Centre for Maritime Futures

The International Maritime Organisation goals for reduction in shipping CO2 emissions require a 40% reduction in CO2 intensity by 2030 as compared to 2008. With the realistic prospect of future fuels being more distant, this reduction will need to be achieved through improving the energy efficiency of existing vessels and those built in the next few years. In the longer term, as shipping moves to de-Carbonise, continued reduction of the energy requirements of ships results in less demand for any future fuel.

This theme will continue work into the efficiency of shipping that has been conducted at the University of Southampton for over 30 years and supported by Shell Shipping and Maritime for over a decade.

There are continual developments in technology to reduce fuel consumption and emissions from shipping. These include novel coatings and propeller technologies as well as devices to alter flow behaviour around ships. Key to optimising the design of any device, or ship to use a device, is understanding the complex and unsteady flow regime around a vessel in its actual operational environment (waves, wind) and across varying operational conditions (speed, draught, trim) rather than in calm water at one, so-called, ‘design speed’. New hydrodynamic facilities, such as the 138m towing tank at the University’s Boldrewood campus, the largest such facility in the UK equipped with detailed motion and flow measurement capability, together with advanced computational fluid dynamics techniques using the UoS Iridis 5 supercomputer are essential to gain this understanding and design ships of the future.

Work in this theme focuses on improvements to both ship design and operation and encompasses study into new technologies as well as fundamental understanding of unsteady hydrodynamics.

Modelling hull, propeller and rudder interaction

Understanding the complex unsteady flow around a ship’s hull, propeller and rudder is key to designing them as a complete system and to thus increasing their combined efficiencies. This PhD project developed and demonstrated new computational fluid dynamic (CFD) modelling tools for the simulation of these complex flows.

Draught and trim optimisation using machine learning

It is increasingly common for vessels at sea to record data continuously, including the propulsive (shaft) power together with operational parameters such as speed, draught and trim and environmental parameters such as wind speed and direction. Using these data to understand the influence of these parameters on the propulsive power is challenging using traditional methods due to the stochastic nature of the data and the interaction between the parameters. This project has developed machine learning techniques to predict shaft power within an accuracy of 2%. Such a level of prediction accuracy has enabled these techniques to be incorporated into a system to optimise a vessel’s draught and trim to reduce emissions. The system has now been deployed for >60 ships and resulted in fuel savings of 3-7%, depending on the vessel. This saved >250000 tonnes of CO2 in 2019.

"Physics-based shaft power prediction for large merchant ships using neural networks"

Further understanding of the physical causes of these changes in power with small changes in draught and trim is provided through use of computational fluid dynamics (CFD) techniques to study the flow around the vessel. The figure illustrates bow and stern flow details for a tanker with small changes in draught and trim travelling at a Froude number of 0.162 (left) and 0.174 (right) for displacements of (a) 100% (b) 106% (c) 109% (d) 112%.

Predicting power for fleets of merchant vessels

Recognising that measuring detailed parameters onboard all vessels is not viable, particularly for older vessels or for vessels under Charter, rather than Owned, this project is working to develop machine learning tools capable of fusing data from vessels where data are recorded to predict the shaft power requirements for vessels without the same level of measurements. This project has demonstrated that prediction of power for Sister ships within a fleet can achieve an accuracy of 4%. This accuracy is sufficient for some fuel-saving applications and will be deployed in the near future.

Air lubrication systems

One of the few technologies capable of reducing a vessel’s power requirement by more than a small percentage is air lubrication. These systems create bubbles in the boundary layer of the ship’s hull, reducing the frictional resistance (drag) of the ship. For most slow-speed merchant ships the frictional resistance is more than 70% of the total resistance and hence power requirement.

The University have support Shell Shipping and Maritime’s studies into air lubrication systems through the use of computational fluid dynamics (CFD) modelling of a vessel to investigate the placement of air release units and in the independent verification of analysed power savings from initial test deployments of an air lubrication system. Shell Shipping and Maritime intend to retrofit air lubrication systems to Liquefied Natural Gas (LNG) carriers in 2020.

Wind-assist technology

Auxiliary propulsion devices to take advantage of the wind have the capability to reduce the power required by a ship significantly, clearly depending on the wind encountered by the vessel. A study into one such device type, Flettner rotors, was conducted in association with the University’s Wolfson Unit for Marine Technology and Industrial Aerodynamics (WUMTIA). This study combined Computational Fluid Dynamics (CFD) modelling using the University supercomputer with the WUMTIA’s expertise in predicting the performance of sailing vessels using a purposely modified version of its Velocity Prediction Programme. The study investigated the application of Flettner rotors to both oil and liquefied natural gas carriers and focused in particular on the interaction effects between multiple rotors and between the ship’s hull, superstructure and Flettner rotors.

A summary of the work was published in a conference paper, ‘Predicted fuel savings for a Flettner Rotor assisted tanker using computational fluid dynamics’ at the RINA Wind Propulsion 2019 Conference in London in October 2019.

Hull and propeller fouling management

Marine fouling and growth on a ship’s hull increase its power requirement and hence fuel consumption. Despite improvements in coating technologies these increases can be significant over the typical 5-year dry-docking periods of merchant vessels. How a vessel is operated influences the rate of fouling, with slower speeds, warmer waters, time in port and lower salinity all causing increases. It is therefore imperative for vessel operators to monitor fouling, to assess effectiveness of coating schemes and to plan cleaning and/or re-coating. Ship’s propellers are not always coated and will also foul with time, therefore also requiring cleaning.

