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1 INTRODUCTION

The International Maritime Organization (IMO) aims

to ameliorate human element management in the

shipping industry. The empirical evidence and

accident data point towards the impact of human error

in maritime accidents and most shipping failures,

including collisions, allisions and groundings. An

analysis of accident data from Australia, Canada,

Norway, and the UK revealed that despite the overall

reduction of maritime accidents, human error

remained the main reason behind them in up to 80-85%

of all cases, or even 96% [2, 3]. Likewise, the Japan P&I

Club considers human error as the primary factor in

84% of 1,390 cases of maritime accidents [4], regardless

of advances in marine technology contributing to

reducing the frequency and severity of marine

accidents [5].

This paper aims to assess the current and future

technology used for navigational purposes, the

advantages and disadvantages of autonomous vessels,

and the importance of the human element in future

navigational technology and reach conclusions

regarding our proximity to the era of industry-wide

autonomous navigation.

2 NAVIGATIONAL TECHNOLOGIES: BRIDGE

INSTRUMENTS

2.1 The Radar

The name "Radio Detection & Ranging" (RADAR)

comes from the initials of the English phrase RADAR.

This means "detection and range of electromagnetic

waves". As the name suggests, the operation of radar is

based on electromagnetic waves, and according to Gao

et al. (2022), in particular, the distance determination is

based on a time measurement from the point when the

electromagnetic wave pulse is emitted to the returning

echo, the waves ultimately representing the detectable

object) [6]. Also, the Radar uses a rotating antenna to

determine the direction it emits and emits pulses of

A Theoretical Analysis of Contemporary Vessel

Navigational Systems: Assessing the Future Role of the

Human Element for Unmanned Vessels

D. Polemis

, E.F. Darousos

& M. Boviatsis

University of Piraeus, Piraeus, Greece

World Maritime University, Malmoe, Sweden

ABSTRACT: This article aims to investigate the contemporary challenges of electronic navigation and assess the

appropriate amendments should autonomous vessel technology becomes widespread in the near future. Vessel

control systems and maritime communication are essential and sending and receiving alarm signals is critical to

contemporary ship navigation. Numerous location and shipping information systems, such as GPS, Loran-C, and

Decca, have arisen in recent decades to improve navigational safety. Other systems, including VHF and Inmarsat,

have been developed to enhance the efficiency of maritime communication on board and to transmit risk and

safety-related data. Additionally, safe navigation requires systems like Navtex, EGS, DSC, Epirb, and others [1].

http://www.transnav.eu

the International Journal

on Marine Navigation

and Safety of Sea Transportation

Volume 16

Number 4

December 2022

DOI: 10.12716/1001.16.04.05

638

electromagnetic waves in the form of a beam of light. It

also receives an echo back to it [7].

Today, depending on their use, the main types of

radars relevant to the shipping industry are as follows

[8]:

− Surface detection radar or navigation

− Air detection radar

− Meteorological radars

− Fire control radar

− Radar speed measurement

2.1.1 Surface detection radar or navigation

Surface detection radars or navigation radars are

installed on the coast or on vessels to detect the surface

of the sea. However, they can also detect airspace, but

at minimal heights. Instead, they detect solid objects

from relatively conductive material at sea level or low

altitudes and provide accurate information about the

distance and view of the target they locate. Precise

detection is possible regardless of the visibility

conditions and at distances more significant than the

visible horizon [9].

2.1.2 Air detection radar

Placed on the ground (near mountain peaks or

airfields) and boats, they explore long-distance and

high-altitude airspace. The air detection radar ensures

air traffic control to ensure the direction of the aircraft

and the detection of enemy aircraft from long

distances.

2.1.3 Meteorological radars

These weather radars ensure the timely detection

and monitoring of upcoming storms and cyclones.

2.1.4 Fire control radar

Part of various weapon systems, they provide the

necessary launch elements and even corrective

elements for the direction of certain types of remote-

controlled projectiles.

2.1.5 Radar speed measurement

Used to accurately measure the speed of ships in sea

areas where speed limits apply [10].

3 THE AUTOMATIC RADAR PLOTTING AID

(ARPA) AND GYROSCOPIC COMPASS

3.1 The ARPA System

Obligations in Article 7(b) and other relevant

provisions of the International Collision Avoidance

Code refer to the observation of targets on a bridge

deck or further corresponding systematic observation,

performed via an automated printing system called

automatic radar protection equipment (ARPA) [11, 12].

