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8238

April 1986

THE NATIONAL

SHIPBUILDING

RESEARCH

PROGRAM

Flexible ProductionScheduling System

U.S. DEPARTMENT OF TRANSPORTATION


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ACKNOWLEDGEMENTS This publication was produced for the Los Angeles Division of Todd PacificShipyards Corporation by L.D. Chirillo Associates of Bellevue, Washington.

The material on which the contents are based was compiled by a team for whichoverall management was provided by Y. Ichinose, President of IHI Marine Technol-

ogy, Inc., New York City. Y. Okayama, Deputy Senior Manager, IHI InternationalDivision, Tokyo, is the principal author. He was assisted by T. Hatsuzaki, S. YAiro,F. Morimoto, K. Sayama, and T. Hotehama, all Senior Engineers in productionorganizations of IHIs Kure Shipyard. Editing and some supplemental writing wasperformed by L.D. Chirillo assisted by J.F. Curtis of Manufactured Systems, Inc.,

Seattle, Washington.

Appreciation is also expressed to B.A. Dill and L.A. Willets of Todds LosAngeles Division and to T.W. Lamoureaux and C.K. Kiyonaga of Todds NavalTechnology Division, who furnished essential support.

This publication is an end product of one of the many projects managed and costshared by Todd for the National Shipbuilding Research Program. The Program is acooperative effort by the Maritime Administrations Office of Advanced Ship Devel-opment, the U.S. Navy, and the U.S. shipbuilding industry. The objective, describedby Panel SP-2 of the Ship Production Committee of the Society of Naval Architectsand Marine Engineers, is to improve productivity.


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FOREWORD In Japan the word takuto is used when referring to implementation of integratedschedules for different types of work such as inherent in shipbuilding. Takuto isderived from the German word taktstock which means baton. In the takuto concept,the principle operating manager of a shipyard is envisioned as a conductor whocontrols many musicians to insure the same tempo. Given that schedules for differ-

ent types of shipbuilding work are integrated and based on ranges of variation for

processes in statistical control, anyone being ahead of schedule when building shipsbecomes as detrimental as an orchestra member who exceeds the prescribed tempo.

Just as a conductor, in realizing a musical composition, directs a change in tempo,the principle operating manager, e.g., when adopting an improved work method,directs changes in tempo (updates schedules). For both the music conductor and themanager, the overriding need is to maintain integration.

But, unlike an orchestra conductor, who in the extreme might apply a littletaktstock on the head of someone as a reminder to maintain tempo, in the takuto

concept, controls for insuring adherence to schedules are decentralized. Schedulesare organized in tiers so that daily-schedule lapses are apparent to workers, weeklyto immediate supervisors, hi-weekly to the next level of supervision, and so on.That is, for each lapse the organization of schedules prompts a reaction by a level ofsupervision commensurate with the seriousness of the situation.

The control responses are: transfer of man-power from work flows that are aheadof schedule to those that are behind, use of overtime, and obtaining assistance fromsubcontractors. Of these, the first alternate is the most effective and also the mostdependent upon some degree of trade flexibility.

The methods described herein are those developed by Ishikawajima-HarimaHeavy Industries Co., Ltd. for controlling shipyard workloads. By adaptation theyare applicable to other shipyards which employ product-oriented manufacturingsystems.


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1.0 INTRODUCTION

A schedule which is developed inphases is far more effective than aschedule which attempts a level of de-

tail beyond the progress of design.

Prerequisites for scheduling thatresult in high performances by produc-tion processes and constant improve-ments in a scheduling system are:

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accurate information of material vol-ume (total materials required) cor-responding with each level of designdevelopment,

a system for first assessing allmaterials required in large groupsor units and, as each design phasedevelops, for refining all materialrequirements into small groups orunits,

statistically acquired parameters,based on past performances, whichassociate man-hours normally requiredwith each material group or unit so

as to accurately predict work volume(material volume x parameter = workvolume),

timely preparation of drawings, mate-rial lists and purchase order speci-fications,

effective material management systemsfor material procurement and marshal-ing per schedules, and

procedures for workload leveling andfor regulating the rate of work.

A traditional system work breakdownis impractical for applying the firstthree of the above prerequisites.

System-by-system approaches involvedifficulties in estimating work volume.Production supervisors in charge ofdifferent systems are, to a large de-gree, left to coordinate among them-selves. Each supervisor is relativelyuninformed beforehand of other super-visors! work that will take place inthe same region at the same time. As aconsequence, work is characterized bycompetition for access and reworkwithout corporate knowledge afterwardsof the problems encountered. Mischargesof labor man-hours for work performedare prevalent. Materials and man-hoursare not sufficiently related.

A product approach permits the prin-cipals of Group Technology to be ex-ploited. Work packages classified byzone/problem area/stage are envisionedeven as contract design starts. Prob-lems inherent in the implementation of

such work packages, i.e., producingdistinct interim products (parts, sub-assemblies and assemblies) on produc-tion lines, are much more apparentbeforehand. Work performed which wasclassified by problems, regardless ofinterim-product differences, is readilyanalyzed by statistical methods. Theanalyses constantly direct managers,supervisors and workers to the mostimmediate problems. Also, the analyseskeep current for future work, the pa-

rameters needed for accurately relatingmaterials to required man-hours.


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While there may be other solutions tothe problem of estimating work volumesfor different end products, this publi-cation describes the methods applied byIshikawajima-Harima Heavy Industriesco., Ltd. (IHI) which is a world leaderin the application of a product workbreakdown structure for constructingships, particularly one of a kind, andfor simultaneously constructing endproducts other than ships. Thus, theFlexible-Production Scheduling System(FPSS) described herein is compatiblewith earlier publications which de-scribe other aspects of IHI'S manufac-turing approach. [1]

1.1 Logic and Principles

As compared to other manufacturingendeavors, shipyard operations areunique. Contract design is regarded asa vital part of the manufacturing pro-cess and the time between contractaward and delivery for each end productis set at an optimum duration in orderto achieve the lowest overall cost.Particularly as compared to automobileand home appliance manufacturing, wheredesign and material definition arecompleted before sales efforts begin,

most design details of shipyard endproducts are not known until a consid-erable period after contract award.

