57
1 INTRODUCTION
Tropicalcyclone avoidance in shipping by merchant
shipsisaconstantelementofbothoceanandcoastal
navigation. It has a significant influence upon the
economicalandsafetyaspectsofthevoyage.Thekey
decision in tropical cyclone avoidance is the
determining of the moment of the beginning of
av
oidance manoeuvre and the determining of the
correct course and speed with maintaining the
commercialandeconomicviabilityofthevoyage.
By commercial and economic viability of the
voyagethefollowingisunderstood:
1 Minimalization of fuel consumption during the
avoidancemaneuver.
2 Maintaining the voyage schedule. Depending by
thetypeofshippingitisunderstoodas:
maint
ainingthechartererspeedthroughoutthe
voyage–tramping,
arrivalatthedestinationportaccordingtothe
charterpartyconditions–tramping,
arrival at the destination port within the port
window–regularshipping.
Threetypesofencountersituationsarepossiblein
open(ocean)areas(Wiśniewski&Kaczmarek2012):
1 Opposite courses – courses of the ship and the
cyclonedifferby150°to210°.
2 Crossing situation– courses of the ship and the
cyclonecrossatanangleof30°‐90°.
3 Overtakingofthecyclonebytheship.
In each of them a certain type of act
ion (course
alteration,slowingdownorspeedingup)isregarded
asthemosteffectiveone.
Determination of the avoidance maneuver in
coastal and restricted waters is a separate
issue.Withintheareaofthetropicalstormthewindis
veryviolentandtheseasarehighandconfused.Swell
isalsohighandconfused,withseveraldifferentswell
systems, often crossing and int
erfering with each
other.Becauseofthatitisadangerousthreatevento
the biggest and well‐found chips. The danger is
especially enhanced when the ship is caught by the
storminrestrictedorshallowwatersorinthevicinity
of land, without adequat
e room to manoeuvre. It is
recommended to remain all the time no less than
80Nm, however, 250Nm is regarded as the safe
distance.(UK Hydrographic Office, NP100, 2016)
Early and effective action might be essential to
precludeanysuchsituationarising.Thekeydecision
intropi
calcycloneavoidanceisthedeterminingofthe
Tropical Cyclones Avoidance in Ocean Navigation
–
Safety of Navigation and Some Economical Aspects
M.Szymański&B.Wiśniewski
M
aritimeUniversityofSzczecin,Szczecin,Poland
ABSTRACT:Baseduponthetruevoyagesvarious methods of avoidancemaneuver determinationin ship
–
cycloneencountersituationswerepresented.Thegoalwastofindtheeconomicallyoptimalsolution(minimum
fuel consumption, maintaining the voyage schedule) while at the same time not to exceed an acceptable
weatherrisklevel.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 12
Number 1
March 2018
DOI:10.12716/1001.12.01.06
58
moment of the beginning of avoidance manoeuvre
and also determining the correct course what might
poseaproblemincoastalandrestrictedwaters.
There are no recommended actions in terms of
efficiency in tropical cyclones avoidance in coastal
and restricted waters with regard to type of
encounter.Vicinityofland,
navigationalhazardsand
obstructions (straits, narrows, shoals and shallow
waters) force treatment of each such case
individually.Thefollowinggeneralstrategiescan be
identified:
1 Steamingawayfromthecycloneatasafedistance
andwaitingitout.
2 Separationfromthecyclonebyland.
3 Waiting out the cyclone
in port or other place of
refuge.
Inthispaperalltypesofencountersituationswere
discussed and analyzed in the aspects of safety and
seatransporteconomy.Theanalyzesarebasedupon
the true voyages by ships in the regions where
tropicalcyclonescanbeencountered.
2 METHODOLOGY
Thefollowing
toolswereemployed:
ORS(Onboard Routing System) BVS 7.0 – Bon
Voyage System 7.0 (Applied Weather
Technologies,2014),
ORS SPOS Fleet Management 7.0.0.1 (Meteo
ConsultBV,2009),
1‐2‐3rule(Holweg,2000),
manualanti‐collisionplot,
CYKLON programme (Wiśniewski&Kaczmarek
2012)(Wiśniewski2012),
shorebasedweatherroutingrecommendationsby
AWT.
In cases, where data were available, determined
avoidanceactionshadbeenevaluatedwiththeuseof
theweathercoefficientK
1/3inventedbytheauthors.
Weatherdatausedandtheirsources:
the weather data file for ORS BVS containing
weather analysis and prognosis up to 16 days in
advance(AWT),
the weather data file for ORS SPOS containing
weather analysis and prognosis up to 9 days in
advance(SPOS),
EGCforecasts,outlooksandadvisories,
surface pressure analysis and prognosis charts
fromJMA(JapaneseMaritimeAgency),
typhoon prognosis charts from JMA (up to 120
hrswith70%probabilitylevel),
typhoonstrongwindsprognosischartsfromJMA
(upto72hrs),
weatherchartsfromNOAA(NOAA)
Results obtained
were compared. The best
solutions in terms of safety and possibility of route
executionwerechosen.