Whilst measurement of ship propulsive (shaft) power is now relative common, it is extremely rare to measure propeller thrust directly. Without propeller thrust measurements, it is impossible to separately monitor hull and propeller fouling directly. This study utilised understanding of vessel powering and efficiency to devise a practical method to separate hull and propeller fouling and thus allow their development to be monitored independent of each other. This method has now been deployed within Shell Shipping and Maritime and allows more accurately targeted interventions to optimise vessel cleaning.

Economic operational speed of a time-chartered ship

The speed a ship travels is fundamental to its operation and to the fuel it will consume and hence its emissions profile. However, the actual operational speed of ships varies even for similar ship types, sizes and technical characteristics. It is hard to always explain these variations and yet understanding them is of fundamental importance in reducing shipping emissions through legislation, or through changes in ship Chartering agreements, or through changes in operational patterns including reduced port turnarounds.

This project applies an approach based on cash-flow functions and novel to the shipping industry to develop models to better understand how speed decisions are made when using a chartered ship to transport bulk cargo. The models developed exhibit the characteristics and trade-offs experienced decision makers take into account. This gives confidence that such models form an appropriate basis to investigate novel contractual arrangements to reduce ship emissions.

This theme aligns with Shell Shipping and Maritime’s goal of a future of zero incidents, zero harm, caring for the mental and physical well-being of all its employees. Whilst ship safety has improved in recent decades, seafaring remains a relatively more dangerous occupation compared to equivalent land-based occupations.

Seafarer health and well-being
The University has conducted research aimed at safeguarding those onboard ships for several years, through improved understanding of the behaviour of crew and translation into effective training and guidance.

One particular focus was Project MARTHA, a $3M research project into seafarer fatigue conducted by an international partnership of researchers and industry, sponsored by the TK Foundation, over a three-year period from 2013 to 2016. Project MARTHA was presented to the IMO.

The aim of the study was to explore the levels of sleepiness and the psycho-social issues associated with long term fatigue and motivation of seafarers, using a sample of volunteers in the natural setting of work onboard their vessels. Two PhD students, working beyond Project MARTHA, are now investigating the influence of stress and fatigue on specific aspects of cognitive performance directly relevant to ship operations.

A third recent PhD project investigated the decision-making procedures for a vessel’s shipboard management and the extent to which safety is embedded within them at an organisational level.

An independent review into the causes of serious maritime incidents was conducted on behalf of Shell Shipping and Maritime in 2015. Applying a root cause analysis methodology indicated that human factors error related causal factors were responsible for approximately 90% of incidents.

Feasibility of autonomous ballast tank inspection

The inspection of enclosed spaces onboard ships remains a challenging task, in particular ship’s ballast tanks. Ballast tanks are enclosed spaces surrounding cargo holds, used to trim and stabilise vessels during normal operations and filled by pumping seawater into and out of the spaces during voyages. There is no natural lighting or ventilation to these spaces. Ballast tanks are a hazardous working environment, since work in confined and enclosed spaces has a greater likelihood of causing illness, severe injuries and fatalities than any other type of shipyard work or onboard ships.

This project investigated the feasibility of using an autonomous quadcopter vehicle to undertake a survey of a ship’s ballast tank space. Using a series of prototype platforms and a representative ballast tank space at the University (see figure), this project concluded that it is possible to use a multi-rotor vehicle within a ballast tank space and maintain the distance from the tank structure required for visual inspection purposes, although challenges remain around the size of the vehicle due to access spaces and power consumption of such vehicles for available battery technologies.

Ship structural integrity
Within the overall aim of improving ship safety, research is aimed at moving the shipping industry to a Digital Health Management approach, with real-time diagnostics and prognostics. This requires a better understanding of structures and their behaviour over time, using increasingly accurate experiments combined with modelling of potential failure modes linked to root causes.

This approach will allow i) improved inspection regimes using a risk-based approach to reduce downtime and in-service inspections, allowing a movement away from rigidly imposed inspection cycles, ii) enhanced understanding of long-term relationships between structural response and the environment, providing the means to enhance rules and provide feedback to designers and constructors, iii) improved tools for structural design through combination of measured data and multi-scale, multi-physics computational techniques.

As an initial step towards this aim the University is working with Lloyd’s Register (LR) to investigate the feasibility of applying a ‘Digital Twin’ approach to modelling corrosion onboard ships over time.

The volume of data acquired from ships and their systems is increasing rapidly, as is the speed of transmission from ship to shore. Sensors may be deployed to monitor numerous internal and external parameters such as energy consumption from distributed electrical loads, environmental parameters and crew activity and sleep patterns. Mobile sensors in the form of drones or robotic systems will acquire data in difficult places. The data collected promises to deliver insights to improve safety and efficiency of vessels, crew, cargo-handling and reduce emissions. Challenges exist in deploying sensor networks on marine platforms where the harsh environment, sporadic communications and infrequent servicing schedules lead to error-prone sensors operating beyond their effectiveness.

Digitalisation is transforming aspects of the shipping industry. Focus areas for the research in the Centre for Maritime Futures include optimising the operations and maintenance of vessels to improve safety and operational efficiency and reduce emissions. The commercial relationships and models within shipping may also be changed by Digitalisation with great potential to decrease the emissions from the global shipping fleet. Digitalisation techniques and modelling are also being applied within the Centre to profile shipping emissions and to investigate the impact of potential future global and regional policy decisions around, say. Carbon taxation.

The Centre for Machine Intelligence (CMI) at the University leads research in this theme, with support from the Centre for Operational Research, Management Sciences and Information Systems (CORMSIS), which is one of the largest groups of its type in the UK and spans Mathematical Sciences and the Southampton Business School. This expertise is being utilised to develop and deploy new methods, with previous projects including the development of pricing systems based on online auction platforms for optimising the charging of electric vehicles and understanding their interactions with the National Grid.