607
1 INTRODUCTION
A lot of ship accidents in the world ocean were caused
mainly by two reasons, human onboard mistake or bad
ship hull technical condition. The second reason was
due to ship age, non- qualitative maintenance and non-
qualitative repair of ship hull thought its life cycle.
There were a couple of scientific publications
analyzed different ship damages and reasons resulted
in accidents. Literature review of cause for ship
accidents was done in [6]. The authors of this
publication summarized the factors caused ship
accident which goal was to detect its root cause with
the aim of applying appropriate corrective actions to
reduce the rate of ship accident and the risks posed.
According their review the main factor for ship
accident is human factor, but it is not just its.
Statistical analysis of ship accidents occurred in the
period 1990-2012 and assessment of safety level of
different cargo and passenger ship types was done in
[5]. Analysis shows that most recent damages with lost
of human life are in passenger and cruise ships. Cargo
ships damages and lost human life are with lowest
frequency.
In [4] was developed and analyzed method for
protecting hull structures by means of cathode
polarization from local corrosion damages at the
potential of the uncharged surface on the juvenile
surface steel. This method was applied for different
steel grades used in shipbuilding and ship repairing.
The results of experimental data shows that this will
allow increasing inter docking period of ships and
marine structures.
2 HULL DAMAGES.
The damages in ship life cycle are unavoidable event as
much as careful to be a crew. They can be divided into
two main groups:
Ship Causalities – Reasons and Statistical Analyze
Y. Denev
Technical University of Varna, Varna, Bulgaria
ABSTRACT: The paper deals with most recently damages caused ship accidents and their number in the World
Ocean. A lot of them are a result of bad technical condition or human mistake. The first reason is due to ship age,
non- qualitative maintenance and non- qualitative repair of ship hull thought its life cycle, while the second reason
is mainly of labour safety neglect. Analyzed period covers 27 years, from 1994 up to 2021. The analyze is done for
two ships group- merchant and special ships. The paper described damages on ship hull and its structural
members caused ship accidents and environmental pollution in relation with age of ships. The number and degree
of marine causalities are analyzed. Moreover, statistical analysis presents the often causalities and areas in the
World Ocean by ship and damage types. Finally, probabilistic density distributions of damages were shown by
Fisher distribution curve. The damages on Fisher distribution curve are presented independent one another.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 16
Number 4
December 2022
DOI: 10.12716/1001.16.04.01
608
− Damages on ship plating and
− Damages in ship structural members;
Damages on ship plating can be caused by:
− Heavy corrosion;
− Collision;
− Cracks;
− grounding etc.
While damages on structural members can be
caused by:
− Collision;
− Grounding;
− Mainly by buckling;
The cracks of structural members are the next level
of buckling development process. Buckling process is
widely described in modern classification
organizations rules. This process is entrained to bad
hull condition damages from one side and increase
ships age and material fatigue from other. The
figures from 1 to fig.5 clear shows typical ship hull
damages.
Figure 1. Ship collision[9]
Figure 2.Crack in ship hull[10]
Figure 3. Intensive ballast tank corrosion[7]
Figure 4. Intensive weld seam corrosion[8]
Figure 5. Intensive plating corrosion[8]
3 STATISTICAL DATA AND ANALYZE OF SHIP
INCIDENTS.
The number of serious accidents for the six years
period (2014-2020) is 25%, very serious is 3% and less
serious is 57%, fig.6.
Figure 6. Types of causalities[2]
Reduction of serious causalities was noticeable in
2020, while the number of marine incidents was
increased in same period. The peak number of serious
causalities was noticeable between 2016-2018.
Main ship types involved of marine causalities and
accidents were classified in several main group: cargo
ships, fishing vessels, passenger ships, service ships
and other. For six years period 2014-2020 cargo ships
are most recently involved in marine accidents and
causalities, followed by passenger ships.
609
During six years period the number of cargo ships
causalities take first place, followed by passenger
ships. The fishing vessel causalities take third place.
Figure 7. Ship types accidents 2014-2020[2]
Figure 8. Merchant ship types involved in accidents [2]
According [ 1] the age of world fleet was
dramatically increased. About 40% of ships are of age
more than 25 years old.
The heighten ship age is a precondition for
accidents. From table 1 was clear that about 40% from
world fleet was at age more than 25 years old. First
place in this ranking was for general cargo ships leads
from oil and chemical tankers and bulk carriers. Take
into account that ship was designed to live about 30-35
years we can to claim that a lot of world fleet is till to
end of his life. Through ship life cycle her hull
condition loss its main property- strength. Possible
reason for this was intensive corrosion of plating and
hull members although cathode protection. This was
precondition for ship accidents and environmental
pollutions.