3 WEATHERCOEFFICIENTK
1/3
Definitionofaweathercoefficientofdifficultyofthe
sea voyage is given in (Wiśniewski, 1991) and in
(Wiśniewski1995).Theseworkscontaindefinitionsof
2weathercoefficientsofdifficulty,weathercoefficient
ofdifficulty1andweathercoefficientofdifficulty2,
based on the maximum wave height in
the whole
voyage (coefficient 1) and a height of wave as
observed by the navigators (coefficient 2) which the
ship would encounter en route in the function of
angle of attack and on a calculated or for each ship
definedsafe/acceptableanddangerouswaveheights.
Definitions of safe/acceptable and dangerous wave
heightsarealsogivenintheseworks.
Forevaluationofasafetylevelofroutes testedin
this article a modified weather coefficient 2 was
adopted (Wiśniewski 1995). The modification lies in
replacing the observed wave height h
c with a
forecasted significant wave height h
1/3. A modified
weather coefficient K
1/3 is given by the following
formula:
1
1/3
1/3
1
K11
i
q
ds
in
d
h
nhq
(1)
where:
h
1/3(q)–significantwaveheight(h1/3)forecastedona
givensectionoftrack(h
1/3=1,11hc);
h
c –wave height as observed onboard by the
navigators;
h
d(q)–safe/acceptablewaveheight
h
s–dangerouswaveheight
α
d=nd/n–aratioofnumberofcaseswheresignificant
wave heights ere equal or bigger than h
d to a total
numberofobservationsinagivensectorofangle of
waveattack
α
s=ns/n–aratioofnumberofcaseswheresignificant
wave heights ere equal or bigger than h
s to a total
numberofobservationsinagivensectorofangle of
waveattack
4 RESULTS
4.1 TyphoonSOUDELOR–restrictedandcoastalareas
Big (LOA=336m,GT=97500, DWT=71274MT)
postpanamaxcontainershiphasencounteredtyphoon
SOUDELORduringthevoyagefromYantian(China,
ETD: 07.08.2015 0300UTC,) to Vancouver (Canada,
ETA:19.08.2015,2100UTC)in
August2015incoastal
andrestrictedareaoftheTaiwanStraitandnorthern
SouthChinaSea..
Routeasrecommendedbynauticalpublicationsis
shown in Fig. 1 (UK Hydrographic Office NP136
2014).Itwas,however,impossibleto steamalongit.
Immediately after commencment of the voyage the
typhoonSOUDELORwasencountered.It
wasmoving
WNWfromthePhilippineSeaoverTaiwantowards
continentalChina–Fig.2.
59
Figure1. Great circle route Yantian– Vancouver (Own
studybasedonBVS7.0)
Figure2. SOUDELORtrackinJMAoutlooksfrom 7and8
August(JMA)
Threeoptionsofavoidancemanoeuvrewerethus
outlined:
1 PassingNorththroughtheTaiwanStraitcrossing‐
Tthetyphoon’strack.
2 WaitinguntilthetyphoonpassesbysteamingSW
fromTaiwanintheSouthChinaSea.
3 Deviation to SE towards the Luzon Strait and
passing S of the typhoon through
one of the 3
available deep water passes in the Luzon Strait:
Bashi Channel, Balintang Channel or Babuyan
Channel.
4.1.1 AvoidancemaneuverwiththeuseofORSBVS7.0
TestingbyBVScarriedout on3,4 and 5 August
generated the routes through the Taiwan Strait. At
that time
that route was already closed – see Fig. 2.
SOUDELOR intensifies and heads WNW. Choice of
routethroughtheTaiwanStraitwouldleadtocross‐T
thetyphoon’strackonarestrictedarea,closetoland
and shallow waters. Therefore these routes were
rejectedbythecaptain.
The option to wait
out the typhoon in the south
wasalsorejectedastootimeconsuming.
Thecorrectsolutionsistheroutepassingthrough
the Balintang Channel in the Luzon Strait, S of
Taiwan(themostsouthernrouteinFig.3).Thisroute
hasbeenprogrammedmanually.Distancefromthe
centreofthetyphoon
alongthatroutewasreasonably
safe (150‐200Nm) and it run through the deep and
safeBalintangChannel.EquallydeepBashiChannel,
situated farther to the N, was rejected due to
insufficientdistancefromthecentrefromthetyphoon
(100Nm) and the Babuyan Channel, situated farther
totheS,wasregarded
navigationallyunsafe.
