SYSTEMS ENGINEERING The architecture of maritime systems Prof. K.J. Rawson, M.Sc, F.Eng., F.R.I.N.A., F.S.I.A.D. Indexing terms: Engineering administration and management, Project and production engineering, Management Abstract: Systems can be seen simply as collections of resources directed towards defined functions. A ship is a self-contained system that can draw on few additional external sources when at sea. The analysis of the system policy yields very different results according to the purpose of the ship, whether it is for trade or for war. The former generates an inflow of earnings that the latter does not. The maritime architect has to address a number of boundaries, including time, geographic, social, ethnic, physical, organisational, industrial, economic and poli- tical. There is also the shore-based investment in compatible cargo transport and handling systems. A process model of ship design becomes a spiral configuration of a decision tree. 1 Introduction Noah was probably the first to apply systems engineering to maritime affairs. His objective was in no doubt. It is clear, however, that his time boundary was uncertain so that optimising his logistics and especially his supply of ravens and doves must have presented problems. Unlike ships today, the Ark had a single predominant objective function (metacentric height) to remain upright. As propul- sion and ship motion were of limited concern, he adopted a short fat ship built of gopher wood in bulk, covered in pitch outside and inside, where the environment must have been powerful indeed, which was more than adequately reliable. Information technology appears to have been based on a dove and an olive leaf and Noah's management difficulties seem to have been substantially emotional, although none the less formidable. Today, without attempting to draw further comparisons with Noah, it is necessary to ensure that one's audience is aware of a speaker's idiosyncrasies in English to minimise the almost inevitable misunderstandings in communica- tion. Systems will be simply collections of resources directed towards defined functions. Design will be regard- ed as a creative iterative process serving a bounded objec- tive. This latter definition introduces all five major features of design: creativity, iteration, process, objective and boundary. The important consideration of boundaries and environment provide the scope for optimisation, choice and change. 2 Purpose design of ships It is probable that, despite their image of clumsy conserva- tism, ships have always been very well matched to their objectives. The tea clippers had a low payload but served superbly well their objectives of fast passage and pro- motional image giving a high utility for the owner. Obsol- escence of transatlantic liners was forced not by poor design but by the greater pace of international business made possible by aircraft. There was no need to consider container traffic until port labour became excessively expensive. It would, indeed, have been a foolish concept in the economic environment of the 1930s. In their days ships served their overall transportation systems well. It is Paper 4775A (M3, M4), received 24th February 1986 First presented at the IEE Colloquium on Systems engineering: its nature and scope, at the IEE, Savoy Place, London, on 13th November 1985 The author is Pro Vice Chancellor and Dean of the Faculty of Education and Design, Brunei, University of West London, Runnymede Campus, Englefield Green, Egham, Surrey TW20 OJZ, United Kingdom equally false to suggest that naval architects did not con- sider the whole system; they worked well with owners, economists, cargo brokers and seamen within the trans- portation system, and with engineers of many disciplines within the ship system design. What has changed is the speed of change. The prol- onged process of designing and building [1] and the enduring quality of such large capital investment are becoming steadily less compatible with the rapid fluctua- tions in trade, national economies [2] weapon develop- ment and available technology. Pressures for flexibility, erosion of safety standards and increasing cost effec- tiveness are inexorable. 3 Policy analysis for a fleet Fleet wide policy analyses for trade and for war are similar only to the extent that they address objectives of cost effec- tiveness (CE) crudely in a form CE = (value = CAW)/cost. Capability C for merchant ships is, of course, profit-related in terms of transport efficiency or cost-benefit analysis, while for ships of war it is almost always a multiheaded monster defined in terms of attack and defence roles and functions. Availability A in merchant ships is predomi- nantly a question of remaining mobile, while in warships it is related in addition to a satisfactory state of every func- tion. W has been used for the demon 'utility' and its equiv- alence in military affairs, military 'worth'. For shipowners, utility is a matter of judging markets and opportunities, while, for any defence ministry, it is beset with strategic assessments and the provision of the right mix of capabil- ities at some unknown time and place in the future. The author [3] challenged the application of discounted cash flow to defence expenditure a long time ago when it was being discovered by the civil service and applied to everything. While debate was never joined, it has since fallen somewhat into disuse. The point is that defence expenditure is almost always long-term and the alternative schemes considered on the basis of outflow of public expenditure will always favour those which prevaricate the most. Unless a scheme can be devised which discounts also inflow, i.e. value, or at the very least availability, the exer- cise is misleading. It is, of course, cost effectiveness which should be discounted were that to be possible. Time is one of the boundaries that define the environment which maritime architects need to address and define with care. Others [4] are geographical, social, ethnic, physical, organisational, industrial, economic and political. Examination of the extent of the boundaries and how they may be manipulated to advantage must, of IEE PROCEEDINGS, Vol. 133, Pt. A, No. 6, SEPTEMBER 1986
Transcript
SYSTEMS ENGINEERING
The architecture of maritime systemsProf. K.J. Rawson, M.Sc, F.Eng., F.R.I.N.A., F.S.I.A.D.