Current technology, especially in cases of multiple

targets and situations of limited visibility, can lead to

limited monitoring, an issue expected to be solved

through ARPA. Many targets are accomplished with

the help of the Automatic Radar Plotting Aid (ARPA),

including reducing the minimum effort required to

obtain more target information displayed on the radar

screen. Also, the ability to evaluate situations

accurately and continuously as the ARPA

microcomputer equipment receives information on the

target area and line of sight for radar equipment. Plus,

the course and speed of the nearing vessels vessel are

combined for sublimation, specifically the Closest

Point of Approach (CPA) and the Time of the Closest

Point of Approach (TCPA) in which the target will

pass, giving the navigators the target's direction and

speed the direction and speed of the target. The ARPA

range is 16 nautical miles [13, 14].

3.2 The Gyroscopic Compass

The gyroscope is an instrument rotating around an

axis, passing through its centre. Solids are rotary and

symmetrical around this axis. Initially conceived by

Foucault in 1851) and with the first gyroscopic compass

constructed in 1908, the gyroscopic inertia proves that

the Earth revolves around its axis [15].

Regardless of its specific subtype, each

contemporary gyroscope requires frictionless action

for one or two gyroscopic flywheels that are part of a

three-phase motor. In addition, of course, the engine

must have a unique power supply to rotate. A suitable

control system is also necessary so that their axis of

rotation or the component of the axis of rotation of a

gyroscope or two gyroscopes looks for the meridian

direction of the site. Finally, there must be a sufficient

power transmission system, which the instructions of

the wind turbine of the main compass to be electrically

transmitted to their wind turbines repeatedly via an

electrical supply [16].

3.3 Free gyroscope and its properties

A free gyroscope consists of a torsional mass, most of

which is distributed on its periphery and is thin and

balanced. The clamp has 3 degrees of freedom; that is,

it can move three axes freely around its axis of rotation,

the horizontal axis and the vertical axis. This is

achieved by using the correct suspension. When the

free gyroscope rotates around its axis, the gyroscopic

inertia and transition are received, with the former

being the free gyroscope that retains its properties. The

transition is the property of the gyroscope. As a result,

if a particular force is applied to the free gyroscope, a

specific force will cause the axis of rotation of the

moving gyroscope. Thus, the free gyroscope will

become a controlled gyroscope, free for a short time yet

controlled upon using the compasses. There are two

methods for the free gyroscope to turn the Compass

gyroscope: The Sperry method, with a northern part of

the gyroscope and the Anschutz method, with weight

at the bottom of a system of two round flywheels [17].

3.4 Gyroscopic compass errors

A regular series of inspections are needed to avoid

multiple errors associated with the gyroscopic

compass, including the (a) error of navigation,

direction, and velocity, (b) depreciation error, (c)

ballistic diversion error and (d) ship wall fault. The

inspections include comparison with magnetic

compass indications at least daily and checking the

accuracy of the observations on the ground objects or

celestial bodies [16].

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4 THE RADIOGONIOMETER

4.1 Radiogoniometer properties

A Radio Direction Finder direction detector (RDF) is

the oldest radio navigation aid used to identify the

address of the station to which the received

transmission was sent to the receiver of the device's

signal. The basic principle of operation of a

radiogoniometer is based on its antenna characteristics,

providing the receiver with a variable power signal

depending on the direction from which the signal

reaches the transmitter. The simplest radiogoniometer

antenna is a simple loop or frame antenna, which may

have a circular shape, rectangle, triangle, etc. [18].

4.2 Radiogoniometer errors

Under ideal viewing conditions, the radiogoniometer

can be highly accurate. However, this is often not the

case. Indicatively, when the recipient determines the

address from which he receives the transmitter’s signal

(beacon, ship, etc.), it is usually not the same as the

corresponding signal. This difference is due to several

factors affecting radio wave propagation and

producing deviations from their regular route. These

factors contribute to various errors in the

radiogoniometer. They are errors due to meridians,

polarities or nocturnal effects, coastal refraction or its

effects due to ship bugs and square error, semicircle

error, total error and radiogoniometer calibration [19].

