Simulation Modelling Practice and Theory 11 (2003) 597–608
www.elsevier.com/locate/simpat
Simulation of marine traffic in Istanbul Strait
Ercan K€
ose *, Ersan Basßar, Emrullah Demirci,
Abdulaziz G€
unero
glu, S
ß ebnem Erkebay
Faculty of Marine Science, Karadeniz Technical University, 61530 Camburnu, Trabzon, Turkey
Received 25 September 2002; received in revised form 2 October 2003; accepted 22 October 2003
Abstract
The Turkish Straits, comprising the Strait of C
ß anakkale, the Strait of Istanbul and the Sea
of Marmara, are unique in many respects. The very narrow and winding shape of the strait,
gives it river like characteristics, and it is an established fact that for mariners the Turkish
Straits are one of the most hazardous, crowded, and potentially dangerous, waterways in
the world. All the dangers and obstacles characteristic of narrow waterways are present and
acute in this critical sea lane.
In this research, the simulation of the Istanbul Strait was done under unique traffic conditions and results of this simulation, and the effects of probable increase in marine traffic due to
new oil pipelines, are discussed.
2003 Published by Elsevier B.V.
Keywords: Istanbul Strait; Marine traffic; Scenarios; Simulation
1. Introduction
The Turkish Straits, comprised of the Istanbul, the C
ß anakkale Straits and the Sea
of Marmara, form a waterway of strategic and economic importance. As the only
water route between the Black Sea and the Mediterranean, the Turkish Straits both
geographically and metaphorically connect Europe to Asia.
The Strait of Istanbul, in particular, presents the greatest challenge for navigation
as it snakes through the heart of Istanbul, a city of over 10 million people and rich
with thousands of years of history, which is declared as a ‘‘World Heritage City’’ by
UNESCO.
*
Corresponding author.
E-mail address: [email protected] (E. K€
ose).
1569-190X/$ - see front matter 2003 Published by Elsevier B.V.
doi:10.1016/j.simpat.2003.10.001
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E. K€ose et al. / Simulation Modelling Practice and Theory 11 (2003) 597–608
Fig. 1. Strait of Istanbul.
The Strait of Istanbul is approximately 31 km long, with an avarage width of 1.5
km. Among the straits of the world, it is the narrowest, constricted to a mere 698 m
between Kandilli and Bebek (Fig. 1).
2. Maritime traffic in the straits
The maritime traffic in the Turkish Straits is exceptionally dense due to the merchant traffic, coasters, fishing vessels and local traffic causing difficulties with navigation (white dots in Fig. 2 shows ships either passing strait or waiting at the both
enterances). This dense traffic includes the transport of noxious, dangerous and hazardous cargo (oil, LNG, LPG, chemicals, other explosive and environmentally hazardous substances).
Internal vessel movement in the Strait of Istanbul is more than 2000 per day. This
figure does not include the movement of transiting ships, leisure craft and fishing vessels. In I_ stanbul [2], 1.5 million people are daily on the move at sea by intro-city ferries and other shuttle boats, crossing from one side to the other.
E. K€ose et al. / Simulation Modelling Practice and Theory 11 (2003) 597–608
599
Fig. 2. Satellite image of Istanbul Strait.
The Strait of Istanbul takes several sharp turns. The vessels must change courses
at least 12 times. At the narrowest point (Kandilli), a 450 course alteration is required. At Yenik€
oy, the necessary course alteration is 800 . At the turns (Kandilli
and Y€
onik€
oy) where significant course alterations have to be made, the rear and forward sights are totally blocked prior to and during the manoeuvre. The ships
approaching from the opposite direction cannot be seen round the bends [1].
The volume of traffic is expected to increase by 40–50% with additional traffic
coming from the Main-Danube, Volga-Baltic and Don waterways. Traffic congestion will further intensify with the increase in the volume of foreign trade from
the Black Sea states.
The maritime traffic within the Istanbul Strait is one of the most difficult waterways in the world. Therefore, the traffic within the strait can be investigated by simulation techniques. Some strategies such as ship passing time, priority rules, waiting
time etc. can be developed and maritime traffic can be investigated when the traffic
increases. A simulation model can calculate the performance indicators, which has
been used in different systems such as urban, economic, production, and transportation fields [3]. A simulation model can be used for determining the effects of
changes (scenarios), namely, in order to evaluate the future of the Istanbul Strait,
a simulation model has been used, for example Hayuth et al. used a simulation
model to evaluate the future of the port and ensure optimum investment strategies
[4]. In this study, the compute simulation language AWESIM [5] was used as
the primary modelling tools. Thiers and Jonssens [6] made detailed models of
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traffic on the rivers, including navigation logic, tides and lock planning. Or and
Kahraman [7] conducted analysis of various accident contributing factors and for
scenario analysis.
