12th International Marine Design Conference Toyko ...

12th International Marine Design Conference 2015

Proceedings Volume 1

12th International Marine Design Conference Toyko, Japan th 11 -14th May, 2015 State of the Art Report on Design Methodology by David Andrews Design Research Centre, Marine Research Group Department of Mechanical Engineering University College London and Stein Ove Erikstad Department of Marine Technology Norwegian University for Science and Technology

- 89 -



THE DESIGN METHODOLOGY STATE OF ART REPORT INTRODUCTION TO THE DESIGN METHODOLOGY STATE OF ART REPORT The last comprehensive Design Methodology State of the Art report was to IMDC 2009. In 2012 there was no Design Methodology State of the Art report but a Design for X report, which largely focused on Design for Layout and recent cooperative work by the University of Michigan, Technical University Delft and University College London. It also included an introduction to Design for X and Design for Production (particularly Operations Research in Ship Production Logistics). These three sections were produced by D Andrews (editor), A. Papanikalaou and F Dong & D. Singer, respectively. This 2015 Design Methodology State of the Art report, therefore follows on from the 2009 Report and has two sections which will be explained, shortly. Before that it is consider worth summarising the introductory remarks to the 2009 Design Methodology State of the Art report, as there may be readers unfamiliar with the history of the IMDC Design Methodology State of the Art reports. Thus the 2009 report followed on directly from the two previous Design Methodology State of the Art reports to IMDCs 1997 and 2006, providing updates on the major design topics of general design theory, systems engineering and preliminary ship design methods. Given that the 2009 report followed on the 2006 IMDC report and so there were not many new developments, it was decided to include several innovative features. The first of these was the introductory section, which provided recent attendees at IMDC with some background on the origin of the IMDC State of the Art reports, the structure of the three reports presented and, specifically, the scope of the design methodology report. The second new feature consisted of some key “Statements on Designing” with a brief commentary. Next the section on preliminary ship design, rather than providing any additional summaries of approaches to preliminary ship design, as in the 2006 report, presents a chronological set of twenty-six graphical representations of the ship design process, commencing with Harvey-Evans’ Design Spiral. Each model had a few explanatory key words and the source reference for interested readers to follow up. The last technical section in the 2009 DM Report was on multi-criteria methods and optimisation. This also departed from past practice by presenting a listing and brief summary of eleven key references on optimisation and a further thirty-six on the application of genetic and other heuristic algorithms applied to ship design. Finally the conclusion revisited the nine points raised in the recorded discussion of the 1997 report as it was considered those points as were (and are?) still highly relevant to an understanding of the nature of marine design practice. The section in the 2009 State of the Art Report on Design Methodology on scope outlined the history of the SoA Reports to IMDC and the topics covered in the previous two Design Methodology reports. The IMDC International Committee prior to the Sixth IMDC held at Newcastle in May 1997 decided that a new activity at that conference would be the presentation of a series of State of Art reports which would also be discussed in open plenary session and the discussions recorded and published along with the discussion on each of the presented papers in the main sessions of the Conference. The motivation behind this new feature of the 1997 IMDC was the desire to raise the status of IMDC within the marine technology field to be comparable to the long established fora dealing with marine hydrodynamics (the ITTC) and marine structures (the ISSC). It was felt by the proponents for SoA reports that production of such reports by a team of experts in each of the intended topics presented and discussed at the triannual conference, would complement the presentation and discussion of specific international research and practice in marine design provided by the normal medium of the technical conference papers. Such a set of SoA reports could, after the initial conference, where a degree of wider review and scene setting was seen to be appropriate, then constitute a statement on the developments and current issues in the component topics in marine design that have arisen since the previous IMDC. The five topics chosen for the 1997 conference were:• Design Methodology • Design for Operation • Design for Production • The use of Computers in Marine Design • Design Education

- 90 -



Thus the topics chosen were essentially generic rather than specifically on areas of marine design application, such as offshore, naval ships, transportation carriers, passenger ships, service vessels and small craft. Each SoA report tried to capture its specific issues across all these areas so its conclusions were of general applicability. The Design Methodology report in particular tried to address this difficulty by having six generic sections and six area specific sections. The latter covered passenger ships, multihulled vessels, high speed craft, small craft, offshore (including floating platforms) and naval vessels (including submarines). It had also been intended to include the two major categories of merchant shipping, namely, bulk carriers and cargo capacity carriers, but sections on these were not finally produced due to the tight timescale. To some extent issues of limited authorship (due to time limits) and lack of comparison between draft reports were also pertinent to the 2006 set of SoA reports. For the 2000 and 2003 IMDCs, SoA reports were not produced, however it was decided it would be worthwhile, after a nine year break, to include SoA reports in the 2006 conference. Because of the particular interests of the US marine industry in naval ships and offshore engineering, rather than the building of ocean going commercial vessels, both the conference themes and the SoA report topics at that conference emphasised these topics. The six 2006 SoA topics were:• • • • • •

Naval ship design Design methodology Design for Operation Marine-Related Education Offshore design Design for Production

The 2006 design methodology report was restricted to the 1997 report’s generic design topics (namely, design theory and design research, systems engineering, preliminary ship design methodology, combined multi criteria methods and decision support methods, and design for safety) and was a continuation of the first 1997 Marine Design Methodology SoA report. Each section attempted to carry on from the earlier report, although it was appreciated that many readers would not be familiar with the 1997 version. The conclusion to this SoA report called for a discussion of the worth, scope, manner of production, presentation and timing of the IMDC SoA reports, which was undertaken by the Report’s editor in a paper reviewing all the SoA reports presented to the IMDC International Committee in August 2006. It was decided to present three SoA reports at IMDC 2009:• Design Methods and Tools • Design for X (e.g. Safety, Economy, Production, Operation, Artic Conditions, Comfort) • Design and Technology Trends (e.g. by ship type such as Post-PANAMAX (NPX)) This clearly limited the “Design Methodology” report to a similar scope to that of the 2006 Report, namely, a broad generic review. The 2009 Design Methodology State of the Art report concluded with a recapitulation and further remarks on the nine topics first raised in the discussion on the first 1997 Design Methodology report, as these issues were still seen to be relevant. While the bulk of the report focused on developments of a methodological nature since 2006, the third main section was a more wide ranging survey of preliminary ship design (PSD) methods and models than just those arising since the 2006 IMDC. A comprehensive presentation of PSD models and representations was done as it was considered that previous reports had only provided example models and that therefore there was an opportunity to provide the marine design community with a more comprehensive survey. This diversity of visions and explanations of marine design was seen to be in keeping with the objectives of IMDC. Coming to the current set of SoA reports presented at IMDC 2015, they consist of one on Risk Based Design by Professor Vassalos and this Design Methodology State of the Art report, which has two features: reviews (by Professor Andrews) of some ten very recent key design methodological papers; and an essay like review (by Professor Erikstad) on current design methodological developments. The first set of reviews address four topic areas: systems engineering applied to ship design; design insight into the nature of ship design; the use of techniques in marine design; and overview papers which are seen as relevant to marine design methodology. The second review is complemented by an extensive set of references to enable delegates to further pursue the design methodology topics discussed. This is a break in format for Design Methodology State of the Art reports and it is hoped the report’s presentation at IMDC 2015 will give delegates the chance to debate how IMDC State of the Art reports should be presented in future IMDCs.