5 THE AUTOMATIC RUDDER

5.1 Automatic rudder

Autopilot is an advanced electromechanical and

electronic system. It is connected to the gyroscopic

transmission system through ship repeaters to know

that the ship deviates from its steady course, and with

a turn of the rudder blade, the vessel may return to its

course. An alternative automatic rudder also exists,

which uses separate magnets and a compass to

automatically follow the correct route in case of a

vessel’s gyroscopic compass failure [20].

5.2 Automatic rudder function

When the ship leaves its course, the sailor must turn his

steering wheel to the opposite to reestablish the

system. This depends on how many times the number

of degrees the ship is off course has, so it should be

placed at a right angle. Its rudder is usually small

enough to bring the boat back into orbit. On its bridge

is a deck control unit in which a repeater (relay motor)

is operated by a gyroscopic compass on board,

activating the entire autopilot mechanism [21].

5.3 Double unit rudders

Transmission of electrical signals from the deck control

unit to the steering wheel of a double unit to the power

unit of the stern turns into a mechanical or hydraulic

drive. Of course, one should follow the operating

schedule as accurately as possible. The stresses of the

ship, the rudder, the automatic rudder, and the

automatic rudder must also be reduced. This also

depends, of course, on the sea conditions and the

towing capacity of the vessel. Finally, the autopilot is

nowadays equipped with a computer unit that can

plan the entire trip and automatically performs the

required course changes during this time [22].

6 THE NAVIGATION SONAR

6.1 The sonar technology

The sonar is an electronic naval instrument that

informs sailors of the ocean’s depth under a ship’s keel.

The operation of the device is based on the emission of

sound waves under the keel perpendicular to the

bottom. The emitted sound waves travel to the bottom,

face it, and then are absorbed, diffused or reflected in

different directions. Most of the reflected sound energy

will return to the source as an echo. With a properly

programmed operating cycle, an audio device changes

its operation from an audio transmitter to a receiver.

The device accurately measures the time elapsed

between the onset of a sound wave and its reflection is

received and determines the depth of the sea by

calculating the speed-space-time ratio [23].

6.2 Principe of operation of sound instruments

The operation of the sonar is based on the constant

speed at which it moves. Ultrasonic waves in seawater

where their reflections when they hit the seabed or

other solid objects from which they return to the

reflected waves form echoes. Unique grooves in the

area of the keel are in place to prevent its destruction.

At the same time, a particular oscillator has been

installed that can receive pulses and ultrasonic waves

of high power of a very short duration perpendicular

to the bottom. Part of the energy of each ultrasonic

pulse as it hits the bottom is also reflected in the form

of echoes at the same frequency as the ultrasonic pulse

returning to its keel and being taken from another

sensitive oscillator. After the frequency propagation,

the time from the launch time to the launch time of the

ultrasonic wave is constant, but the return time is also

constant from projection time to projection time. The

return corresponding to each echo pulse will be

proportional to twice the distance from the ship's keel.

The propagation rate of ultrasonic waves is constant

[24].

7 LORAN – C PRINCIPLES OF OPERATION &

ERRORS OF THE LORAN SYSTEM – C

Loran-C is a long-range positioning system whose

position lines are determined by time difference

measurement and phase comparison. The location of

the corresponding chain is used to determine the

location in the zone. A Loran-C station chain consists

of a primary station, M and two, three or four

secondary stations denoted by the letters X, Y, Z and

W, which are located around the central station in the

centre of the area. Each station emits a long-distance

pulse signal at a frequency of 100 kHz. To determine

the position, the system receiver on board measures the

time difference it receives from the central station. Each

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master-slave station determines the position line above

and the ship's position by the intersection of the two

unnecessary position lines. In practice, the seafarer

identifies the Loran-C position in one of the ways: by

using unique Loran-C maps on which the excessive

position lines corresponding to the measured time

differences are drawn, or by measuring matrices, or

even directly by the indications of width and length

provided by certain modern receivers [25,26].

The points identified by the Loran-C system are

some that are divided into systematic and random.

According to some physicists, systematic errors or

mathematical laws lead to the same result in all

measurements—errors due to the Loran-C signal

propagating on land [27].

Random errors due to unbalanced factors are

generated, and it is not accidental since they are not

even observed, so it is impossible to calculate the

corresponding correction [28].