Figure3. Track of the typhoon SOUDELOR and route
throughtheLuzonStrait(ownstudybasedonBVS)
4.1.2 AvoidancemaneuverwiththeuseofORSSPOS
7.0.0.1
ORS SPOS generated the routes through the
Taiwan Strait until August 3rd inclusive. Then the
SPOSautomaticgeneratedroutesledthroughLuzon
Strait, initially Bashi Channel (Fig. 4), and from
August6
th
(Fig.5)throughBalintangChannel.
Figure4.SPOSgeneratedroutefrom3August(Ownstudy
basedonSPOSORS)
Figure5. Results of testing in SPOS on 4, 5 and 6 August
(OwnstudyinSPOSORS)
4.1.3 Avoidancemanoeuvreby1‐2‐3rule
Current position of the typhoon SOUDELOR
togetherwith34knotswindzoneismarkedwiththe
bluecolourforAugust4
th
(Fig.6)andAugust6
th
(Fig.
7)from1200UTC.Furtherconsecutivepositionsofthe
typhoon’seyearemarkedgreen.Zonesofwindsof
60
velocity of 34kts and more forecasted for cyclone’s
positions after 24‐, 48‐ and 72 are increased by 100,
200 and 300Nm with regard to radii received in the
typhoon warnings according to the 1‐2‐3 rule
methodology.Theonlyreasonablesolutionobtained
bythismethodistosteam
toSWandwaituntilthe
typhoon passes. 1‐2‐3 rule was visualized in the
CYKLONinterface.
Figure6. 34 knots wind zone of the typhoon SOUDELOR
calculatedbythe1‐2‐3ruleon4August(Ownstudy)
Figure7. 34 knots wind zone of the typhoon SOUDELOR
calculatedbythe1‐2‐3ruleon6August(Ownstudy)
4.1.4 AvoidancemaneuverwiththeuseofCYKLON
programme
Thesoftwarewasfedwiththedataregardingthe
typhoon from 7 August 1200UTC, when the voyage
hadbegun.Safecourseis125º.InitiallyCYKLONhad
calculatedthedangerouscoursessectorbetween015º
and122º(Fig.8and9).After15hrsthenew
dangerous
sector was 298º and 092º. After 15hrs steaming on
course 125º it is safe to 095º towards Balintang
Channel–Fig.10.
Figure8. Determining the avoidance manoeuvre with the
use of CYKLON programme on 7 August1200UTC(Own
study)
Figure9. Determining the avoidance manoeuvre with the
use of CYKLON programme on 7 August1200UTC(Own
studybasedonCYKLON)
Figure10. Determining the avoidances maneuver with the
use of CYKLON programme on 8 August0300UTC(Own
studybasedonCYKLON)
4.1.5 Shorebasedrecommendations
Basis of recommendations was the intention to
avoid the SOUDELOR’s strong winds zone of 35kts
and more. Initially passage through Balintang
Channelwasrecommended.On5
th
and6
th
ofAugust
itwaschangedtoBabuyanChannel,situatedfarther
tothesouthandonAugust7
th
,afterthevoyagehad
begun, again the recommendation was changed
BalintangChannel.
4.1.6 Summary–typhoon SOUDELOR,coastaland
restrictedareas
Intheanalyzedcasethecorrectactionwastopass
thetyphoonfromthesouthandusethelandmassof
Taiwan as a screening protection for the part
of the
route.Itisthesafestandalsoeconomicallythemost
viable solution. To wait the typhoon out in the
southwestwastoo time‐consuming and would have
caused the disruption in the ship’s schedule. Route
leading through the Taiwan Strait was too risky –
requiredspeedwason
thelimitofship’spropulsion
capabilitiesandwasverycostly.
61
4.2 TyphoonMOLAVE–oceannavigation,crossing
situation
The determination of the typhoon avoidance
manoeuvreinoceannavigationbyabig(LOA=336m,
GT=97500, DWT=71274MT), powerful and fast
(20knots),postpanamaxcontainervesselonavoyage
from Yantian (China, ETD= 07.08.2015 0300UTC) to
Vancouver (Canada, ETA=19.08.2015 2100UTC) by
variousmethodswasanalysed.
The recommended route between the two above
mentioned ports is the route shown on Fig. 1 (UK
Hydrographic Office NP136 2014). However, in an
initial, coastal stage of the voyage, typhoon
SOUDELORwasencountered(Fig.2,3).Itprevented
the vessel from using the route shown on Fig.
1.Consequently, after
numerous testing of other
routes and consultation with land based weather
routing, the route through the Luzon Strait was
chosen, clearing the typhoon SOUDELOR from the
south.
In an ocean stage of the voyagethe typhoon
MOLAVEwasencountered.Itwas movingfromthe
PhilippineSeatowardsJapan–seeFig. 11
(JMA).The
routetakesintoconsiderationnavigational andlegal
restrictions – allowed routes in the Bering Sea and
Aleutian Chain and the US and Canadian ECA
zone(Szymański&Wiśniewski,2016).