- 91 -



A REVIEW OF METHODOLOGICALLY RELEVANT RECENT PAPERS (D. J. ANDREWS) A. Systems Engineering 1. Martin 2013 – “How classic Systems Engineering process must change to be effective for use in Ship Design” J L Martin (SAMOSC Ltd UK) ICCAS Busan, Korea Oct 2013.

Figure 9: Proposed change to Systems Engineering process for Ship Design (Martin 2013) This paper, by a former Engineering Fellow at BAE Systems, draws on his work in IT in marine design and as the author of several key papers. It thus summarises his view as to how systems engineering can be better matched to naval ship design practice. In particular it integrates the requirement elucidation philosophy for early stage ship design with an argumentation framework (see Jin & Geslin 2009) (to address “non-functional issues, which Martin uses to encompass the whole ship characteristics “not generally though of as functional”) and thereby modifies the classic S.E. “V” diagram into what he calls a “t” diagram (see Figure 9) for ship design. This amendment to systems engineering applied to large and complex vessels, such as nuclear submarines produced by BAE Systems, shows there is still scope to modify a software and aerospace methodology in its application to the high end of marine design.

2. Sevaldson 2012 – “Systems Oriented Design in maritime design” B Sevaldson, A Paulsen, M Stokke, K Magnus, J Stroemses (Oslo School of Architecture) RINA Systems Engineering Conf London March 2012. Systems Oriented Design (S.O.D.), originating in the field of industrial design research and drawing on generic design research, which has been highlighted in the decade or more of IMDC SoA Design Methodology reports, is now being applied

- 92 -



to marine design. The applications reported here are specifically focused on the “dynamics of human activity systems and its interactions with technology” Thus the examples presented relate to “very complex offshore operations demanding visualisations” to staff on the bridge or similar control situations. Rather than just standard HF techniques, GIGA-mapping (see Figure 1 and Seveldson (2011)) helps the designer create a detailed view of the landscape in which a design project will play out. Its five aspects are: wide size; free styling in information representation; process focused (for designers not stakeholders); not just descriptive but also highly generative; and layered to include sketching, speculation and forecasting. Examples given to date are specific to offshore, oil spill incidents and bridge design but is said to open up a more extensive picture than previous approaches. Another counter intuitive and so interesting output from the Oslo School of Architecture is entitled “Why we should and how we can make the design process more complex” (Berg 2009) which is justified by design becoming more genuinely interdisciplinary. This then requires the designer to have the “capacity for holistic thinking” with “synthesis nurtured through visualisation and creativity”. It thus justifies the provocative statement on complexity seeing the usual engineering desire to simplify as being inadequate for really complex design with major human factor components.

Figure 1: GIGA-map of relations between stakeholders, technologies, operations and responses during a ship accident resulting in oils spill. (Seveldson et al, 2012)

Design Insight 1. Keane & Tibbitts 2013 – “The Fallacy of using a Parent Design – “The Design is Mature”” R G Keane (Ship Design USA, Inc) & B F Tibbitts (USN Capt (RET)) SNAME Expo & Ship Production Symposium Bellevue WA Nov 2013. This is an insightful paper by two very senior US Navy ship designers who have published extensively in US ship design fora and Keane was a Keynote author at IMDC 2003. The paper’s argument (backed up by analysis of several major US Navy designs) is that actually (despite the political and bureaucratic hierarchy’s belief) using an existing design (sometimes called “modified-repeat”, second batch/flight or parent vessel) is not attractive. This is usually believed to be attractive because it is seen to be low risk and a means to constrain performance and control price growth. Rather the authors conclude that “experienced early stage ship design engineers.. (can) rigorously explore the design solution space” (using in the US Navy

- 93 -



the Rapid Ship Design Environment summarised in the paper’s Figure 10 reproduced below). This it is argued counters government assuming “mature designs’ can be easily adapted.

Figure 10: Rapid Ship Design Environment (RSDE) Product Architecture (Keane & Tibbitts 2013) However, the authors see this as being primarily achieved through a greater quantity and types of analyses being done during “early design development” so that confidence is increased “that the design meets the requirements”. This reviewer would question ever-greater analysis in early design for its own sake. Rather the aim of undertaking any such analyses should primarily be consistent with the Requirement Elucidation philosophy propounded by Andrews (2013) (see below). Several excellent quotes are made in the paper and are seen to be highly relevant to the nature of complex ship design: “Success (in engineering design) is Foreseeing Failure” – from Petroski (1992); ‘a successful ship design starts with establishing the initial philosophy for the “new” design”; “design is a one-time process that can only add value when we do something differently”.

2. Andrews 2012 –“Art and science in the design of physically large and complex systems” D Andrews (UCL, UK), Proc Roy Soc Lond A, Vol 468, 2012. This is the third article to a wider scientific audience on the nature of the design of complex systems, drawing on the sophisticated end of the spectrum of marine design. This particular article considers the challenge of such design practice being driven by evermore capable digital computer based techniques and whether such design is now largely the practice of science rather than an art. The whole issue of art and science in design is considered, as is the specific issue of not just complex but also physically large systems (PL&C systems), such as civil engineering structures, chemical processing plant and sophisticated marine vessels and structures. Thus the crucial early stages of such design and the choice of design style are related to both art and science in design. The explosion in computational capability and a series of issues seen as relevant to the future practice of engineering design (specifically applied to PL&C systems) are discussed, including the nature of design synthesis, optimisation, the “wicked problem”, large scale integration and controlling CAD to aid not automate the creative “art” aspect in design. Finally the article concludes that actually art and science remain complementary in such complex design processes, particularly due to the visual dimension, which computer aided graphics is now enabling. Several quotes are made which are again seen as relevant to the nature of complex ship design: “the visual very often has the central role” (in art and science) - from M. Kemp (2000) “Visualisations: The Nature book of Art and Science”, OUP. “Having a visual, geometric representation of a design process is crucial, for designers are spatial thinkers” – from F. P. Brooks (2010) “The design of design – essays from a computer scientist”, Addison-Wesley.

