The suitability of placing batteries near 
the hull sides from a collision and safety 
perspective 
Based on statistics and simulation data 
 

Bachelor thesis for Marine Engineering Programme 

 
 

DEPARTMENT OF MECHANICS AND MARITIME SCIENCES 
 

CHALMERS UNIVERSITY OF TECHNOLOGY 

Göteborg, Sweden, 2024 

JOHANNA PERRYD MATTSSON  
MAGNE PEDERSEN 
 



 

 

 

 

 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

[Intended to be blank, please remove this text]  



 

 

 

 

 
 

 

                 

 

 

 

  
 

 

 

 

 

 

 

 

The suitability of placing batteries near 
the hull sides from a collision and safety 

perspective 
Based on statistics and simulation data 

Bachelor thesis for Marine Engineering Program 

JOHANNA PERRYD MATTSSON 
MAGNE PEDERSEN 

 

Department of Mechanics and Maritime Sciences 
Division for Maritime Studies 

CHALMERS UNIVERSITY OF TECHNOLOGY 
Göteborg, Sweden, 2024 



 

 

 

 

 
 

 

 

 

 

 

 

 

The suitability of placing batteries near the hull sides from a collision and safety 

perspective  

Based on statistics and simulation data 

 

 

JOHANNA PERRYD MATTSSON 

MAGNE PEDERSEN 

 

 

© JOHANNA PERRYD MATTSSON, 2024 

© MAGNE PEDERSEN, 2024 

 

 

Department of Mechanics and Maritime Sciences 

Chalmers University of Technology 

SE-412 96 Göteborg 

Sweden 

Telephone: + 46 (0)31-772 1000 

 

 

Department of Mechanics and Maritime Sciences 

Chalmers University of Technology 

Göteborg, Sweden 2024 



 

 

 

 

i 
 

Preface 

This report was written during the spring of 2024 as a Bachelor thesis of the Marine 

Engineering program at Chalmers University of Technology.  

 

The idea for this report sprung out of the rapid development of electrical vehicles and ships, 

and from being informed about battery fires during some parts of the education. As the World 

tries to phase out fossil fuels, alternative propulsion methods such as battery electric 

propulsion is on the rise, and with it comes certain challenges that need to be faced, including 

appropriate infrastructure, operational range, and safety. Hearing and learning about maritime 

accidents over the years has made it clear that the forces involved in such scenarios can lead 

to catastrophic damages to the ship and its cargo, and that precautions must be in place to 

limit the damage extent as much as possible. Batteries are quite fragile by nature, and abusing 

them can to short circuits, thermal runaway, and fires that are difficult to extinguish. Because 

of this, it is important to protect the batteries from external damage, and to try to determine 

were to store the batteries to ensure this.  

 

We would like to thank Per Mottram Hogström at Chalmers University of Technology for 

being our supervisor during this project, and fellow students at Chalmers for their input at the 

seminars, and the teachers for their enthusiasm in their work. We would also like to thank our 

classmates for the four years of higher education that we have faced together, and we hope 

that we will see each other out on the ocean waves someday. 

 

 

 

 

     Johanna Perryd Mattsson & Magne Pedersen, 2024  



 

 

 

 

ii 
 

The suitability of placing batteries near the hull sides from a collision and safety 

perspective 

Based on statistics and simulation data  

JOHANNA PERRYD MATTSSON 

MAGNE PEDERSEN  

Department of Mechanics and Maritime Sciences 

Chalmers University of Technology 

 

 
SAMMANDRAG 
Ambitionen att minska globala utsläpp av växthusgaser är större och starkare än någonsin, 

och alla branscher måste göra sin del för att det målet ska kunna nås. Sjöfartsindustrin är en 

självklar del av detta, eftersom en stor del av jordens internationella transporter sker med 

hjälp av fartyg. Det finns många idéer och potentiella lösningar på hur utsläppen av koldioxid 

från branschen kan minskas, och det finns en stor fokus på alternativa drivmedel. Att låta 

fartyg drivas av batterier är ett alternativ som utvecklas mer och mer, men den lösningen 

kommer med sina begränsningar, som framför allt gestaltar sig i räckvidd och infrastruktur för 

att ladda batterierna.  

 

För att öka den möjliga räckvidden på fartyget kan det vara lockande att nyttja vartenda ledigt 

utrymme till förvaring av batterier, men även det kan ha sina nackdelar. Utrymmen som 

skulle kunna nyttjas till förvaring av batterier är till exempel utrymmen som finns nära 

bordläggningen, men anledningen till att utrymmen här är tomma eller används till annat 

ändamål till att börja med är ofta av säkerhets- eller stabilitetsskäl. De utrymmen som är 

konstruerade ur ett säkerhetsperspektiv finns ofta runt tankar med känsligt innehåll, till 

exempel kemikalier och olja, som hade kunnat skada miljön om de skulle läcka ut vid en 

olycka där skrovet skadas. 

 

Batterier är benägna att börja brinna om de skulle kortslutas till följd av deformation, och att 

då placera batterier i utrymmen som riskerar att utsättas för deformationer vid en kollision kan 

vara riskfyllt, eftersom en potentiell brand kan leda till ännu större skador på fartyget än vad 

kollisionsskadorna i sig hade orsakat.  

 

Denna studie försöker svara på om det är lämpligt att placera batterier där de riskerar att 

träffas vid en kollision med ett annat fartyg, sjöbotten, eller en kaj. Statistik och 

simulationsdata om batteriers motståndskraft mot deformation, skrovskador, och 

olycksfördelning har samlats in i en systematisk litteraturstudie och sedan använts för att 

skapa en riskanalys gällande var batterier bör placeras. 

 

Resultatet visar att battericeller enbart kan komprimeras med ett par millimeter innan cellen 

fallerar och därav blir risken för brand hög vid en kollision om deformationen skulle nå 

batterierna.  

 

Nyckelord: Batteridrivna fartyg, kollision, grundstötning, konstruktion, brandsäkerhet, 

statistik, skrovskador 

 
 
 
 



 

 

 

 

iii 
 

 
 

The suitability of placing batteries near the hull from a collision and safety perspective 

Based on statistics and simulation data 

JOHANNA PERRYD MATTSSON 

MAGNE PEDERSEN 

Department of Mechanics and Maritime Sciences 

Chalmers University of Technology 

 

 

ABSTRACT 
 

The ambition to decrease global greenhouse gas emissions is more prevalent than ever, and all 

industries must do their part to reach that goal. The shipping industry plays a vital role, as a 

large part of the international transport is being done by ships. There are many ideas and 

potential solutions on how to reduce the emissions of carbon dioxide from the shipping 

industry, and those are largely focused on alternative fuel types. Building ships that use 

batteries as an energy source for propulsion is a concept that is evolving more and more, but it 

does come with limitations, which are most obvious when it comes to the range of operation 

and the infrastructure needed to charge those batteries.  

 

To expand the range of operation of the ship it can be tempting to make use of every available 

space to store batteries, for example spaces close to the side casing or within the double hull, 

but the reason why the space is empty to begin with, or is used for some other purpose, is 

often due to the safety or stability of the vessel. The spaces that are constructed from a safety 

perspective are often found around tanks that can contain sensitive cargo or bunker, like 

chemicals and oil, which could damage the environment if they were to leak out in case of an 

accident where the hull would be damaged.  

 

Batteries are prone to catch fire if they are short circuited due to deformation, therefore 

placing batteries in spaces that can be exposed to deformation in a collision carries a potential 

risk, since a potential fire can lead to more substantial damage on the ship than what the 

collision alone would have made.  

 

This study aims to answer if it is appropriate to place batteries where they risk being hit in a 

collision with another ship, the sea bottom, or a berth. Statistical and simulation data 

regarding hull damages, accident distribution, and a battery’s resilience against deformation is 

compiled in a systematic literature review and then used to create a risk analysis on the 

appropriate placement of batteries. 

  

The results show that battery cells can only be deformed by a few millimetres before the cell 

fails, meaning that the risk of fire is high in a collision if the deformation would reach the 

batteries.  

 

 

Keywords: Battery powered ship, collision, grounding, construction, fire safety, statistics, 

hull damage 



 

 

 

 

iv 
 

  



 

 

 

 

v 
 

TABLE OF CONTENTS 

1. Introduction ........................................................................................................................ 1 

1.1 Background ...................................................................................................................... 2 

1.2 Aim of the study ............................................................................................................... 2 

1.3 Research questions ........................................................................................................... 2 

1.4 Delimitations .................................................................................................................... 2 

2. Theory ................................................................................................................................ 3 

2.1 Battery Design and Safety ................................................................................................ 3 

2.1.1 Battery design and components ..................................................................................... 3 

2.1.2 Battery safety ................................................................................................................. 4 

2.2 Development of Battery Vehicles .................................................................................... 6 

2.3 Development of Battery Ships ......................................................................................... 7 

2.4 Maritime Regulations ....................................................................................................... 9 

2.5 Ship construction requirements ...................................................................................... 10 

2.6 Maritime Accidents ........................................................................................................ 13 

3. Methods ................................................................................................................................ 14 

3.1 Overview ........................................................................................................................ 14 

3.2 Literary study ................................................................................................................. 14 

3.2 Method of Searching ...................................................................................................... 14 

3.2.1. Search Engines and Databases ................................................................................... 14 

3.2.2 Search Process ............................................................................................................. 16 

3.3 Evaluation of Sources ..................................................................................................... 18 

3.4 Results of the Information Search .................................................................................. 18 

3.5 Risk Assessment ............................................................................................................. 19 

3.6 Ethics of the Information Search .................................................................................... 20 

4. Results .................................................................................................................................. 21 

4.1 Overview of Results ....................................................................................................... 21 

4.2 Number and Nature of Maritime Accidents – Statistics ................................................ 21 

4.2.1 Recorded number of accidents and incidents .............................................................. 21 

4.2.2 Accident Location type ............................................................................................... 23 

4.2.3 Distribution of Accident types .................................................................................... 24 