Figure11.TrackofMOLAVEforecastedfor5daysinJMA
outlooks9and10August(JMA,2015)
4.2.1 Avoidancemanoeuverbytherecommendationfrom
shorebasedweatherrouting
Shore based recommendations from AWT were
receivedon6
th
and7
th
ofAugust.Theyareshownon
Fig. 12 together with their navigational parameters.
The recommended routes were moved south due to
the typhoon MOLAVE developing south of Japan.
Bold route on Fig. 12 is from August 7
th
. Its
corresponding navigational parameters in the table
below the weather chart are highlighted blue. The
route runs too close to the typhoon and generates
weather alerts – exceeding the maximum allowed
wave height (8m) and wind velocity (34kts). Alerts
aremarkedbyvioletcirclesvisiblealongtherouteon
Fig.
12. Finally the AWT had accepted the route
passingtheMOLAVEfromthesouthandenteringthe
PacificviatheBalintangChannelintheLuzonStrait.
Figure12. Routes recommended by AWT from August 6
th
and August 7
th
and their navigational parameters (own
studybasedonBVS)
4.2.2 AvoidancemaneuverwiththeuseofORSBVS7.0
Planning of the MOLAVE avoidance manoeuvre
hadbegunon9Augustafterthesuccessfulclearingof
the typhoon SOUDELOR on the South China Sea. ).
Optimization used was least fuel with fixed arrival
time.Weather limitations were set for maximum 8m
swell,
seasandsignificantwaveandwindmaximum
velocityfor34knots.
RoutesgeneratedintheBVSuntilAugust9
th
run
along the coast of Japan from the Pacific side. They
cleartheMOLAVEfromthepolarsideandplacethe
shipbetweenthetyphoonandtheland,onanarrow
andrestrictedarea(Fig.13and14).Thecorrectroute
clears the typhoon from the south. It is highlighted
blue (bold route) on Fig. 13.It was programmed
manually.
Figure13. Testing results of routes passing the typhoon
MOLAVEonAug9th.(OwnstudybasedonBVS7.0)
Figure14.ResultoftestinginBVSfrom9August–position
of the ship and typhoon for 11.08.2015, 0000UTC (Own
studybasedonBVS7.0)
62
4.2.3 AvoidancemanoeuvrewiththeuseofORSSPOS
7.0.0.1
Oceanroutetestingbeganon7August.SPOSORS
enables to programme the minimum distance to the
tropical cyclone and tropical depression
(Wiśniewski&Szymański2016).
Figure15.AvoidancemanoeuvreinSPOSfrom7,8and9of
August(OwnstudybasedonSPOS)
Maximum wave heights and wind velocity were
programmedas8mand34knots.Minimumdistance
to typhoon was determined as 250Nm. Type of a
chosenoptimizationwasOptimumHigh&Wide,with
speed of 19,5 knots, corresponding to the calm sea
speedfortherouteoptimizedinBVS7.0ORS.Results
oftesting
arepresentedonFig.15.SimilartotheBVS
system, routes generated in the SPOS system until
August9
th
runalongthesouthernandeasterncoasts
of Japan and were clearing the typhoon form the
polarside.Theyplacedtheshipbetweenthetyphoon
and the land, in a narrow and restricted area.
Consequently,theserouteswererejectedbytheship’s
captain.
4.2.4 Avoidancemaneuverbythe1‐2‐
3rule
Figure16.30knotswindzoneofMOLAVEascalculatedby
1‐2‐3 rule from 8 August for the next 3 days (Own study
basedonCYKLON)
Blue colour in Fig 16. marks the position of the
typhoon MOLAVE together with the 30knots wind
zone according to the warning from 8 August,
1200UTC. Green colour circles mark the further
position of the typhoon together with the 35 knots
wind zones. The 24hrs, 48hrs and 72 hrs predicted
zones’
radii are increased by respectively 100Nm,
200Nm and 300Nm with regard to values from the
warnings, in accordance with the rule methodology.
For visualization of the 1‐2‐3 rule the CYKLON
programmewasused.
4.2.5 AvoidancemaneuverwiththeuseofCYKLON
programmeandmanualanti‐collisionplot
Manual
anti‐collision plot and CYKLON
programmehavethesame sourcemethodology.Their
resultsareshowninFig.17and18.Thesoftwarewas
fed with the data regarding the typhoon from 8
August1200UTC,whenthevoyagebegan.
The safe course is065º, the software calculated
initiallythedangeroussector047º
and061º(Fig.17),
andafter12hrs,forupdatedpositionsandforecastsof
MOLAVE’s movement,the dangerous sector was
between054ºand064º(Fig.18).
Results obtained by the manual plot are
comparable with those obtained by the CYKLON
programme.