Indexing terms: Engineering administration and management, Project and production engineering, Management
Abstract: Systems can be seen simply as collections of resources directed towards defined functions. A ship is aself-contained system that can draw on few additional external sources when at sea. The analysis of the systempolicy yields very different results according to the purpose of the ship, whether it is for trade or for war. Theformer generates an inflow of earnings that the latter does not. The maritime architect has to address a numberof boundaries, including time, geographic, social, ethnic, physical, organisational, industrial, economic and poli-tical. There is also the shore-based investment in compatible cargo transport and handling systems. A processmodel of ship design becomes a spiral configuration of a decision tree.
1 Introduction
Noah was probably the first to apply systems engineeringto maritime affairs. His objective was in no doubt. It isclear, however, that his time boundary was uncertain sothat optimising his logistics and especially his supply ofravens and doves must have presented problems. Unlikeships today, the Ark had a single predominant objectivefunction (metacentric height) to remain upright. As propul-sion and ship motion were of limited concern, he adopteda short fat ship built of gopher wood in bulk, covered inpitch outside and inside, where the environment must havebeen powerful indeed, which was more than adequatelyreliable. Information technology appears to have beenbased on a dove and an olive leaf and Noah's managementdifficulties seem to have been substantially emotional,although none the less formidable.
Today, without attempting to draw further comparisonswith Noah, it is necessary to ensure that one's audience isaware of a speaker's idiosyncrasies in English to minimisethe almost inevitable misunderstandings in communica-tion. Systems will be simply collections of resourcesdirected towards defined functions. Design will be regard-ed as a creative iterative process serving a bounded objec-tive. This latter definition introduces all five major featuresof design: creativity, iteration, process, objective andboundary. The important consideration of boundaries andenvironment provide the scope for optimisation, choiceand change.
2 Purpose design of ships
It is probable that, despite their image of clumsy conserva-tism, ships have always been very well matched to theirobjectives. The tea clippers had a low payload but servedsuperbly well their objectives of fast passage and pro-motional image giving a high utility for the owner. Obsol-escence of transatlantic liners was forced not by poordesign but by the greater pace of international businessmade possible by aircraft. There was no need to considercontainer traffic until port labour became excessivelyexpensive. It would, indeed, have been a foolish concept inthe economic environment of the 1930s. In their days shipsserved their overall transportation systems well. It is
Paper 4775A (M3, M4), received 24th February 1986First presented at the IEE Colloquium on Systems engineering: its nature andscope, at the IEE, Savoy Place, London, on 13th November 1985The author is Pro Vice Chancellor and Dean of the Faculty of Education andDesign, Brunei, University of West London, Runnymede Campus, Englefield Green,Egham, Surrey TW20 OJZ, United Kingdom
equally false to suggest that naval architects did not con-sider the whole system; they worked well with owners,economists, cargo brokers and seamen within the trans-portation system, and with engineers of many disciplineswithin the ship system design.
What has changed is the speed of change. The prol-onged process of designing and building [1] and theenduring quality of such large capital investment arebecoming steadily less compatible with the rapid fluctua-tions in trade, national economies [2] weapon develop-ment and available technology. Pressures for flexibility,erosion of safety standards and increasing cost effec-tiveness are inexorable.