4.3 Statistics and Simulations on Ship Damage ................................................................... 26 

4.3.1 Collision damage ......................................................................................................... 26 

4.3.2 Grounding Damage ..................................................................................................... 29 

4.4 Battery Information ........................................................................................................ 31 

4.4.1 Battery Statistics .......................................................................................................... 31 

4.4.2 Battery Safety, Guidelines, and Common Practice ..................................................... 33 



 

 

 

 

vi 
 

4.5 Compilation and Calculation of statistics ....................................................................... 34 

4.5.1 Accidents per port call ................................................................................................. 34 

4.5.2 Distribution of accident types ..................................................................................... 34 

4.5.3 Battery Damage Statistics ........................................................................................... 35 

5. Discussion ............................................................................................................................ 38 

5.1 Battery Resilience and Fire Safety ................................................................................. 38 

5.2 Risk Analysis .................................................................................................................. 38 

5.2.1 Identification of Accident Scenarios ........................................................................... 38 

5.2.2 Accident Frequency ..................................................................................................... 38 

5.2.3 Initial Accident Severity .............................................................................................. 39 

5.2.4 Initial Risk Index ......................................................................................................... 41 

5.2.5 Risk control options .................................................................................................... 42 

5.2.6 Accident Severity after implementing the risk control option. ................................... 42 

5.2.7 Risk Index after risk control option ............................................................................. 42 

5.3 Discussion on Battery Placement ................................................................................... 42 

5.3.1 Existing Recommendations on Battery Placement ..................................................... 42 

5.3.2 Battery Placement based on statistics and simulations. .............................................. 43 

5.3.3 Summary of Battery placement ................................................................................... 43 

5.4 Discussion on the Results ............................................................................................... 45 

5.5 Discussion on the Method .............................................................................................. 46 

6. Conclusion ............................................................................................................................ 49 

7. Recommendations for further research ................................................................................ 50 

References ................................................................................................................................ 51 

Appendix 1 ............................................................................................................................... 55 

 

 

 
 
 
 
 
 
 
 
 
 
 
 



 

 

 

 

vii 
 

LIST OF FIGURES 
Figure 1. Simplified overview of the battery cell’s internal components ................................. 4 
Figure 2. Simplified cross section of a double hulled ship. .................................................... 11 
Figure 3. A visualisation of a ship’s perpendiculars and length ............................................. 12 
Figure 4. Ship overview with collision bulkhead. ................................................................... 13 
Figure 5. Longitudinal collision damage location ................................................................... 27 
Figure 7. Battery placement seen from above ......................................................................... 44 
Figure 8. Battery placement seen from the side. ..................................................................... 45 

 

 

 
 
LIST OF TABLES 
Table 1. Double hull distance measurements. ......................................................................... 11 
Table 2. Requirements on the construction location of the collision bulkhead. ...................... 12 
Table 3. The search process of the information search ........................................................... 17 
Table 4. Categorisation and numbers of sources found. .......................................................... 21 
Table 5. The number of port calls made in main European ports. .......................................... 21 
Table 6. The number of marine casualties recorded by EMSA in 2018-2022. ....................... 22 
Table 7. Accidents and incidents reported per 10.000 port calls in Sweden 2018-2022. ........ 22 
Table 8. The total number of port calls in Baltic ports between 2006-2011. .......................... 23 
Table 9. Accidents reported in the Baltic Sea during 2006-2011. ........................................... 23 
Table 10. Distribution of marine accidents based on type of location. ................................... 23 
Table 11. Relevant accidents compared to all the reported accidents each year. .................... 24 
Table 12. Collision, grounding, and contact accidents recorded by EMSA 2018-2022. ........ 25 
Table 13. Distribution of the relevant accident types reported to the IMO 2005-2017. ......... 25 
Table 14. Overview of accident frequency analysis results. ................................................... 26 
Table 15. Longitudinal collision damage location. ................................................................. 27 
Table 16. Vertical collision damage location. ......................................................................... 28 
Table 17. Hull penetration depth depending on bow type. ...................................................... 29 
Table 18. Transverse grounding damage location. .................................................................. 30 
Table 21. Longitudinal grounding damage location. ............................................................... 31 
Table 22. Depths reached when a short circuit of the cylindrical battery cell occurred. ........ 32 
Table 23. Indentation limits of different indenters on a pouch battery cell............................. 32 
Table 24. Data found regarding port calls and accidents within a specific area. .................... 34 
Table 25. Data found regarding the distribution of accidents within a specific area. ............. 35 
Table 26. Overview of deformation data on cylindrical battery cells. .................................... 36 
Table 27. Overview of deformation data on pouch battery cells. ............................................ 36 
Table 28. Overview of deformation data on prismatic battery cells. ...................................... 37 
Table 29. Frequency Index table ............................................................................................. 39 
Table 30. Severity Index table ................................................................................................. 41 
Table 31: Risk Index table ....................................................................................................... 41 

 
 
 
 



 

 

 

 

viii 
 

ACRONYMS AND TERMINOLOGY 
 

EMSA 

FSA 

IACS 

ILLC 

IMO 

MARPOL 

 

RoPax 

RoRo-cargo 

SOLAS 

 

European Maritime Safety Agency 

Formal Safety Assessment 

International Association of Classification Societies 

International Convention on Load Lines 

International Maritime Organization 

International Convention for the Prevention of Pollution from 

Ships 

Roll On and Roll Off cargo combined with Passenger ship 

Roll On and Roll Off Cargo 

International Convention for the Safety of Life at Sea 

 

  

  

  

  

  

 



 

 

 

 

1 
 

1. INTRODUCTION 

The global goal of reducing greenhouse gas emissions by removing carbon fuels has led to 

extensive research and development of the electrical grid and to shift the energy demand from 

fossil fuels to electricity (Keane, 2023). One of the sectors that is subject to these changes is 

the transportation sector. The development of electric vehicles has progressed quickly in recent 

years and electric cars are now available for purchase by most car manufacturers. 

 

Anwar et al (2020) write that the trend of electric transportation also extends to the maritime 

sector, as the hybridisation of ships has increased. The development of a fully electric maritime 

industry faces several obstacles of various kinds, for example limited voyage distances, 

infrastructure for battery charging, and regulations regarding the construction of ships.  

 

According to Liu et al. (2023), one of the most commonly perceived issues with battery electric 

road vehicles is the operational range, in other words how far the vehicle can drive on one 

charge. This issue could also translate into the maritime industry, as battery ships also face the 

problem of limited range. The European Maritime Safety Agency (2023, November 14) has 

recognised that the low electrical energy density of batteries makes fully electric ships more 

suited for short-distance voyages and that deep-sea voyages are less suitable.  

 

Liu et al. (2023) found that one way of solving the range anxiety could be to add more or bigger 

batteries to the vehicle, but that also comes with some concerns, for example decreased 

efficiency and increased cost. They also state that that more or larger batteries would take up 

more space in the vehicle, which could also be applicable in the maritime industry.  

 

Trombetta et al (2024) illustrate that while both road vehicles and ships are part of the 

transportation industry, the order of magnitude regarding the energy needed for the two 

industries is considerably different. Despite this, the adopted battery technology is usually the 

same for all parts of the transportation sectors, the maritime industry face particular challenges 

in the form of weight and space constraints, among others. They also point out that batteries 

can be a safety hazard if they were to be abused, as it can lead to the battery catching fire and 

generating toxic gases. 

 

If the method of installing more batteries would be used as way to extend the range of the ship, 

more batteries would naturally take up more space onboard. They could be placed in areas or 

spaces that are normally empty or used for something else, as it would be unfavourable to place 

them in such a way that would decrease the available cargo space. There are some areas that 

are less suitable for them to placed however, as it could compromise the safety of the vessel. 

One type of area which could be less suitable for battery placement is close to the hull, in spaces 

like the double hull compartments. Those areas are most likely to be affected by deformation if 

a collision would occur, and batteries are prone to catch fire if they are subjected to mechanical 

abuse.  

 



 

 

 

 

2 
 

1.1 Background 
The background of this report is the ongoing development of ships with battery propulsion, and 

how such a propulsion system could possibly alter the way that collision safety is currently 

handled onboard ships. Trying to use more available space onboard a ship to install more 

batteries could potentially be dangerous in a collision situation, as damaged batteries can cause 

a fire. 

 

1.2 Aim of the Study 

The aim of this report is to examine the risk of placing batteries in double hull spaces by 

investigating which parts of a ship that is statistically more likely to receive damage in an 

accident, what would happen if the batteries were to be deformed in a collision, and then make 

a risk analysis of which spaces would be more suitable or less suitable to contain batteries from 

a collision safety perspective. 

 

1.3 Research Questions 
The following questions will be addressed: 

- What parts of a ship is statistically more likely to sustain damage in an accident? 

- Where could batteries be located to reduce the risk of mechanical abuse? 

- Can placing batteries in more sensitive spaces to increase the operational range be 

justified by the risk?  

 

1.4 Delimitations 
In this report, there are several different aspects that has not been included as considerations 

when constructing an electric ship.  

 Firstly, no considerations have been made for the economical aspect. Batteries are one 

of the most expensive parts of a fully electric ship, and adding more batteries in the double hull 

space might not be economically viable. 

 Secondly, no consideration has been made regarding how the amount or placement of 

batteries within the double hull could affect the stability characteristics of the ship. Batteries 

are generally very heavy and dense, so the placement of them could severely impact the 

stability. It is also worth mentioning that the double hull spaces are often used for ballast tanks, 

which can be filled and emptied to adjust the stability and the draught of the ship, which would 

no longer be possible if those spaces were filled with battery packs.  

 Thirdly, no considerations have been made for how different battery types can be 

affected differently by deformation and mechanical abuse, this applies to both the material of 

the electrodes as well as the type of electrolyte used. Only one type of battery will be considered 

in this report. Furthermore, no consideration has been made regarding the state of charge of the 

battery and how that could change the effects of mechanical abuse.  