8 THE GLOBAL POSITION SYSTEM (GPS)

The Global Position System (GPS) system is a second-

generation satellite system. Its development began in

the early 1970s and was completed between 1992 and

1995. It can give sequentially to any area on Earth (a)

High precision placement in three dimensions (width,

length and height of the sea ) (b) Accurate World Time

U.T.C. (c) Ship speed data [29].

GPS positioning is based on the measurement of the

distance of the receiver from three satellites whose

positions are determined at the intersection of three

spheres focused on the position of the satellite, with the

measured distance as a radius, accurately identifying

the location of any part of the earth. The computer

which controls and coordinates all the functions of the

receiver shall be selected by the most appropriate

available satellite, applying corrections, and

calculating the position and speed as well as the

location of the vessel and the dispersion to be followed

to reach the destination and the distance from the given

point [30].

9 AUTONOMOUS VESSELS

9.1 Introduction to autonomous vessels

Maritime transportation faces tremendous challenges

in our time, such as a significant increase in transport,

environmental and institutional requirements, and

expected reductions in human resources. The

development of technology led to the development of

new navigation equipment solutions, a gradually but

steadily advancing wave of automation. This

development may improve shipping operations by

promoting the adoption of a more sustainable mode of

navigation by reducing the time of seafarers’ onboard

engagement and the subsequent elimination of

seafarer fatigue, stress, and errors [31].

The terms "autonomous" and "unmanned" can be

used several times to identify the same thing. At this

point, it would be reasonable to give the full definition

of the above words. Referring to the word

"autonomous", we explain that the ship can then carry

out some defined operations with little or no care by

the guard officers of the bridge. It does not close the

possibility that there may be a human being. Contrary

to the term "unmanned", we mean that there is no one

in the cockpit of the bridge to supervise any action.

Apart from that, however, the crew may still be on

board. With the term " Maritime Autonomous Surface

Ship " (MASS), it has already been proposed by the

IMO to characterise as a term an autonomous ship.

MASS was established as "ships which have varying

degrees of autonomy and can operate independently of

human interaction" [32].

The Maritime Unmanned Navigation through

Intelligence in Network (MUNIN) organisation carried

out a preliminary Conception and Research for the

Implementation of Unmanned Ships in the shipping

industry; however, several difficulties and doubts

prevent unmanned ships from being widely adopted

by the industry, involving, indicatively, loss of control

while the ship is at sea, accidental damage to the ship

and during the voyage, and insufficient monitoring in

dangerous areas [33].

The absence of a human element is not the only

difference between traditional and autonomous ships.

An essential difference between the two is the

formulation, management and implementation of

individual decisions made by the crew and the master

on conventional ships. Unmanned ships can be

achieved through a combination of remote, automatic

and autonomous control, according to the IMO [34].

An autonomous vessel is a vessel controlled by

automated systems for navigation, including its

engine. These systems will be pre-programmed as we

can now have a pilot who follows the prescribed route

plans. However, autonomous ships are not necessarily

uncrewed. The maintenance team may be involved

during the voyage to maintain or repair systems on

board, as described above, where ships are expected to

be manned as they approach and leave the port. A

reliable communication system will be one of the

challenges of the system; if the autonomous systems

cannot cope, such systems will be retained as a last

resort. An increase in autonomy is expected to reduce

the need for the crew on board [35].

The IMO proposed the following four degrees of

autonomy [32, 36]:

− Ship with automated processes and advanced

decision-making functions. The crew should be on

board and control and operate all its systems and

functions.

− Remotely operated ship with a crew on board. The

ship is controlled and operated from some remote

location, but the crew is still on board.

− Remote-controlled ship without crew on board. The

ship is controlled and operated from some remote

location, with no crew on board.

− Fully autonomous ship. The ship's operating

system can make decisions and handle all situations

without human intervention.

9.2 The importance of technology for autonomous vessels

Recently, the strengthening of satellite

communications and the continuous improvement of

other transport aids/systems, such as the AIS, The

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GMDSS Risk and High Identification and Monitoring

System, or the scope of LRIT, is a reality. All these

have laid the technical foundations for the

advancement of the shipping industry, being strongly

related to its group of remote-controlled ships.