3 Policy analysis for a fleet
Fleet wide policy analyses for trade and for war are similaronly to the extent that they address objectives of cost effec-tiveness (CE) crudely in a form CE = (value = CAW)/cost.Capability C for merchant ships is, of course, profit-relatedin terms of transport efficiency or cost-benefit analysis,while for ships of war it is almost always a multiheadedmonster defined in terms of attack and defence roles andfunctions. Availability A in merchant ships is predomi-nantly a question of remaining mobile, while in warships itis related in addition to a satisfactory state of every func-tion. W has been used for the demon 'utility' and its equiv-alence in military affairs, military 'worth'. For shipowners,utility is a matter of judging markets and opportunities,while, for any defence ministry, it is beset with strategicassessments and the provision of the right mix of capabil-ities at some unknown time and place in the future.
The author [3] challenged the application of discountedcash flow to defence expenditure a long time ago when itwas being discovered by the civil service and applied toeverything. While debate was never joined, it has sincefallen somewhat into disuse. The point is that defenceexpenditure is almost always long-term and the alternativeschemes considered on the basis of outflow of publicexpenditure will always favour those which prevaricate themost. Unless a scheme can be devised which discounts alsoinflow, i.e. value, or at the very least availability, the exer-cise is misleading. It is, of course, cost effectiveness whichshould be discounted were that to be possible.
Time is one of the boundaries that define theenvironment which maritime architects need to addressand define with care. Others [4] are geographical, social,ethnic, physical, organisational, industrial, economic andpolitical. Examination of the extent of the boundaries andhow they may be manipulated to advantage must, of
IEE PROCEEDINGS, Vol. 133, Pt. A, No. 6, SEPTEMBER 1986
course, depend on objective and utility judgment; the poli-tical boundary, for example, might consider embracinghighly profitable trading with an unstable overseas regimeat high risk. It might also be argued that the developmentof an aircraft carrier in the guise of a through deck cruiser,after the 1966 UK government's withdrawal of involve-ment in aircraft carrier activity, was an act of deft manipu-lation of political boundaries. Ironically, it resulted inHMS Invincible, the Deus ex machina of the Falklandscampaign
4 Cargo transport and handling systems
At the level of policy analysis, maritime systems designersare concerned substantially with geographical, organis-ational, economic, time and political boundaries. Outsidethe offshore, the most spectacular examples in the mercan-tile field have been those resulting in the container trafficand in the roll-on/roll-off ferries. Both of these resultedfrom the examination of the economics of port handling.These can be seen in retrospect in Table 1, comparing thedivision of annual costs for cargo liners on a particularroute to the Far East [5]. It is not, of course, the wholestory; for the same payload both container and Ro-Roships need to be somewhat larger for example. However, itdemonstrates the great differences in cargo handling costswhich originally prompted the designers to push out theboundaries of ship design to embrace cargo handling, and,indeed, even the road and rail transportation systemsinland.
Some exceedingly interesting problems in operationalanalysis derive from the container concept. Worldwide dis-position of empty and full containers can lead an unwarydesigner to container costs many times the cost of the shipif it is not planned and controlled with care and, as is nowcommon, pooled. It is clear also from Table 1 why manyowners are considering wind assistance to reduce fuelcosts.
Complicated as the design of transportation systems maybe, the analysis of military systems can lead to enormouscomplexity and the blind application of systems theory [6]which was developed for the Kennedy administration haslong ago been debunked. The reason for its demise was itsdemand for total numeracy where imprecision or absenceof knowledge prevailed. Because its completion dependedon numbers applied usually in sequence, these wereguessed where they were not known and the results werequickly corrupted. It was a good lesson. It warned clearlyof the misuse of systems engineering. The steps fromacceptable philosophy to numeracy have to be accom-plished with infinite care and there must be a recognitionthat judgement has its part to play together with emotion,communication and faith. As a result, the military systemdesign is today subject to marginal costing and sub-
334
optimisation separating the numerical comparisons fromthe innumerate. Forcing judgment into a numerate stateby such devices as fuzzy sets is, in my view, fraught withdanger.