 Fourthly, no considerations have been made for other conditions that could affect the 

battery if a collision would occur, for example the effect of water ingress on the battery packs.  



 

 

 

 

3 
 

2. THEORY 

The information found concerning the design of batteries, the conventions and rules that 

regulate the shipping industry, and the development of electric vehicles and ships will be 

presented in this chapter. The battery design and its parts will be explained, as well as the 

procedure used when evaluating risks in a maritime setting.  

 

2.1 Battery Design and Safety 
The design and safety of batteries plays a large part in how vehicles and portable devices are 

constructed and designed to ensure the safety of the intended user. The choice of battery type, 

size, and placement are important factors to consider during the design process, as it affects not 

only safety, but also the weight, size, and the range or period of operation of the object it is 

supposed to power. 

 

2.1.1 Battery Design and Components 
A Lithium-ion battery cell consists of four parts, two electrodes, a semi-permeable barrier (also 

known as a separator), and an electrolyte in liquid or solid form (Australian Academy of 

Science, 2016). The negative electrode is called the anode, and the positive electrode is called 

the cathode. At the anode, the material that it consists of reacts with the electrolyte and it results 

in free electrons accumulating at the anode. A chemical reaction also takes place between the 

cathode and the electrolyte, which enables the cathode to accept electrons. If the two anodes 

are connected by a wire for example, the electrons will flow from one side to the other, and an 

electrical current is created. To balance the movements of electrons through the wire, the semi-

permeable membrane and the electrolyte allows positive ions to move through it in the opposite 

direction of where the electrons are going. Bisschop et al (2019) points out that from a safety 

point of view, the separator’s ability to isolate the anodes from each other is very important. If 

the separator was to break or contract, it could lead to an internal short circuit within the battery 

cell. This means that the separator must be durable and strong to withstand high temperatures 

and stresses. If it would be subjected to too high temperatures, the material of the separator 

could melt and give way to a short circuit and chemical reactions that cannot be controlled, 

which can lead to an explosion of gases that have been created by the reactions. They also write 

that the electrolyte is an integral part of both the performance and safety of a battery. One issue 

regarding the electrolytes commonly chosen for lithium-ion batteries is its flammability, which 

can vary greatly depending on the chemical compounds used.  

 



 

 

 

 

4 
 

Note: Illustration of the internals of a battery cell. When the battery cell is powering something, the current flows 

from the anode to the cathode, and when the battery is charging, the electrons flow the opposite way. 
 

Shapes  

When thinking about batteries, the common AA or AAA standard cylindrical battery often 

comes to mind, but they can also come in the shape of a pouch cell or a prismatic cell (Bisschop 

et al, 2019). The packaging that gives the batteries their shapes are mainly done in three 

different ways, and all have different pros and cons when it comes to heat regulation, energy 

density, and ability to withstand stresses. The most common type of battery shape found in 

vehicles is the prismatic cell, as their rectangular design allows them to be tightly packed and 

thereby have a high packing efficiency and high energy density, and they also have a rigid outer 

shell. Pouch cells can also be tightly packed, and their lack of a rigid outer shell allows for the 

highest energy density out of the three types, but on the other hand it also means that they have 

an increased vulnerability to external damage. Cylindrical cells can distribute forces evenly 

over their circumference, which gives them high mechanical stability. However, their shape 

makes them more difficult to pack tightly together, but this also means that there is more space 

for air to move around them, which is good for thermal management. Battery packs consist of 

several battery modules that are connected and arranged together, and the battery modules in 

turn consist of several connected battery cells.  

 

2.1.2 Battery Safety 

Bisschop et al (2019) indicates that the safety concerns regarding batteries are one of the largest 

obstacles that needs to be overcome to make people comfortable with their presence in the 

transportation sector. They describe that there are various things that can cause a battery to fail 

and become unstable and unsafe, for example overcharging the battery, over-discharging, being 

exposed to too high or too low temperatures, mechanical deformation, manufacturing flaws, 

and poor electronic control of the battery. Any of these potential faults can lead to a so-called 

thermal runaway, which can cause gas emissions that can be toxic and/or flammable, and a 

pressure build-up can lead to the battery exploding. 

 

Mylenbusch et al (2023) describes a thermal runaway as uncontrollable exothermal chemical 

reactions that develops within a battery cell, which causes the battery temperature to surpass 

the intended threshold temperature, which further increases the ongoing process, and can result 

in fire, explosion, and emission of toxic and/or flammable gases. The process of the battery 

generating more heat than can be dissipated results in a so called “runaway” state which cannot 

 Figure 1. Simplified overview of the battery cell’s internal components 



 

 

 

 

5 
 

be stopped until all the thermal energy and chemical components have been consumed. This 

excessive heat can cause fires and build up pressurised gases inside the battery cell as the 

chemical compounds within begins to degrade, which in turn can cause an explosion.  

 

Bisschop et al (2019) further explain that failures within a single battery cell can spread to other 

cells, a phenomenon known as thermal propagation. This occurs when the failed battery 

generates heat that is transferred to the intact cells around it, potentially causing them to have 

uncontrolled chemical reactions as well.  The likeliness of this occurrence, and the speed at 

which it develops, largely depend on how the battery cells and modules are packed together, 

with cylindrical cells performing the best because of the airgaps left between the cells and the 

small contact area they share with each other, and the pouch cells perform the worst as they 

tend to be very tightly packed. The limiting factors for thermal propagation are the size of the 

battery pack with bigger battery packs having a higher energy potential and more cells for heat 

and fire to spread to, and the charge of the battery pack where a higher charge leads to more 

violent thermal propagation. There is also a correlation between the amount of oxygen in a cell 

and the propagation speed, as more oxygen makes the heating process faster, and when gas 

pressure builds up inside the battery, the venting of those gases enables more oxygen to reach 

the battery and speeds up the process even more.  

 

Moreover, Bisschop et al (2019) state that there is a correlation between the battery’s charge 

level, also known as the state of charge, and the rate at which the energy in the battery is 

released, as a higher state of charge makes the energy release faster. 

 

Bisschop et al (2019) state that most cases of thermal runaway are caused by abuse or 

deformation of the battery cell, which can be done in different ways, for example by 

mechanical, thermal, or electrical abuse. Thermal abuse is when the temperature of battery is 

not kept within the intended range, electrical abuse can be caused by overcharging for example, 

and mechanical abuse is when the battery becomes deformed because of various types of 

impact, for example in a car crash involving an electric vehicle. The impact and consequent 

deformation of the vehicle’s battery pack can cause internal short circuits by rupturing the 

separator, for instance, leading to a quick energy discharge and rising temperatures, which can 

trigger a thermal runaway. They also found that a crash may not immediately lead to a fire 

however, and that the effects of the crash could have a delayed reaction. The probability of a 

crash resulting in a fire increase with the collision energy of the accident, and the delay of 

ignition can vary greatly, from igniting instantly, to igniting hours, days, or even weeks after a 

collision event, sometimes reigniting several times after the fire has been put out.  Fires have 

also been reported to have started without the vehicle being involved in a crash, such scenarios 

include the car charging for an extended amount of time, being immersed in saltwater, or while 

being driven.  

 

Mylenbusch et al (2023) write that using water is the most effective way of stopping a thermal 

runaway, as a large amount of water can act as a heat sink, taking up all the excess heat that is 

being generated by the battery. Cooling the battery cells will slow down the chemical reactions 

within it, and perhaps even stop them. There is a risk of the water creating a short circuit of the 

battery however, and the method of dousing a battery fire should be carefully considered for 

every individual event.  



 

 

 

 

6 
 

 

Bisschop et al (2020) disclose that a battery with a lower state of charge burns in a more 

“friendly” way, and that when all the flammable materials of a battery have been consumed, 

there is no longer any risk of fire. Installing a water mist system inside the battery pack that can 

cool it in the case of increased heat can help prevent a thermal runaway and gas generation in 

the battery, which int turn can prevent explosion. This can be difficult however, as there can be 

limited space between the battery cells depending on how they are packed together. The gases 

generated by an overheated battery can be vented from the battery, but those gases are often 

toxic and flammable, making the surrounding area unfit for humans.  

 

Willstrand et al (2020) found that the main gases that can be vented from a battery that can be 

harmful to humans is carbon monoxide (CO) and hydrogen cyanide (HCN) as they inhibit 

bodily functions, and gases such as carbon dioxide (CO2), hydrogen gas (H2), and nitrogen gas 

(N2), as they can displace the oxygen within a space, which can lead to asphyxiation. Irritant 

gases can also be generated, and they can be toxic even at low concentrations. They include 

sulphur dioxide (SO2), hydrogen fluoride (HF), hydrogen chloride (HCl), and nitrogen dioxide 

(NO2), among others. These gases can be corrosive to the respiratory tract when inhaled, and 

they can form acids in contact with water. They also found that the concentration of the gases 

vented from the battery varies with the state of charge of the battery when the reactions occur, 

with a higher charge leading to a greater generation of carbon monoxide and hydrogen gas. 

 

As a way of mitigating the risks of batteries onboard ships, the European Maritime Safety 

Agency (2023, November 14) has published a non-mandatory guide on how to integrate 

lithium-ion batteries on board ships. When it comes to the battery space, they recommend the 

location of the battery system to be predetermined to enable suitable design and testing of the 

space, and that the location of the battery space should be in areas of the ship that have a low 

probability of collision damage, as far as it is practicable.  

 

Furthermore, the European Maritime Safety Agency (2020) also commissioned the 

classification society Det Norske Veritas to conduct a study on battery systems for the maritime 

industry. They found that the solid-state electrolyte is a technology that could be well suited for 

ships, but further development was still needed at the time of investigation. Their suitability 

stems from the fact that they are expected to pose a lesser fire hazard, as the liquid electrolyte 

used in most current batteries is flammable, and the solid electrolyte also has the potential of 

enabling tighter packing of the battery cells.  