Reliance is placed on productionengineers devising a build strategy intime to guide the start of contractdesign. As subsequent design phasesproduce more knowledge, reliance isplaced on phased refinement of thebuild strategy until a level is reachedwhere production engineers provide tac-

tical requirements that are to be in-cluded in the final design products;literally work instructions per zone/area/stage. Most of the work so classi-fied is readily performed as organizedwork flows. Thus, reliance is alsoplaced on production lines (also calledprocess lanes or work flows) whichanticipate tiers of interim products

classified by problem categories in-stead of design simils.rities. The pro-cess lanes are divided into distinctwork stages as shown in Figure 1-1.Ideally, the facilities for such workflows are arranged so that minor flowssupport major flows with minimal needfor transporting interim products fromsites where they are completed to siteswhere they are needed.

Emphasis on organizing material inlike manner with commensurate refine-ments as design phases unfold, simpli-fies scheduling. This approach con-trasts remarkably with traditionalistswho schedule without evidence of workvolume scientifically derived from ma-terial volume. Their only option is to

produce detailed production schedulesusing mostly information that wasavailable from the onset. Such sched-ules, based on insufficient and inac-curate inputs, are a significant reasonfor productivity stagnation. They areinsufficient to regulate process flows.Man-hour losses are inevitable.

Effective schedules are also based onbest known work methods, work processesin statistical control (i.e., having

predictable and repeatable outputs),and integration. Thus, schedule accur-acy means that work is being executedper schedule, not late or not early.Such shipyard schedules, like airlineschedules, require exact compliance. Ifdeparture is too early, would-be pas-sengers are left behind. If flight timeis longer than scheduled, passengersare late. If any aspect of ship con-siiruction proceeds too fast or tooslow, integration is lost and costsrise. Schedules are ineffective unlessthey reflect expected ranges of varia-tion for work processes performingnormally, i.e., work processes in sta-tistical control. In other words,schedule accuracy means that both re-quired man-hours and time durations areknown beforehand. Statistical controlis essential. Effective schedules aremade on the basis of certainty. [2]


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Achieving certainty involves consid-eration of accuracy level, flexibilityrange and integration of schedulesFigure 1-2 illustrates the conceal ofaccuracy level which primarily addres-ses reducing daily man-hour consumptionwithout shortening production duration.Flexibility range is illustrated in

Figure 1-3 which shows normally distri-buted man-hour variations per workpackages of the same classificationthat when averaged yield the same man-hour total scheduled per month. Figure1-4 emphasizes the need for a schedu-ling system to integrate design andmaterial procurement activities withproduction activities in a shipyardmaster schedule. The schedules for allsuch activities must be coordinated.Subgroups within each activity mustcoordinate with each other and withcorresponding subgroups of the othertwo activities.

FPSS employs a statistical approachand integrates activities such as pro-duction planning, scheduling and engi-neering, design, material procurement,and production and achieves high quali-ty schedules. Successful implementationof FPSS requires support, see Figure

1-5, as follows:o

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application of Frame SchedulingMethod (FS14),

coordination by Integrated Hull Con-struction, Outfitting and Painting(IHOP) Scheduling and Tracking,

operation by Decentralized Produc-tion Planning, Scheduling, and Engi-neering, and

assurances for On-Schedule Availabil-ity of Information and Resourceswork instructions, manpower, mate-rial, facilities, etc.). [3]

The support elements are described inChapter 2.0. Their effectiveness isdirectly related to the degrees ofachieved modularization and standardi-zation, not only for raw materials andfinished components but also, for in-terim products, production processlanes, design procedures and documenta-

tion, material management procedures,etc.

1.2 Consistency in the Organization ofWork, People and FPSS

The organization of any type ofscheduling system, of work and of peo-ple should be on the same basis formaximum effectiveness. Also, work vol-umes should be hierarchically organizedand should be assigned times and dura-

tions level by level. This consistentdivision is prerequisite for manpowerallocations by groups that are alsohierarchically organized and managed.

For example, when welding replacedriveting a product work breakdown be-came natural and hull blocks evolved.Eventually, some shipbuilders recog-nized blocks and prerequisite subassem-blies and parts as products. They aban-

doned system orientation as they rea-lized that further productivity gainswere dependent upon adopting a hierar-chical organization of people special-ized along product lines.

1.2.1 PWBS and FPSS

FPSS will not operate well withoutparallel development of a Product WorkBreakdown Structure (PWBS). PWBS pro-vides for separation of work hierarchi-

cally so that numerous interim productsare planned as needed to construct anend product. In the Zone OutfittingMethod (ZOFM), for example, each inter-im product is regarded as a work pack-age for which assorted materials (re-gardless of system) are marshaled pera specific material list of fittings(MLF) in order to comprise a pallet.Thus the terms work package, pallet andMLF are used synonymously as hey eachrepresent outfitting work associated

with a particular zone/area/stage. [4]

[3] As of January 1986 computers are employed in IHI shipyards for calculating the parameters needed


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1.2.3 Organization of People

While process lanes are organized tomatch the nature of interim products,the same organization and the processyard concept serve for budgeting man-hours.

The left side of Figure I-6 shows theorganization of production acti.vititiesin a typical IHI shipyard when ship-building activities peaked, circa 1974.It describes an organization whichmatches a hierarchical division of workby problem categories. There is nosingle production department. Instead,because they each address an inherentlydifferent type of work, there are sepa-rate departments for hull construction,outfitting and painting. Each depart-

ment is subdivided into fabricationand assernbly sections which areprimarily specialized by problem cate-gory. For example, within the hullconstruction department there is aseparate shop for part fabrication andseparate sections for sub-block assem-bly, block assembly, and erection. [5]

Similarly within the outfitting de-partment there is a specialized shopfor pipe-piece fabrication and separatesections for assembly work per variousregions of a ship. The shops and sec-tions are subdivided into process yardsand relate to process lanes as previ-ously described. Most process yardsinvolve several trades.

Shops and sections are, in effect,separate factories each of which pro-duces a specific product line. Theworkers and their assistant foremen

collectively, the foremen, and the shopmanagers are generalists to the degreesrequired by their product lines. Pri-mary focus is on man-hours per product,rather than man-hours per trade. Thus,the right side of Figure 1-6 shows man-hour costs primarily collected by pro-cess flows (problem areas).

The hierarchical product organizationfacilitates a standardized schedulingframework within which each level is

controlled by a level above while beingresponsible for producing a unique andmore definitive schedule. Each levelalso has responsibilities and authority

for making and controlling man-hourbudgets, allocating and leveling man-power, monitoring man-hour consumptionand production progress, and evaluatingproductivity.

A compatible grouping of design in-formation for predicting material vol-ume, and of course work volume, is verynecessary. Such grouping of informationis facilitated by a form of productorganization of design people whichmatches production

s

product organiza-tion; see Figure 1-7. Otherwise, devel-oping process lane work instructionsand the information needed for a FPSSis difficult.