Therefore, the concept of unmanned vessels presents

many vital concepts, such as advantages in the design

and construction of ships, in the reduction in operating

costs such as fuel and labour and, finally, the

environmental impact associated with conventional

vessels. However, the implementation of such

autonomous systems focuses on long-distance

commercial maritime transportation and is still limited

to passenger vessels. Naturally, the autonomous

operation of unmanned ships requires as much

possible navigation and control with high reliability,

error detection and a high safety rate [37].

This requirement, however, includes an inherent

need to provide basic information such as the position

of the ship in real time to avoid allisions and collisions

with other vessels or other obstacles. Contemporary

technology offers automatic collision avoidance and

critical reconnaissance systems, sensors such as radars

and cameras to identify and sweep the vessel’s

environment, and sea navigation and support for

passenger services [38].

Future needs must also focus on the interaction

between manned and unmanned vessels and

autonomous ship control centres. The IMO defines

electronic navigation as a unified collection, integrity,

exchange, visibility and separate analysis of marine

information on board and on land by electronic means

to improve navigation, anchorage and improvement

services responsible for safety and development,

marine protection and protection of the marine

environment. The international conventions lay down

rules for the prevention of collisions with ships and

regulations for the prevention of maritime collisions,

the so-called COLREGS by the International Maritime

Organization IMO. While the COLREGS Convention

mainly focuses on manned vessels, the main objective

is that these regulations also apply to automation

regulations and systems [39].

On an autonomous ship, the implementation of the

system has requirements imposed by the COLREGS

Convention for information provided by the sensor

system and the correct actions in dangerous situations.

Both autonomous and conventional ships must have

an automatic AIS system specifying that radio waves

contain helpful information about the available

position, speed and vessel, such as the type of cargo.

Furthermore, given the necessity for communication

with lights and sound instruments, one should expect

the implementation of a relevant protocol expanding

radio communications to support autonomous

operations. Vessels deploy 400 to thousands of sensors

collecting data for various functions. The transition

will not reduce the number of sensors used, as the data

must be reported to a shore control centre to check the

vessel’s condition effectively [32, 40].

An up-to-date example comes from Rolls-Royce,

which recently announced its development of a centre

of autonomous operations with remote control in 2015.

This joint research program between production,

education and research, entitled Autonomous Floating

Application (AAWA), presents the idea of autonomous

vessels controlled by minimal human resources

through a land control centre. The program currently

runs a series on Finferries' 65m double-ended ferry

Stella, trying to determine how to implement possible

combinations of current communication technologies

in unmanned ships to achieve navigational autonomy

[41].

9.3 Future technological applications in autonomous

vessels

The spearhead of the Fourth Industrial Revolution's

current wave is information technology, which

performs human-like advanced information

processing activities (cognitive, inferential learning

and decision-making). More recently, this technology

was reintroduced as ICBMS, signifying the

collaboration in IoT, Cloud, with Big Data, Security and

more, as follows [42]:

9.3.1 Internet of things

According to Shancang Li & Li Da Xu & Shanshan

Zhao (2020), the Internet of Things (IoT) means that

everything is connected to the internet now; there is no

point in relating physically or conceptually to each

other. Therefore, although there are many values, it is

essential that the interconnection of things produces

valuable data and that the price used is for the user’s

benefit [43].

9.3.2 Big Data and Analytical Services

Big data has the opportunity to store and process

the traffic data that create a post for in-depth analysis

support; these are all called the data platform. The

innovative autonomous architecture of ships and Big

Data platforms are divided into two types. There is, for

a start, a large data platform inside the ship, an in-

memory analytics platform (Edge Analytic Platform);

the information generated can be collected and stored,

made equal to it in real-time on and off-board, allowing

for the data to be processed in detail in seconds, using

various relevant application services. The next type is

a comprehensive analytics platform that collects and

stores information on the status of selective vessels and

other information systems onshore [44].

9.3.3 Security – IoT & Security

According to Cabbar (2022) in Shipbuilding

Industry, technology has introduced automation and-

enabled services of vessel information for efficiency. At

the same time, IT expansion exploits its vulnerabilities

in the data hubs of ground transportation of IT

equipment which is widely implemented, such as

information leaks, attacks on infrastructure and

systems, malware, cyber-attacks, personal attacks such

as data spoofing, etc. Firstly, identity control and data

protection by preventing damage to information

equipment where ships are currently being built

onboard ships. Communication between autonomous

vessels and land, e.g. (Satellite, LTE) data centres.

