.
2 MANOEUVRABILITY
ASSESSMENT
2.1 Manoeuvringsimulator
About 70 free and fixed turning manoeuvers were
simulatedonafullmissionmanoeuvringsimulatorat
Flanders Hydraulics Research, which has been
specially developed for inland navigation research.
The inland navigation simulator is composed of a
bridge with 210° aerial view displayed on 52” LCD
monitors,
as shown in Figure2. The bridge is
equippedwith:
ECDISandradar
Controllablecameraviews
Controllablebridgeheight
Verticalviewdownformanoeuvresclosetoalock
orawall
Figure2. Manoeuvring simulator for inland navigation
(FlandersHydraulicsResearch,Belgium).
2.2 Shipmodels
Extensive model testing has beencarried out with a
scalemodelofaclassVa(110moffullscalelength)in
the Towing Tank for Confined Water at Flanders
Hydraulics Research to provide data for the
mathematicalmanoeuvringmodelsatdifferentdrafts
andunderkeelclearances(10to100%
ofthedraft)[7].
Byscalingfrommodeltodifferentfullscaleclassesof
inlandvessels(betweenclassIVwith85mlengthand
classVa) the mathematicalmodels could be used to
evaluate the manoeuvring behaviour of inland
navigation vessels in design cases such as the Quai
des Trois
Fontaines. Based on fast time simulations
withthederivedclassIVandclassVavesseltypesat
interpolated conditions for the draft and the under
keel clearance, the mathematical models were
validated in [8] based on measurements on real
vesselsinFlemishwaterways.Forthepresentstudy,
359
two new models were derived for class IV vessels
withalengthof80mand90mfromtheexisting85m
longmodel.Themathematicalmodelsalsotakebank
effectsintoaccountandhavetheoptiontoincludea
bow thruster, the use of which can be restricted
dependingonthesimulationscenario.
2.3 Evaluationcriteria
Different criteria are used to evaluate the difficulty
and safety of the manoeuvres. The most critical
parameter is the distance between the ship and the
depth line corresponding to the draft of the vessel,
whichiseither1.7mor2.5m.
Three other parameters that are used as criteria,
are thereserve of the propeller, the reserve of the
bow thruster and the reserve of the rudder. In
general, the reserve of a control parameter n
represents the reserve that is available in case a
problem occurs and is defined by the
following
formulation:
ˆ
1
n
max
n
R
n
with:
n
R
:Reserveofthecontrolparametern
ˆ
n
:Meanvalueoftheparametern
max
n :Maximumvalueoftheparametern
Forthethreecriteriamentionedabove,thecontrol
parameternisequaltothenumberofrevolutionsof
themainpropeller,thenumberofrevolutionsofthe
bowthrusterandtherudderanglerespectively.
Themanoeuvrabilityoftheshipcantheneasilybe
evaluated
based on the criteria using a colour code.
Table 2 indicates for which values for each of the
parameters a colour changes. A manoeuvre is
unacceptable whenever at least one of the criteria
turnsred.
Table2.Safetycriteria.
_______________________________________________
Reserve Reserve Reserve Min.
main bow rudder distance
propeller thrustertoisolines
_______________________________________________
Inacceptable <10%<10% <10% <10%
10%‐25% <30% <50% <50%
Acceptable 10%‐50% <100%50%‐70% <100%
Noconstraints >50%100% >70% 100%
_______________________________________________
2.4 Skippers
Therealtimesimulationsinthisstudywereexecuted
byprofessionalskipperswhohaveampleexperience
both with class IV vessels and with the navigation
area.
After each simulation a debriefing session was
organized, during which the skipper could give his
opinion about the simulation and the manoeuvres
that were performed. The difficulty as well as the
safetyofthemanoeuvreisratedonascalefrom1to6.
This feedback adds relevant information to the
analysis considered along with the safety criteria
whenamanoeuvreisevaluated.
2.5 Hydraulicconditions
The current flow was implemented using
a 3D
hydraulic model developed by IMDC (International
Marine and Dredging Consultants). Different
hydraulic conditions were modelled based on
representative flow rates measured upstream. An
overviewofthesimulatedconditionsisgiveninTable
3 from low water flow to the maximum operational
conditions.
Table3.Hydraulicconditions
_______________________________________________
Cond. Flow MeanWaterlevel
rate currentspeed upstream
(m³/s) (m/s)(mNGF)
_______________________________________________
Qmin 29.0 0.1699.55(min)
Qmed. 87.4 0.3699.65(Normal)
Q60% 114 0.499.75(max)
Q75% 177 0.699.75(max)
Q90% 310 0.8599.75(max)
QMax 400 1.199.75(max)
_______________________________________________
3 EXISTINGENVIRONMENT‐EVALUATIONOF
TURNINGMANOEUVRESCARRIEDOUTWITH
CEMTCLASSIVVESSELS
3.1 80mLongvessels
The turning manoeuvre near the Quai des Trois
Fontaineswas first simulatedwitha80 m long ship
withadraftof1.7m,representativeofanemptyship.