Another important prerequisite forFPSS is a high degree of coordinationbetween people who are concerned withinterim products of the various manu-facturing levels. For example, in boththe Hull Structural Design Group andthe Hull Construction Department, coor-dination is needed between levels,i.e., parts fabrication, sub-block as-sembly, block assembly and hull erec-tion.

1.2.4 Cost Center System and Produc-tion Organization

The Cost Center System (CCS) for Man-power Cost Classification should matchproduct organized process lanes. Asshown in Figure I-6 which is not de-tailed below the shop/section level,nearly all costs are derived from pro-cess flows, i.e., per problem area.

Note should again be made that FigureI-6 is a representation of an IHI ship-yard organization when workloads inJapanese shipyards peaked in about1974. In the decade following, commen-surate with the shipbuilding recessionand a 45% work force reduction, paint-ing was abolished as a department andorganized as a section in the outfit-ting department. Sub-block assembly andblock assembly were assigned to a sin-gle section manager, and subsequently,

the separate hull construction andoutfitting departments were combinedinto a single production department.


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Figure 2-2 is a tabulationent levels of frames for:

o design,

o material definition, and

o man-hour allocation.

of differ- The work volumes for each monthlyschedule are calculated from theparametric component weights whichappear on the MLF associated witheach pallet. Monthly schedules areupdated every 2 weeks for hull con-struction and monthly for outfitting.Each indicates:

With regard to Figure 2-3 which par-ticularly displays the hierarchicalnature of FSM:

o Each shop/section schedule shown isfor a specific ship, i.e., theyare made ship by ship and shop/sec-tion managers are responsible fortheir preparation. Each applies to arelatively long period, usually 6months for hull construction and 12months for outfitting, and is updatedevery 2 months for hull construction,and upon completion of material listsby systems (KLS) and again upon com-pletion of MLF for outfitting. Foroutfitting, an initial shop/sectionschedule is based on the known mate-rial volume after pallets are definedon a transition drawing, i.e., aftersystems and zones are interrelated.It is used for establishing material

procurement and drawing issue sched-ules and, afterwards, is updated withthe material volumes of defined pal-lets. Each shop/section schedule in-dicates:

a shop's/section's key milestones,

work periods for each summary unit,

work volumes by number of workersper craft, and

number of workers per craft foreach 10 working days.

o A monthly schedule applies to work tobe performed for all ships by asingle process yard during the coming1 months for hull construction and 2months for outfitting. It is some-times called a yard schedule such asfor an on-unit outfitting yard, on-block outfitting yard, and on-board

outfitting yard. A monthly scheduleis the responsibility of a foreman.

a process yard's detailed mile-stones,

work periods per pallet,

pallet work volumes, and

number of workers Per craft foreach 5 working day;. As shown inFigure 2-2 the scheduling process,starting at a large frame (masterschedule level), continues to week-ly schedules for which assistantforeman are responsible. Dailyschedules are the concern of work-ers and are usually not formallyprepared.

All schedules are coordinated witheach other and are the basis for asses-sing progress during a weekly meetingof each shop's/section's production

engineers and, sometimes, foremen. Act-ing for the shop/section manager, pro-duction engineers redistribute man-power, authorize specific amounts ofovertime, assign surplus work to sub-contractors, and update schedules, ifnecessary with carry-over notations asshown in Figure 2-3.

Figure 2-.4 shows an FSM logic model.It illustrates how to:

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imagine work frames,

group work frames in large summaryunits, and

sequence and schedule work frames.

Work from lofting to final paintingare each represented as a large workframe plotted against a time frame. Asmore concrete work instructions aredeveloped, subdivisions of these framesto represent subordinate schedules as-sure their coordination.


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2.2 Integrated Hull Construction,Outfitting and Painting (IHOP)Scheduling and Tracking Operation

IHOP requires great cooperation be-tween all shipyard functionaries. Hullconstruction design and production en-

gineers are required to have under-standing of outfitting and paintingneeds. "Integrated planning is achievedby discussion, trade-offs and ultimate-ly mutual consent. The overriding goalis an increase in productivity for anentire shipbuilding system." [2]

Integration of the Zone OutfittingMethod (ZOFM) and Zone Painting Method(ZPTM) into the production processesfor the Hull Block Construction Method(HBCM) necessitates coordination oftheir scheduling and tracking opera-tions as shown in Figure 2-5.

With simultaneous reference to Fig-ures 2-4 and 2-5, note is made thathull block erection work is scheduledfirst (Figure 2-4 shows that the pyra-mid method will be used and the blocknext to the forward engine-room bulk-head will be the first to be erected).

Afterwards, other work, including out-fitting and painting, is scheduledbefore and after the scheduled erectionof each block by moving backward andforward in time respectively and withinthe large frames designated.

Tracking operations are conducted atweekly meetings similar to that de-scribed in Part 2.1.

2.3 Decentralized Production Planning,

Scheduling, and Engineering2.3.I Decentralization

Decentralized production planning,scheduling and engineering is verypractical for FSN and IHOP schedulingand tracking. At the same time decen-tralization promotes so-called top-down/bottom-up and lateral informationinterchanges in a tree-structured net-work. Production engineers and other

planning, scheduling, and engineeringstaff functionaries having real re-sponsibilities at every level, arereadily able to:

o prepare realistic integrated sched-ules,

o regulate process flows to insuretheir coordination and conformancewith higher tier schedules.

Production planning and engineeringfunctions, specifically includingscheduling, are decentralized. People

having such responsibilities are dis-tributed as shown in Figure 2-6. TheProduction Control Department shown inFigure 2-6, acting for the ShipyardManager, is responsible for maintainingthe Shipyard Master Schedule (top-down)and for providing information (bottom-up) about resource availability whichpermits corporate headquarters to main-tain a Shipbuilding Division MasterSchedule.

Similar top-down/bottom-up, plus lat-eral, information exchanges take placeat each of the succeeding levels, i.e.,by departments, shops', and sectionslplanning, scheduling, and engineeringstaffs, and by foremen and assistantforemen. At the highest levels, strate-gic information is exchanged. At thelowest levels, the information ex-changed is tactical in nature.

2.3.2 Consistency of Organization andSchedule Levels

Figure 2-7 illustrates a typicalorganization breakdown and consistentschedules for each of the followinglevels:

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shipyard,

department,

shop,

foreman (F-group),

assistant foremen (AF-group), and

worker.