Finally, the coverage in terms of user identification, the

protection of existing data and the prevention of

intrusion by foreign users [45].

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9.3.4 Mobile Technology

According to Ken Dulaney(Dulaney, n.d.) on an

unmanned autonomous navigation ship, mobile

service providers exchange information (messages,

voice, video) with the visitor and with the ground data

centre to resolve any potential problem with the

equipment of the ship. This information is managed in

real-time as the maintenance history and is used as

data for preventive maintenance analysis [42].

9.3.5 Artificial Intelligence

The term Artificial Intelligence (AI), according to

B.J. Copeland (Copeland, n.d.) , refers to intelligence

that machines have created. From a philosophical point

of view, artificial intelligence is divided into Powerful

(Powerful AI) and Weak (Weak AI). the weak part is

not about intelligence but about imitating specific

steps; a prepared set of rules is used. Numerous vessels

are associated with weak AI due to the use of computer

development programmes for risk assessment while

learning security is based on accurate data [46].

9.3.6 Intelligent autonomous ships and land services

For ships to be autonomous in the ocean, they must

consist of operational and essential data. In addition,

the ship can be controlled according to a crisis outcome

of an autonomous nature. In contrast, the existing state

of emergency of the ship is spread in real-time from the

land centre if necessary. A function designed to

perform remote control by land through the collection

of operational checks from the ship to the land control

centre when passing through the port area [47].

9.3.7 Automatic navigation system

The automatic navigation system mentioned in the

AAWA report will include various features such as

route planning (PR), critical recognition unit SA case,

CA collision avoidance unit, and the Ship Status

Detection Unit (Ship Status Detection Unit) SSD

module (Ship status detection). Each unit combined

will have its system function with a dynamic

positioning system and operator data connection

system in the control centre. Then, a complete set of

autonomous navigation systems will be used, such as

SSD Ship Status Detection Unit and Unit Virtual VC

Captain having the highest priority because they

collect information from all other systems and decide

under what conditions the ship operates. According to

other systems, the VC unit determines whether the

vessel should operate autonomously, remotely or if it

failed in safe mode. Situational awareness is an

integral part of the safe navigation of ships.

Understanding unmanned ships must be at least as

good in condition as conventionally manned. The

CA then assesses and avoids the risk of a collision. In

contrast, the RP route planning unit is used as a tool,

and when programming, the CA unit is always active

and real-time, according to current conditions [48].

9.3.8 Land Control Center

Communication with Shore Control Center (SCC)

should always be available. If the computer system

fails to deal with the dangerous situation, the operator

must, with the possibility of remote control, solve the

danger immediately and effectively from the ferry. Not

all data need to be transferred while you find the boat

in fully autonomous mode, but it should be

immediately available when necessary. A quantity of

data will have to be assigned as the number of sensors

currently used on board increases. Lidar and HD

cameras will be used as blind parking spot detection

aid and for light and range detection. Vessels will, in

most cases, operate autonomously from the control

centre, receiving the minimum data rate for effective

vessel surveillance. However, different ways of data

transmission, fast connections that are usually

available near land, where ships may use a 4G

connection or another reliable network sailing close to

land, must be considered along with offshore

connection and other alternatives, such as satellite or

VHF frequencies [32].

9.3.9 Artificial Intelligence (AI)

Current growth dynamics in artificial intelligence

synthesis in areas such as automation can often be

controversial, especially in the shipping sector.

However, Artificial intelligence provides enormous

opportunities for all sectors of society, including the

shipping industry, which will benefit greatly and move

on to automated processes on and off-board, increasing

the reliability and efficiency of global shipping [46].

9.3.10 Electric propulsion

In the areas of power and propulsion, energy

production in the shipping industry will rapidly

change in the coming years. There is evidence

regarding the creation of alternative fuels, energy-

saving equipment, renewable energy sources and

hybrid power generation systems, and this will play an

essential role in the development of the system. The

developments foreseen in GMTT 2030 include dual-

fuel engines running on alternative fuels. Common rail

and other technologies will be redesigned to harmonise

and accommodate them as a new fuel. Of course, the

GMTT report states that in the future, the central

propulsion unit will include larger, more powerful

two-stroke internal combustion engines; ergo, the

automation will allow autonomous monitoring of the

current state of essential and non-essential

components, the monitoring of new engine heat flows,

and its operating parameters will be redefined as well

as an integrated combustion quality control. The

overall performance of the propulsion unit will be

significantly enhanced with new materials, such as

graphene and alloys, in piping alternators and

condensers. This will dramatically improve the overall

thermal efficiency of the engine while maintaining

maintenance costs [49].