 

2.2 Development of Battery Vehicles 

Electric vehicles can often be believed to be a recent invention, but they have existed in one 

form or another since the nineteenth century (Enge et al., 2020). The important inventions and 

discoveries that laid the foundation for fully electric vehicles were made in the early eighteen 

hundreds, such as the first battery that could provide a continuous current, the direct current 

motor, and the relationship between electricity and magnetism. The first electric motor that was 

able to transport people was installed on a paddle boat and used to carry a dozen people over a 

river, and four years later the first battery powered locomotive was built. In 1859, the French 

physicist Gaston Planté presented the first rechargeable battery, and in 1881 Gustave Trouvé, 

a French electrical engineer, invented the first electric vehicle able to drive on roads.  



 

 

 

 

7 
 

 

Burton (2013) explains that in the first year of the twentieth century, almost 40 per cent of all 

cars sold had electric propulsion. Their popularity stemmed from their ease of use and lack of 

dirty emissions compared to other types of cars, and the limited range did not become a problem 

until better roads were built between cities, which made longer trips more common, as car 

transportation were mostly done within city limits before. 

 

Enge et al (2020) writes that the internal combustion engine and the steam engine were 

developed around the same time as the electrical motor, and they proved to be a much more 

economical mode of transportation. As time went on, battery powered vehicles became less 

popular, especially in north America, since the abundance of oil made it cheaper and more 

comfortable to own a car with an internal combustion engine. 

 

Burton (2013) informs that the opinion of electric cars turned when the batteries started being 

too heavy for the vehicles, the electric starter motor made it easier to start internal combustion 

engines, and the petroleum industry spreading across America made petroleum more easily 

accessible and cheaper. Petrol stations could be found throughout the country, and refilling the 

fuel tank was a fast and simple affair, while there were very few battery charging stations 

outside of large cities. When Henry Ford’s Model T car became widely available and 

affordable, it took over the American market and the electric car started fading into obscurity.   

 

Enge et al (2020) explains that the rising oil prices in the latter half of the twentieth century led 

to an increase in interest of electric vehicles again, and Matulka (2014) discloses that NASA 

also played a part in increasing the interest in electric vehicles, as electric lunar rovers were 

used in the Apollo space program.  

 

In more recent years, the goal of decreasing global greenhouse gas emissions has made electric 

vehicles more popular than ever, and the European Environment Agency (2024) has noted that 

the percentage of newly registered vehicles with electric drive has gone up in the last few years.  

 

Modern electric vehicles rely on large lithium-ion batteries to store the energy needed to drive 

them. Moseman & Paltsev (2022) disclose that the production of those batteries consumes a lot 

of energy and resources, but over their life cycle they produce less emissions than a vehicle 

with an internal combustion engine, which makes them attractive in a world where greenhouse 

gas emissions need to be reduced.  

 

2.3 Development of Battery Ships 

One of the first ships with electric propulsion was the USS Jupiter, which was a naval ship from 

the United States of America (Babb, 2015). She entered service in 1912 and was the first ship 

with turboelectric drive and exceeded the economical expectations. More navy vessels were to 

be built some years later, but the new propulsion system started a controversy between the 

Bureau of Steam Engineering and several national shipbuilders, as they saw the turboelectric 

propulsion as a threat to traditional propulsion. The shipbuilders would also be making bigger 



 

 

 

 

8 
 

profits when installing traditional propulsion, as those systems were much cheaper and easier 

to make than turboelectric drives.  

 

Engineering and Technology History Wiki (2014) states that turboelectric drives were also 

powered by steam, but instead of mounting the steam turbines directly onto the propeller shaft 

to rotate the propeller when the steam was let into the turbine, the turbine was mounted 

separately and drove an electric generator which provided electric motors on the propeller shaft 

with power. This made the system more efficient and less prone to damage, as the turbines 

could keep running at a constant speed independent of the rotational speed of the propeller, 

which can vary a lot when navigating in or out of ports for example. 

 

Babb (2015) reports that several more navy ships with turboelectric drive were built in the 

following years, but they never proved to be so much more efficient than their mechanically 

driven counterparts as they were expected to be, so the use of turboelectric drive was eventually 

phased out from the navy.  

 

Paul (2020) explains that electric propulsion of ships became more relevant when the fuel prices 

rose, and exhaust emissions faced stricter regulations. The use of electric propulsion proved to 

increase the efficiency of the system, which reduced the exhaust emissions. As larger batteries 

developed, they became more prevalent to use onboard ships for various purposes, such as to 

reduce emissions, or as an uninterruptable power supply.  

 

Wärtsilä (n.d) defines a fully electric ship as a ship that relies on batteries to power every system 

that is onboard, including the propulsion system, heating, ventilation, etc. If the electricity 

comes from fully renewable sources, it enables the ship to operate with zero emissions of carbon 

dioxide during its operational lifetime. 

 

The World’s first fully electric ferry entered service in May 2015 between the Norwegian towns 

of Lavik and Oppedal. Mikkola et al (2016) explains that the ferry, named Ampere, is powered 

by lithium-ion batteries and transports passengers and vehicles across the Sognefjord as part of 

the E39 road route, and one crossing is completed in roughly twenty minutes.  

 

Anwar et al (2020) state that the battery propulsion does come with its limitations however, 

most notably the range of operation of the ship. This comes as a natural consequence to electric 

propulsion, since the batteries need to be recharged in a port that has the necessary infrastructure 

to supply the huge amount of power that the ship batteries demand. The quantity and type of 

batteries that the ship carries will also have a maximum amount of power that can be supplied 

to necessary systems, and when that power runs out, the only way to be operational again is to 

recharge the batteries. This makes battery propulsion more suitable for ships that travel only 

over short distances and between predetermined ports, and ferries are a good example of a ship 

that does just that. Ferries mostly carry passengers and Ro-Ro cargo between ports that are 

geographically close to each other, and they have a regular schedule of when they are to be on 

what location. The battery type chosen for maritime propulsion is often lithium-ion batteries, 

as they can be charged quickly, they are cost-effective, they have good safety specifications, 



 

 

 

 

9 
 

they are lighter and more energy dense than some other battery types on the market, which will 

help improve the efficiency of the ship.  

 

The development of fully electric ships is ongoing in several parts of the World, for example, 

Stena Line (n.d.) has a vessel in development that will be entirely free from emissions and fossil 

fuel. ‘Stena Elektra’ is planned to travel between the port of Gothenburg and Frederikshavn 

before the year 2030 and will be able to carry up to 1500 passengers as well as RoRo-cargo. 

 

To operate such a large vessel solely on battery electric propulsion is no small feat, which is 

made obvious when comparing the batteries of road vehicles and those used on ships. Trombetta 

et al (2024) explained that the capacity of a car battery generally is around 60 kWh, and a truck 

has a capacity of 1000 kWh, while a small commuter ferry requires a battery capacity of 4,3 

MWh and a RoRo ferry can require up to 70 MWh worth of battery power. 

 

According to the European Alternative Fuels Observatory (n.d.) there were 125 vessels 

worldwide that were fully electric in the year 2022, and the most common ship type with fully 

electric operation is the car/passenger ferry.  

 

2.4 Maritime Regulations 

The maritime sector is subject to several different conventions and codes which have 

requirements and demands regarding, among others, safety, security, and pollution prevention. 

The requirements differ somewhat depending on the type of ship, the intended operational 

location, and the size of the ship.  

 

Ships are of course subject to those regulations, codes, conventions, and standards, but the 

demands can differ somewhat depending on the trade route, weight, and the type of cargo the 

ship will carry. The requirements that ship face have developed and increased over the years, 

which most commonly happens after the occurrence of incidents or accidents that have shown 

weaknesses in the current system. Two of the most important conventions are the International 

Convention for the Prevention of Pollution from Ships (MARPOL) and the International 

Convention for the Safety of Life at Sea (SOLAS), which covers pollution prevention and safety 

of life respectively. 

 

The SOLAS convention is one of the most prevalent and important conventions in the maritime 

industry and handles every subject that affects the safety and stability of ships (International 

Maritime Organisation, n.d.C). The convention has created and specified standards that are the 

minimum requirements for ships to have regarding their operation, construction, equipment, 

and safety. 

 

The MARPOL convention came about in 1973 and was further improved upon after an increase 

of accidents involving tank ships in around 1977, and it has been further improved upon over 

the years (International Maritime Organisation, n.d.D). The convention covers several different 

types of pollution, but the emission of harmful substances into the sea is the most prevalent 

type of pollution that is to be prevented. Two of the earliest MARPOL annexes covers the 

prevention of oil pollution and the prevention of noxious liquid pollution, which were added in 

1983.  



 

 

 

 

10 
 

 

MARPOL covers measures to ensure the safe operation of ships when it comes to all substances 

that can potentially be emitted into the sea, including both substances that are allowed to be 

emitted and those which are not. Substances that are allowed to be emitted into the ocean shall 

be done so under controlled circumstances and need to be documented properly, and emissions 

that are not allowed, for example oily substances and dangerous chemicals, need to be 

documented meticulously too. The convention also states some demands that need to be 

followed when a ship is constructed, which are meant to prevent harmful substances from 

entering the ocean if an accident would occur. Those construction demands will be used as 

guidelines when it comes to evaluating what areas on a ship are deemed less safe for placement 

of certain things or substances. 

 

The International Maritime Organisation (n.d.A) uses Formal Safety Assessments (FSA) as a 

tool to create new regulations and to develop existing ones, with the goal to further enhance the 

safety, security, and pollution prevention of the maritime industry. This is done by identifying 

potential risks and evaluating them, and to compare the likelihood of an accident and how much 

effort and money would need to be spent to reduce that accident from happening.  

 

A Formal Safety Assessment usually consists of five steps: 

1. Identification of hazards  

What could go wrong? Identify all scenarios and activities which could pose a risk to 

those involved, and then identify what could cause an accident and what could be the 

result. 

2. Assessment of risks 

How bad could something go wrong and how likely is it to happen? Identify what type 

of injury or damage the specific scenario could cause, how dangerous that would be, 

and estimate how frequently such an incident is likely to occur. 

