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Delivering Submarine Capability and Availability with Agility and at Pace

Submarine Design and Build is a complex and challenging process that often requires years to refine and produce the desired vessels. In an age of increasing technological development tempo, this conference will seek to explore mechanisms for delivering high-quality capabilities at pace. In particular, it will focus on availability and how to improve availability through design, life maintenance and consideration of crew availability and human factors constraints.


Conference Fees:

Before 17 April 2023 From 17 April 2023
RINA Member £800 + VAT £900 + VAT
RINA Non-Member £900 + VAT £1000 + VAT

(retired/students etc.)

£400 + VAT £400 + VAT
Authors £200 + VAT £200 + VAT
Additional Authors £800 + VAT £800 + VAT
  • The drinks reception will be held at the Roman Baths.


Annabelle Ransome-Williams - Keynote speaker (Warship-2023)

Annabelle Ransome-Williams


Starting my career as a naval architect, I am proud to lead major defence projects, a track history of delivery spanning over two decades. Having worked at all stages of the lifecycle (bar disposals) my experience is broad across air, land and maritime domains, as well as private and third sectors.
Currently, I am Programme Director of SSN AUKUS; we are delivering Submarine Capability and Availability at Pace through ‘designed-in’ asset management principles to deliver availability and sustainment benefits to the Royal and Australian Navies.
Today more than ever I am a catalysing change agent for pace, momentum and long-term results for Defence programmes generating warship outputs for global impact.


RINA also invites papers on the impact of evolving / future technologies and process improvements on the design, build and support of Naval Submarines. Including but not limited to:

  • Application of Intelligent Systems
  • Design for Availability
  • Design for Submarine Disposal
  • Digitalisation in Submarines
  • Driving down through life cost
  • Human-Autonomy Teaming and Human Factors Considerations in Design
  • Innovative power systems and energy storage
  • Lean Crewing Considerations
  • New technologies on submarine operations. Future scenarios.
  • Novel materials and underwater application
  • Streamlining build processes. Reduction of time and cost
  • Survivability and evacuation (escape and rescue)
  • Sustainable Technologies
  • The role of class in submarine acceptance


Please note that other abstracts will be confirmed at a later date.

Capability versus Availability in Submarine Design?

David Andrews, University College London

Capability and Availability are seen as terms to encapsulate major features required in designing a new major warship, such as a new submarine. These terms are worth considering what they mean in designing such complex naval vessels. This paper first considers each of these terms in turn and questions whether capability is often too narrowly defined and, aside from affordability issues, which are clearly crucial in designing any complex system to meet a set of capabilities, could be seen to be all embracing in regard to desired qualities. If this is so, then “capability” ought to cover availability among other whole boat performance characteristics.

Turning to availability, from a design stance it is considered this has been something of a Cinderella topic as far as discussions in open literature on submarine design are considered. Thus, a brief review of published sources, including the RINA submarine conferences starting with the RINA 1983 International Symposium, is presented. This leads to consideration as to why availability seems to be addressed relatively late in the traditional submarine design process, such that any drop off in a class of submarines, in regard to the expected availability, might not be revealed until such a new squadron of vessels is fully in-service. This then raises the question as to how the process of designing such complex vessels might be better focused, in early stage design, to address the issue of availability, so that the other operational capabilities sought in an affordable new design are effectively deployed at sea in an appropriate level of availability.

Delivering Submarine Availability Through Design 

Ross Millard and Alex Walchester, BMT

Submarine availability is critical to being able to deliver capability when required, and submarine operating navies seek to maximise operational availability (i.e. mission tasking at sea) and minimise non-operational time (i.e. planned or unplanned maintenance, inspection and training). The importance of availability is brought home in the capability planning stage, where the planned availability for a given submarine design influences required fleet numbers and procurement costs.

Submarine availability is influenced by a variety of factors including (1) the submarine design itself and (2) the wider submarine enterprise engaged in support (i.e. infrastructure, personnel capacity and capability, supply chain aspects). It is necessary for designers to understand these considerations in the early stages of the submarine design process and to identify design features that maximise the chance of meeting the defined availability targets. This can be extremely difficult to address with the risk that design decisions made early can quickly lead to “locked in” costs only realised in the future in-service support phase.

This paper revisits BMT’s research into submarine availability and takes a fresh look at how availability requirements influence the design. This paper proposes that by driving maintainability features into all aspects of the design process, and by developing the support model from an early stage in parallel, it is possible to maximise confidence across the enterprise that the defined availability target will be met.