- 94 -



3. Andrews 2013 –“The true nature of Ship concept Design – and what it means for the Future Development of CASD” D Andrews (UCL, UK), COMPIT 2013, Cortona, Italy, Apr 2013.

Figure 2: Representation of the overall ship design process emphasising key decisions (Andrews 2013) It is common to consider the initial, concept or early stages of the ship design process to be the most important phase as the clear majority of the main design decisions are made then, despite the resources employed being minute in comparison to the rest of the ship design process. However it is still largely seen as just an early version of the rest of the design process and so the approach is to quickly conclude on a solution that can then be progressively worked up through the subsequent “real design work”. This paper argues this is wrong and that initial design phase is quite different in its objective. It is not about starting to work up a solution but to elucidate (primarily with the customer/requirement owner) the right (and affordable) set of requirements. Thus for PL&C Systems, at least, the initial design task is to tackle the “wicked problem” of what is really needed and achievable. Various descriptions of the Concept Design Phase are examined before this elucidation approach is justified and the concept process given a robust but not a rigid structure. The final section of the paper looks at the implications this quite different motivation for the concept phase has on various proposals to “improve” the concept phase

- 95 -



(such as producing vast number of numerically derived options, finding “the optimum solution”, getting further into the “design’s description” with first principles analyses) only to argue that an architecturally based initial design best meets the needs of requirement elucidation. Thus any concept phase focused CASD ought to be of a nature that further opens up the requirement elucidation necessary to make the selected design robust beyond the initial phase. It is worth pointing out that the representation of the overall ship design process is seen as one of consciously selecting highlevel choices (Figure 2 in this paper and one presented several times in previous IMDC State of Art Reports). For the first time this model of the ship design process was accompanied by a detailed explanation of each of the fourteen steps in the process and is given in an appendix to the paper and furthermore reproduced in this SoA report, at the end of this section. That explanation gives specific ship design examples to clarify each step in the diagram.

Use of Techniques 1. Nordin 2014 – “Operational analysis in System Design of Submarines during the Early Phases” M Nordin (Defence Research Agency, Stockholm and Chalmers Univ, Gothenburg, Sweden), IJME Vol 156, 2014. This is one of a series of papers, which together outline “a novel submarine design method”. (The title of a recent PhD awarded to Nordin (2015 Chalmers University) based on his work over more than 20 years in the Swedish Navy and Defence Material Administration (FMV) to develop modern computer based methods for submarine design.) The papers have been published in various journals and at conferences and explain in some details the basis behind an integrated approach to the design of the series of Swedish conventional submarines, drawing on a large amount of classified data necessary to detail such specialist military vessels. While the submarine design aspects are spelt out in more depth in the companion paper “A functional approach to Systems Design of Submarines during the Early Phases” (USNEJ Vol 127, Issue 2, June 2015), this paper has been highlighted because it gives the most comprehensive exposition on the application of military Operational Analysis as part of the early design “requirements elucidation” process for such complex vessels. The OA model used can evaluate requirements aggregated in synthesised initial design concepts (using in this case the Swedish “Play-cards” representations of the (so-called) functions domain) and establish their Measures of Capability (MoC) and Measure of Effectiveness (MoE). Details are given on the OA method, how a OA simulation model was produced for submarines for some ten mission types and how these were linked to an “aggregated systems function structure”, how a planned operation profile could be decomposed (including a “tactical decision model”) and then related to MoEs. Most usefully MoE for Surveillance & Reconnaissance and for anti-submarine missions are outlined (without sensitive numerics). Finally a “simulation example” is provided for “the Gotland raid” with ten alternative submarine designs and normalised OA results for MoE and MoC.

Figure 21: The generic submarines model – a synthesised model for Play-Card design, including parametric variation (Nordin 2015) This is a very comprehensive exposition showing how OA can be integrated into the “requirements elucidation process” even if all the sensitive aspects (like signatures so critical to submarine design) can only be indicated, rather than specified. It might also be argued that the Swedish submarine constraints ease the decision and design (or “systems”) space – to the extent that the apparently “functional design” approach (detailed further in several figures in the companion USNEJ 2015 paper) actually require the “style” selection (suggested by Andrews 2013 above) to achieve a matching of “functions with form”. This is acknowledged in Nordin’s PhD at Figure 21, “The generic submarine model” where the second step “Set Design

- 96 -



Parameters and Philosophy “ has “Style” inserted at the end. This recognition that there are philosophical issues in the design of such complex vessels, in acknowledging the designer’s fundamental choice of the style of a new design concept, is seen as justifying the IMDC’s continued emphasis on a philosophical vision to future developments in marine design.

Gaspar 2012 – “Handling Temporal Complexity in the design of non-transport ships using Epoch-Era analysis” H M Gaspar, S O Erikstad (NTNU Trondheim, Norway), A M Ross (M.I.T. Cambridge, MS), IJME Vol 154, Part A3, 2012. This is one of a series of papers applying the M.I.T. developed Epoch-Era Analysis (EEA) approach to the marine domain and specifically to the offshore support vessel design task, where there is no simple measure of merit like Required Freight Rate. Given that the requirement for such non-transport or service vessels is liable to future market and contractual uncertainties, this approach is said to widen the design environment for complex vessel design. Thus the traditional “structural” and “behavioural” aspects are added to, with “temporal”, “contextual” and perceptual” aspects, in order to assess the performance of each alternative design. This is done for distinct “epochs” combined into many possible “eras”, each representing a possible life cycle scenario for each vessel. The authors conclude that the EEA method, in combination with the Trondheim Ship Design and Deployment Problem approach (SDDP), enables such temporal complexity to be tackled in a manageable modular manner. There is a written discussion that further probes the paper’s proposal.

Gaspar 2014 – “Data-Driven Documents (D3) applied to Conceptual Ship Design Knowledge” H M Gaspar (Aalesund Univ College, Norway), P O Brett, A Ebrahim, A Keane (Ulstein Int AS Norway), COMPIT 2014 Darlington, UK, Apr 2014. This paper describes a sophisticated exploitation of the internet using data-driven documents (D3) for early stage ship design. The traditional ship breakdown structure with cost and subsystems elements are encapsulated using tree layout, force layout, pack layout, sunburst layout and Sankey diagrams, as analogous representations. The paper’s discussion focuses on how the proposed approach allows the designer to better interact with a conceptual ship design dataset, as well as facilitating better stakeholder engagement. However there is the clear question as to whether overlaying potentially simplistic initial sizing models with a venier of extensive cloud data, is just a “super black box” approach. There is clearly a need to have the equivalent of the interrogational feature that is provided in some Expert Systems to show the impact of assumptions and the probabilistic validity of design options drawn from such amorphous large databases.