3. Risk control options.  

Can something be done to reduce the risk? Analyse potential factors that could help 

reduce either the severeness of the injury or damage, the frequency of the incident 

occurring, or both. 

4. Cost benefit assessment  

What would a control option cost and how effective would it be? Investigate if the cost 

of implementing the risk reduction measure would be justified by how much it would 

decrease the risk.  

5. Recommendations for decision-making  

What should be done about the hazard? Compile all the previous information in a 

presentable way, this will be the basis for the recommendations in the decision-making 

process. 

 

If the risks assessed in step two are deemed to be too great, the next step investigates if the risk 

can be reduced either by making the accident less frequent or by mitigating the severity of the 

consequences. Those risk control options are then compared to the cost of implementing them 

in step four, and the last step is to come to a conclusion on what should be done about the risk. 

 

2.5 Ship Design Requirements 
In the case of ships that carry oil as cargo, MARPOL requires them to have a double bottom 

and double side hull constructed to protect the cargo oil tanks. The International Maritime 

Organisation (n.d.E) regulation 19 states that the distance between those hulls is to be measured 



 

 

 

 

11 
 

at right angles from the inside surface of the outer hull. They also state in regulation 16 that no 

oil shall be carried forward of the collision bulkhead. 

 

The International Association of Classification Societies (2024) writes that the extent of the 

double bottom hull on oil tankers is to be fitted in such a way that it protects the cargo spaces, 

and thereby gives no specific demands on how far the double hull spaces need to extend along 

the length of the ship, provided that the cargo tanks are protected.  

 

Oil is not only carried as cargo however, as it is also used as fuel for the ship, and it is then 

carried in bunker tanks. Construction of bunker tanks and cargo tanks does not follow the same 

requirements. The International Maritime Organisation (n.d.E) regulation 12A states that 

individual fuel oil tanks cannot carry more than 2500 m3 of fuel, while regulation 26 states that 

cargo oil tanks can carry up to 50.000 m3 of oil, with the actual applicable volume depending 

on the placement of the tank. The smaller tank volume of bunker tanks means that the 

construction distance safety margin is slightly lower than for cargo tanks. The side 

measurements between the hulls are the same for both tank types, namely at least one meter 

and at most two meters, but the distance between bottom of the hulls is different for cargo tanks 

and bunker tanks. The distance must be at least 0.76 meters and at most two meters for bunker 

tanks, and at least one meter and at most two meters for cargo tanks. The hull transitions from 

bottom to side at 1,5 times the distance between the hulls at the bottom. Figure 1 and Table 1 

can be used to get an overview of the distances required and how the affected compartments 

are situated.  

 

 

 Table 1. Double hull distance measurements. 

Tank type Hmin (m) Hmax (m) Wmin (m) Wmax (m) 

Oil cargo tanks 1  2 1 2 

Oil bunker tanks 0,76  2 1 2 
Note: The information in this table is gathered from the ‘MARPOL convention annex I’ by the International 

Maritime Organisation (n.d.E). http://dmr.regs4ships.com/ . This is a compiled list of distance measurements that 

are demanded by MARPOL when constructing a double hull. 

 

 Figure 2. Simplified cross section of a double hulled ship. 

 
Note: Simplified cross section of the cargo hold on a double hulled ship, such as an oil tanker. H signifies the 

distance between the double bottom hulls, and W signifies the distance between the sides of the double hull. 

http://dmr.regs4ships.com/


 

 

 

 

12 
 

The International Maritime Organisation (n.d.F) regulation 12 states that a collision bulkhead 

shall be constructed and extend up to the freeboard deck or the bulkhead deck on cargo ships 

and passenger ships respectively. The collision bulkhead shall not be closer to the forward 

perpendicular than 5% of the ship’s length or 10 meters, whichever distance is smaller. The 

collision bulkhead shall also not be constructed farther from the forward perpendicular than 8% 

of the ship’s length or 5% of the ship’s length plus 3 meters, whichever distance is greater. The 

area that remains between the two distances is the location where it is acceptable to construct 

the collision bulkhead.  

 

The length of the ship used when calculating the distance of the collision bulkhead is the 

distance between the perpendiculars, as defined by the International Maritime Organisation 

(n.d.D) in chapter I regulation 3. The forward and aft perpendiculars are found at each end of 

the ship’s length, which can be defined as the distance along the waterline between the front of 

the stem to the axis of the rudder. This means that the forward perpendicular is at the front of 

the stem where it meets the waterline, and the aft perpendicular is placed along the axis of the 

rudder stock. Figure 3 shows a visualisation of the location of the perpendiculars and the ship’s 

length.   

 

 

 Table 2. Requirements on the construction location of the collision bulkhead. 

 Min Max  

Closest distance 

to forward 

perpendicular 

5% of L 10 meters Choose the 

smaller value 

Furthest 

distance to 

forward 

perpendicular 

8% of L 0.05% of L + 3 

meters 

Choose the 

greater value 

Note: The information in this table is gathered from the SOLAS convention chapter II-I by the International 

Maritime Organisation. (n.d.F). http://dmr.regs4ships.com/  
 

 

 Figure 3. A visualisation of a ship’s perpendiculars and length 

 
 

Note: The distance named L.P.P, or Length Between Perpendiculars is another name for the length of the ship. 

 

The International Association of Classification Societies (2024) state that all ships must have a 

collision bulkhead and an aft peak bulkhead. The aft peak bulkhead should enclose the rudder 

trunk and the stern tube in a watertight compartment, alternative arrangements can however be 

made if the previously stated requirement is too impractical. The previous requirements are also 

expressed by the International Maritime Organisation (n.d.F) in regulation 12.  

 

http://dmr.regs4ships.com/


 

 

 

 

13 
 

The International Association of Classification societies (2024) describes the area forward of 

the collision bulkhead as the fore peak. This area often contains a ballast tank which can be 

filled or emptied depending on the cargo load conditions. There shall also be an afterpeak 

bulkhead fitted, and it is to be located at the aft end of the machinery space, and the aft peak is 

located aft of the aft peak bulkhead. The aft peak often contains a ballast water tank, just as the 

forepeak does.  

 

 Figure 4. Ship overview with collision bulkhead. 

 
Note: A simplified illustration of the collision bulkhead and forepeak area seen from above. The wing spaces 

usually contain ballast tanks. 

 

2.6 Maritime Accidents 

Several different organisations and agencies worldwide record the number of accidents and 

incidents occurring every year, for example the Swedish Transport Agency and the European 

Maritime Safety Agency (EMSA). They present annual overviews of accidents and incidents 

that have occurred in the maritime industry in Sweden and Europe respectively and organise 

the data into statistics. The likelihood of maritime accidents increased with a growing trade, 

and Zhang et al (2019) explain that such events can lead to substantial damage of the 

environment, cargo, and human life as well. The European Maritime Safety Agency (2017) 

states that more than 3000 accidents and incidents are reported to them every year, and that 

some of the most common accident causes are collision, contact, and grounding. 

 

 

 

 

 

 

 

 

 

 

 



 

 

 

 

14 
 

3. METHODS 

The methods used are presented in this chapter. The websites used to gather information, the 

keywords used in the search for sources, and the choice of sources and their reliability will be 

disclosed. The method used for the risk assessment is also presented. 

 

3.1 Overview 

In the search for sources to be used in this report, the databases of Chalmers University library 

and Web of Science were used to find informative and relevant academic articles, and Google 

was used to find publications on statistics, guidelines, and safety matters related to the topics 

of this report. Keywords applicable to the subjects were used in the information search, and 

they evolved as the search process went on, and new words were also added to make the 

searches more specific. Filters were added during the searches to narrow down the results, the 

sources found were checked for relevancy, and those applicable to the topics at hand were 

examined. This procedure was used to find information for both the Theory chapter and the 

Results chapter, however the sources used in the Results chapter faced stricter criteria when 

evaluated, which are explained in chapter 3 section 2.2 and section 3. 

 

3.2 Literary study 

This report was conducted as a systematic literary study. The eBooks The Good Research Guide 

by Martyn Denscombe and Doing Your Literature Review by Jill K. Jesson, Lydia Matheson, 

and Fiona M. Lacey were used as guidelines when writing this report.  

 

Denscombe (2014) explains that a literary study demands a more meticulous investigation into 

sources, and the method used when finding, evaluating, and choosing sources shall be 

transparent and clear. The purpose of a literary review is to examine what previous work has 

been done within a field of research or subject of study, and to come to conclusions based on 

the evidence and research found. A systematic literature review aims at lessening the potential 

bias by informing the readers about how the study and source finding was conducted, and how 

the decision to include or exclude sources was made.  

 

3.2 Method of Searching 

Various sources in the form of academic articles, eBooks, websites, and publications were 

found through several different search engines, websites, and databases. The information found 

was evaluated, compiled, and presented in the Results chapter. All information searches were 

done between the 5th of February and the 5th of May 2024, during the period when this report 

was scheduled.   

 

3.2.1. Search Engines and Databases 

When searching for academic sources relating to the relevant subjects, the databases of 

Chalmers University Library and Web of Science were used. Both databases and their search 

engines, as well as the Regs4Ships website, which is a maritime regulation database, were 

accessed through the Chalmers University Library website. These databases and search engines 



 

 

 

 

15 
 

were determined to be enough, as using more search engines would have made the information 

search too extensive and take too much time for the purpose of this report. 

 

The information search began at the Chalmers University Library as it was familiar to work 

with. In addition to Boolean search operators, the website features six different types of filters 

that can be applied to the search results to find sources with the right subject focus.  

 

Web of Science was used after a recommendation from a librarian at Chalmers University. The 

Web of Science database features sources in the form of academic articles, conference 

proceedings, and book chapters to name a few. In addition to Boolean search operators, this 

search engine and database offers several additional appliable filters that can be used to find 

relevant sources, compared to the Chalmers University Library website. 