Capability, Availability, Cost; the Trade and the Balance 

Robert Chaplin, BAE Systems Submarines and Gavin Wainwright, Babcock – Future Submarines

Dr Eric Grove’s has asserted that the top two challenges facing the Royal Navy Submarine Service today are “maintaining the operational availability of what we have and maintaining enough personnel to man them.” [[1]]

Operational Availability, AO is one part of the trade space. Capability and cost are the other primary discriminators for any decision relating to the design of a submarine or the provision of maintenance and sustainment. Each one of these discriminators can be optimised but at the potential detriment and sub-optimisation of the other two.

The Submarine, Attack, Nuclear Replacement Programme, SSN(R) is the next generation of SSNs to be built for the Royal Navy after the Astute Class last of Class.

The current design phase of SSNR offers a prime opportunity for getting this trade right with a truly balanced submarine being delivered to the Royal Navy in time to replace the Astute Class. Whilst the Astute Class SSNs are recognised as having one of the best capability offerings currently in-service, they are also known to have considerable maintainability challenges [[2]].

SSN(R) has adopted a collaborative approach between the major prime contractors and through the 12 elements of Integrated Product Support (IPS) the objective is to achieve a global benchmark for AO. This report will outline this collaborative approach, the roles and responsibilities of each of the major primes within the IPS framework and how a viable submarine design can be matured to achieve a stable balance between the three discriminators. The objective to drive supportability and maintainability into the DNA of the design alongside capability and cost.

[1] Defence Sub-Committee Oral evidence: Defence in the Arctic, HC 388, Wednesday 24 January 2018, Q33 P1

Oral evidence – Defence in the Arctic – 24 Jan 2018 (

[2] Defence Sub-Committee Oral evidence: Defence in the Arctic, HC 388, Wednesday 24 January 2018, Q33 P2

Oral evidence – Defence in the Arctic – 24 Jan 2018 (

Explorations of Novel Nuclear Propulsion for Submarines 

Rachel Pawling, University College London

With a handful of exceptions, most notably the lead-bismuth cooled reactors in the Soviet-era “Alfa” fast attack submarines, all nuclear submarines to date have used a pressurised water reactor, in either dispersed or integral configurations. As far as is publicly known, all current programmes also use this technology, which is in contrast to the variety of different technologies known as “Generation IV”, such as high-temperature gas cooled reactors, under development for land-based use.
This paper will briefly summarise some UCL student designs, developed in the three month Submarine Design and Acquisition Course, which have their “special feature” as being a non-traditional type of nuclear reactor. These have included low-power types and also high-power density installations. Comparison will also be drawn with possible technologies and limitations of the Russian “Poseidon” nuclear-powered torpedo. The paper will conclude with an attempt to use a contemporary high-temperature reactor design to produce a modern version of 500 tonne mass-producable SSN originally proposed in the USN Project Nobska of 1956, which had a major influence on US Navy Cold War ASW technology and tactics.

Inclusive Submarine Design Considerations

Allen Dutton, BMT Canada

Today’s submarines need to accommodate for a variety of sailors. From the 5th to the 95th percentile, submarine designs need to account for differences in size, height, body type and gender all whilst supporting optimal operational performance. This demographic shift demands re-evaluating elements of traditional submarine design and operation to optimize crew performance and attract, accommodate, and retain the most qualified sailors regardless of physical or social characteristics. This paper will present inclusive submarine design considerations from both anthropometric and social perspectives, present some examples, and discuss some potential solutions for addressing these design challenges.

Wakes of Surface-Piercing Cylinders 

Douglas Potts, Australian Maritime College

Surface-piercing cylinders, such as those which project up from submerged platforms generate wakes as a function of diameter, velocity, and immersed aspect ratio. Laboratory testing of surface-piercing cylinders has predominantly been confined to the characterisation of the forces and the motions with little focus on the wakes, which influence the aforementioned. Additionally, previous experiments have been conducted whereby the cylinder is mounted from above the free-surface.
The characterisation of the wakes of bare cylindrical structures is important for several reasons: the first is that it provides a baseline dataset, which can be for validation of numerical or theoretical models; the second is that quantification allows for comparison against vibration suppression devices such as helical strakes or fairings; thirdly the visual and acoustic noise become a known and thus efforts can be made to reduce the wakes signature by implementing an alternate geometry.
This paper presents a portion of an experimental programme undertaken in a towing tank to characterise the wake of cylindrical structures of various diameters at steady state speeds in calm water. The models were mounted in a novel manner to replicate the real-world scenario of a cylindrical structure protruding up through the free-surface whilst mounted from a submerged platform.