Figure 16: Parametric design methodology (Gaspar et al, 2014)

Overviews Sharma 2012 – “Challenges in computer applications for ship and floating structure design and analysis” R Sharma (IIT Chennai, India), T Kim, R L Storch, H Hopman, S O Erikstad, CAD Vol 44 (2012). This review article is said to address “the key research areas in the design and analysis of ships and floating structures” and said to emphasise “the methodologies, the modelling and the integration of the design and analysis process”. However the

- 97 -



article is primarily focussed on computer techniques, such as CFD and FEM, downstream in the design and manufacturing process of mainstream commercial ships, such as large containerships. Although reference is made to the proceedings of ISSC, ICCAS, IMDC and PRADS in particular, the ship focus seems rather limited with no recognition of the leading roles played in CASD applications, both to offshore craft and naval vessels, particularly in the crucial earliest stages of design. Thus the one initial sizing sequence shown (Figure 3. “the basic ship design approach” is for a classic transportation vessel (VLCC or Containership)) is very simplistically “type-ship” based, with none of the subtleties of requirement elucidation and Design for Layout addressed in recent (2009 and 2012) IMDC Design Methodology reports. As a good indication of major developments in large scale hydrodynamic, structures and, even, production computer applications, the review is worthwhile but its view of ship design and advances being made in the more holistic approaches incorporating human factors and safety issues, particularly in the most demanding and novel applications, is felt to be somewhat limited, despite the reference to IMDC.

McCartan et al 2014 – “European Boat Design Innovation Group: The Marine Design Manifesto” A McCartan, D Harris, B Verheijden (Coventry Univ, UK), M Lundh, M Lutzhoft, D Boote, JJ Hopman, F E Smulders, K Norby, RINA Marine Design Conf, Coventry, UK, Sept 2014. This publication has been included because it is a distinct methodological statement, albeit essentially from the “Marine Design” fraternity, which consist of the Industrial Design discipline now being applied to what is called “boat design”. How ever the example “marine designs” briefly presented are a 130m long pentamaran super yacht and a 63m long HYSWAS hybrid ferry, both of which might be considered to be on the limits of most definitions of “boats”. In postulating “Ship Design Challenges and Recommendations” the paper gives an industrial design emphasis on human factors consistent with motions concerns relevant to fast craft. The lack of a wider appreciation of developments in mainstream ship design methodology is questionable. This is reinforced by the actual “manifesto” drawing on the now historic Bauhaus manifesto and the very mass produced product design stance of the designer Dieter Rams, with questionable relevance to the majority of maritime engineering products, consisting of very large ships and offshore structures. The proposed manifesto consists of 10 “key tenets” which are either very “motherhood-like” (e.g. “Design user experiences not just marine structures”) or reveal a rather narrow view of ship design (e.g. “Advanced platform (sic) technology to reduce propulsion power requirements..” and “Don’t forget the engine room and engine control room (sic)”). All this suggests that the industrial design fraternity, in applying their discipline to “large boat” design, need to have a better discourse with the main ship design discipline? Not one reference (in 81) is to the key papers and reports of IMDC, which seems very remiss.

APPENDIX: DESCRIPTION OF THE STEPS IN THE SHIP DESIGN PROCESS (Figure 2 of Andrews (2013) – see review of Design Insight item 3) a) Perceived need – This should emerge from the customer’s consideration of the market drivers or, in the case of naval vessels, from a threat analysis, the need to get a new sensor or weapon to sea in a new class of vessels or just the replacement of a class of ships that are reaching their end of life. This need is best approached (given the wicked nature of requirement elucidation) in broad terms: thus ‘a new general combatant/fleet escort’ or ‘a replacement amphibious landing (dock) ship’. b) Outline of initial requirements – This should also be very broad in that beyond the basic capability ‘everything should be negotiable’. Aspects, such as cost and time, are still important, but even these should be in the equation as the individual vessel size or style might yet be better met in a manner yet to emerge from the requirements elucidation dialogue. c) Selection of the style of the emergent ship design – This is the first design choice. Given the exploration stage should consider a range of technological solutions, each of these may have specific styles associated with their particular technology (e.g. commercial design standards for a utility helicopter carrier (HMS OCEAN), low underwater signature for an ASW frigate (UK Type 23)). But also there are generic style choices, such as being robust, highly adaptable, high sustainability or low manning, which should be considered for specific concepts. While adopting such style issues is inherent in commencing any design study it is important that this is done consciously since each one has implications for the eventual design outcome and therefore ought to be investigated before that style aspect is incorporated or rejected. d) Selection of major equipments and operational sub-systems – Given an indication for a given solution type on the Concept Exploration solution space (such as a fast trimaran frigate or a utility carrier) and its appropriate performance (e.g. fleet speed, sustained endurance, maintenance standard), it is necessary to postulate from a likely ship size the likely