 

No search words or phrases were needed when finding SOLAS and MARPOL through the 

Regs4Ships database, as they were easily found at the home page of the website when logged 

in. SOLAS and MARPOL were examined for information on ship design and construction 

requirements. ILLC was found by searching for ‘load lines’ on the website.  

 

Google was also used as a search engine to find sources. The sources found were the websites 

of various agencies, organisations, companies, and institutes, which had relevant information 

on battery vehicles, battery ships, statistics, guidelines and conventions for the maritime 

industry, and similar topics. Jesson et al (2011) explain that these types of sources are known 

as ‘grey literature’, which is any source that is not an academic journal article, such as technical 

reports, reports commissioned by an organisation, policy reports, and these types of sources 

require special care when assessed. These sources will be presented here. 

 

Det Norske Veritas: A maritime classification society and a member of the International 

Association of Classification Societies. 

European Environment Agency: An agency of the European Union with the purpose of 

collecting, validating, and delivering data and knowledge that is used to support climate and 

environmental goals in Europe. The European Union uses this data to create new policies or 

develop existing ones.  

European Maritime Safety Agency: A decentralised agency of the European Union located 

in Portugal. Their purpose is to provide information and guidance to governments and 

authorities with the goal of improving maritime safety and security, and to prevent various 

forms of pollution from the maritime industry.  

Eurostat: The statistical office of the European Union with the purpose of providing the union 

with high quality data and statistics on Europe.  

International Association of Classification Societies: An organisation consisting of 

recognised classification societies with the goal of regulating and improving ship construction, 

safety, pollution prevention, and maintenance. They provide technical and operational expertise 

to regulatory bodies and the maritime industry, with standards that are globally uniform. The 

organisation is a technical advisor to the IMO. 



 

 

 

 

16 
 

International Maritime Organisation: A specialised agency within the European Union 

which regulates safety, security, and pollution prevention of the maritime industry in several 

different ways, such as ship construction, equipment, operation, and disposal. The rules they 

create are universal for all member nations, and make sure that ship owners and others cannot 

compromise on safety, security, or pollution prevention to save on costs.  

Massachusetts Institute of Technology Climate Portal: A website founded by Massachusetts 

Institute of Technology with the goal of providing people with science-based information about 

climate change, its causes, consequences, and what can be done and is being done about it.  

Nordregio: A Nordic research institute founded by the Nordic Council of Ministers. It is 

included among the research entities of the Statistical Office of the European Union and 

conducts research on, for example, regional development, urban planning, and other projects 

that can face environmental, economic, and social challenges. 

RISE Research Institute of Sweden: A research institute founded and owned by the Swedish 

government. Their goal is to contribute to the innovative development of society, and that they 

are to do so by conducting high-quality research, encourage cooperation between the academic 

sector and the trade and business industry. The organisation consists of researchers, scientists, 

and experts in various fields of innovation.  

Swedish Transport Agency: An agency of the Swedish government that handles for example 

regulations, permits, and supervision of all things concerning the transport sector. Their work 

covers all types of transportation, including railroads, air travel, and shipping.  

U.S. Department of Energy: A department within the federal government with the mission to 

address energy, environmental, and nuclear challenges in America through transformative 

solutions of science and technology.  

  

3.2.2 Search Process 

Broad keywords and search phrases were used in the beginning of the information search 

process to get an overview of the topics, and the process of finding interesting sources made 

the search terms and words evolve and become more specific. The new keywords were added 

to the existing ones to narrow down the search results. When conducting the information search, 

the subject of the report was divided into two main branches to streamline the process, the 

branches were Ship design and accidents statistics and Battery design and damage statistics. 

The keywords and phrases used were:  

 

General keywords: Ship, Battery, Safety, Propulsion, Electric, Collision, Vehicle, Accident 

Specific keywords: Mechanical abuse, Double hull, Maritime industry, Statistics, Lithium-ion, 

Deformation, Thermal runaway, 

Additional keywords (used as filters): Marine accidents, Double hull, Lithium-ion battery, 

Mechanical abuse, Battery protection, 

 

Multiple keywords were used at the same time in various combinations, along with Boolean 

search operators. Filters in different forms were then added to the search terms to further narrow 

down the search results, the filters used were as follows: 

- Year of publication. The publication time span was limited to the years 2015-2024. This 

was because the development of electric vehicles and ships has progressed quickly 



 

 

 

 

17 
 

within the last decade, and older results were estimated to be less relevant than more 

contemporary publications. The timespan of the sources was therefore limited to within 

ten years from this report being written.  

- Type of source. The source types were limited to academic articles or journals. 

- Peer review. When looking specifically for academic articles, the Peer Review filter 

was added to find more credible sources.  

- Additional keywords. This applies both to the Chalmers University Library search 

engine and to the Web of Science search engine, but they differ somewhat in their 

design. In Web of Science, additional keywords appeared after conducting a search. The 

search operator of those added keywords could be changed to ‘should include’ and 

‘must include’, or ‘do not include’ to further narrow down the results. The Chalmers 

University Library has a drop-down menu where additional subjects can be added as a 

filter to the original search words or phrase.  

 

 Table 3. The search process of the information search when using the keywords “Ship 

AND Damage AND Statistics”, and how they were narrowed down using search filters. 

The result from Chalmers University Library is presented on the left, and Web of Science 

on the right. 

 

Note: When the sources had been narrowed down to the second to last step of the ones shown above (N = 103 

and N = 64), the titles of all the results were read, and if the article appeared to be relevant, the abstract was also 

read. The last step shows how many of the articles were included as sources in the final report. 

 



 

 

 

 

18 
 

The title and the abstract of the articles were read first to discern the relevancy of the source. 

Those articles regarded as having high relevancy were further investigated by reading the 

introduction and conclusion, to determine if the source was applicable to this report (Jesson et 

al, 2011, p 115). The articles found to be relevant were scanned in their entirety and browsed 

for important data to include in the report, and the source was added to the bibliography. This 

process was repeated for both Chalmers library and Web of Science for each combination of 

search words used. 

 

When using Google to find sources, the process was different. Search phrases were constructed 

using the some of the keywords as stated above in section 3.2.2, but without using Boolean 

search operators and instead using prepositions to formulate a coherent search phrase. The 

inclusion criteria the sources faced were a publication year between 2015-2024, they had to be 

written in Swedish or English, and they had to be published by reputable agencies, 

organisations, or institutes.  

 

3.3 Evaluation of Sources 

The sources used in this report were evaluated according to the CRAAP test (Library Guide at 

the University of Chicago) to investigate the relevance, currentness, accuracy, and potential 

bias of the information found. Some of the search filters described in section 3.2.2 were used 

to find sources with high relevancy and accuracy, for example by finding recent articles that 

have been peer reviewed. The publishing date of the sources was deemed to be an important 

criterion to meet to ensure that the results found were contemporary, as older articles and 

publications may contain information that is no longer relevant or accurate. Furthermore, the 

articles being peer reviewed was an important criterion as well, since their quality is 

investigated more meticulously by other experts within the field before being published. The 

academic articles that were found and had been published in magazines were checked for 

quality by using UlrichsWeb to determine whether that magazine practices peer review of the 

articles they publish. Sources that were deemed too advanced for the purpose of this report were 

scanned but not included, and the sources of the articles could be investigated further if it 

appeared that they could be relevant. 

 

Sources that were not academic articles were evaluated using the CRAAP test as well, and 

special care was taken to investigate the organisation, institute, or agency that had published 

the source. Their connection to other reputable and official bodies was examined to ensure the 

credibility and relevance of their publication. The authors of these types of sources are 

presented in chapter 3 section 2.1 – Search Engines and Databases of this report. 

 

3.4 Results of the Information Search 

As the information search went along, some issues arose along the way. Many of the potential 

sources found were too advanced for the purpose of this report, as they utilized advanced 

mathematical models, and many of them were not applicable to this report, as they did not 

utilize simulations or statistics. Finding sources about distribution of different accident types 

within a certain number of reported maritime accidents was straightforward, while finding 

reliable statistics on the number of accidents occurring in relation to the total amount of ship 

movements within an area proved to be more difficult. It was also difficult to find exact and 



 

 

 

 

19 
 

definitive answers regarding the deformation limits of batteries, as there are many factors that 

play a part in how a battery deforms.  

 

It was also challenging to find information on collision safety of the fully electric ships that 

already exist, as they are quite few, have not been operating for very long, and they seem to not 

have been involved in any accidents. 

 

Some of the sources used could be found through both the Chalmers University Library 

database and Web of Science, and if those sources had either been included or already been 

investigated and deemed to be irrelevant or unsuitable, they were swiftly disregarded during 

the other searches when they appeared. Some sources were found by examining the sources of 

the articles and publications found through the search engines and databases.  

 

3.5 Risk Assessment 
The risk assessment in this report is based on the steps of IMO’s Formal Safety Assessment 

mentioned in chapter 2.4 Maritime Regulations. However, there is two major and three minor 

changes to the approach of the risk assessment in this work, compared to the original 

procedure presented by the International Maritime Organisation (n.d.A). The changes are as 

follows: 

 

Major changes 

1. Step number four, which covers the cost benefit assessment, is excluded from this 

report. This is due to one of the delimitations stated in chapter one, namely that 

economical standpoints are not to be considered in any way in this report.  

2. The table used to determine the frequency of a scenario occurring is altered to be 

applicable to only one ship, instead of the fleet of ships that is normally used. The 

frequency is calculated in “per port call” instead of “per ship year”. 

 

Minor changes 

1. Step number one is shortened, as there is a finite number of scenarios that are 

identified and considered in this report, meaning that not all scenarios and activities 

that could pose a risk are identified.  

2. The effect on human safety is not considered and evaluated for a severity index, only 

the effects on the ship.  

3. The table used to determine the severity of an accident will have additional 

descriptions of ship damage added to the existing ones, to better present the damages 

expected on the different levels. 