Themanoeuvres
wereevaluatedtobesafe,butwith
relativelylowsafetymarginsatthehighestflowrate,
asindicatedforonesimulationinTable4andFigure
3. Overall, the analysis indicates that the turning
basin is well designed for 80 m long vessels with a
draftof1.7m. Pilots
canbeconfidentwhen turning
with empty vessels in this area as the underkeel
clearanceissufficientatalltimes.
Table4. Manoeuvrability assessment, free turn of an 80 m
longvessel.
Distances
Res erve Difficulty
/6 /6
5.5 64% 64% 69% 3 3
Reserve overview Pilot feedback
Min dist
1.7m [m]
Q 90% (310m³/s)
Main
propeller
Bow
thruster
Rudder
Figure3.Plotofthetrajectorywithan80mlongvesselwith
adraftof1.7m,turningfreelywithQ90%.
360
3.2 85mLongvessels
Themanoeuvresbecomemoredifficultwithashipof
85 m long. As indicated in Table 5, the manoeuvres
are only acceptable below Q75%. There is enough
space available in the longitudinal direction to
accommodatethedriftmotionoftheshipthatoccurs
dueto
windandcurrent.However,thewidthofthe
riveristoorestricted.Whentheshipisalignedwith
theriver,theskipperiscounteractingthelongitudinal
current/wind forces, which are directed against the
heading of the ship. When the ship is then turning,
thesewind/currentforcescomefromtheside
andthe
skipper needs to adjust the controls quickly to
counteract the lateral forces in time. However, the
reaction of the vessel takes some time and the force
equilibrium is broken for a while. As a result, the
skipperdoesnotmanagetokeepasafedistancefrom
thebanks,as
indicatedforonesimulationinFigure4.
The analysis indicates that a larger safety margin is
required. In addition, the simulations show that the
use of bow thruster is necessary during the turning
manoeuvre, as indicated by Figure 5. Without bow
thruster, the turning manoeuvre takes too long, the
vessel
is too difficult to control under the imposed
environmental circumstances and it comes too close
totherightbank.
Table5. Manoeuvrability assessment, free turn of an 85 m
longvessel.
Distances
Min dist
1.7m [m]
Main
propeller
Bow
thruster
Rudder
Res erv e
/6
Difficulty
/6
3.5 68% 69% 63% 3 3
1.8 75% 78% 72% 3 3
2.9 61% 68% 68% 2 2
0 73% 87% 67% 5 6
0 42% 29% 40% 5 6
Q 60% (114m³/s)
Q 75% (177m³/s)
Q 90% (310m³/s)
Reserve overview Pilot feedback
Q min (29m³/s )
Q med (87.4m³/s )
(a)(b)
Figure4.Freeturnofan85mlongvesselexecutedwith(a)
andwithout(b)bowthruster.
3.3 90mLongvessels
Whenthemanoeuvreiscarriedoutwitha90mlong
ship,theskipperisunabletocompletethemanoeuvre
without touching a bank.The river is simply not
wideenoughtocarryoutthemanoeuvre,asindicated
inTable6.
Table6. Manoeuvrability assessment, free turn of a 90 m
longvessel.
Distances
Min dist
1.7m [m]
Main
propeller
Bow
thruster
Rudd er
Res erve
/6
Difficulty
/6
0 78% 84% 65% 5 4
0 79% 72% 60% 5 4
0 73% 70% 54% 5 4
0 67% 68% 59% 5 5
Q 75% (177m³/s)
Reserve overview Pilot feedback
Q min (29m³/s)
Q med (87.4m³/s)
Q 60% (114m³/s)
4 MEASURESTOOPTIMIZETHEDESIGNOFTHE
TURNINGBASIN
Thenextstageinthestudywastoproposemeasures
whichwouldallowthesafeturningof85mand90m
longvessels.
From the analysis of the simulations executed in
the actual existing environment, it wasconcluded
that
the width of the river at the location of the
turning basin was the most critical parameter.
Thereforetwonewdesignswereproposed,enlarging
thewidthoftheriverto100mand105mtoallowthe
turning of an 85 m long and 90 m long vessel
respectively, as
indicated in Figure 7. These widths
were proposed based on the superposition of the
envelope of the ships’ trajectories obtained from the
simulationsintheexistingenvironment,cf.Section3.