Experimental Developments in Assessing the Seakeeping Behaviour of an Underwater Vehicle Operating on the Surface 

Mathieu Courdier, Australian Maritime College – MARIN

Underwater Vehicles (UV) are widely used and optimised to operate deeply submerged. However, UV are also required to spend significant time at the surface in a wide range of sea states for mission critical tasks. These surfaced operations present constraints on the speed, stability and dynamic behaviour of the UV compared to submerged operations. As such, an understanding of the seakeeping behaviour of a surfaced UV is critical. However, data is limited and the knowledge of surfaced ships is not applicable. The UV’s unique hull presents very specific resistance and motion response. Of particular interest is the pitch behaviour presenting a double peak of resonant frequencies, unlike conventional surface vessels. This paper presents an experimental investigation into the heave and pitch motion response of an UV in waves and their evolution as being a function of the wave height and the Froude number. A novel experimental test rig is presented, and the case is made that a single post seakeeping setup presents superior characteristics for surfaced UV seakeeping compared to a conventional double-post setup. Also, the hull was tested in two outfitting configurations to quantify the influence of the Aft Control Surfaces (ACS) on the motion response behaviour. Understanding the influence of the ACS allows for a better explanation of the coupling between pitch and heave motions. Further work is ongoing on the underlying physics of the UV seakeeping to provide better consideration into the operation limiting factors and hull shape design of UV in surfaced conditions.

Leveraging cross-industry approaches to enable submarine disposal through improved design

Jake Rigby, BMT

Decommissioned submarines that have not yet been dismantled and disposed of represent a logistical and financial burden to the MoD.  Overcoming barriers of capability and capacity of the disposal of these vessels requires the development of approaches that facilitate the recovery of the 90% of the platform that is made up of recyclable metals. However, even if such approaches are adopted, there is still the question of spent nuclear waste which continues to be a resource drain on the MoD until it is disposed of. As stated in the NAO 2018 SDP audit “Since 1980, 20 submarines have been removed from service and to date, the Department has not yet disposed of any of its 20 retired submarines, with nine still containing irradiated fuel.”
This paper looks at nuclear and conventional waste streams to identify ways the design process can leverage concepts already applied in other industries to examine the capability and capacity of the disposal of submarines. From a nuclear waste perspective, potential options of disposal of nuclear waste such as geomelting will be examined. The paper will explore approaches that can be adopted to facilitate optimisation, regenerative design opportunities and resource efficiency in the recycling process for decommissioned submarines resources. These approaches include the use of versatile substances to reduce the number of different materials within a composite material, as well as ‘Design for Disposal’ through the classification of parts into different groups during the design phase to facilitate recovery at the end of their operational life.

Deriving Signature Requirements for Submarines 

Bill Wood, BMT Canada

It is commonly accepted that stealth is critical to the operational effectiveness of submarines, but how does one translate an abstract concept like ‘stealth’ into a set of performance requirements that can be captured in a Systems Requirement Document?

This paper will discuss the challenges that must be faced when deriving signature requirements, and how the approach taken will need to vary for different signature types. It will also discuss how this methodology can guide decision-making as the design matures, to optimise the stealth performance of the final design, and provide a means to express the resulting operational effectiveness of the submarine in terms that non-experts can understand.

Submarine Vulnerability Reduction: WYVERN and Purple Fire 

Crawford Ritchie, Survivability Consulting Limited

Vulnerability reduction and management is an accepted and mandated part of UK warship design, but the same processes have not been fully applied to submarine programmes.
Reducing the vulnerability of submarines has been historically of lower priority in the design process, however there are features that can be incorporated into a submarine design that can significantly reduce vulnerability. This is demonstrated by assessing BMT’s WYVERN SSK design in SCL’s Purple Fire Vulnerability and Lethality tool.
The WYVERN design was developed to meet the varied requirements of international customers looking to establish a new capability or upgrade existing platforms, in order to provide Anti-Submarine Warfare protection and deterrence. WYVERN’s double hulled design gives good scope for vulnerability reduction.

Purple Fire is a fast running vulnerability and lethality tool developed by SCL and authorised by UK MOD. It has been used extensively across numerous warship assessments since 2015.