In accordance with the decentraliza-tion of responsibility, each level has

certain authority to schedule as notedin the right side of Figure 2-7. Whatappears to be illustrated on the leftside of the figure is a hierarchicalorganization similar to the organiza-tion charts of many bureaucracies. But,at each level there is scheduling au-thority in addition to other pro-duction planning and engineering author


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2.3.3 Tree-Structured Networki i


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Organization

Per framed orders that come downthrough the tree-structured organiza-tion, each worker reports progress,behind or ahead of schedule, to anaosisant foremen. Such reports are

used by assistant foremen to updateweekly schedules. If something coulddelay the start of work at a followingstage of the work flow, the assistantforeman reports to a foreman. The lat-ter coordinates with other foremen,updates a monthly schedule and/or, whennecessary, reports to the productionengineer-in-charge. The latter coordi-nates with other engineers-in-chargeand if the delay affects a shop/sectionschedule, reports to the shop/section

manager who would coordinate with other/shop section managers. Coordinationtakes place among people at the samelevel as well as up and down betweenlevels. The tree-structured network, asshown in Figure 2-8, operates likecasting fishnets of different meshes.Nets from small to large mesh "catch"problems of "sizes" that are commen-surate with the resolution authoritythat exists at each level. [3]

2.4 On-Schedule Availability ofInformation and Resources

From preparation of a build strategybefore contract award, until the startof work in response to the last workpackage, successful implementation ofFPSS is dependent upon timely informa-tion and resources such as:

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drawings and other end products pre-pared by designers,

manpower available,

facilities including jigs and tools,and

materials including interim products.

Omission or late preparation of anyone, disrupts efforts by productionengineers to achieve effective analyses,decisions, implementation, control andfeedback.

Untimely availability of informationand resources require schedule changeswhich, for a particular level, could bebeyond its resolution latitude or eventhe resolution latitude of the nexthighest level. Continued delays or anaccumulation of such delays cause esca-lation to higher schedule levels andultimately postponement of a ship'sdelivery. Coordination of low-tierschedules is necessary even for support

activities by design and material mana-gers.

The various lead times, in additionto manufacturing lead times, for amaterial procurement example are shownin Figure 2-9. Such lead times alsoapply to required information and otherresources.

The need for reliable schedule inputsalso emphasizes why shipyard managers

have to deal with fewer suppliers withwhom they have relatively great experi-ence. Adopting a limited number ofvendor catalog items (about three perfunctional requirement) as shipyardstandards with reliable schedulingdata, among other prerequisites, hasbeen found by leading shipbuilders tobe more effective than selection ofmaterials based on low bids only. [4]

Obviously, the various production

planning and engineering staffs whichhave scheduling responsibilities haveto standardize and systematize theiractivities in concert with design andmaterial managers. Figure 2-10 showsthe necessary information flows thatare required to produce integratedschedules that truly predict how workwill be performed.

[3] The system is supported by a human-oriented organization to facilitate participation by allmembers. See Strength and Weaknesses of Japanese Management, by Jiro Tokuyama, Kenshu, The AOTSQuarterly, published by The Association for Overseas Technicsl Scholarships, Tokyo, Summer 1985, pp. 6


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3.O SHIPYARD MASTER SCHEDULE

3.1 General

The shipyard manager controls theintegration of production scheduleswith design and material procurementschedules. This coordination functionia vital. Further, the shipyard managercontrols the delegation of authorityper management level, i.e., department,shop/section, foreman, and assistantforeman. As the most effective way tomaintain such controls, usually thenext senior manager in the shipyard isassigned as the head of the productioncontrol department who reports directly

to the shipyard manager as shown inFigure 3-1. In practice the heads ofthe Hull Construction, Outfitting, andPainting Departments (or the head ofthe Production Department) report tothe Shipyard Manager through the Pro-duction Control Manager.

An additional prerequisite for effec-tive control is assignment of purchas-ing, subcontracting and material con-trol responsibilities to the production

control department as also shown inFigure 3-1. Immediately acting for theshipyard manager, the production con-trol manager readily balances top-levelallocations of materials and man-hourswith schedules. [1]

So organized, the shipyard managerassisted by the production controldepartment produces a shipyard masterschedule which consists of:

long-term schedules and assessmentsfor the future with a manning plan,

specific ship schedules based onIHOP, and

o design and material lead-time assess-ments for schedule integration.

Aside from being the top-level framefrom which lower level frames are de-rived, the shipyard master schedule isused for establishing sales' goals andkeeps the top manager apprised of re-quirements for manpower and facilitiesrelative to contracts in hand and tocontracts contemplated in a sales plan.

Within the production control depart-ment, the production control section is

responsible for actually preparing andmaintaining the shipyard master sched-ule for the shipyard manager. The pur-chasing and subcontracting section con-tributes by performing material pro-curement research and maintaining filesof up-to-date and reliable materiallead-times as required for masterscheduling.

[1] The linkage of purchasing, material control and scheduling responsibilities also facilitatesopen-end labor subcontracts with delegation of triggering action to shop/section managers. When itbecomes apparent that subcontractor assistance is needed to insure schedule adherence, a shop/sectionmanager is not encumbered with bureaucratic procedures. Labor subcontracts are entered into andmanaged by the shops/sections They are processed through the Purchasing Section only as a formality


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3.2.1 Prerequisites

The prerequisites for a shipyard Shipyard Manager as the only alterna-


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p q pymaster schedule are the:

hull construction, outfitting andpainting man-hour cumulativeschedules,

design man-hour cumulative schedule,and

major-material lead-time schedule.

3.2.2 Procedure

a.

b.

c.

d.

e.

Choose the S-curve most adaptable tothe specific ship and adjust it asnecessary to achieve a best fit.Distribute the budgetary man-hoursmonth by month per the S-curve se-lected.

Redraw the S-curve to fit the man-hours available.

Add the man-hours of all S-curvesfor each month in a given periodas shown in Figure 1-2.

Compare the monthly accumulated man-hours with the man-hours availableat the shipyard.

Check major long-lead time materialsto ascertain whether they can bedelivered in time to meet need datesin production schedules. If someare not going to be available intime, the need dates must be modi-fied accordingly. Otherwise, theschedule is not feasible.

Steps a. through d. determine the

capacity of the shipyard in a largeframe sense. They could be eliminatedfrom this scheduling level if the mas-ter schedules of each department wereof high quality. Then, they could sub-stitute for the shipyard S-curve.