- 98 -



power plant. It is also necessary to identify the likely major combat equipment or sub-systems. (Selection of standard items such as medium calibre guns or PDMS but less so if a concurrently developing major combat element, such as the PAAMS for the UK Type 45 Destroyer or the Towed array for the UK Type 23 Frigate, where options may be explored. This could be just the size and split of weapon silos but more likely this would be the subject of trade off studies later in concept. e) Selection of Whole Ship Performance Characteristics – For a naval combatant these may actually have more effect on the whole ship solution than the combat system choices. Thus classical hull form drivers of stability, resistance and seakeeping, which could be seen as emerging from the style choices above or more directly. As performance characteristics or laid down standards, like complementing ‘rules’ are likely to be major size and (ship) cost drivers. So again these should be open to revision – probably informed by the Concept Studies stage. f) Selection of synthesis model – Despite the fact that this is a crucial decision, it is often made by default. Individual design organisations have their own synthesis tools and associated data-bases. These can inhibit the scope of the Concept Exploration, if for example a trimaran design cannot then be considered. As was amply demonstrated for the classical numerical synthesis sequence, Andrews (1986), there are inherent assumptions and data/rules in any approach. The real issue is that these are rarely questioned and their limitations can compromise subsequent baseline design definitions and the trade-off studies refining them and the requirements elucidation dialogue – especially if the modelling tool is a ‘black box’. g) Selection of the basis for Decision Making in Initial Synthesis – This should be a conscious choice before the (selected) synthesis modelling tool or approach is used. Again this is often made by default choice of the synthesis tool. Thus classical numeric sizing will balance an option in weight & displacement and volume required & volume available, while subject to crude checks of stability and powering. Often the metric sought is then (an equally) crude initial (weight based) costing – or at best RFR for merchant ships. Whether this is the right basis for decision-making is questionable particularly as the main design drivers may yet to emerge (e.g. underwater noise signature, amphibious force offloading, air wing sortie rate). The more sophisticated architecturally driven synthesis realised by the UCL Design Building Block (DBB) approach opens up the synthesis and enables a Simulation Based Design practice, where the 3-D configuration can be investigated for human factors aspects or other simulations(such as Design for Production, Design for Support and Design for Survivability). This can then ensure that the balanced synthesis reflects more than a crude initial cost and simple stability and power checks. h) Synthesis of Ship Gross Size and Architecture – With the initial choices consciously made the baseline and subsequent concept studies, and then the Concept Design options can be produced. Provided an architectural definition has been included in this many of the style issues and the requirement elucidation (providing the basis for the dialogue with the requirements owner or customer) can be investigated. i) Exploration of Impact of Style, Major Equipment and Performance Characteristics – Although style is seen to be the most crucial exploration, without an architecturally centred synthesis it is questionable that many style aspects can be explored at this stage. Rather most exploration tends to be focused, in the Concept Design trade off stage on ‘payload’ and powering. If, as well as style issues, different solution types such as SWATH and Trimaran configurations are to be properly considered in this exploration the an architecturally based approach should be employed. j) Selection of Criteria for Acceptance of Emerging Design – This is really setting up the basis for the Concept Design stage trade off studies and sensibly informed by the Concept Studies of what might be the crucial style choices. This should not just be dependent on the perceived overall project needs but also which of the technological (and packing/capability) alternatives have been revealed as relevant and significant to be pursued in more depth in the trade-off exercise, when agreement to proceed to the next project phase needs to be robust for high level approval. k) Analysis of Size and Form Characteristics – If just a simple numerical synthesis has been undertaken in the Concept Studies stage then only default hull form parameters are likely to have been assumed. Before the Baseline Design for each of the (few) selected option from the wide Concept Exploration solution space from which Concept Studies have been performed, then it is necessary to conduct an investigation of the main hull dimensions and principal form parameters

- 99 -



(typically for a monohull this includes Cp, Cm, B/T, L/D and superstructure percentage). This is called a parametric survey at UCL, which is different to US Navy practice where the same term denotes a trade-off of hull sizing. If a proper architecturally based synthesis is performed it is likely that the parametric survey will already have been informed by the internal compartmental disposition so that overall hull sizing and shaping will merge from realistic hull form options. If not then hull form dimension and parameters will be wrongly selected and this will only be revealed later in the design development. If unconventional configurations, including multihulls, are being properly considered and then taken forward the likelihood of an unrealistic parameter selection will be even greater, weakening the conclusions from tradeoff studies. l) Architectural and Engineering Synthesis and Analysis – This step reflects the need in a given project to undertake (as part of Concept Design prior to finalising any comprehensive trade off of requirements, style, configuration etc.) specific detailed engineering design and preliminary analysis. Such more detailed first principles design work is not undertaken comprehensively in the Concept Phase – this being the task of the early iterations of the selected Concept Design solution in the next (and subsequent) phase of design (i.e. Feasibility or Embodiment Design). However it may well be for a given project that in the concept phase that a certain aspect needs to be investigated in more depth. (An example of this being done, was that conducted by the author in the early 1990s in the concept phase of what became the UK RFA WAVE Class Tankers (AO). This AO was the first RFA fleet tanker required to be doubled hulled. It was therefore necessary to undertake detailed damage stability analysis of all the ships’ likely operating conditions. This would not normally be required pre-feasibility and reinforces the adage that ‘the minimum detailed engineering is undertaken in the concept phase’, however sometimes the ‘minimum’ is comprehensive in a specific aspect (namely extensive damage stability here)). The inclusion of the ‘architectural element’ in this step’s title is deliberate as once any detailed engineering synthesis and analysis is undertaken, it must be with reference to the internal architectural arrangement or, once again, conclusions drawn will be found to be inadequate or even misleading once Feasibility is underway. m) Evaluation of the design to meet the Criteria of Acceptability – This evaluation occurs both in the trade-off exercise from which the final Concept Design is selected and essentially to the subsequent design development of that design. Clearly it is necessary to have a basis for evaluation to make that selection and to spell out the criteria for acceptability. These criteria will be quite high level for the Concept Phase and of ever greater detail once downstream. Given that the task of Concept is Requirement Elucidation, it is important that the evaluation is consistent with the evolving refinement of the requirement that emerges from the dialogue with the selected Concept Design. That design provides the start point for the Feasibility Phase with the matching requirement statement providing the specification (along with associated standards and style statements) that can be used for the main design development. n) The remaining three steps in Fig. 2 indicate the rest of the design process, once the Concept Phase has been correctly conducted, and is a process of ever greater detailing of the design through the various design phases to achieve sufficient definition for building, setting to work and through life performance. Given these phases constitute the vast bulk of the time and design resources this can seem a little glib. However the point of this current exposition is to emphasise that all subsequent design is based on both the emergent concept design and the matching requirements, such that the initial process as requirements elucidation is quite different in intent and hence process. That far too many major (naval) ship designs revisit much of the concept and requirement effort is clearly indicative that the Concept Phase is too often inadequately undertaken. This is not least because all too often it is seen as the first part of the rest of the design and not the ship design half of Requirements Elucidation.