The WYVERN design was modelled in Purple Fire as a baseline and assessed against a number of credible underwater weapon scenarios in line with its Concept of Operations. Variants of the baseline design were then created, assessed, and compared to the vulnerability of the baseline. The paper shows that there are several design modifications that could be implemented that result in significant reductions in the vulnerability of WYVERN.

Using the Naval Submarine Code (NSubC) as means for Submarine Assurance during Design, Construction and Operation 

Christian von Oldershausen, DNV

Using the Naval Submarine Code (NSubC) as means for Submarine Assurance during Design, Construction and Operation Submarine Safety is a complex, multi-dimensional task covering all technical areas of the submarine platform. The importance of managing safety is therefore imperative at every major phase throughout the lifecycle of the submarine. In this respect designers, shipbuilders, and navies find themselves faced with many challenges. Typical constraints include budget limitations, a critical dilution of in-house expertise for shipbuilding and design, a shrinking pool of qualified personnel and finally, increasing demands from the public for safety and environmental protection. Ensuring that these objectives are achieved requires a robust and well-proven assurance process. Consequently, the Naval Submarine Code (NSubC) often in conjunction with classification society rules are increasingly being used by navies as a powerful process and assurance tool, bearing in mind however, this is a process depending on the requirements of the respective Naval Administrations. In some cases, additional tec  hnical standards need to be considered to achieve a broader level of assurance. The NSubC, following in the footsteps of the Naval Ship Code (NSC) which was first released as NATO ANEP-77 in 2008 is a goal-based standard, which sets a minimum level of safety for submarines and provides a framework for further work and development in this field. The benefits of this goal-based standard are that it considers the ultimate safety objectives and allows for the consideration of alternative designs and technical solutions that meet the objective. The NSubC has been recently published by NATO as new ANEP-102.

The effect of orthotropic steel on pressure hull collapse 

Alessandro Zambon, Nevesbu b.v.

In general pressure hulls are made of steel and this material is usually considered to be isotropic. Nevertheless, it is well-known that the properties in and perpendicular to the rolling direction will show a difference. Considering the complex stress state in ring-stiffened cylinders, orientation of the orthotropic material must have influence on the collapse pressure, but it is not easy to quantify.

Based on actual tensile tests in longitudinal and transverse direction of a plate nonlinear analyses are carried out to establish collapse pressures by means of the Hill plasticity model. The influence of isotropic behaviour is presented by rotation of the material over the geometry.
This study comprises material with a specified minimum yield stress of 355 MPa. In modern pressure hull design this material may be no longer applied but to demonstrate the effect of orthotropic behaviour the test results are applied to the Potvis class. This is a Dutch submarine design from the mid of the last century with a pressure hull made of St 52 like the material of the actual tests. The material model is rotated from hoop to axial direction, and the resulting collapse pressures are compared. The study reveals that for the material under consideration the orientation of the plate cannot be ignored.
This means that it is imperative to consider material properties in perpendicular directions and based on test results it must be decided how to manufacture the pressure hull.

Pressure Hull Corrosion Modelling and Assessment 

Simon Dawe, Babcock SSE

Availability of assets is a critical factor across all naval fleets. Many nations have platforms that have been through or are going through periods of commission and life extensions due to delays in long-term maintenance periods, major infrastructure availability and delayed entry into service of new platforms.  This presents several challenges for the industry as platforms reach the end of the original design life.

Submarines are susceptible to many age-related degradation mechanisms, in particular corrosion of the steel primary structure. Currently corrosion assessments are carried out using a combination of the tried and tested Submarine Design Formulae and other proprietary assessment tools.  These are based on both empirical and first principles analysis and while these methods are swift and widely accepted, they can be conservative when considering localised defects.  When considered as part of a major refit period this can be a major contributing factor in the length and cost of the final repair programme.
One solution to this is to start routinely carrying out more accurate analysis of the individual corrosion defects using finite element analysis.  Advances in detecting plate corrosion using ultrasonic thickness testing and laser scanning mean we now regularly have access to detailed dimensional data which could be useful if a method of rapidly incorporating  it into a model could be developed.

This paper looks to  test the feasibility of using this data in finite element models of a submarine pressure hull and determining the resulting collapse depth pressure.   Results will then be compared against current assessment methods.