3.2.3 Coordinating

If a schedule is found to be infeasi-ble, the dates for fabrication start,keel laying, launching, and delivery

are modified to match realistic produc-tion and material delivery dates. Adja-cent schedules for other ships areadjusted within ranges that permitrecovery of any incurred delays. If notpossible, the matter is referred to the

tive left is to increase the availabil-ity of manpower through the use ofovertime work and/or subcontractors.

3.2.4 Issue, Updating and Recovery

Master schedules are issued frequent-ly enough, every three months and uponreceipt of each new order, so thatrevisions are not normally required. Noprovision is made for recovering delaysin implementation since master sched-ules are not intended to be used forcontrol of actual work. If somethingunexpected delays a milestone such askeel laying, recovery for delivery asscheduled is attempted on lower activi-ty schedules.

3.3 Shipyard Master Schedule(New Order)

Preparation of a Shipyard MasterSchedule (New Order) is per the flowshown in Figure 3-6. The purpose ofthis schedule is to coordinate allpertinent operations when a new orderis likely to be awarded. When the oc-casion coincides with a periodic issue,the periodic issue is omitted.

Preparation involves inserting thekey dates for the new order in theschedule and adjusting key dates forprojects already in the schedule asnecessary to accommodate work for thenew order. Adjustment of an existingschedule can be done much faster thanpreparing a new master schedule.

An essential aim of the Shipyard

Master Schedule (New Order) is toquickly provide the new workload statusfor the sales department.

3.3.1 Prerequisites

The Shipyard Manager requires theDesign, Hull Construction, Outfittingand Painting Departments to verify thattheir man-hour cumulative schedules arerealistic. In turn, the departmentsrequire similar checks by their shops/

sections. Such active participation inthe scheduling operation by the peopledirectly involved in implementingschedules contributes to awakeningtheir interest and sense of responsi-bility for adhering to schedules.

3.3.2 Procedure

a. Check the S-curve used in the peri-odic schedule If necessary replace

Steps a. through c. finalize a ship-yard master schedule for a new order by


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b.

c.

d.

e.

odic schedule. If necessary replaceit with a more suitable curve.

Revise the cumulative monthly man-hour requirements taking into ac-count the man-hours available. Ifnecessary adjust the man-hour accum-ulations for ships adjacent inthe schedule.

Compare the total cumulative monthlyman-hour requirements with the man-hours available. In doing this,check the man-hour accumulations foreach department against the sum forits shops.

Check the need dates and lead times,

including lead times for preparationof purchase specifications, for cri-tical major materials.

Verify that the Shipbuilding Master)Schedule (New Order thus deter-

mined:

is realistic,

authorizes the individual man-hourcumulative schedules prepared by

the Design, Hull Construction,Outfitting and Painting Depart-ments, and

includes the Purchasing Sectionsmajor material lead time schedule.

yard master schedule for a new order byspecifying key dates in a large framesense. The process does not includechecks of the detail schedules whichwill control individual shops.

3.3.3 Coordinating

If the checking process disclosesthat the lead times for critical majormaterials are not being accommodated thefollowing action should be taken:

adjust the dates of keel laying,launching and delivery, or

increase the man-hours available byarranging for overtime work or for

subcontractors.

3.3.4 Issue, Updating and Recovery

A Shipyard Master Schedule (NewOrder) is issued when a new order isreceived or is imminent, or when aspecial request is received from thesales department. Updating is routinelyaccomplished by the Shipyard MasterSchedule (Periodic). If something unex-pected delays a milestone such as keel

laying, recovery for delivery as sched-uled is attempted on lower activityschedules.


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4.0 HULL BLOCK CONSTRUCTION METHOD

Hull construction schedules are keyinstruments because they also influencethe effectiveness of outfitting andpainting operations. Necessarily, pro-

duction engineers who have hull con-struction responsibilities have to haveknowledge of and assume a degree ofleadership for outfitting and paintingduring the preparation of integratedschedules. Hull construction schedulesmust be based on sound logic becausethey comprise the framework upon whichdesign, material procurement, outfit-ting, and painting people base theircommitments to a master schedule.

A hull construction schedule whichattempts to optimize only hull con-struction processes is sure to entailsacrifice of efficiency in the otherdepartments. Such losses more thanoffset the purported hull constructiongain and eventually jeopardize even thehull construction schedule. Thus, theShipyard Manager insures that otherdisciplines are represented during theestablishment of a hull construction

schedule. An effective tool for ensur-ing the necessary coordination by thediverse participants is the FlexibleProduction Scheduling System (FPSS).

4.1 Organization

Figure 4-1 shows an organization inwhich hull construction productionplanning, scheduling, and engineeringresponsibilities are distributed at theshipyard, department, and shop/section

levels.

Within the Hull Construction Depart-ment, schedules are produced level bylevel for creating long-, medium-, andshort-term schedules for work flows

typically organized as in Figure 1-1.They are used for:

defining time frames,

allocating man-hours,

tracking, i.e., determining whenspecific flows are ahead or behindschedule,

adjusting for recovery of time framesscheduled, and

obtaining reliable feedback for bothproducing better schedules and im-

proving the scheduling system.

In accordance with the principle ofdecentralization, people at each levelhave authority to act and further dele-gate. They periodically or occasiona-lly communicate with and/or report to:

their peers in other departments, and

People in levels above and below.

As shown in Figure 4-1 the Hull Con-struction Department is organized tomatch the zone/problem area/stage clas-sifications that reflect a product workbreakdown. For all work other than hullerection, the various trades needed toproduce products of a particular clas-sifications are grouped under a singleforeman (F-group) per the process yardconcept. In contrast, the erectionsection is grouped by trade because

process yards are impractical. There-fore, when coordinating erection acti-vities for several ships, a prime fac-tor is coordination of the output ofthe process yards. This differentgrouping of workers entails differentscheduling methods.


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4.2 Frame Scheduling Method

Hull Construction Department sched- Another shortcoming of

traditional


43/165

pules are prepared in the sequence shownin Figure 4-2. Within frames prescribedfor the various levels, people at eachlevel prepare schedules as tabulated inFigure 4-3. As shown in Figure 4-2, the

Man-hour Cumulative Schedules (Periodicand New Order) are needed for preparinga Shipyard Master Schedule and forgoverning lower-tier schedules.

Some traditional schedule flows aresequenced as shipyard master, produc-tion control and production executionschedules and seem, at first sight, tofollow the sequence shown in Figure4-2. But, the concepts of man-houraccumulation and backward scheduling

are lacking. Backward scheduling meansstarting with the required completiondate of an operation and obtaining man-hour requirements from statisticalanalysis of past performances in orderto schedule a start date.

