International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 2
Number 2
June 2008
183
Statistical Studies on Marine Accidents
Happened on the Bohai Sea
Zhaolin Wu & Jingjun Zhao
Dalian Maritime University, Dalian, China
Guanghui Li
Ministry of Communications, Beijing, China
ABSTRACT: a statistical study is carried out on the basis of information of marine traffic accidents occurred
from 1996 to 2005 on the Bohai Sea. The time distribution and geographic distribution of the marine traffic
accidents, as well as the relationships between the accidents and weather condition, type of accidents area,
accident category, size of ships are analyzed, which provide references for adopting safety decision-making
and take relative precautionary measures to avoid and decrease occurrence of accidents.
1 STATISTICAL STUDY ON MARINE TRAFFIC
ACCIDENTS
In order to find out the laws of occurrence of marine
traffic accidents, so as to provide references for the
maritime safety administrations to adopt reasonable
safety decision-making, and for seafarers to take
relative precautionary measures, statistical study of
marine traffic accidents is important and effective
tool, which has been often used governmental bodies
and experts worldwide.
A statistics and analysis of marine traffic
accidents in Chinese navigable waters during the
period 1993-2002 have been carried (Wu, et al
2005), the following conclusions have been
formulated:
− with the rapid development of Chinese domestic
economics, the requirements on waterborne
transportation are also enhanced. There is a trend
that the marine traffic in Chinese waters will
continuously increase.
− the marine safety situation in Chinese navigable
waters is still not optimistic. Although the
number of marine traffic accidents reduced
drastically during the period of 10 years, the loss
of life and direct economic still keep at high
levels.
− the causes of marine traffic accidents are
multi dimensional. The major factors that lead to
the accidents in Chinese waters are human error,
marine traffic environment and ship conditions.
The incompleteness of the waterborne
transportation safety ensuring and supporting
system has also somewhat negatively influenced
on the maritime safety situation.
− for the purpose of Chinese waterborne transpor-
tation, it is necessary for Chinese government to
pay more attention to the completeness of
Chinese waterborne transportation safety and its
supporting systems.
The findings of above research is beneficial to the
maritime safety administrations of Chinese central
government to adopt national decision-making on
maritime safety management, but it is also important
to carry out statistics and analysis of marine traffic
accidents in a given sea area to help local maritime
safety administrations to adopt proper safety
management decision-making, and help seafarers to
take relative precautionary measures. In this paper a
statistical study is carried out on the basis of
information of marine traffic accidents occurred on
184
the Bohai Sea from 1996 to 2005, because that the
Bohai Sea is one of important navigable waters in
the northern China and is also a sea area in which
marine traffic accidents occur frequently.
2 STATISTICS AND ANALYSIS OF THE
MARINE TRAFFIC ACCIDENTS ON THE
BOHAI SEA
The data used in the following statistics and analysis
come from the marine traffic accidents investigation
department of four maritime safety administrations
located around the Bohai Sea, which are responsible
for the marine safety of one of part area of
the Bohai Sea .From 1996 to 2005 the total number
of marine traffic accidents occurred in the Bohai
Sea is 1738, including all kinds of marine traffic
accidents.
2.1 Time Distribution of accidents by month
In Figure1 the statistical distribution of marine
traffic accidents on the Bohai Sea by month is
represented. About 145 traffic accidents occur every
month on average. The Figure 1 shows that there are
two periods with high frequency of accident
happening, they are from April to June and from
October to November. During last ten years, most.
The proportion of accidents occurred in April is
10.4% of the total and 24% higher than the month
average. The proportions of October and November
are 10% and 9.8%, and 19% and 17% separately
higher than the month average. The proportions of
May and June are 9.3% and 9.6%. The number of
accidents in the period of from October to April of
next year is 60.7% of the total. The numbers of the
marine traffic accidents in October and November
increase obviously and maintain in a high level,
because that the first cold wave and gale often come
in this two months of each year, which shows that
the first cold wave and gale of each year has a bigger
impact on the safety of the vessels navigating on the
Bohai sea.
0
50
100
150
200
1 2 3 4 5 6 7 8 9 10 11 12
Month
Accident
Number
Fig. 1. Time distribution of accidents by month
2.2 Time distribution of accidents by date
In Figure 2 the statistical distribution of marine
traffic accidents on the Bohai Sea by day is
represented. About 56 marine traffic accidents occur
every day on average. Generally the marine traffic
accidents by day keep fluctuation.
0
20
40
60
80
100
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
Date
Fig. 2. Time distribution of accidents by day
2.3 Geographical distribution of accidents
According to the data of the locations of marine
traffic accidents, geographical distribution of traffic
accidents by the type of water area could be known.
Figure 3 implies that majority of marine traffic
accidents occurred in port waters, up to 63%, the
coastal waters(exclude port waters) is of 34%. It
indicates that it is necessary to strengthen the port
waters safety management, improve the VTS
functions as well, to pull down occurrence rate of
marine traffic accidents.
Other
3%
Coastal
waters
34%
Port
waters
63%
Fig. 3. Geographical distribution of accidents
2.4 Statistics of accidents by accident category
According to Regulations on Statistics and
Reporting of Marine Traffic Accidents established
by Chinese maritime safety administrations, marine
traffic accidents are divided into collisions, contacts,
groundings, fire, heavy weather (such as serious
damage and capsized by strong winds and waves)
and others. By initial accident category, the numbers
of collision, grounding and contacting accidents are
on the top 3 (see Figure 4), which is 73% of the total
accidents. Among them the number of collision
accidents is at the first and is 40% of the total. It
185
seems that because of high speed development of
shipping, higher density of ships, converge of sea
routes, crowded and complicated marine traffic on
the the Bohai Sea increase risk of collision
enormously. On the other hand, fire and heavy
weather accidents do not happen frequently and the
proportion is separately 3% and 1% of the total.