- 100 -



A REVIEW OF DESIGN METHODOLOGY (S.O. ERIKSTAD) “Design methodology” may refer to multiple aspects of the marine system design process. One is procedural, where a design methodology defines a structured sequence of tasks that supports the complete process from an initial statement of needs and requirements all the way to a description of the final design typically captured in a design specification. Another aspect of design methodology is derived from the primary performance goal that is the focus of the process. This is commonly referred to as “design-for-X” (DfX). Here, the “X” may be replaced by operability, environment, sustainability, safety, and production. Finally, design methodology may refer to the predominant strategy for handling the two-way mapping between the description (form space) and the relevant performance (function space) relevant for the design. This reflects the conceptual easiness of mapping from form to performance (aka analysis) and the difficulty, motivating the need for methodological support, of the opposite mapping from needs and requirements to a satisfying design solution. The design spiral, first presented by (Evans, 1959), is perhaps the most well-known model capturing the sequential, iterative nature of the design process. The design spiral prescribes a relatively smooth process of balancing out conflicting requirements. This idealisation is discussed in recent studies of naval ship design processes, pointing to the fact that the design search space contains regions of cliffs and plateaux in the functional relationships between core capabilities, size and cost (Andrews, Percival, & Pawling, 2012). Further, the design spiral is generally criticised for locking the designer to first assumptions. As a response to these failings, System-Based Design (Levander, 2006) emphasises the development of a functional structure that transforms the customer needs and high-level requirements into a relatively detailed definition of specific functional requirements. In this way, the first assumptions about form, i.e. the specification of main characteristics, are postponed until a fairly well balanced solution can be proposed (based on system-driven Gas Turbine requirements). This follows the basic principles of the German VDI-model (Pahl et al , 2007), and have been applied to many ship types, predominantly cruise vessels and ferries, and most recently extended to offshore service vessels (Erikstad & Levander, 2012). Parallel developments include the design building-block design proposed by UCL (Andrews, 1986, 2003a), and the MIT Responsive Systems Comparison method (Ross & Rhodes, 2008), adopted from the systems engineering domain. Alternative models place more emphasis on innovation and creativeness in the design process. (Koelman, 2013) points to the danger that prescriptive design methods may constrain rather than enhance innovation. For instance, the widespread use of 3D prototyping tools in the early stages tends to lock the designer to first assumptions just by making it possible to provide a concrete, visual model with too much detail at an early stage, At the same time these tools may provide a platform for visual, fast-feedback “design sketching” environment (Alonso, Gonzalez, & Perez, 2013; Koelman, 2013) where the designer´s experience and preference for “design style” can be expressed (Pawling & Andrews, 2011). By connecting parametrically defined building blocks in the 3D model with their corresponding functions in a system-based model, changes in customer needs and functional requirements can be seamlessly forwarded to updates in one or several design templates (Erikstad & Levander, 2012). This can be further combined with decision support systems for space configuration, layouts and arrangements, both using spatial models (Oers, 2011) and non-spatial, topological models (Gillespie, Daniels, & Singer, 2012) (Parker & Singer, 2013).

Figure 1: 3-D model in Google SketchUp, showing alternative vessel configurations based on different templates, all having the same areas and volumes (Vestbøstad, 2011)

- 101 -



“Design-for-X” developments, Risk-Based Design In general, the design-for-X concept puts the emphasis on the performance achievement, and, at least in principle, has no specific requirements towards the specific design solution in terms of rule-based descriptive design features. Thus, DfX is closely related to the general notion of goal-based design approaches and, more specifically, risk-based design (Vassalos, 2012). In (Andrews, Papanikolaou, & Singer, 2012) some recent developments related to “design-for-X” (DfX), is summarized. Green shipping initiatives have motivated an increased focus on design-for-environment and design-for-energyefficiency methods. Alternative technology options are reviewed in (Hirdaris & Cheng, 2012). DNV-GL have looked into different options for CO2 reductions (Hoffmann, Eide, & Endresen, 2012). IMO, IACS (The International Association of Classification Societies) and the maritime industry as such have started a process of moving from prescriptive concepts towards probabilistic assessment methods and goal-based standards (GBS). DfX is closely related to the general notion of goal-based design approaches, and, more specifically, risk-based design. Recent applications include design measures to reduce oil outflow (Konovessis, 2012), and a new approach for damage stability calculations based on the evaluation of hull subdivision to increase survivability beyond SOLAS requirements (Gosch, 2013). Excellent summaries of the state of the art in this area are given by Vassalos (Vassalos, 2012) and Lee et al. (Lee, Lee, Park, & Kang, 2012), and is the subject of the companion IMDC2015 SoA report (Vassalos 2015). Another extention of the DfX concept is towards aggregated, lifecycle based measures of performance, also denoted “design ilities”. (Beesemyer, Ross, & Rhodes, 2012; de Weck, Ross, & Rhodes, 2012; Ross, Rhodes, & Hastings, 2008) One example is design-for-flexibility (Beesemyer, Ross, & Rhodes, 2012; de Weck, Ross, & Rhodes, 2012; Ross, Rhodes, & Hastings, 2008.

Developments in ship form-function mapping, trade-space searches The overall mapping from needs and requirements to preferable solutions in the design space can be supported by several competing strategies. One is optimization, which has a long history also in ship design. Many recent developments have applied heuristics and nature-inspired methods, such as genetic algorithms, particle swarm optimization, ant-colony optimization and simulated annealing. An excellent overview is given in (Collette, 2014). Set-based search strategies provide a conceptually simpler approach (T. A. McKenney, Kemink, & Singer, 2011; Thomas A. McKenney, Buckley, & Singer, 2012). Set-based design has been combined with rule-based configuration for arrangement optimization in the conceptual stage for both naval and offshore vessels (Oers, 2011; Oers, Stapersma, & Hopman, 2007). Since the failure of artificial intelligence to live up to its expectations in the 1980´s and 1990´s, we have lately seen renewed interest in using knowledge-based systems in the design process. Cui and Wang (2013) have encoded the experiences of design experts, design rules and successful previous designs into a knowledge base. Other interesting contributions are intelligent arrangement design for naval vessels (Daniels, Parker, & Singer, 2011), knowledge-based systems used in structural design (H.Z. Yang & N. Ma, 2012), and a neural network prediction model trained with optimized structural arrangement data for estimating the structural properties for alternative hull geometries (V.T. Chaves & Andrade, 2014). From a design perspective, the main purpose of the form-to-function mapping is to provide fast, efficient and accurate evaluations of potential design solutions as part of an overall design process. During the last decade such analysis methods have developed considerably, and high-fidelity, first principles tools, such as computational fluid dynamics (CFD) and advanced finite element analysis (FEA), have become an intrinsic part of industrial design processes. There is a trade-off between the model´s expressiveness, i.e. model fidelity level and the resource expenditure. This reflects a fundamental tradeoff between breadth and depth in the search for design solutions, and is thus an intrinsic part of the design process (Zheng, Gao, Qiu, Shao, & Jiang, 2013). From a normative perspective one should generally start with lower fidelity model in the conceptual stage (go broad) and then migrate towards higher fidelity models in the detailed design stages (go deep). However, since we have few explicit, quantitative measures of the relevant model properties, it is difficult to make a rational trade-off throughout the design process. In general, it seems like the low threshold availability of CFD and FEA tools has contributed to a tendency towards too high fidelity models in the early stages. In practice this leads to a single-point design focus, and correspondingly missing potentially preferred solutions in other parts of the design space. This tendency might be further enhanced by the fact that empirical prediction methods that have proved their usefulness for decades, such as Holtrop & Mennen resistance prediction methods or Schneekluth´s weight approximation methods, have not been updated for several decades (Koelman, 2013).