Table 1. Ships age
________________________________________________
Ship age category Total, %
________________________________________________
0-4 years old 9.6
5-14 years old 31.9
15-24 years old 18.3
+25 years old 40.2
________________________________________________
Total 100
________________________________________________
For ship damage analysis was used information
about main reasons like grounding(2), collision(1), fire
on board(3), capsizing(4) and hull failure(5).
Figure 9. Distribution of ship damages from 1994-2021[3]
Distribution of ship hull damages, on fig.9. shown
the most recent damage was from collision, about 42%
form all damages. Grounding is second damage reason
leading form fire on board and capsizing. With about 3
% are the damages caused by bad hull condition. Their
less percent value didn’t corresponds for neglecting.
Capsizing is probability caused by bad technical
condition.
About 60% from causialities was happened in open
sea, 43% of accidents are happened when the ship was
en route , fig. 11. The main reasons for this are heavy
weather condition, human mistakes and bad technical
hull condition. The last reason is as a result of ships
building quality, age, maintanance, type of cargo and
operation area. Other about 35% percent are in port.
In loading and discharging the ship was appeared
factors for accidents in this area. They were not
corresponded with typical accidents. Damages in port
waters was involved mainly by cargo loading and
discharging , non- correct ballast operations, fire on
board and etc.
Figure 11. Damages area distribution from 1994-2021 [3]
For a period from 1997-2022 the number of very
large causalities with container and passenger vessels
take first place, fig.12. and fig.13.
24.6
22.2
8.5
2.6
42.0
0.0
10.0
20.0
30.0
40.0
50.0
1
2
34
5
610
Figure 12. Type of damage statistics 1997-2022
The very large causalities in ,,special” fleet
passenger vessels take first place, after that are towing
vessels. In less causalities ranking the number of
fishing vessels causalities in smallest, Ro- Pax vessels
take first place, fig.13.
Figure 13. Type of damage statistics 1997-2022
The probably density distribution of main damage
was presented by Fisher distribution, fig. 14.
Figure 14. Damage density distribution by Fisher
Density Fisher distribution is independence curve.
It shows damage reasons independence one another.
The curve is non- symmetrical and it is positive
skewed.
4 CONCLUSION.
Collision, grounding and fire on board are the most
often ship damages in relation with human mistake,
heavy weather and bad hull technical condition.
The most frequent ship damage and causalities are
happened in open sea.
A lot of ships involved in accidents are at age of
more than 25 years. This is serious reason for taking
into account about condition of world fleet.
General cargo ships are involved in 32% of the
marine causalities, while container vessels take 18%,
following by bilk carriers with 15%. LNG tanker and
chemical takers are involved in 7% of the accidents,
following by oil tankers.
Most often very large accidents are involved at
container vessels and bulk carriers. Serious accidents
are often in general cargo ships and chemical tankers,
following by bulk carriers.
ACKNOWLEDGMENT.
The present study was developed according National
project,, Young scientists and Postdoctoral”, financed by
Ministry of Education, Republic of Bulgaria.
REFERENCES.
[1] Electronic Quality Shipping Information System, The
2020 world merchant fleet, 2020;
[2] European Maritime Association, Annual overview of
marine causalities and incidents,2021;
[3] IMO, Global Integrated Shipping Information System,
[4] Kramar, V., Rodkina, A., Ivanova, O., Chernyi, S.,
Zinchenko, A., 2021, Analisys technology and cathodic
protection for hull structure of ships and floating
facilities, Inventions, 6,74,
https://doi.org/10.3390/inventions6040074;
[5] Papanikolaou, A., Bitha, K., Eliopoulou, Ventikos, N.,
2015, Statistical analysis of ship accidents that occurred in
the period 1990--2012 and assessment of safety level of
ship types, Maritime Technology and Engineering,
Lisbon, DOI: 10.1201/b17494-31
[6] Shanty, Y., Supomo, H., Nugroho, S., 2021, Cause of ship
accident: A literature review,
[7] https://www.chemcote.com.au/tank-lining-protective-
coatings/;
[8] https://www.dreamstime.com/photos-images/corrosion-
ship-hull.html ;
[9] https://www.fleetmon.com/maritime-
news/2019/24977/norwegian-cargo-ship-breached-
collision-german-con/;
[10] https://remotion.no/applications/hull-crack-repairs/;
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Fisher distribution
Type of damage