Figure17.Avoidancemanoeuvre byCYKLONprogramme
on8August1200UTC(OwnstudybasedonCYKLON)
Figure18.Avoidancemanoeuvre byCYKLONprogramme
on9August0000UTC(OwnstudybasedonCYKLON)
4.2.6 Summary–typhoon MOLAVE,oceannavigation,
crossingsituation
Testingbyvariousmethodshadshownthatinthe
caseanalyzedthemosteffectiveaction,bothinsafety
and economic terms, was a course alteration and
passingthetyphoonfromtheS.
63
4.3 CycloneGASTON–oceannavigation,crossing
situation
Figure19.RouteAntwerp–Caucedo(Ownstudybasedon
BonVoyagesystem)
Weather routing of a PANAMAX container ship
(LOA=281m, GT=46000) from Antwerp(Belgium,
Wandelaarpilotstation),ETD=20.08.2016,2300UTC
to Caucedo (Dominican Republic)ETA = 30.08.2016,
1800UTC, was analyzed. The route is shown in Fig.
19.DuringthevoyagethetropicalcycloneGASTON
was encountered, shown in Fig. 20. Avoidance
actions, determined by
various tools and methods,
were evaluated with the use of weather coefficient
K
1/3. The route was programmed in the ORS Bon
Voyage 7.1.Weather data utilized in testing is also
fromthatORS.Testingwascarriedoutforthewhole
duration of the voyage, every 6 hours since Bon
Voyageprovides6hrssampling.Itwasassumedthat
acceptablewaveheighth
d=6manddangerouswave
heighth
s=12m.
Figure20.CyklonGASTONwprognozachNOAAz25i26
sierpnia(NOAA)
4.3.1 Determinationofavoidancemaneuverwiththeuse
ofORSBVS7.1
Routes were programmed manually in the ORS
BVS7.1.Automaticallygeneratedroutesdidnotmeet
thenauticalrulesoftropicalcyclonesavoidance.Two
variants of a route were prepared for execution on
Aug26
th
,1200UTC:ariskyvariant(Fig.21)andaplay
safevariant(Fig.22).Inbothvariantsthecyclonewas
passed from the equator side. In a risky variant the
route had been programmed on the border of a
parametric roll resonance sector. Its track takes the
shipclosertothe
centreofthecyclone(itseye),thus
the weather conditions along it will be heavier. For
thatreasonitwillrathernotbepossibletoavoidthe
resonance sector by increasing the speed– see
Fig.21.In the play safe variant the end of the ship’s
vectoralsolieson
theborderofresonancesector(Fig.
22),however,duetoamorefavourableseastateand
generally better weather conditions, it would be
possible to both increase the ship’s speed and alter
ship’sheadinginordertocleartheresonancesector.
Riskyvariantiscommerciallybetterthanthepla y
safe variant
in terms of total distance en route and
fuelcosts.Abreakdownofcommercialparametersof
the voyage and weather coefficients K
1/3 for both
variantsisgiveninTable1.
Table1.CommercialparametersandweathercoefficientK1/3
forriskyandplaysaferoutevariants(Ownstudy)
_______________________________________________
RoutePlaysafevariant Riskyvariant
_______________________________________________
Distance[Nm]41174202
Cost[USD]458582476352
WeathercoefficientK
1/3 0,2579170,272604
_______________________________________________
Figure21. Avoidance manoeuvre in Bon Voyage system –
manual programming, risky variant (Ownstudybased on
BonVoyagesystem)
Figure22. Avoidance maneuver in Bon Voyage system –
manualprogramming,playsafevariant(Ownstudybased
onBonVoyagesystem)
To confirm the outcome, only the time frame of
avoidancemaneuverforweathercoefficientK
1/3were
takenintoconsideration,between26.08,1800UTCand
28.08,1200UTC.WeathercoefficientK
1/3calculatedin
that way is 0,272604 for a pla y safe maneuver and
0,341146 for a risky maneuver. Weather coefficients
K
1/3forroutesprogrammedmanually(forbothrisky
and play safe maneuvers) are clearly lower than for
routes generated automatically in the Bon Voyage
system.
4.3.2 AvoidancemaneuverswiththeuseofCYKLON
programme
Safecoursestoavoidthetropicalcycloneobtained
withtheuseofCYKLONprogramme(Wiśniewski&
Kaczmarek2010).ResultsarepresentedintheFig.23.
The dangerous courses sector as calculated by
CYKLON programme are between 206º a 253º.
64
Courses253ºandabovethatcross‐Tthecyclonetrack
and, because of that, they were rejected. The route
withthegeneralcourse206ºwasprogrammedinthe
Bon Voyage system and the weather coefficient K
1/3
wascalculatedforit.Asectionofthatroutetogether
with sections of a risky and play safe maneuver are
presentedonFig.16. Weather coefficient K
1/3forthe
whole route is 0,322958, and for the avoidance time
frames K
1/3=0,58125. A breakdown of weather
coefficients K
1/3 for avoidance maneuvers
programmed with the use of CYKLON system and
manuallyintheBonVoyagesystemarepresentedin
Table2.