For hull construction, backwardscheduling utilizes the date of erec-tion of each block as a date to be heldfirm and from which to count backward.

Time frames are allowed for painting,on-block outfitting, block assembly,sub-block assenbly and parts fabrica-tion. Such backward scheduling withman-hour accumulations eliminate super-fluous time periods between activities.Then, interim products flow so as tooccupy workers and facilities withoutintermissions. Eliminating intermis-sions is necessary for avoiding waste-ful loss of time during production.

The sizes of frames for hull sched-uling are presented in Figure 4-3. Thechanges in sizes from large to small asdesign and material definition pro-gress, represents scheduling refine-ment.

As design and material definitionprogresses, that which is encompassedby a frame is described by its parame-tric weight. The weights are translated

into required man-hours by conversionfactors or parameters that are specificper shipyard, per frame level, and perinterim product. Start dates are accur-ately determined from required dateswith due regard for man-hour accumula-tions. Traditional practice is to spec-ify only start and completion dates for

gscheduling is the use of the same sizeframes and same parameters throughoutthe entire scheduling process. The samerule-of-thumb data is relied upon de-spite the fact that more definitive

information becomes available as designprogresses. The resulting schedules areimpractical and often have to be signi-ficantly revised midway in a projectwith serious affect on a master sched-ule. Such disasters are avoided byconstantly refining work volumes com-mensurate with design refinement.

The recommended scheduling proceduredescribed in the following incorporatesthe previously described support ele-

ments, i.e.:

Frame Scheduling Method (FSM),

Integrated Hull Construction, Outfit-ting and Painting (IHOP) Schedulingand Tracking,

Decentralized Production Planning,Scheduling, and Engineering, and

On-Schedule Availability of Informa-tion and Resources.

4.3 Man-Hour Cumulative Scheduling(Periodic)

4.3.1 General

The pertinent activity flow is de-picted in Figure 4-4.

Purpose:

- to review the Shipbuilding MasterSchedule from the standpoint ofman-hour availability, and

- to coordinate the overall man-hourdistribution between departments.

Prerequisites:

- Shipyard Master Schedule, and

- past records of the relationshipsbetween steel weight and productionman-hours used.

Frames

Subjects treated: ships (and end


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4.3.2 Procedure

Budget Compilation

i bl ifi d f hi

as they would have to advance theirinterface milestones such as ford i i d t i l il


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- Variables specified: type of shipand hull-steel weight.

- Estimating work volumes: For eachship type, the shipyard maintains

in its historical file a plot ofman-hours required versus hull-steel weight. Thus, the estimatedhull-steel weight for a contem-plated ship is readily convertedinto estimated work volume. Assimilar ships may not have beenbuilt in the recent past, the ship-yard manager may judgementally mod-ify this work volume in order toreflect current productivity.

Man-hour Accumulation

- Variables specified: percentages oftotal man-hours required that areestimated to be consumed at con-tract signing, fabrication start,keel laying, launching and delivery.

- Estimating work volumes for indivi-dual frames: Distribute the re-quired work volumes estimated,

month by month, along the S-curveselected.

Leveling

- Comparison between work volume andman-hours available: Compare thework volumes estimated with theman-hours available which is de-rived from the number of workers.Record the discrepancies betweenthe two on a monthly basis. The

manager of the Hull ConstructionDepartment discusses the discrepan-cies with the other departmentmanagers in order to identify thebest possible remedies.

Measures for Leveling the Work Load:The proposed solutions which arepresented to the shipyard managercould consist of any combinationof: advancement of part of theactivities which comprise work load

peaks (this requires careful co-ordination with other departments

drawing issue and material availa-bility dates), redistribution ofthe work force, overtime work, andadditional work shifts.

4.3.3 Coordinating

Items

- Drawing issue situation, i.e, pros-pect of receiving drawings asscheduled.

- Major material availability situa-tion, i.e., prospects of receivingmajor materials as scheduled.

- Reserving necessary work facilitiesis not relevant at this stage.

- Assessing the potential of otherproduction process lanes, e.g., foroutfitting and painting, opera-tions.

Coordination

- Taking into account the foregoingfactors, advance activities on theschedule accordingly.

4.3.4 Output Data and Timing

Output: See Figure A-1. [1]

Timing: Every three months.

4.3.5 UPdating and Recovery

Updating: Every three months.

Recovery: Upon issue of the schedule,every three months, the man-hoursallocated are checked against actualman-hours expended. The balance ofallocated man-hours is determined andan estimate is made of man-hoursrequired for completion. If the re-maining man-hours are insufficientfor the work remaining, in order toprevent delays, a request to revisethe budgeted man-hours is addressed

to the Shipyard Manager.

4.4 Man-Hour Cumulative Scheduling(New Order)

4.4.1 General

4.5 Tentative Erection Scheduling

4.5.1 General

Tentative erection scheduling could


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Purpose

- to review and firmly confirm theShipbuilding Master Schedule for aspecific ship from the standpointof man-hour availability.

Prerequisites

Shipyard Master Schedule (Periodic)

- Budget Control List

Frames

Subject treated: a specific ship.

Unit: departments and shops fortheir respective levels.

Period: each month from fabricationstart to delivery.

4.4.2 Procedure

The procedure is the same as de-scribed for Part 4.3.2.

4.4.3 Coordinating

Items

- Drawing issue situation. In themost serious sense, checks shouldbe made concerning whether drawingsare likely to be issued in time forproduction.

- Material availability situation.Most seriously, check whether steelmaterials are likely to be avail-able in time to start fabrication.


Coordination

- Advance scheduled operations asnecessary.

4.4.4 Output Data and its Timing

Output timing is on command from theShipyard Manager.

gbe overtaken by preliminary erectionscheduling if sufficent prerequisitedata is available at this stage. Thepertinent activity flow is depicted inFigure 4-6.

Purpose

to develop the activities timingschedules for the hull construc-tion, outfitting and painting de-partments.

to inform the hull design office oferection sequences.

to confirm the time frame allocatedbetween keel laying and launching.

Prerequisites

- General Arrangement

- Machinery Arrangement

- Midship Section

- Preliminary Block Arrangement

Frames

Subject Treated: Specific ship.

Frame Size: Several erection blocksframed as a group, i.e., a blockframe.

Time Period: Each day from keellaying to launching.