3. Maritime traffic regulations in the Turkish Straits
Along with the introduction of the Regulations, the Turkish authorities have also
established ‘‘Traffic Separation Schemes’’ (TSS) in the Straits, in accordance with the
provisions of ‘‘International Regulation for Prevention of Collusion at Sea’’ (COLREG). The TSS were approved by the International Maritime Organization (IMO)
General Assembly in November 1995, in association with ‘‘Rules and Recommendations on Navigation Through the Strait of Istanbul, the Strait of C
ß anakkale and
Marmara Sea’’.
In order to ensure the safe transit of vessels which cannot comply with the TSS,
the competent authorities may temporarily suspend two-way traffic and regulate
one-way traffic to maintain a safe distance between vessels. For example, as seen
in Fig. 3, during the passing VARYAG through I_ stanbul Strait two way traffic
was temporarily stopped.
The normal speed in the Straits is 10 NM/h relative to land. This speed may be
exceeded if the steering way cannot be resched, by informing the traffic control stations and taking care to avoid collisions and creating waves harmful to the environment [8]. Vessels navigating in the Straits shall not overtake vessels proceeding
Fig. 3. VARYAG passing through Istanbul Strait.
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601
before them except it is neccessary. Vessels passing through the Strait shall maintain
a distance of at least 8 cable from each other [8,9]
When the main surface current exceeds 4 knots or when southern winds reverse
the main current in the Istanbul Straits, all vessels with dangerous cargo, large vessels and deep draught vessels with a speed of 10 knots or less shall not enter the
Straits.
When the main surface current exceeds 6 knots, or strong northerly currents and
eddies are caused by southerly winds, all vessels with dangerous cargo, large and
deep draught regardless of their speed, shall not enter the Istanbul Strait and, should
wait until the current speed is less than 6 knots or the strong reverse currents disappear.
When visibility in an area within the Istanbul Strait drops to 1 mile or less, vessel
traffic shall be permitted in one direction only. During this time, vessels with dangerous/hazardous cargo, large vessels and deep draft vessels shall not enter to the Istanbul Strait,
When visibility in an area within the Istanbul Strait drops to less then 0.5 mile, the
vessel traffic shall be suspended for both directions.
Table 1
Statistics of passages through the Istanbul Strait 2000
Months
Total vessels
passed
Took
Pilot
Submitted SP-1
Longer
than 200 m
Over 500
GRT
Not called on
Marmara
Ports (Direct
passages)
No. of
tankers
January
February
March
April
May
June
July
August
September
October
November
December
3284
3397
3908
4219
4127
4191
4249
4268
4055
4043
4349
3989
1519
1462
1521
1667
1658
1608
1592
1703
1559
1581
1695
1644
2378
2647
2789
3029
3043
3435
3648
3542
3368
3422
3670
3603
180
154
161
173
191
197
197
206
184
179
193
188
3155
3280
3684
3872
3828
3880
3950
3917
3754
3674
3979
3761
2049
2175
2252
2288
2316
2297
2460
2212
2192
2094
2213
2310
384
345
368
425
435
460
482
448
403
383
425
379
Total
Monthly
average
Daily
average
Percent
48,079
4007
19,209
1601
38,574
3214
2203
184
44,734
3728
26,858
2238
4937
411
134
53
107
6
124
75
14
40%
80%
5%
93%
56%
10%
–
Notes: In year 2000, 53 towing operations were carried out in the Strait of Istanbul. Total number of
tanker passages are 4937; LPG Carriers with 474 passages, Chemical tankers with 682 passages and LNG
Carriers with (0) passages are also included in this number.
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4. Passage statistics
Passages through the Istanbul Strait is given in Table 1 [1,2].
In addition to the above statistics, the following relevant statistics were taken
[2,10]:
• Strait is closed for an average of 20 days/year due to meteorological conditions.
• Two direction is closed for 176 h/years and one direction is for 2731 h/year due to
dangerous cargo vessels.
• Strait is closed for an average of 30 h due to brake down of ships. This increased
to 120 h during the incident of Nassia Ship Broker accident.