The presumed threat, of course, has a major influenceon policy analysis. The threat at sea presumed from the airfor example was so dominant in the design of the Types 43and 44 destroyers as successors to the Type 42 that theywere priced completely out of reach [1]. The solution tothe threat became open-ended. The threat postulated hadno limit. A more balanced argument is possible leading toa stable solution by examining the Type 23 as it has devel-oped with the other extreme of a possible solution. Theprime function of this ship is to tow a passive sonar andreport any underwater contacts and this function is domi-nated by the need for silence underwater. Artists' impres-sions of the extreme solutions are shown in Figs. 1 and 2.Fig. 1 is the current design with sophisticated silent
Fig. 1 Type 23 current design
Fig. 2 Type 23 alternative solution
machinery and a self-defence capability, while the otherextreme Fig. 2 is a simple undefended sailing ship. Withinthe same overall life cost, one may have about 30 times asmany of one extreme solution as of the other.
It is not the intention here to develop the policyanalysis which this basic choice engenders. It clearlyinvolves the consideration of many factors, not least thepublic image of a ship which is totally vulnerable to airattack, however far from land it may be, and howevermany more there are to continue with the task after it hasbeen destroyed.
On the whole, strategic modelling at fleet level is some-what more conceivable than a complete application of
1EE PROCEEDINGS, Vol. 133, Pt. A, No. 6, SEPTEMBER 1986
systems engineering within a ship. 'Top-down' modellingat fleet or national defence level at least makes use of sub-stantially independent units addressing particular func-tions and is able consequently to effect tradeoffs andcost-effectiveness study of a range of combinations.However, its success depends greatly on the prescription ofthe scenario, which requires prediction of the enemy, theplace of encounter, the weapons carried by the enemy andtheir damaging potential, the enemy's allies and their facili-ties, logistics backup and political environment prevailingat some unknown moment in the future. Such a task isdaunting to say the least. The scenario on which the spe-cification for the Type 42 Sheffield Class destroyers wasdrawn up was an air-defence ring around a transatlanticconvoy in massive interdependent formation out of sight ofland. But, of course, the Falklands task force had nochoice but to use what it had. No wonder that there issuch conflict between the naval staff seeking maximumflexibility in every unit of the fleet and the operationalanalysts seeking to minimise costs through selectivity.
6 Design mode
The policy analysis phase must determine, in generalterms, the environment of operations and, in particular,the maritime system boundaries in terms of geography,time, politics and economics. It will have been concernedwith fleet-wide operations, either mercantile or military,and will have determined the number of units and some oftheir principal characteristics together with their inter-facing with other units of the system, such as bunkering,port facilities, size, speed and communication. It could nothave been accomplished, of course, without some fore-knowledge of feasible units through the inevitably iterativenature of design activity. However, let us drop a level toconsider the design of a ship within that prescribedcontext.
The first and most important task is to define the physi-cal environment in which the ship will work internally andexternally. From this must emerge the design policy for theship. Possible environments are shown in Table 2. Most of
these are defined by invaluable national or defence stan-dards built up over many years and most are in terms oftheir extremes. Fortunately, the extreme values of each donot occur simultaneously or continuously and are not gen-erally additive. Design policy must clearly state which, ifany, of the extremes should be considered together.Extreme wind and high seas would appear sensibly con-current, but should instability in manoeuvre be alsoassumed? Should a careless closure of a freeing port beassumed during green seas operation? In drawing up thedesign policy, the designer and the owner (whose decisionit is) are drawn quickly into consideration of probabilitiesand operator error, leading on to reliability assessment,risk analysis and the allocation of values for partial safetyfactors. Much of this has, in fact, been done intuitively inthe past, but numeracy is being applied increasingly.Perhaps this is because many wreck reports place theblame on an unfortunate coincidence of two or moreevents.
7 Hazards in warships
In military affairs, the problems are deeply compoundedby an environment exacerbated by enemy action,enhanced natural hazard or the pressure of work underaction conditions. Such additional hazards are shown inTable 3. Let it be said at once that the cost of protectionagainst some of these hazards may be several orders higher
IEE PROCEEDINGS, Vol. 133, Pt. A, No. 6, SEPTEMBER 1986
than those of the previous table. One protection system inanswer to a single hazard may cost 10% of the whole shipprocurement. Once again, design policy must be decidedby the owner or his agents to accord with the policyanalysis of the total maritime system and is absolutely vitalinformation for the ship designer. The deliberate decisionsmade by the politicians of the day on the protection andstandards to be adopted in the Type 21 frigate and theType 42 destroyer, late in the 1960s, had a profound effecton their performance during the Falklands conflict. It wasknown clearly in the 1960s what privations would beincurred by the very severe limits placed on procurementcost. But such risks after 20 years of peace must haveappeared small in comparison with the current nationaleconomic crisis. Such decisions are very difficult and aremuch reviled by a hostile media after events have shownthem to be wrong. This same media in 1979 was able,overnight, to change without a blush from a derogation ofthe designers of gold-plated warships to a condemnationof inadequate standards. While politicians inevitably con-sider the media to be within the boundaries of theirendeavours, designers have been slower in this respect, butwould be wise to do so in view of the increasing manipula-tion of the media and the fickle nature of so-called public
335
opinion through our plethora of current-event commen-tary on radio and television.