4.5.2 Procedure

Determine the erection sequence onthe preliminary block arrangementbased on records of erection sequen-ces employed for previously builtships.

Level the numbers of block frames tobe erected each week between keellaying and launching with reference

to erection schedules for previouslybuilt ships.

Man-hour Cumulation is not relevant.

Comparison with man-hours availableis not relevant.


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Output: See Figure A-2.

Timing: After signing of a contract

blocks may not have been built inthe recent past, the Hull Depart-ment manager may judgementally mod-ify this work volume in order toreflect current productivity


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Timing: After signing of a contract.

4.5.5 Updating and Recovery

Updating: NO updating is performed

unless key milestones, e.g., keellaying and launching dates, are re-vised before issue of the preliminaryerection schedule.

Recovery is not relevant.

4.6 Hull Construction ActivitiesTiming Scheduling

4.6.1 General


Purpose

- for the hull construction depart-ment to coordinate the activitiestiming schedule with other depart-ments.

reflect current productivity.

Determining the starting and finish-ing dates for assembly and fabrica-tion, and the deadline dates for

drawing and material issues per blockframe.

- Obtain erection dates per blockframe from the tentative erectionschedule.

- Determine the starting and finish-ing for assembly and fabricationper block frame, and the drawingand material issue deadline datesby backward scheduling from theerection dates.

Man-hour accumulation is not rele-vant.


Leveling is not relevant.

- to determine the starting and fin-

ishing points of frames and toestimate their work volumes.

Prerequisites

- Block Arrangement

- Block Assembly Plan

- Machinery Arrangement

Frames

- Subject Treated: Specific ship.

- Frame Size: Individual activitiesof the hull construction processfor each frame of blocks.

- Time Period: each span of 10 work-days from keel laying to launching.

4.6.2 Procedure

o Determining the work volumes of blockframes.

- Variables Specified: Type of shipand kind and size of blocks.

Estimating Work Volumes: For each

4 . 6 . 3

Items to be coordinated.

- Drawing issue deadlines: Verifythat drawings can be issued by thedates needed for fabrication.

- Material issue deadlines: Verifythat important materials can beissued by the dates needed forfabrication.


- Other production process lanes:Have the outfitting and paintingdepartments coordinate and finalizethe durations and timing theyrequire for outfitting and paintingon-unit and on-block.

Coordination

- If the timing of any activities,e.g., drawing and material issues,are revised for any reason, allensuing fabrication, assembly, out-fitting, and painting activitiesmust be shifted accordingly andsimultaneously in one stroke ash i Fi 4 8 Shifti


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Output: See Figure A-3.

Timing: A few days after the tenta-tive erection schedule is issued.

4.7.2 Procedure

Determine the final erectionsequence.

Determine the erection date for eachbl k f k l


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Updating: Not relevant.

Recovery: Not relevant.

4.7 Preliminary Erection Scheduling

4.7.1 General


Purpose

to develop preliminary schedulesfor outfitting and painting.

- to develop preliminary IHOP sched-ules.

Prerequisites

General Arrangement

Midship Section

Hull Construction Key Plans

Block Arrangement

Machinery Arrangement

Each department's activities timingschedule

Iieight of each block (estimatedfrom hull construction key plans)

Frames

- Subject Treated: Specific ship.

Frame Size: Block or grand block.

- Time Period: Each work day fromkeel laying (K) to launching (L)

block from work volume:

No. of Blocks Erected/Day =

Total No. of BlocksNo. of Working Days between K & L

Weight of Blocks Erected/Day =

Total Hull Steel WeightNo. of Working Days between K & L

Level work load peaks for:

Numbers of blocks erected per day

Total weight of blocks erected per day


4.7.3 Coordinating

Items to be coordinated.

Drawing issue deadlines are notrelevant.

Material need dates are notrelevant.

Operating facilities are notrelevant.

Timing for landing main machinery(main engine, auxiliary boilers,diesel generators, etc.).

Timing for landing superstructure.

Timing of main accessories (shafts,propeller, rudder, steeringengine, cranes, anchor chain,etc.).

Coordination

Reduce as necessary the allocateddurations of the different activi-

ties which relate to block erec-tion.

- Modify as necessary the sequencefor block erection.


55/165


o Output: See Figure A-4.

o Timing: Immediately after finalizinghull key plans.

- Shipfitting Activity: Based on theshipyards experience, man-hoursfor shipfitting are usually ex-pressed as a multiple of weldingman-hours. In the most effectiveshipyards the ratio of erectionwelding to erection fitting is as


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4.8 Erection Section Scheduling,

4.8.1 General


0 Purpose

- To develop shop schedules for hullconstruction assembly and fabrica-tion and for deck, accommodation,machinery and electrical (DAME)outfitting and painting operations.

- To develop a definitive IHOP Sched-ule.

- To confirm the definitive erectionschedule and to develop a monthlyschedule and the numbers of workersrequired for erection.

o Prerequisites

Erection joint lengths (meters)estimated from key plans.

- Main milestone dates supplied bythe Outfitting Department for land-ing main machinery, shaft align-ment, and keel sighting.

o Frames

- Subject Treated: Specific Ship.

Frame Size: Grand Block/Trade.

- Time Period: Each Work Day fromK to L.

4.8.2 Procedure

o Determining the Activities Budget:

- Iielding Activity: For each type ofship and for each block problemcategory (flat , curved, specialcurved, etc.), the shipyard main-tains in its historical file a plotof welding efficiency (meters/man-hour) versus hull-steel weight.Thus, after estimating the erec-tion-welding length for a contem-plated block, estimated work volumeto erect the block is determined bythe formula:

welding to erection fitting is asmuch as 2:1. This favorable ratiois attributed to statistical accur-acy control.

o Determining the Work Force Required

Derive the numbers of welders re-quired by means of the formula:

Welding Man-days =

Welding Man-hours(No. Work Days Allocated) x 8 hrs

The number of shipfitters requiredper day is determined in the samemanner.

The work force required is a func-tion of the number of work daysallocated and vice versa. An optimumcombination of the two should bechosen for determining the schedule.

Matching the Work Force Required to

that Available

Compare the required numbers ofworkers derived for each trade withformulas similar to those above withthe man-hours available. For avoidingshortages in man power, shift activi-ties in order to eliminate unassignedtime between the work to be done byworkers of different trades; seeFigure 4-72 and 4-13.

4.8.3 Coordinating

0 Items to be coordinated

- Drawing issue deadlines are notrelevant.

- Material issue deadlines are notrelevant.