5. Simulation of the system
The developed model is to simulate the traffic within the Istanbul Strait. This
model investigates behaviour of traffic according to the different scenarios, different
ship arrival and waiting times. Namely, the model simulates traffic at the Istanbul
Strait and gives information about future traffic according to different scenarios.
Model developed includes only national and international transpassing ships.
Therefore, inputs for the model such as the number of ships at both ways were taken
from Table 1. Weather conditions were obtained from the State Meteorological Office.
Five sub-systems were used to simulate the system. These are traffic flow from
direction 1; traffic flow from direction 2; two information systems representing big
ships and simulation of bad weather conditions. Each of these processes is modelled
by the movement of an entity through a subnetwork.
When a bigship (L > 200 m) passes through the strait, it cannot stay in course
(Fig. 4). Therefore, traffic from the opposite direction has to be stopped. This is simulated by gates open, which represents no big ship through or closed.
To insure that only one ship enters the strait from one side, a resource with capacity of one is employed in conjunction with the gate. These resources are named ka-
Fig. 4. Traffic system at Istanbul Strait: (a) vessels L < 200 m; (b) vessels L > 200 m.
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603
radeniz and marmara corresponding to k1 and m1, and represent the starting location before each direction (Black Sea and Marmara Sea entrance). The starting location is seized by each ship entity before passing through and then freed immediately
after it passes. The FIFO rule is applied at the entrances.
The network model is depicted in Fig. 5. Although the decision logic for traffic flow
for both direction is the same, arrival time and time in system are different, therefore,
two networks are used to model both traffic flows with attributes employed to specify
the resources and gates required. ATRIB(2) is used to maintain the resource number
and file number associated with the first location. If ATRIB(2) equals 1, the ship entity requires the resource k1. If ATRIB(2) equals 2, then resource m1 is required [11].
Entities representing ships are created at two CREATE nodes, one for each direction. The time between ship arrivals is uniformly distributed. Following the creation
of the entities, ATRIB(2) is set to 1 for direction 1 and 2 for direction 2. Ships that
Fig. 5. Network model for Istanbul Strait.
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wait for the entrance will be put in file 3 or 4 and ATRIB(3) is used to indicate these
numbers. Thus, entities are assigned and ATRIB(3) value of 3 for direction 1 and 4
for direction 2. Once an entity is allocated the starting location, it proceeds to the
next AWAIT node where it waits for the gate defined by ATRIB(2), that is either
m1 or k1. If the appropriate line closes (which means a big ship goes through to
the other line) then the entity will wait in file 3 or 4 in accordance with the value
given by ATRIB(3). A COLCT node is used to record values of the waiting time
of the ship at the entrance.
Two other segments of the model controls the big ship or dangerous cargo vessels
entering from each directions and consists of a series of OPEN and CLOSE nodes
separated by ACTIVITY’s. In this segment of the model, resources and gates are referred to by the label given to them in the RESOURCE and GATE blocks. GATE 1
refers to a line from the Black Sea to the Marmara, and GATE 2 vice versa. If a gate
is open the ship can proceed, otherwise, they have to wait until the gate is open. The
system closes the gate according to uniform distribution between 1290 and 1350 min
and duration of 190–230 min which corresponds to approximately 1394 h per year.
This means one line is closed about 1394 h. This agrees with the statistics which is
about 2731 h for two line per year.
The last segment of the model is to simulate the dangerous passages and bad
weather conditions to close two lines.
Scenarios:
To simulate the system, the following assumptions are made:
•
•
•
•
Vessels do not overtake each other.
Vessels enter the strait one at a time from each entrance.
All vessels are transpassing (not stopping for loading and unloading within strait).
Local crossing traffic does not interfere with transit traffic.
Ship arrivals were simulated with six different uniform distributions and intervals of
these are given in Table 2.
One direction was assumed to be closed with the uniform distribution between
340 and 380 min. This corresponds to 2730 h of closure in a year. Closure of two
direction was modelled also with uniform distribution between 2300–2500 min,
which is about 219 h in a year.
Model was run for 43,200 min (1 month) for six different arrival times. The results
of the six scenarios are given in Table 2.