Fire
3%
Contact
16%
Grounding
17%
Heavy
Weather
1%
Other
23%
Collision
40%
Fig. 4. Statistics of accidents by initial accident category
2.5 Statistics of accidents by accident grade
Marine traffic accidents are divided into four grades,
according to the losses of lives and property, in
Chinese marine traffic accidents reporting and
statistics regulations, which are small accident,
general accident, serious accident and very serious
accident separately. Figure 5 gives proportions of
different grade of marine traffic accidents occurred
on the Bohai Sea. As seen from the Figure 5, most of
the accidents were small accident, accounted for
72%; then general accidents for 16%; thirdly, serious
accidents for 7%; lastly, very serious accidents for
5%.
Small
acccidents
72%
Very
serious
accidents
5%
Serious
accidents
7%
General
accidents
16%
Fig. 5. Statistics of accidents by accident grade
2.6 Statistics of accidents by ship appearance
According to statistics by ship appearance, the
proportion of accidents of underway ship is largest,
about 79%, and then accidents of anchoring ships
(11%), accidents of going / leaving berth ships (6%),
and accidents of mooring ships (3%), see Figure 6. It
is consistent to that majority of accidents is
collisions and groundings.
Going &
leaving
berth
6%
Mooring
3%
Other
5%
Anchoring
7%
Underway
79%
Fig. 6. Statistics of accidents by ship appearance
2.7 Relationship between accidents and wind
For weather condition the wind is an important
factors affecting navigational safety of ships. From
Figure 7. It could be seen that the proportion of
marine traffic accidents under the wind condition
(Beaufort scale) of No. 5 (Fresh breeze) and below
accounts for 39%, and under the wind condition of
No. 6 (Strong breeze) is 61%. It indicates that the
wind conditions have important influence on
occurrence of marine traffic accidents.
No.8
(Gale)
10%
No.9
(Strong
gale)&
above
2%
No.5
(Fresh
breeze)
&below
39%
N0.6
(Strong
breeze)
32%
No.7
(Near
gale)
17%
Fig. 7. Statistics of accidents by wind condition
2.8 Relationship between accidents and wave
For sea condition the wave is another important
factors affecting navigational safety of ships. From
Figure 8, it could be seen that the proportion of
marine traffic accidents under the condition of very
rough sea account for 8%, and under the condition of
rough sea, moderate sea, light sea account for 23%,
36% and 33% separately. It indicates that the sea
condition has important influence on occurrence rate
of marine traffic accidents.
186
Fig. 8. Statistics of accidents by wave condition
2.9 Statistics of accidents by ship type
According to statistics by ship type, the proportion
of accidents of general cargo ship is the largest one,
about 45%, then oil tanker for 11%, and then bulk
cargo vessel and fishing vessel for 10%. The
proportion of accidents of passenger/Ro-Ro ship is
only 6%, see Figure 9.
Tug
4%
Other
9%
Fishing
ship
10%
Passenger
ship
6%
Tanker
11%
Container
5%
Bulk
vessel
10%
General
cargo
45%
Fig. 9. Statistics of accidents by ship type
2.10 Relationship between accidents and length
of ships
According to statistics by ship length, the largest
proportion of accident lay on ships which length is
between 50m and 90m, about 32%. Ships of length
between 90m and 135 m are about 24%, as the same
as ships of length below 50 m. The lowest
proportion of accidents lay on ships which length is
above 246m, see Figure 10.
50～90m
32%
90～135m
24%
135～195m
14%
195～246m
5%
246m above
1%
50m below
24%
Fig. 10. Relationship between accidents and ship length
2.11 Relationship between accidents and gross
tonnage of ships
According to statistics by the gross tonnage of ships,
the proportion of accident of ships whose gross
tonnage is between 500 and 2999 is the largest,
amount to 48%. Followed by ships gross tonnage
between 3000 and 9999 (25%), ships gross tonnage
below 500 (15%), ships gross tonnage between
10000 and 29999 (6%), ships gross tonnage 30000
(2%), see Figure 11.
3000～
9999t
25%
10000～
29999t
11%
30000～
59999t
2%
500t below
15%
500～2999t
47%
Fig. 11. Relationship between accidents and ship tonnage
3 CONCLUSION
The above statistical study indicates that the
occurrence of marine traffic accidents occurred on
the Bohai Sea in last ten years has its statistical laws
and has different relationship with conditions of
ships and some influence factors, which is valuable
for the officers of maritime safety administrations
and seafarers to consider, because that accident data
used for above statistical study is reliable data from
official resources, and the accidents data cover the
whole part of the Bohai Sea in ten years time. But it
is also suggested that the findings of above statistical
study should be properly referenced and used by
consideration of local environments, practical
conditions and individual experiences. Further work
to be done is statistics and analysis of causes and
contributing factors of marine traffic accidents
occurred in last ten years time on the Bohai Sea, then
more valuable information could be provided for
reference and consideration.
REFERENCE
Wu, Zhaolin & Liu, Zhengjiang (2005). Statistics and analysis
of maritime traffic accidents in Chinese navigable waters.
IAMU Journal, 1, 2005, 63-72.