Table2. Breakdown of weather coefficients K1/3 for some
chosenroutes(Ownstudy)
_______________________________________________
RouteCoefficientK1/3
_______________________________________________
Riskymanoeuvre,wholeroute0,272604
Riskymanoeuvre,avoidancetimeframes 0,341146
Playsafemanoeuvre,wholeroute0,257917
Playsafemanoeuvre,avoidancetimeframes 0,263542
CYKLON,wholeroute0,322958
CYKLON,avoidancetimeframes0,58125
_______________________________________________
Figure23. Avoidance maneuvers results of cyclone
GASTON obtained with the use of CYKLON programme
(OwnstudybasedonCYKLONprogramme)
Figure24. Avoidance maneuvers route sectionsin
CYKLON(redshipsymbol)variantandriskyandplaysafe
variants inBon Voyage system(Own study based onBon
Voyagesystem)
4.3.3 Summary–cycloneGASTON, oceannavigation,
crossingsituation
Testing by various methods had shown that the
most effective action in the case analyzed in the
course alteration. Its scope and influence upon the
economic results of the voyage and route’s weather
safetylevelcanbeevaluatedwiththeuseof
weather
coefficientK
1/3.
4.4 CyklonGASTON–akwenotwarty,kursyprzeciwne
Voyage of a postpanamx containership (LOA=336m,
GT=97500) from Gibraltar to New York has been
analyzed. ETD GIB = 30.08.2016, 0000UTC (36 00N
00718W),ETANewYork(AmbroseP/S)=06.09.2016,
0800UTC.During the voyage the cyclone GASTON
was encountered, moving after recurving
in ENE
directionoverthecentralNorthAtlantic.
Route of the ship together with the track of
GASTONispresentedinFig.25.Weathercoefficient
K
1/3,calculatedforatimeframeoftheclosestapproach
to the cyclone (01.09.2016, 0000UTC – 03.09.2016,
0000UTC), is 0,3625, thus the level of weather
risk/safety is acceptable. However, the ship’s route
crosses‐Tthetrackofcycloneandpassesitfromthe
polar side of its predicted track what constitutes a
violation of nautical rules of cyclone avoidance.
Steamingalongthatroutemustbeseenasamistake
anditcouldhavehaddisastrousconsequencesforthe
shiphadthe GASTON moved more to the N or NE
and had the forecasts for the movement of other
tropical systems developing at that
time over the
Atlantic shown to be correct (Fig. 26). The correct
courseof action was to steamS of Acores along the
Acores High, well visible in Fig. 25. A greater
deviation from the original route would have to be
necessary, however, the weather risk would have
beensignificantly
smaller.
In the analyzed case the effective and efficient
maneuverisgreatcoursealterationtothesouth.
Figure25. Route Gibraltar – New York and track of
GASTON(AWT)
Figure26.ForecastfortwotropicalsystemsintheAtlantic
from31.08.2016,0300UTC(NOAA)
65
4.5 CycloneNICOLE–oceannavigation,overtaking
Weather routing of a PANAMAX container ship
(LOA=294m, GT=53000) from Charleston (USA),
ETD=12.10.2016, 0300UTC) to Southampton, Nab
Tower(GreatBritain)ETA=22.10.2016, 0200UTCwas
analyzed. During the voyage passing the cyclone
NICOLE was necessary. It was moving over the
central North Atlantic Ocean in
NE – ENE, after
recurving.
Avoidanceactionwasdeterminedwiththeuseof
ORS Bon Voyage 7.1and evaluated with the use of
weather coefficient K
1/3. Testing was performed for
the time of the whole voyage with 6hrs sampling
periods.Itwasassumedthatacceptablewaveheight
h
d=6manddangerouswaveheighths=12m.
InFigs.27–29va riousvariantsofroutesavoiding
the cyclone NICOLE were presented. Their
navigationalandeconomic parameters are shown in
Table3.
Analysis of data in Table 3 points that in this
particular case speed reduction, although effective
andjustifiedinthesafetyaspect,would
nothavebeen
correctintermsofeconomicandcommercialviability
ofthe voyage.Intheroutevariantrecommendedby
theshorebasedweatherrouting(AWT)thespeedof
the ship would have to be reduced more than the
valueinthetableinordertohaveacceptableweather
conditions throughout
the voyage (K1/3<0,8).
However, that would cause a delayed arrival in Le
Havre and a disruption in ship’s whole coastal
schedule. A better option is a route programmed
manuallyonboard– slight course deviationtowards
equator and overtaking the cyclone form the south.
This route leads also through better weather
conditions(K
1/3~0,6).
Routegenerated automaticallyintheORSBVSis
not realistic operationally – it runs for a long time
throughECAzone,thereisnotenoughofULFSOfuel
onboardforthisvariantotobefeasible.Sucharoute
passes the cyclone form the polar side of its track
what is
a violation of one of the nautical cyclone
avoidancerules.