8 Design-process model
With a knowledge of required standards and a definitionof the environment to be embraced, the designer mayembark upon the process of ship design. A crude rep-resentation of the overall process is given in Fig. 3 (from
or weight as the principal free variable, it would use func-tion. Thus, every role prescribed for the ship requires iso-lation and the system serving that role may be defined interms of its resources. Some matters are easy. The role 'tofloat' for example is served by an impermeable hull. Therole 'to float when damaged' is rather more difficult. Itrequires definition of the levels of various types of damageand the system serving the role will comprise internal sub-division, information, closure devices, pumping and piping,
complement prime4 parameters
2/VT/eas«
production
L/D
SFCFig. 3 A ship design process model T/D flare B/T
Reference 5) and is a good way to illustrate the order ofevents, the principal parameters, their complex interactionsand the iterative nature of design. It also illustrates thatthose who claim a great breakthrough in one sector arealmost always obscuring disadvantages in other sectors.
Tradeoff is of course a natural consequence of inter-action, and this design spiral illustrates some of those pos-sible. Quantification of these tradeoffs is partially possible,but it is normally at present a matter of judgment as towhat suboptimisation is acceptable and which interactionsare weak enough to be ignored, at least temporarily. Thegreat feature of this traditional approach to the design of aship is that it is convergent, if it is skilfully applied.
One very interesting suboptimisation presented recentlyto a joint meeting of the Nautical Institute and RINA, bySchmidt of the University of Ulster [8], was concernedwith the marginal utilities of various configurations ofhatches and holds in several merchant ship designs. Theauthor related the topography of the ship through sixlevels of increasing detail to the economics of building,stowage and cargo handling and was able to draw quanti-tative comparisons. In such a competitive market, suchstudies are important.
An approach to ship design through the lore of systemsengineering may not be convergent. Instead of using space
336
electricity supply, trained people and a control subsystem;means of maintaining these all in a satisfactory state.These resources are not exclusive to that system. They maybe shared with many other systems. At a glance, it is clearthat the application of systems engineering to ship designis not entirely straightforward.
Military roles require such complicated description thatit is easier to infer them from knowledge of a namedinstallation, e.g. Sea Wolf or Goalkeeper. Nevertheless, aworking functional model of the entire ship can be devisedand was indeed described by Coates [7], in 1968, when hedescribed the embryo Ship Upkeep Information System(SUIS). This system was designed to establish rapidly aship's material state and its consequent availability for awide range of roles; by this both effectiveness and costwould have been known.
Among the reasons for the tragic disbandment of SUISwere its complication and the dependence for informationon unconvinced operators and busy contemporary mana-gers. One of the consequences is that now, 17 years later,we have no information by which to feed a functionalmodel which would quantify the complex interactions.There is no data base. Thus in the application of systemsengineering to ship design we have yet to be somewhatmore modest than to invest in a total functional ship
IEE PROCEEDINGS, Vol. 133, Pt. A, No. 6, SEPTEMBER 1986
model. This is not to say that lesser models are not usefulin effecting tradeoffs within the ship where the demandscan be quantified. They are currently quantified in terms ofspace and weight and, to a lesser extent, cost through thespiral design modelling which, over very many years andthousands of ships, has built up a database. While it isimperfectly a mixture of performance and physical attrib-utes shown in each sector of the design spiral, it does existand the task of replacing it by another albeit more logicalmodel is daunting.