- 102 -



To counter this development, there are basically two strategies available. The first strategy is to shift outwards the Pareto frontier that represents this trade-off. This can be achieved by a more efficient, seamless integration of high fidelity tools into CAD software (Roberts, Macadam, & Pegg, 2013; Yu, Callet, Tong, Li, & Reynolds, 2012; Cui & Wang, 2013). Alternatively, this can be achieved by more efficient searches through the design space by updating empirical prediction methods, or by applying surrogate modeling methods (Collette, 2014; Prebeg, Zanic, & Vazic, 2014). This includes response surface methodologies (Pajunen & Heinonen, 2013; V.T. Chaves & Andrade, 2014), and experimental design methods (Zheng et al., 2013). A second strategy is to support a better-informed balance between model fidelity and resource expenditure, by associating available tools and methods. This would require the development of relevant metrics. One example of this is the hydrodynamic optimization of catamarans, in addressing the choice between high fidelity (URANS) and low fidelity (potential flow) methods. Using simulation to derive system performance can also be achieved by capturing the complex operation of a ship using a discrete event model. These have been used for both deriving a more detailed and realistic operational profile for the vessel (as opposed to idealized design cases – “service speed, design load line, flat water”), as well as aggregating life cycle performance measures, such as energy efficiency, operability and safety. This will typically call for an extensive modelling of the operating context of the vessel, such a meta-ocean, fleet logistics and ice. This has been applied to the design of LNG transport (Erikstad & Ehlers, 2014), arctic transport (Bergström et al, 2014), the design of ships in rouge sea states (Bitner-Gregersen & Toffoli, 2014) and for ship transport energy efficiency (Coraddu, et al, 2014). This reflects a general extension of system boundaries, analysing ship performance as a part of larger operation or a fleet/logistic chain, see (Hagen & Grimstad, 2010; Ulstein & Brett, 2012; Andrews, 2003b, 2011).

Handling Uncertainty in Future Operating Context There is a considerable degree of risk and uncertainty related to key aspects of a system´s future operating context that needs to be taken into consideration in marine systems design. Examples of uncertain economic factors include the market size, GDP growth rates and oil prices, which affects both the size and structure of the market, as well as freight/day rates. Further, future environmental regulations, such as new emission control areas and potential CO2 trading schemes, will be important for the selection fuels as well as other emission controls. Furthermore, rapid technology development may make current designs non-competitive after only a few years. Thus, there is a fundamental trade-off between adapting to the short-term relatively certain operating context and the investment in additional functionality and performance capabilities to meet future requirements and changes in operating context. These additional capabilities might either be made part of the vessel at the design time, or they may be provided as design options, to be used depending on information only available in the future. Thus, there is a need to develop efficient methods to be used for the conceptual design of innovative ship solutions that are able to deliver value to stakeholders over time, in a complex, uncertain and changing life cycle. Quantitative risk management developed first in the financial sector, designing client portfolios with a predetermined risk profile. This was further developed into a theory for pricing financial options (Black & Scholes, 1973) and later adapted to engineering systems using real options analysis. By this approach it became possible to put a value on future opportunities to change or expand the capabilities of a design, switching between markets, or retrofitting components and technology. Related to marine systems design, real options analysis has been applied to the valuation of combination carriers (Sødal, et al, 2008), shipbuilding contract options (Høegh, 1998) and naval ship design and acquisition (Gregor, 2003). An alternative path for handling uncertainty is stochastic optimization, which explicitly models alternative future scenarios and corresponding probability distributions, taking into consideration real opportunities for design modifications (twostage/multi-stage models). Marine technology applications include the design of emission controls for ships (Balland, et al, 2013), uncertain environmental policy (Niese & Singer, 2013) , and vehicle routing problems (Fagerholt, et al, 2010). Further, the proposed research area will share important characteristics with the emerging field of “Risk-based Design” (Papanikolaou & Soares, 2009) in taking a probabilistic approach towards modelling future events and scenarios (Wagner & Bronsart, 2012). A broader engineering systems perspective on designing for flexibility is provided in the book “Flexibility in Engineering Design” (de Neufville & Scholtes, 2011). Here, a combined theoretical and practical framework is provided for identifying, analysing and implementing flexibility in a broad range of large-scale engineering systems. Other work has integrated design for flexibility and real options evaluation as part of a more complete systems design process (Beesemyer, et al, 2011), (Ross & Rhodes, 2008), which has further been adapted to ship design (Gaspar, et al, 2012).