Table3. Economic and navigational parameters of the 3
variantsofarouteCharleston–Southampton(ownstudy)
_______________________________________________
RouteBVS AWT Ship’sownvariant
_______________________________________________
Cost[USD] 225185 248365 245301
CoefficientK
1/3 0,5787451,1311550,605814
Distance[Nm] 3572 3858 3915
SC[kts]15,4 17,2 17,1
SOG[kts] 14,7 16,0 16,4
_______________________________________________
Figure27.RouteCharleston–Southampton,optimizationin
theBonVoyage(ownstudybasedontheBonVoyage)
Figure28. Route Charleston – Southampton,
recommendationoftheAWT(ownstudybasedontheBon
Voyage)
Figure29. Route Charleston – Southampton, variant
programmed manuallyonboard (own study based on the
BonVoyage)
4.6 TyphoonDUJUAN–coastalandrestrictedareas
Postpanamax containership (LOA=336m, GT=97500)
has encountered the typhoon DUJUAN during the
voyagefromYantian(China,nearHongKong),ETD=
24.09.2015,0100UTC,toVancouver(Canada),ETA=
06.10.2015,2000UTC.Thetyphoonwasmovingfrom
the Philippine Sea over the coastal areas of China,
TaiwanandJapan.Forecastsofitsmovementfrom23
and 24 Septemeber are presented in Fig. 30 and 31.
Theship’sroutewasprogrammedinORSBVS7.0.
Analysis of the true and forecasted track of
typhoonpoints that itis in the decisive stage for its
furtherdevelopmenton
September23.Recuvrvingto
NorNEtowardsJapanisequallyprobableasfurther
movement WNW towards coastal areas of Taiwan
andChina.
Onthe23September,beforethecommencementof
thevoyage,automaticgenerationofrouteintheORS
66
BVShadbeendone.ItisshowninFig.32. Typhoon
DUJUANisherevisiblestillastropicaldepression21
(TS TWENTY ONE) and is forecasted to move N
towards Japan. Thus the route shown in Fig. 32 is
incorrect.Itplacestheshipbetweenthetyphoonand
theland.
Inthiscasethecorrectsolutionistosteamas
fastaspossiblethroughtheTaiwanStrait,EastChina
SeaandKoreanStraitandfurtherthroughtheSeaof
Japan and Tsugaru Strait. Japan Archipelago forms
here an effective anti‐typhoon screen. Such route,
programmed manually in the BVS, is
shown in Fig.
33. DUJUAN is then already fully fledged typhoon
andsoitisalsodepictedinBVS.
Figure30. DUJUAN movement forecasts, 23 September
(JMA)
Figure31. DUJUAN movement forecasts, 24 September
(JMA)
Figure32. Routegenerated automatically inBVS 7.0 on23
September(ownstudybasedonBVS)
67
Figure33. Route utilizing land mass as a „screen” against
thetyphoon(ownstudybasedonBVS)
4.7 TropicalStormHERMINE–coastalandrestricted
areas.
Postpanamax containership (LOA=336m, GT=97500)
hasencounteredthetropicalstormHERMINEonthe
approaches to thePort of New York (Ambrose Pilot
Station)on6–9September2016.TrackofHERMINE
and the optimal ship’s route as recommended by
shorebasedweather
routingisshowninFig.34.
In the course of determining the most effective
actiontwooptionswereconsidered:
1 Slowdown or drift E of TS HERMINE to wait it
over.
2 Deep deviation to south from the route, passing
theTSHERMINEfromS andapproachAmbrose
P/S
fromS.
Inordertochoosetheoptimalandsafesolutionit
was necessary to cooperate with the shore based
weather routing strictly. Option 1), favoured by the
ship’s command proved to be economically less
favourable.Itwouldhaveresultedinbiggertimeloss
and delay in arrival in port. Option
2) was more
favourable. Weather information available onboard
wereinsufficienttocorrectlyassessthesituationand
timely drawthe right conclusions. Movement of the
tropical system in the vicinity of the land is very
complicated, dependant on many factors and
subjectedtoconstantchanges.Toolsandinformation
available onboard are
insufficient to a correct and
timely evaluation of such movement. Strict
cooperation and consultation with the shore based
weather routing is here essential. Shore based
weatherroutingcentershavemore,betterandquicker
weatherinformationavailableandalsomorecapable
tools.
In the analyzed case the captain of the ship had
concurredwiththerecommendationoftheshoreand
hadexecutedthedeepdeviationtothesouth,passing
theTSHERMINEfromthesouth.