9.3.11 Sensors

The ability of the vessel to operate remotely, thus

allowing them to sail independently, is based on the

use of sensors for wireless monitoring. A new wave of

sensor technology will automatically collect data and

transmit this information in real-time to the land

control centre’s of respective shipping companies. This

data will allow shipowners to improve the overall ship

maintenance cycle, including more efficient, targeted,

predictive and cost-effective monitoring of the vessel's

condition. The relevant emerging trend of the

innovative "biosensor" technology provides a

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biological component that can create sensitive sensors

that are extremely fast and easy to use. However, these

exciting detection methods require intelligent use of

sensor integration technology robust and data

processing capability. Then smart innovation can

transform vast amounts of sensory data into proactive,

helpful information not only for practitioners but also

for regulators and authorities, i.e. in the case of

environmental data collection [50].

9.3.12 Cybersecurity

Cybersecurity and adaptive security architecture

solutions will be required to support flexible digital

ecosystems. The construction of ships and intelligent,

innovative technology infrastructure independent of

the human factor will create further exposure to

potential risks. An effective communication platform,

and a strong level of data encryption, when

transmitting and receiving data from the vessel to the

land control centre, combining dynamic and efficient

to prevent cyber-attacks, satellite navigation systems

will help in uninterrupted and fully efficient

operations on autonomous ships and therefore are

expected to provide robust reliability and efficiency, in

a new era of autonomous shipping [51].

10 ANALYSIS

10.1 Advantages of autonomous vessels

Autonomous transportation has the potential to bring

many benefits to transport in the shipping industry, the

most prominent of which are the elimination of human

error, the minimisation of operating costs, and the

avoidance of environmental degradation [32].

As mentioned above, human error is the leading

cause of maritime accidents. Replacing the crew with

automatic navigation and surveillance systems will

undoubtedly result in its elimination. Likewise, naval

transportation safety will be significantly improved.

These developments may also provide a more

enjoyable working environment where factors such as

stress and fatigue will no longer affect the operators of

ships on land to the same extent as they would be

involved in onboard conditions. Further reasons

behind maritime accidents, indicatively incorrigible or

incorrect map calculations or weather conditions, will

also be eliminated [52].

In addition to protecting human life, another

potential benefit is that fuel costs are practically

eliminated by reducing the introduction of

productivity gains. Furthermore, crew costs –

including catering costs, equipment, crew

accommodation and other amenities, and their salaries

where seafarers can achieve 10 – 44% of the operating

expenses the owner saves by the nature of the ship a

significant profit. On the one hand, it is evident that the

cost savings associated with the operation of

autonomous vessels lie in the elimination or reduction

of the crew in it; on the other hand, additional features

that allow the vessel to operate autonomously and

additional staff will be housed in the land control

centre to attend autonomous trips, which certainly

need a significantly increased amount. However,

unmanned ships should be able to operate more

efficiently, thanks to a more efficient energy

management system and improved navigation and

routing systems. Most importantly, it makes sense for

the boat to be more aerodynamic without the

superstructure, such as decks and accommodation

spaces. This will reduce the overall resistance of the

vessel, thereby increasing efficiency and reducing fuel

consumption and operating costs [53, 54].

Last but not least, autonomous transport will

reduce fuel emissions as automation allows unmanned

ships to sail more efficiently and consume less fuel,

thus reducing the environmental pollution. Due to the

integrated accommodation infrastructure, the vessel’s

smaller deadweight is the same. Furthermore, the cost

may be reduced if the various actors in the shipping

and port industry cooperate in time. All interested

parties can coordinate their schedules, depending on

how the goods are shipped, and exchange the

information they have. The alternative fuel use is the

slow use of steam, which is an essential solution in

times of falling demand and the ample supply of ships

for economic reasons crisis. Its use reduces carbon

dioxide emissions and fuel costs by reducing

consumption, and, as a result, unmanned ships are

expected to be less polluting than conventional ships.