As seen from Table 3, when the arrival time of a ship decreases from average of 21
to 9, the number of observations increases from 2160 to 3881 ships. These results
also indicate that the best situation is the uniform distributions of UNFRM(18,22)
and UNFRM(18,21) which simulate the existing situation and suggest that there is
no waiting at the both the entrances of the Istanbul Strait. However, when arrival
times reduces to an average of 10 min waiting time, and the number of waiting ships,
increases rapidly (Fig. 2). This shows that although traffic in the strait is in acceptable condition now, it cannot handle the increment in traffic.
E. K€ose et al. / Simulation Modelling Practice and Theory 11 (2003) 597–608
605
Table 2
Distribution of ship arrivals
Scenarios
1a
2a
3
4
5
6
Low
High
B
M
B
M
20
18
16
14
12
8
21
18
17
14
11
8
23
22
18
16
14
10
23
21
19
17
13
11
K: Black Sea enterance, M: Marmara Sea enterance.
a
Existing situation.
Table 3
Results of six scenarios
Scenarios
1
2
3
4
5
6
K
M
2160
2057
2400
2400
2630
2435
3061
2730
3151
3303
3881
3238
K
M
20.67
22.63
22.40
27.74
24.89
29.271
31.40
38.01
35.66
782.77
479.31
930.63
Standard deviation
K
M
42.49
44.15
44.05
49.10
46.54
50.59
52.90
56.91
55.57
439.65
226.719
477.03
Minimum
K
M
1.475
1.399
1.399
1.738
1.477
1.776
1.69
1.291
1.609
3.560
6.02
5.143
Maximum
K
M
209.88
208.598
206.87
205.856
205.678
206.918
211.751
213.32
211.672
1581.01
923.88
1796.75
K
M
0.708
0.765
0.89
1.185
1.131
1.288
1.796
2.006
2.180
61.687
50.394
99.967
Standard deviation
K
M
1.975
1.969
2.308
2.614
2.706
2.741
3.648
3.511
3.981
34.932
24.934
53.411
Maximum length
K
M
10
10
11
11
12
12
15
13
15
126
99
195
Current length
K
M
0
0
0
0
0
0
0
0
14
125
99
195
Average waiting
time (min)
K
M
14.155
16.06
16.02
21.32
18.58
22.83
25.354
31.743
29.736
777.162
471.122
918.234
0.917
0.916
0.920
0.918
0.913
0.895
0.632
0.688
0.785
0.815
1.00
1.00
# of observation
Time in system
Mean value
Waiting
Average length
Percent of time
open
Average utilization
K: Black Sea enterance, M: Marmara Sea enterance.
Average waiting time
(min)
E. K€ose et al. / Simulation Modelling Practice and Theory 11 (2003) 597–608
Average # of waiting
ships
606
120.00
100.00
80.00
60.00
40.00
20.00
0.00
-20.00
0
10
5
1000.00
800.00
600.00
400.00
200.00
0.00
0
2
Scenarios
Blacksea ent.
Marmara ent.
4
6
8
Scenarios
Blacksea ent.
Marmara ent.
Fig. 6. Average number of waiting ships and waiting time.
Fig. 6 indicates that only 36% increment in ship arrivals caused ship waiting time
to increase from 16 to 918 min for Marmara entrance. Similar results were also
found for Black Sea entrance.
6. Discussions
The first simulation is the current level of maritime traffic. Results of this simulation, waiting time at the Black Sea enterance is average 14 and 16 at the enterance of
Marmara. This can also be seen from Fig. 7, white dots at the Marmara enterance
corresponds to waiting vessels.
Additional traffic especially tanker traffic through new pipelines (Fig. 8) of Novorossiysk and Supsa, will increase the traffic at the Turkish Straits. This will increase
the waiting times as seen from runs of 4 and 5. This will increase the pressure on the
Traffic Control of Istanbul Strait. In addition to causing the traffic problem, this
would increase the probability of accident at straits [12].
Fig. 7. Marmara entrance of Istanbul Strait.
E. K€ose et al. / Simulation Modelling Practice and Theory 11 (2003) 597–608
607
Fig. 8. Existing and proposed pipelines.
Every one recognizes that given the nature of the Turkish Strait, and existing
grave situation created dense traffic congestion, the strait cannot bear additional
oil shipments without putting into danger the security of Istanbul, the lives of its
population, its unique historical and precarious environment.
7. Future work
Future work should deal with the risk assessment of oil transportation and the
effect of increment in oil tankers size, before a disaster occurs. Also C
ß anakkale Strait
and the whole Turkish Straits (Istanbul Strait, Marmara Sea, and C
ß anakkale Strait)
should be considered.
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