Despite the strict cooperation with shore based
weather routing delay was unavoidable. Safe
approach to Ambrose P/S was only possible 9
September.Therecommendationwastoremain
atall
times at least 250Nm from TS HERMINE. On
September 4 it became the extratropical storm,
however, on 4 and 5 September it intensified and
regained its tropical character. Approaches to
Ambrose P/S from all directions were thus closed
until September 9.The only feasible option was to
waitthestorm
overatthesafedistance,atbestonthe
equatorialsideofitspredictedtrack.
Figure34.AvoidanceofTSHERMINEontheapproachesto
thePortofNewYork,September2016(AWT)
4.8 TyphoonMEGH–specialcase
A bulk carrier (LOA=190m, GT=32929) has
encountered the typhoon MEGH in anIndian Ocean
during the voyage from Singapore to Suez in
November2015.Initiallyitwastheencounteron an
openocean,thenboththeshipandthetyphoonhave
entered the coastal and restricted
area – the Gulf of
Aden.
The ship had attempted to overtake the typhoon
on November 6 2015, 1200UTC. Fig. 35 depicts the
situationinthe momentwhentheovertakingbegan.
The further tracks of both the ship and the typhoon
aredepictedinFig.36.
OnNovember5the
distancebetweentheshipand
the typhoon was 250Nm. Attempt to overtake the
typhoon by a slow, low powered ship, on the
dangerous semicircle, has to be considered a very
risky maneuver. On November 6, 1200UTC, in the
momentdepictedinFig.34,theshipwasonly38Nm
fromtyphoon’s eye.
She would have been in a very
unfavourablesituationhadthetyphoonrecurvedNE,
asitcouldhavebeenexpected,atthisverymoment.
Besides,acloseanalysisofFig. 36 points to the low
effectivenessofthewholeovertakingmaneuver.The
shipwassteamingpracticallynearandinthe
vicinity
ofthetyphoonallthetimeuntilNovember9.Atthat
time the maximum distance to the typhoon’s
eyewhichtheshipwasabletohold, wasonly160Nm
which is well below the minimum 250Nm as
recommended by the nautical publications (UK
HydrographicOffice2015).Atthattime, on 7
and 8
November, MEGH has reached the hurricane force
(12B)withwindvelocitiesexceeding 110kts(0600UTC
– 0900UTC, November 8). On November 10 the
typhoonweakenedandfinallybrokeupuponmaking
theYemenicoast.
Acorrectdecisioninthiscasewastostaybehind
thetyphoon,totheE
andSofit.Attempttoovertake
thetyphoonshouldnothavebeenmade.
68
Figure35. Typhoon MEGH and the route of the ship
overtaking it, 6 November 2015, 1200UTC (Deutscher
Wetterdienst2016)
Figure36. Track of MEGH and the route of the ship
overtaking it in the Gulf of Aden in November 2015
(DeutscherWetterdienst2016)
5 SUMMARY
Cases presented and their analysis generally
confirmed the conclusions entailed in publication
(Wiśniewski&Kaczmarek,TRANSANAV2012).
Onanopenocean,incrossingsituation,themost
effective maneuver in terms of both safety and
economyistheaslightalterationofcourseorspeed
or both of them together. On
opposite courses
maneuverassuringthesafeavoidanceofthecyclone
andalsobettereconomicresultsofthevoyageisthe
major alteration of course and passing the cyclone
fromtheequatorialside.Attemptstopassthecyclone
on its polar side have to be considered very risky.
Suchanaction
issometimeseconomicallymorevia ble
(shorter voyage time, shorter distance, less fuel
consumption),however,therisktobeengulfedbythe
cyclone’sstrongwindszoneandexcessiveapproach
to its eye is all too significant. Overtaking of the
cyclone should be attempted only by fast, high
powered ships, with good seakeeping
abilities.
Overtaking should be on the equatorial side of the
cyclone’s track with a minimum distance of 250Nm
fromcyclone’seye.
Determining of the effective maneuver to avoid
thetropicalcycloneinthecoastalandrestrictedareas
isbyallmeansmoredifficultthaninanopenocean.
Inthe
vicinityofthelanditisdifficulttoestimatethe
movement of the cyclone. There are a lot of factors
influencing its movement. It is often not possible to
evaluatethemcorrectlyandtimelyonboard.
Alsothecharacterofcoastalshippingtoday,very
tiresome and stressful for the ship’s command, with
manyandfrequentportcalls,naturalconcentrationof
the captain and nautical officers on cargo, pilotage,
numerous and never ending controls, audits and
surveys, does not contribute to the proper and
constantweathermonitoring.
Assistance of the shore based weather routing is
here essential. It monitors the weather situation
constantly,
has access to many sources of weather
data which are not available onboard. It can also
utilizethetoolswhichtheshipsareequippedwith.
Actiontoavoidthetropicalcycloneincoastaland
restricted areas requires bigger course and speed
alterations than in the open ocean. It should not be
consideredasadeviationbutratherasanamendment
orchangeofvoyageconcept.
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