Athirdoptionthatwasproposed,istouseafixed
point at the end of the Quai des Trois
Fontaines to
whichthevesselcanattach with a rope andaround
whichitcanthenturn.Thisfixedpoint,thatisplaced
in the original environment and studied separately
fromtheprevioustwooptions,isineffectadolphin
aroundwhichtheshipcanturn,asshowninFigure8.
361
Figure5.Timeseriesofan85mlongvesselturningfreelywithQ90%.
362
(a)(b)
Figure7. Proposed widening of the river in order to
improvetheturningconditionsfor85mlong(a)and90m
longvessels(b).
Figure8. Fixed point (dolphin) implemented in the
simulatortoimprovetheturningconditions.
4.1 85mlongvessels
Thesimulationsshowedthattherewerenoproblems
whentheriverwaswidenedby5mtoatotalwidthof
100mattheturninglocation.
Differentpositionswerestudiedforthefixedpoint
(dolphin) around which the ship could turn best.
Basedonthe
simulationsresultsandthefeedbackof
theskippers,apositionontheleftbankseemedmore
appropriate. Consequently, safe manoeuvres were
successfullyexecutedwitha85mlongvesselturning
aroundthispoint,asshowninTable7andFigure9.
Table7. Manoeuvrability assessment, 85 m long vessel,
actualturningbasin,butwithafixedpointontheleftbank
towhichthevesselcanattachandaroundwhichthevessel
canthenturn.
Distances
Min dist
1.7m [m]
Main
propeller
Bow
thruster
Rudder
Reserve
/6
Difficulty
/6
4 65% 72% 72% 3 3
Reserve overview Pilot feedback
Q 90% (310m³/s)
Figure9.Trackofan85mvessel,actualbasinwithafixed
pointontheleftbank.
4.2 90mLongvessels
Thesimulationsshowedthatwideningtheriverby10
mtoatotalwidthof105moveralengthof65mwas
not sufficient for the safe turning of a 90 m long
vessel.AsindicatedinFigure10,thedowstreampart
ofthe
turningbasinshouldbewidenedaswell.The
presence of rocks at this location would make this
measureratherexpensive.
Figure10.Trackofa90mvessel,wideningof105m.
Whenafixedpointisprovidedaroundwhichthe
vessel can turn, the distance to the bank is better
controlled. Safe manoeuvres can be carried out
without widening the river locally, but the distance
from the right bank during the turning manoeuvre
becomesquitesmall,asindicatedinTable8.
Table8. Manoeuvrability assessment, free turn of a 90 m
longvessel,actualbasin,withafixedpointontheleftbank.
Distances
Min dist
1.7m [m]
Main
propeller
Bow
thruster
Rudder
Reserve
/6
Difficulty
/6
0.5 69% 63% 79% 3 3
Reserve overview Pilot feedback
Q 90% (310m³/s)
5 CONCLUSIONS
AstudywascarriedouttoinvestigatewhetherCEMT
ClassIVvesselscanturnsafelyattheQuaidesTrois
Fontaines (Chooz) inFrance.Real time simulations
were carried out with experienced skippers on a
363
dedicated inland ship manoeuvring simulator at
FlandersHydraulicsResearch.
Thesimulationsshowedthat80mlongvesselscan
safely carry out turning manoeuvres in the existing
environment. The manoeuvres can be carried out
safely with or without bow thruster and in any
hydraulicconditions.Thisisnolongerpossiblewith
85mlong,letalone90mlongvessels.
Inordertobeabletoturnsafelywith85mand90
m long vessels, a local widening of the river on the
right bank to 100m and 105m respectively was
proposed. The proposed widening would be over a
length
of 65m. Analysis of the simulations indicate
thatthisissufficientfor85mlongvessels.However,
in order to turn safely with 90 m long vessels, the
local widening to 105 m needs to be extended over
morethan65m.
A third measure that was proposed, is to use
a
fixed point (i.e. a dolphin), to which the vessel can
attachandaroundwhichthevesselcanthenturn.The
simulationsshowthatwithafixedpointneartheend
ofthequay,safemanoeuvresarepossiblewith85m
and90mlongvessels.
Themeasureofusing
afixedpointaroundwhich
thevesselcanturn,ischeaperthanwideningtheriver
locally, but it renders the turning manoeuvre more
cumbersomeforthecrewaslinesneedtobeattached
and manipulated correctly. It may be noted that the
twomeasuresofwideningtheriverlocallyandusing
a fixed point around which the vessel can turn, can
also be combined in order to let the skipper choose
dependingonhisfeelingandweatherconditions.
ACKNOWLEDGEMENTS
This study was commissioned by Voies Navigables de
France(VNF).
The results of the analysis were at several occasions
discussed in Givet (France) with representatives of the
inlandnavigationsectorandwithstakeholdersoftheQuai
desTroisFontaines,whosevaluableinputisacknowledged.
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