 

Methods that can be used while performing a risk analysis include using accident and failure 

data (International Maritime Organisation, 2018), which is the basis for the analysis and 

assessment in this report. Statistical data and simulation data on maritime accidents is presented 

in the Results chapter, and the findings are synthesized into numbers that are used when 

performing the risk analysis. The outcome of the results is discussed in the Discussion chapter, 

where Appendix number 4 in the document created by the International Maritime Organisation 

(2018) is used in combination with the results to evaluate the risks by determining the frequency 

and severity of an accident. Statistics on the number, nature, and distribution of accident types 

is used to evaluate the likelihood of a ship being damaged, and the statistics and simulation data 



 

 

 

 

20 
 

on the extent of hull damage is used to evaluate the severity of the accident. The statistics and 

simulation data on the location and extent of damage on a ship’s hull is used to evaluate where 

batteries face higher risk of deformation, and what locations would be better suited to contain 

batteries.  

 

3.6 Ethics of the Information Search 

As there is no data collected from individuals during this study, there is no need to gain anyone’s 

consent on data collection or personal information being published. Ethics regarding consent 

of participants is important, but it is not applicable in this report. In a systematic review it is 

instead important to ensure that the data collected is truthful and not interpreted in an inaccurate 

way. The data collected should also be quality checked to ensure that the source or its authors 

are not biased or skewing the results, which was done by confirming that the articles had been 

peer reviewed. When it comes to grey literature, that becomes more difficult, as the sources are 

often written and published by governmental agencies or similar organisations that are not fact 

checked to the same extent. In such situations the publisher and their purpose were investigated, 

as well as their relationship to other organisations that are highly esteemed within the industry. 

The information found was gathered and compiled in a structured way, but no information from 

the sources were changed to fit into a predetermined narrative, which would rid the report of its 

credibility.  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 



 

 

 

 

21 
 

4. RESULTS 

The results found in the information search is presented, and the statistical and simulation 

numbers are synthesised in preparation for use in the discussion chapter. 

 

4.1 Overview of Results 
This section gives and overview of the sources and results found in the information search. The 

total number of sources used in the results chapter is 20. 

 

 Table 4. Categorisation and numbers of sources found. 

Subject Number of sources 

Deformation of batteries 7 

Electric Vehicle safety 2 

Maritime accident statistics 6 

Hull damage extent 3 

Batteries onboard ships 2 
Note: This table displays the numbers of sources found within each type of subject. A more detailed table on the 

sources can be found in appendix 1. 

 

4.2 Number and Nature of Maritime Accidents – Statistics 
Many different organisations and agencies keep a record over maritime accidents and incidents, 

for example the Swedish Transport Agency, EMSA, and IMO. The scope they cover are 

different and can overlap, for example because EMSA covers accidents in Europe and European 

ships all over the world, and the numbers recorded by the Swedish Transport Agency is 

naturally a part of those accidents recorded by EMSA.  

 

4.2.1 Recorded Number of Accidents and Incidents 
Eurostat (2023) compiles statistics on the maritime industry for the benefit of the European 

Union, covering things such as the weight of seaborne freight, what type of cargo that is 

handled, and the import and export ratio of the freight for each country of the union. One part 

of their statistics is also the number of port calls that has been made by vessels in main ports in 

Europe during each year. They found that approximately 2 million port calls are made in main 

European ports every year. The documented total number of port calls made each for each year 

between 2018-2022 can be found in table 5. The actual number of port calls in Europe is much 

higher however, as main ports are defined as ports that handle more than one million tonnes of 

goods or 200.000 passengers every year.  

 

 

 Table 5. The number of port calls made in main European ports. 

Year 2018 2019 2020 2021 2022 Average 

Port 

calls 

2.189.422 2.278.469 1.944.030 1.993.617 2.232.354 2.127.578,4 

Note: The information in this table is gathered from table 2 in the publication “Maritime Freight and Vessel 

Statistics” by Eurostat (2023, December 13). https://ec.europa.eu/eurostat/statistics-

explained/index.php?title=Maritime_ports_freight_and_passenger_statistics&oldid=218671  

Main ports are defined as ports that handle more than one million tonnes of goods or 200.00 passengers every 

year, which means that not all port calls in Europe are recorded here. 

 

During the same period, 2018-2022, the European Maritime Safety Agency (2023, October 27) 

recorded a combined average of 800 serious and very serious marine casualties. These two 

https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Maritime_ports_freight_and_passenger_statistics&oldid=218671
https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Maritime_ports_freight_and_passenger_statistics&oldid=218671


 

 

 

 

22 
 

types of categorisations cover ships that have sustained damage that results in severe structural 

damage, like the hull being ruptured under the waterline, or even the loss of the ship, as a 

consequence of for example collision, grounding, or contact, to name a few.  

 

 Table 6. The number of marine casualties recorded by EMSA in 2018-2022. 

 2018 2019 2020 2021 2022 Average 

Serious 

casualties 

824  759 724 747 612 733,2 

Very 

serious 

casualties 

106 75 51 58 44 66,8 

Total 

casualties 

2669 2782 2594 2692 2510 2649,4 

Combined 

percentage 

of casualties 

34,8% 29,9% 29,8% 29,9% 26,1% 30,2% 

Note: The information in this table is gathered from the publication “Annual Overview of Marine Casualties and 

Incidents 2023” by the European Maritime Safety Agency (2023, October 27). 

https://www.emsa.europa.eu/publications/reports/item/5052-annual-overview-of-marine-casualties-and-

incidents.html 

Only the serious and very serious marine casualties from the publication are featured in this table. 

 

The Swedish Transport Agency (2023) compiles and publishes safety overview reports 

concerning the maritime industry each year, which features statistics of accidents reported to 

the agency. They have noticed a recent increase in the number of reported accidents and 

incidents, but still believe that the number of unreported incidents is high. Between the years 

2018-2022 there was on average 9,4 marine accidents per 10.000 port calls in Sweden. The 

yearly reported accidents and incidents during the period 2018-20222 are shown in table 7. 

 

 Table 7. Accidents and incidents reported per 10.000 port calls in Sweden 2018-2022. 

Type of 

occurrence 

2018 2019 2020 2021 2022 Average 

Marine 

accident 

8 7,5 9,1 13,3 9,1 9,4 

Marine 

incident 

3 4,5 8,1 7,5 12,9 7,2 

Note: The information in this table is gathered from the publication “Säkerhetsöversikt sjöfart 2022” by the 

Swedish Transport Agency (2023, May 29). https://www.transportstyrelsen.se/sv/publikationer-och-

rapporter/rapporter/sjofart/sakerhetsoversikt-sjofart-2022/ . 

 Marine accident signifies the number of actual accidents that has happened, and marine incident 

signifies the number of occurrences that could have turned into accidents if they had not been avoided. 

 

Sormunen et al (2016) conducted a study on maritime accidents in the Baltic Sea, examining 

the most common accident types and their causes, as well as how many port calls were made 

in Baltic ports. They found that more than 450.000 port calls were made in Baltic ports each 

year, based on statistics from Eurostat combined with estimations on port visits in Russia. The 

results are shown in table 8. 

 

 

 

 

https://www.emsa.europa.eu/publications/reports/item/5052-annual-overview-of-marine-casualties-and-incidents.html
https://www.emsa.europa.eu/publications/reports/item/5052-annual-overview-of-marine-casualties-and-incidents.html
https://www.transportstyrelsen.se/sv/publikationer-och-rapporter/rapporter/sjofart/sakerhetsoversikt-sjofart-2022/
https://www.transportstyrelsen.se/sv/publikationer-och-rapporter/rapporter/sjofart/sakerhetsoversikt-sjofart-2022/


 

 

 

 

23 
 

 Table 8. The total number of port calls in Baltic ports between 2006-2011. 

 2006 2007 2008 2009 2010 2011 Average 

Total 

number 

of port 

calls 

475.319 489.767 505.178 470.169 468.234 475.119 480.631 

Note: The information in this table is gathered from the article “Marine traffic, accidents, and underreporting in 

the Baltic Sea” by Sormunen, O.V.E., Hänninen, M., & Kujala, P. (2016). Scientific Journals of the Maritime 

University of Szczecin, 118(46), 163-177. https://repository.am.szczecin.pl/handle/123456789/1224 

 

Sormunen et al (2016) also found that that the most common accidents reported in the Baltic 

Sea during the period 2006-2011 was grounding, contact, and collision, the numbers are 

presented in table 9. Nevertheless, they estimate that the actual number of accidents in the area 

is much higher, and that the real number or accidents are at least double the number of recorded 

accidents.  

 

 Table 9. Accidents reported in the Baltic Sea during 2006-2011. 

 Collision Contact Grounding Total number 

of accidents 

Number of 

accidents 

92 122 236 653 

Percentage 14,1% 18,7% 36,1% 100% 
Note: The information in this table is gathered from the article “Marine traffic, accidents, and underreporting in 

the Baltic Sea” by Sormunen, O.V.E., Hänninen, M., & Kujala, P. (2016). Scientific Journals of the Maritime 

University of Szczecin, 118(46), 163-177. https://repository.am.szczecin.pl/handle/123456789/1224 

 

4.2.2 Accident Location Type 
When it comes to the type of waters navigated as the accident took place, the Swedish Transport 

Agency (2023) found that they most commonly occur close to shore or ports. Accidents in port 

areas account for one in four occurrence locations and is therefore the most common accident 

location. Even so, the numbers have gone down compared to the previous year (2021), when 

the port area accounted for 38% of all accident locations in Swedish waters. The distribution of 

the accident locations is displayed in table 10.  

 

 Table 10. Distribution of marine accidents based on type of location. 