In-Process Ultrasonic Inspection During Fusion Welding of Large-Scale Fabrications 

Anthony Burnett, Cavendish Nuclear Ltd (Babcock International Group)

Traditionally, the welding and inspection of welds on large-scale fabrications, such as submarine pressure hull components, are distinctly separate manufacturing processes, which limits productivity and throughput along with increasing re-work if defects are detected post-build. The Advanced Welding Equipment System Inspection and Monitoring (AWESIM) project introduces ultrasonic phased array inspection directly during welding to allow detection of imperfections and flaws as they occur, thus reducing rework, repair and delivering high-quality welds right, first time.

High-temperature dry-coupled Phased Array Ultrasonic Testing (PAUT) is introduced directly during Gas Tungsten Inert Welding (GTAW) deposition. A novel high-temperature automated weld inspection roller probe, alongside new imaging algorithms, compensate for the effect of negative process parameters such as temperature gradients, partially filled grooves and electromagnetic noise interference to enable in-process inspection.

Results of this work are presented on sub-scale plate and pipe demonstrators with both intentionally controlled and unintentional defects. The signal to noise ratio and sensitivity of the imaging and inspection system is measured, evaluated, and quantified offering impact benefits such as reduced rework, schedule slippage and cost.

A brief explanation by a representative from the Babcock International Group will highlight the benefit it aspires to achieve from deploying this technology in its work on submarine system fabrication and maintenance for the UK MoD.

Submarines on patrol in the Metaverse

Rodrigo Perez Fernandez, Siemens

In this paper we will submerse in the latest paradigm of Metaverse apply to the design and fabrication of submarines, we will analyze the closed loop connections between the digital and real worlds across the value chain enable actionable insights and information decisions. The objective of this paper will be to study how to produce an optimum product, how to simulate real production priorities and constructions process, commissioning, and operations applied to submarines. We will review important aspects of the Industrial Metaverse like virtual worlds, live interactions, real world relevance, interoperability, functional economy, secure and evolution of the communications, training, AR of the digital twin in both worlds, meeting, remote control, collaboration, continue and interactively evaluation, monitoring analysis and manage of real and virtual data.

Application of Systems Engineering (SE) within the Naval Architecture Domain, with specific application of Model Based Systems Engineering (MBSE) & Naval Architecture 

Morgan Flexer, BAE Systems – Marine – Submarines

The future of submarine design is set to hold more challenges of complex design evolution than previous decades; the introduction of automation, requirement for integration with unmanned vehicles and the need to shift to higher levels of availability will drive new and previously unexplored requirements. While Systems Engineering (SE) methods are widely used within the defence sector, the application of Model Based Systems Engineering (MBSE) is relatively new and untested, particularly through the whole life cycle of a submarine. MBSE is rapidly becoming an industry standard for complex design, and is professed to offer advantages in quality, knowledge retention and agility to design change.

Questions arise around where Naval Architects sit within this new world order; some significant questions being asked such as are Naval Architects Systems Architects or System Owners, can methods traditional methods such as the design spiral work within SE processes?

BAE Systems Naval Architecture have been working to expand our knowledge in this area, both internally and through academic studies.  While this work is still ongoing, this paper intends to report initial findings from this work, including the need for both the detailed knowledge and whole boat view that Naval Architects brings to the process.  In addition while SE, specifically MBSE, bring new tools and more formalised language, synergy with these ways of working can seen with naval architecture processes.  This is seen a significant to naval architecture and specifically the training and skills needed for submarine design going forward into the 21st century.

MBSE driving down through life cost in Naval applications 

Ilya Tolchinsky, Ansys

Model Based Systems Engineering (MBSE) has become a well-established practice in the defense industrial base, especially for aerospace platforms, and is proven to lower life cycle costs. In this paper we explore the adoption and return on investment of MBSE practices in naval programs, specifically the US NAVY. MBSE methods applied during the acquisition, and throughout the life cycle, have made measurable reductions in cost for engineering, software development, and maintenance as well as providing a framework for implementing new technologies on existing platforms. The MBSE methodology enables the reduction of life costs as it provides a way to better manage the increasing complexity of naval platforms and weapons systems integration. Systems complexity and software integration are key issues in driving higher development and program support costs and leading to substantially longer dev  elopment cycles. MBSE methods provide an authoritative source of truth (ASoT), accurately describing the system, the interactions within the system, and providing  a mechanism to verify the behavior of the system and ensure the requirements are met. Specific examples from open source material will be presented and analyzed to demonstrate how MBSE methods are delivering on the promise.


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31st May, 2023 - 1st June, 2023    
All Day


The Guildhall
High St , Bath, BA1 5AW