- 103 -



REFERENCES ALONSO, V., GONZALEZ, C., & PEREZ, R. (2013, 2013/04/15/17). Efficient Use of 3D Tools at Early Design Stages. Paper presented at the Computer and IT Applications in the Maritime Industries (COMPIT). ANDREWS, D J: “An Integrated Approach to Ship Synthesis”, Trans RINA, Vol. 128, 1986. ANDREWS, D. J. (2003a). A Creative Approach to Ship Architecture. International Journal of Maritime Engineering. ANDREWS D J (2003b). ‘Marine Design – Requirement Elucidation rather than Requirement Engineering’ IMDC 03 Athens May 2003 ANDREWS, D J (2011). ‘Marine Requirements Elucidation and the Nature of Preliminary Ship Design’, IJME Vol. 153 Part A1 2011. (DOI No: 10.3940/rina.ijme.2011.a1.202) ANDREWS, D, PAPANIKOLAOU, A, & SINGER, D. (2012). Design for X. State of Art Report presented at IMDC12 - The 11th International Marine Design Conference, Glasgow, Scotland. ANDREWS, D. J, PERCIVAL, V, & PAWLING, R. (2012). Just how valid is the ship design spiral given the existence of cliffs and plateaux? Paper presented at the IMDC12 - The 11th International Marine Design Conference, Glasgow, Scotland. BALLAND, O, ERIKSTAD, S. O, FAGERHOLT, K, & WALLACE, S. (2013). Planning vessels air emission regulations compliance under uncertainty. Journal of Marine Science and Technology, DOI 10.1007/s00773-013-0212-7. BEESEMYER, J. C, FULCOLY, D. O., ROSS, A. M., & RHODES, D. H. (2011). Developing Methods to Design for Evolvability: Research Approach abd Preliminary Design Principles. Paper presented at the 9th Conference on Systems Engineering Research, Los Angeles, CA. BEESEMYER, J. C, ROSS, A. M., & RHODES, D. H. (2012). An Empirical Investigation of System Changes to Frame Links between Design Decisions and Ilities. Procedia Computer Science, 8(0), 31-38. doi: http://dx.doi.org/10.1016/j.procs.2012.01.010 BLACK, F, & SCHOLES, M. (1973). The Pricing of Options and Corporate Liabilities. Journal of Political Economy, 81(3 (May-June 1973)), 637-654. DE NEUFVILLE, R., & SCHOLTES, S. (2011). Flexibility in Engineering Design: MIT Press. DE WECK, O.L., ROSS, A.M., & RHODES, D.H. (2012). Investigating Relationships and Semantic Sets amongst System Lifecycle Properties (Ilities). Paper presented at the 3rd International Conference on Engineering Systems, TU Delft, the Netherlands. ERIKSTAD, S. O, & LEVANDER, K, (2012). System Based Design of Offshore Support Vessels. Paper presented at the IMDC12 - The 11th International Marine Design Conference, Glasgow, Scotland. EVANS, J. H. (1959). Basic design concepts. ASNE Journal. FAGERHOLT, K, HVATTUM, L. M, ESBENSEN, E. F, & NYGREEN, B. (2010). Using Decision Trees for a Stochastic Maritime Routing Problem. Paper presented at the EURO XXIV, Lisbon, Portugal. GASPAR, H, ROSS, A. M., & ERIKSTAD, S. O. (2012). Handling temporal complexity in the design of non-transport ships using epoch-era analysis. International Journal for Maritime Engineering (RINA Transactions Part A), (AP). GILLESPIE, J. W., DANIELS, A. S., & SINGER, D. J. (2012, 2012/06/11/14). Approaching Ship Arrangements from a Nonspatial Point of View Using Network Theory. Paper presented at the International Marine Design Conference. GOSCH, T. (2013, 2013/04/15/17). Simulation-Based Design Approach for Safer RoPax Vessels. Paper presented at the Computer and IT Applications in the Maritime Industries (COMPIT). GREGOR, J. A. (2003). Real options for naval ship design and acquisition : a method for valuing flexibility under uncertainty. (MSc), MIT, Cambridge, MA. Retrieved from http://hdl.handle.net/1721.1/33422 HIRDARIS, SPYROS, & CHENG, FAI. (2012). The role of technology in green ship design. Paper presented at the IMDC2012, Glasgow, Scotland. HOFFMANN, P. N., EIDE, M. S., & ENDRESEN, Ø. (2012). Effect of proposed CO2 emission reduction scenarios on capital expenditure. Maritime Policy & Management, 39(4), 443-460. doi: 10.1080/03088839.2012.690081 HØEGH, M. W. (1998). Options in Shipbuilding Contracts. (MSc), MIT, Cambridge MA. KOELMAN, H. J. (2013). A Mid-Term Outlook on Computer-Aided Ship Design. Paper presented at the COMPIT 2013, Cortona, Italy. KONOVESSIS, D. (2012). An Investigation on Cost-Effective Tanker Design Configurations for Reduced Oil Outflow. Ocean Engineering, 49, 16-24. LEE, J-K, LEE, GYEONG J, PARK, B. J, & KANG, H. J. (2012, 2012/06/11/14). Risk-Based Approaches in Design for Ship Safety. Paper presented at the International Marine Design Conference. LEVANDER, K. (2006). System Based Ship Design. Kompendium. TMR 4110 Marine Design and Engineering, Basic Course, NTNU. Trondheim. NIESE, N. D., & SINGER, D. J. (2013). Strategic Life Cycle Decision-Making for the Management of Complex Systems Subject to Uncertain Environmental Policy. Ocean Engineering, 72, 365-374. OERS, BART VAN. (2011). A Packing Approach for the Early Stage Design of Service Vessels. (PhD), TU Delft, Delft.

- 104 -



PAHL, G, BEITZ, W, BLESSING, L, FELDHUSEN, J, GROTE, K-H, & WALLACE, K. (2007). Engineering Design: A Systematic Approach. London: Springer-Verlag London Limited. PAPANIKOLAOU, A., & SOARES, C.G. (2009). Risk-Based Ship Design: Methods, Tools and Applications: Springer. PARKER, M. C., & SINGER, D. J. (2013, 2013/04/15/17). The Impact of Design Tools: Looking for Insights with a Network Theoretic Approach. Paper presented at the Computer and IT Applications in the Maritime Industries (COMPIT). PAWLING, R, & ANDREWS, D. (2011). Design Sketching – The Next Advance in Computer Aided Preliminary Ship Design? Paper presented at the COMPIT 2011 - 12th International Symposium on Computer and IT Applications in Shipbuilding, Berlin, Germany. ROSS, A. M., & RHODES, D. H. (2008). Architecting systems for value robustness: Research motivations and progress. 2008 2nd Annual Ieee Systems Conference, 110-117. ROSS, A. M., RHODES, D. H., & HASTINGS, D. E. (2008). Defining changeability: Reconciling flexibility, adaptability, scalability, modifiability, and robustness for maintaining system lifecycle value. Systems Engineering, 11(3), 246262. doi: Doi 10.1002/Sys.20098 SØDAL, S, KOEKEBAKKER, S, & AADLAND, R. (2008). Market switching in shipping — A real option model applied to the valuation of combination carriers. Review of Financial Economics, 17(3), 183-203. doi: http://dx.doi.org/10.1016/j.rfe.2007.04.001 VASSALOS, D. (2012, 2012/06/11/14). Design for Safety: Risk-Based Design Life-Cycle Risk Management. Paper presented at the International Marine Design Conference. WAGNER, J, & BRONSART, R. (2012, 2012/06/11/14). Build-Up Scenarios for Ship Life-Cycle-Methods for Descriptor Analysis. Paper presented at the International Marine Design Conference.

ACKNOWLEDGEMENTS The first contributor, as editor of this State of Art Report, would like to acknowledge the helpful comments on the drafts of this SoA report from Professor J J Hopman of Technical University Delft and Dr D J Singer of University of Michigan. The assistance of Lucy Collins, Research Assistant at UCL, in formatting the report and capturing the various images used is also gratefully acknowledged.

- 105 -