Type of water navigated Percentage of marine accidents 

Port area 25% 

Cramped coastal waters 19% 

Coastal waters close to shore 12% 

At berth, dock, etc.  11% 

Channel, river, shipping lane marked with 

buoys 

7% 

Lakes 5% 

Open coastal waters 4% 

Open ocean 3% 

Unknown 14% 
Note: The information in this table is gathered from the publication “Säkerhetsöversikt sjöfart 2022” by the 

Swedish Transport Agency (2023, May 29). https://www.transportstyrelsen.se/sv/publikationer-och-

rapporter/rapporter/sjofart/sakerhetsoversikt-sjofart-2022/  

The areas close to shore, ports, and shipping lanes represent the majority of the areas where maritime accidents 

occur. 

https://repository.am.szczecin.pl/handle/123456789/1224
https://repository.am.szczecin.pl/handle/123456789/1224
https://www.transportstyrelsen.se/sv/publikationer-och-rapporter/rapporter/sjofart/sakerhetsoversikt-sjofart-2022/
https://www.transportstyrelsen.se/sv/publikationer-och-rapporter/rapporter/sjofart/sakerhetsoversikt-sjofart-2022/


 

 

 

 

24 
 

The statistics from table 10 illustrates the findings of the Swedish Transport Agency (2023), 

and they further theorise that accidents occurring in regions close to shore are more likely to be 

reported, as there are more people and ships in the surrounding area that can observe the 

accident and report it. Regarding accident locations Antão et al (2023) mention that ships that 

have a higher number of port calls are at a higher risk of collision since doing coastal navigation 

makes them exposed to high traffic more frequently.  

 

The accident and incident locations that the European Maritime Safety Agency (2023, October 

27) recorded during the years 2014-2022 shows that the trend of a higher number of accidents 

and incidents occurring in port areas compared to other locations is a trend that not only applies 

to Sweden. They recorded that 51,5% of the casualties reported during that period had occurred 

in inland waters, out of which 39.6% were in port areas. This is comparable to the 38% of 

accidents that the Swedish Transport Agency (2023) recorded to have happened in port areas 

in Sweden during the year 2021. 

 

4.2.3 Distribution of Accident Types 
There are many different types of maritime accidents and incidents that can occur, but those 

that are more likely to result in hull damage are collision, contact and grounding. The European 

Maritime Safety Agency (2023, October 27) defines a collision as an event where one ship is 

striking or being struck by another ship, a contact event is when a ship strikes any external 

object that is not another ship or the ground (for example a berth, floating obstacle, or a man 

made structure) and grounding is an event where a navigating ship strikes the sea bottom, 

underwater wrecks, or the shore.  

 

The records kept by the Swedish Transport Agency (2023) on accident events show that those 

types of occurrences on average account for 42% of the initial events of all accidents reported. 

This means that collision, contact, and grounding events as a consequence of some other initial 

occurrences are not recorded in that percentage. The number of accidents for the period 2018-

2022 can be seen in table 11 below. 

 

 Table 11. Relevant accidents compared to all the reported accidents each year. 

Type of 

accident 

2018 (%) 2019 (%) 2020 (%) 2021 (%) 2022 (%) Average 

Collision with 

foreign object 

18  

(10%) 

18  

(12%) 

24 

(13,1%) 

32 

(14,7%) 

41 

(20,1%) 

26,6 

(14,3%) 

Collision with 

other ship 

19  

(10,5%) 

16 

(10,9%) 

25 

(13,6%) 

26  

(12%) 

20 

(9,8%) 

21,2 

(11,4%) 

Grounding 

impact 

33  

(18%) 

31 (21%) 32 

(17,5%) 

31 

(14,3%) 

25 

(12,3%) 

30,4 

(16,3%) 

Total number 

of accidents 

each year 

180 147 183 217 204 186,2 

Note: The information in this table is gathered from the publication “Säkerhetsöversikt sjöfart 2022” by the 

Swedish Transport Agency (2023, May 29). https://www.transportstyrelsen.se/sv/publikationer-och-

rapporter/rapporter/sjofart/sakerhetsoversikt-sjofart-2022/.  

 These numbers only represent the initial accident occurrence, meaning that collisions due to other 

causing factors, for example loss of steering, are not included. It is important to note that the collisions registered 

between ships is registered once per ship, not once per occurrence. The results from the publication by the 

Swedish Transport Agency (2023) that were not relevant to this report have been excluded from the table.  

 

https://www.transportstyrelsen.se/sv/publikationer-och-rapporter/rapporter/sjofart/sakerhetsoversikt-sjofart-2022/
https://www.transportstyrelsen.se/sv/publikationer-och-rapporter/rapporter/sjofart/sakerhetsoversikt-sjofart-2022/


 

 

 

 

25 
 

The Swedish Transport Agency (2023) points out that the collisions recorded by them is 

registered once per ship involved in the collision, not per instance of a collision occurring.  

 

EMSA also keep records of reported accidents and incidents, and their statistics for the same 

period can be seen in table 12 (European Maritime Safety Agency, 2023, October 27). They 

found that the casualty event ‘Collision’ has been surpassed by ‘Loss of propulsion power’ in 

recent years, breaking the trend of the previous years. The number of ‘Contact’ occurrences has 

remained stable, and the number of ‘Grounding’ occurrences has been decreasing slightly.  

 

 Table 12. Collision, grounding, and contact accidents recorded by EMSA 2018-2022. 

 2018 2019 2020 2021 2022 Average 

Collision 494 

(21,9%) 

564 

(23,1%) 

370 

(16,8%) 

441 

(18,9%) 

383 

(17,4%) 

450,4 

(19,7%) 

Contact 323 

(14,3%) 

343 

(14,1%) 

328 

(14,9%) 

344 

(14,7%) 

323 

(14,7%) 

332,2 

(14,5%) 

Grounding 266 

(11,8%) 

243 (10%) 229 

(10,4%) 

251 

(10,7%) 

207 

(9,4%) 

239,2 

(10,5%) 

Total 

number of 

occurrences 

2255 2440  2196 2332 2198 2284,2 

Note: The information in this table is gathered from the publication “Annual Overview of Marine Casualties and 

Incidents 2023” by the European Maritime Safety Agency (2023, October 27). 

https://www.emsa.europa.eu/publications/reports/item/5052-annual-overview-of-marine-casualties-and-

incidents.html 

 

Antão et al (2023) investigated the distribution of accident types within a sample collected from 

the accidents reported to the IMO between the years 2005-2017 and found that collision was 

the most common accident type, and that grounding accidents came in second place. Contact 

was the eighth most common accident type within the sample. The results are presented in table 

13.  

 

 Table 13. Distribution of the relevant accident types reported to the IMO 2005-2017.  

Type of accident Number of accidents Percentage of accidents 

Collision 936 19,7% 

Grounding 768 16,2% 

Contact 251 5,3% 

Other 2797 58,9% 
Note: The information in this table is gathered from the article “Quantitative Assessment of Ship Collision Risk 

Influencing Factors from Worldwide Accident and Fleet Data” by Antão, P., Sun, S., Teixeira, A.P., & Guedes 

Soares, C. (2023). Reliability Engineering & System Safety. Volume 234. 

https://doi.org/10.1016/j.ress.2023.109166   

 The total number of accidents in the sample is N = 4752. The accident scenario statistics from the 

article by Antão et al. (2023) that were not relevant to this report have been excluded from the table.  

 

Endrina et al (2018) conducted a report concerning risk analyses of RoPax ships in the Strait of 

Gibraltar. The estimated number of ship movements in the area is 110.000 per year, out of 

which approximately 33% is made by RoPax ships. When doing the frequency analysis, they 

made calculations based on both frequency per ship year and frequency per ship movement. 

They argue that it is more suitable to calculate the frequency based on ship movements, as ships 

that complete a larger number of journeys face a greater risk of being involved in an accident. 

 

https://www.emsa.europa.eu/publications/reports/item/5052-annual-overview-of-marine-casualties-and-incidents.html
https://www.emsa.europa.eu/publications/reports/item/5052-annual-overview-of-marine-casualties-and-incidents.html
https://doi.org/10.1016/j.ress.2023.109166


 

 

 

 

26 
 

The actual values that Endrina et al (2018) used when carrying out the frequency analysis of 

different scenarios, as well as the results thereof, are presented below in table 14. The 

calculations are based on the number of ship movements in the Strait of Gibraltar between the 

years of 2000-2011, when 1.170.120 movements were recorded in total. Those statistics were 

provided to the authors by the Spanish Maritime Safety Agency. Out of the total number of ship 

movements, 383.213 of them were estimated to have been made by RoPax ships. Endrina et al 

(2018) found that the RoPax ships are statistically more likely to be involved in a ship collision 

than other types of vessels, which can be seen on the right side of table 14. 

 

 Table 14. Overview of accident frequency analysis results. 

 Ship type All Ships (including RoPax ships) 

Accidents Number Frequency 

Accident type   

Collision 14  1,2 x 10-5 

Grounding 9 7,7 x 10-6  

Contact 6 5,13 x 10-6 

Note: The information in this table is gathered from the article “Risk Analysis of RoPax vessels: A Case of 

Study for the Strait of Gibraltar” by Endrina, N., Rasero, J.C., & Konovessis, D. (2018). Ocean Engineering. 

Volume 151. 141-151. https://doi.org/10.1016/j.oceaneng.2018.01.038  

 The total number of ship movements during the period was N = 1.170.120.  

 The results from the report by Endrina et al. (2018) that were not relevant to this report have been 

excluded from the table.  

 

Antão et al. (2023) writes that the growing fleet of the maritime industry will increase ship 

traffic, and in doing so the probability of ship collisions is also likely to increase. They found 

statistics from the IMO that approximately 20% of all accidents reported to them are ship 

collisions.  

 

4.3 Statistics and Simulations on Ship Damage 
When collisions, contact, or grounding occurs, there will be damage done to the ship or ships 

involved. The amount of damage sustained by the parties can vary greatly depending on ship 

speed, the area of the ship that is struck, and if the ship strikes something or is being struck.  

Pilatis et al. (2024) conducted a statistical analysis of world-wide ship casualties between the 

years of 1990 and 2020. They reviewed more than a thousand casualty reports to create a sample 

of 213 casualties involving collision, grounding, and structural failure. The information of the 

marine accidents was compiled to give an indication of which