Despite these problems, systems engineering isundoubtedly a beneficial addition to the traditional spiraldesign method in provoking lateral thought, in consideringalternative strategies and redundancies and in breakingdown the traditional barriers among the disciplines con-tributing to the total ship design.
9 Maritime systems management
Some of the boundaries of endeavour which did notfeature largely in policy analysis or in ship design becomemore important when considering systems management.Social and ethnic boundaries, for example, must be ofimportance to a shipping company seeking to retain theiremployees. Should the company bring the seaman's familywithin his management orbit? Should married accommo-dation and schools be provided on his ships and how farshould his pension arrangements go? The Japanese go faralong the road and ensure, thereby, a loyalty to thecompany which is uncommon in Europe. What religiousrecognition is necessary? Should salary be paid to mini-mise tax commitments? With a business which is inevita-bly international all of this is possible and invitesdeliberate structuring of the human system.
The time boundaries will already have been partiallysettled during the policy analysis phase so the degree ofcommitment to systems of maintenance, logistics, trainingand real estate will have been made on the basis ofthrough-life costing. Each represents a major systemdesign in itself and may indeed exceed the cost of procure-ment by a large margin. Amortised through-life costs for adestroyer show procurement to be only a quarter of thetotal. Choice of life obviously affects both effectiveness,through obsolescence, and cost, through modernisationpolicy.
Control of the individual systems serving the throughlife of a fleet requires special study. There is no doubt thatthe larger the management system the higher the inertia indirect management. One wonders often whether the largerministries have not already reached a condition ofmaximum viscosity. The larger the system, the lighterneeds to be the touch of control if it is not to stifle. Indus-trial giants have long recognised this by providing virtualautonomy for their major elements and controlling themas cost centres through cash flow alone. At the otherextreme are the naval dockyards whose control over manyyears has been attempted centrally, and whose efficiencyhas been gravely inhibited by the conflicting influences of adozen or more power centres in the Ministry of Defence,Treasury and Civil Service.
10 Provision for political-policy reversal
Defence, in fact, suffers from special problems when Gov-ernment and Opposition differ fundamentally in dogma.Much of defence is concerned with long-term preparationand investment and long-term production, and, without anational maritime policy [2] stretching clearly ahead,instability and gross inefficiency can result. The permanentofficials feel obliged in serving the country to retain suffi-cient potential to accommodate a reversal of policy at thenext election. This is not, of course, always possible as thedominant loyalty is to the current elected representatives,but a sense of responsibility for a future administration isinevitable in a democracy. There is something to be saidfor separation of defence into an enduring policy agreedamong all political parties and that policy which is not.There is more to be said for breaking up the Ministry ofDefence into truly autonomous elements, where it is pos-sible, and where customer/contractor relationships, advo-cated so long ago, can work.
Some such delegation has, of course, taken place overthe years. Once a contractor, for example, has been coaxedinto developing a satisfactory organisation he is whollyresponsible for quality assurance. Many contracts are nowlet on the basis of performance, but with little of thatmaterial specification which used to be aimed at stan-dardisation and satisfactory interfacing with historical per-formance and with the other fleet systems, logistics,maintenance etc. Much of this hard-earned experience hasbeen dissipated.
11 Conclusion
Within the space of this paper, it is not possible to dojustice to the application of systems engineering to mari-time affairs. The philosophy is undeniably pertinent. Thecollection of sciences which serves that philosophy is readyto apply. Databases are patchy and incomplete. The scopefor adoption in maritime affairs is vast. But let no one seesystems engineering as a panacea or as a novel solution toour problems. It is, however, a way of life which rationallyexplores what needs to be done, just as a design method-ology should achieve.
12 References
1 BRYSON, SIR LINDSAY: The procurement of a warship', Trans.RINA, 1984
2 'British Shipbuilding Policy'. Paper 20/01/85, British Maritime League,July 1985
6 Weapon System Effectiveness Industry Advisory Committee. Report1963
7 BUTTON, M.J., and COATES, J.F.: 'Naval material: advice onrequirements and the feedback of Service data to industry' (Institutionof Mechanical Engineers, 1968)
8 SCHMIDT, F.A.: 'The concept of utility analysis and its application toship analysis' (The Nautical Institute, 1985)
IEE PROCEEDINGS, Vol. 133, Pt. A, No. 6, SEPTEMBER 1986