This mode of transport can make ships more

environmentally friendly thanks to the slow steam.

Slow vaping is the practice of operating cargo ships,

especially even if the speed of the container ship is

significantly lower than its maximum speed [55, 56].

10.2 Disadvantages of autonomous vessels

The main disadvantages associated with autonomous

vessels are attributed to the cost of construction, the on-

shore management of the vessels, safety issues, and

macro-economical consequences related to the

changing pattern of employment in shipping [57].

To begin with, the construction cost of building a

ship with the technology required to be remote or

independent can be significantly higher than a regular

vessel. Moreover, the automation systems required for

these ships have nothing to do with regular ships.

Now, today's shipyard workers cannot cope with the

new conditions. Most likely, they need further training

- which means augmented costs - and recruitment of

new ones with specialisation and knowledge of

autonomous ships, which means increased labour

costs since the salaries of shipbuilding units will

increase. In conclusion, the shipowner bears the

improved maintenance services and fees [58, 59].

Proceeding with the vessel's management, an

autonomous vessel's control lies with the pilot in

charge of the Shore Control Center. The pilot will

monitor the ship from its embarkment until it reaches

the port, where it will be temporarily manned until the

loading and unloading process is completed. The

pilot’s idea raised many questions about the safety of

the ship because the remote control can be lost at any

time in there and the boat will thus remain unattended

until the control centre regains access, which is very

dangerous, not only for the ship itself but also for other

ships that happen to be sailing nearby. Staff members

will carry out active activity on the high seas to be alert

daily and solve problems. It will participate, for

example, in very active to less active tasks, so

644

monitoring ships from the coast can perhaps facilitate

other types of human errors [60,61].

Although unmanned vessels are expected to be

safer, several safety, regulatory and legal issues must

be resolved before fully adopting autonomous

navigation in shipping. This process will take a long

time as maritime law and conventions are revised and

adapted to meet the needs of autonomous ships to

adapt to the new chain of responsibility. Also, as

mentioned above, vessels are designed to eliminate

human error, which is the leading cause of marine

accidents. The relevant research results show that the

accident rates, such as collisions and others, will be

significantly reduced. However, scenarios involving

extreme cases, i.e. fire or structural damage to the

vessel, or cases where partial or total loss of control

occurs as a result of a maritime disaster, have yet to be

thoroughly analysed and processed, leaving a gap in

risk management-wise [32, 62].

Finally, the demand for active seafarers will

gradually decline. Consequently, it should be expected

that many existing crews will lose their jobs, which will

increase over time. This phenomenon can cause

massive socioecononomical issues, as this changing

employment pattern must be addressed

internationally; the positive externalities that seafarer

income has for the immediate and broader social

environment are undoubted, and the impact of its

reduction will be tremendous [58].

11 CONCLUSIONS

In the last decades, many navigational systems have

been introduced, changing the face of the maritime

industry. In the Fourth Industrial wave, new

technologies based on innovation, such as the Internet

of Things or AI, have made fully autonomous vessels

feel closer than ever. The adoption of unmanned

vessels will reshape maritime transportation,

excluding the physical interaction of human elements

initially the physical and any exchange in the final

stage of their operation.

Currently, the importance of human interaction for

the efficient operation of those systems and the proper

assessment of the relevant information is undoubted.

However, unmanned vessels are primarily expected to

redefine maritime transportation by minimising or

eliminating human error, possibly leading to

substantial economic, ecological, safety, and security

benefits. Potential hazards (e.g., fire, structural or

mechanical damage, etc.) and obstacles (e.g.,

responsibility, building and control centre functions,

etc.) must be identified. Furthermore, changes in

construction and communication technology costs will

be counterbalanced by more cost-effective routes,

using Big Data, and eliminating crew costs. However,

the need for the human factor will remain for some

time, as autonomous vessels will require human

surveillance, control and intervention through an on-

shore control centre.

While a highly crucial issue for the condition and

development of the shipping industry, and despite the

various challenges which might logically emerge as a

result -indicatively, safety, regulatory, and monitoring-

only the industry-wide deployment of those vessels

will allow for the extraction of more safe conclusions

regarding the adoption of those new technological

innovations. One thing is certain: the shipping industry

will never be the same.

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