- Operating facilities availabilities

are not relevant.- Welding of heavy fittings on main

structure must be completed beforeshaft alignment and keel sighting.

- Painting on board.


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4..9.2 Procedure

o Determining the Activities Budget

For each type of block (flat,curved, special curved, etc.) thatconstitutes a different problem cate-

- Other process lanes. The informa-tion required includes the partfabrication finishing date for eachblock, the timing and durations foron-unit and on-block outfitting and


60/165

constitutes a different problem cate-gory, the shipyard maintains in itshistorical file a plot of assemblyefficiency (meters/man-hour) versusblock weight. Thus, after estimatingthe assembly joint length for a con-templated block, estimated work vol-ume is determined by the formula:

Assembly Man-hours =

Assembly Joint LengthAssembly Efficiency

Determing the Work Force Required

Derive the number of workers neededby the formula:

Assembly Man-days =

Assembly Man-hours(No. Work Days Allocated) x 8 hrs

o Matching Required to Available ManPower

Compare the number of workers de-rived for each trade by the formulagiven above for each 10 work days.Where the work load exceeds availableman power, advance part of the over-load, i.e,, perform work load level-ing by advancing work in the sched-ule.

4.9.3 Coordinating

o Items to be Coordinated

Drawing issue deadlines are notrelevant.

Material need dates are not rele-vant.

Indicate on the schedule the numberof assembly work stations availableeach day. Level any shortage ofwork stations by advancing excesswork activities. If leveling is notpossible, some of the work might bedone outside of the originallyintended work stations

on-unit and on-block outfitting andpainting, and the possibility ofmeeting the erection date for eachblock.

Coordination

shift assembly activities, and/fir

shorten the durations of activitiesas necessary.


Output: See Figure A-6for block

assembly and Figure A-7 for grand-block assembly.

Timing: A few days after issue of theErection Section Schedule.


o Updating: Every two months (periodic)and when erection dates are revised.

o Recovery: Employ this schedule to

monitor work progress. Regulate onthe monthly schedule by adjustmentsin work-force distribution, arrangingfor overtime, etc.

4.10 Fabrication Shop Scheduling

4.10.1 General

The pertinent activity flow is shownin Figure .4-15.

0 Purpose

- To confirm the deadline dates fordrawing issues and material availa-bilities.

- To develop a definitive IHOP sched-ule.

- To determine the work force re-quirements for fabrication.

- To monitor work progress and de-velop the monthly schedule.

o Prequisites

- Quantities of steel materials to beprocessed and number of parts to be


61/165

o Frames

- Subject Treated: Ships for whichfabrication work is progressingsimultaneously.

Frame Size: Fabrication/process

tion in order to be sure that mate-rials will be available in time tostart fabrication.

- Need for storage space for finishedparts is coordinated with shop/sec-tion engineers.


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pyard/block. [2]

- Period: Each workday for the next

6 months.

4.10.2 Procedure

o

0

0

Determine the Activities Budget

Part Fabrication Activity: For eachtype of part (parallel edge, non-parallel edge, internal and struc-tural) and for each process yard, theshipyard maintains in its historicalfile a plot of fabrication efficiency

(man-hours/part) versus number offabricated parts. Thus, after estima-ting the number of parts to be fabri-cated for a contemplated block, esti-mated work volume to estimate partsrequired per block is determined bythe formula:

Fabrication Man-hours =

(Fab. efficiency) X (No. Parts)

Determine Start and Finish Dates forthe Different Work Stations:

Obtain dates that parts per blockare required from the preliminaryIHOP schedule. Then with a typicalfabrication schedule from theshipyard's history, establish startand finish dates for blasting and

priming, marking, cutting and bendingstations.

Level conspicuous Desks in daily workforce requirementsfor each processyard.

4.10.3 Coordinating

o Items to be Coordinated

- Drawing issue deadlines are coordi-

nated with the Design Department inorder to be sure that drawings willbe issued in time for fabrication.

- Material need dates are coordinatedwith the Material Procurement Sec-

- Coordination with other processlanes concerns issue dates after

material preparation and subassem-bly starting dates.

o Coordination: Shift activities fore-ward or backward as necessary.


o Output: See Figures A-6 and A-7 whichshow schedules similar to a fabrica-tion shop schedule.

o Timing: A few days after issue of theassembly section schedule.


o

0

Updating: Every two months and when-ever there is a change to theassembly section schedule. Care mustbe taken to insure that drawing issueand material need dates always main-tain their coordination.

Recovery: Emplov this schedule tomonitorprogress of work. Regulatework speed on the monthly schedule byadjusting work force distribution,arranging for overtime work, etc. Ifdrawings or materials are slightlydelayed, arrange recovery on themonthly, weekly or daily schedules.If irrecoverable delays will affectassembly, bring the matter to theattention of the Hull Construction

Department Manager for adjustinghigher level schedules as necessary.

4.11 Monthly Scheduling

4.11.1 General

The pertinent activity flow is shownin Figure 4-16.

0 Purpose

To determine the work force distri-bution.

To distribute activity durations bytrade.

To monitor the progress of work.


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o Prerequisites

Stage plans, i.e., work instruc-tions per station (If not availablein time for budgeting man-hours, usethe man-hours budgeted in shop sched-ules. ) .

- While holding the Erection Schedulefirm, change the sequence of blocksto be assembled.

While holding the Erection Schedulefirm, plan certain interim productsto be partially completed and des-


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0

)

Frames

- Subject Treated: All ships forwhich work is to progress simul-taneously, except for erection workwhich is to be on a ship-by-shipbasis.

- Frame Size: process yard/trade.

- Time Period: Each workday for thenext two months.

4.11.2 Procedure

o

0

0

0

Determine man-hour budget.

Estimate the weekly work force re-quirements with the formula:

Workers/week =

Required Man-hoursAllocated Weeks x 8 x (workdays/wk)

Compare the work force requirementsderived above with the man-weeksavailable for each process yard andfor each trade.

Level any shortage of work force byarranging for work force redistribu-tion, overtime work, and/or subcon-tracting.

4.11.3 Coordinating

o Items Requiring Coordination

Check the actual situations ofdrawing issues. Obtain confirmationfrom the Design Department on issuedates for drawings not yet issued.

Check the actual situations ofmaterial availabilities. Obtain

confirmation from the MaterialProcurement Section for deliverydates of materials not yet issued.

- Reserve process work stations basedon the shop/section scheduleswhich govern the weekly schedules.

p y pignate them for completion in afollow process yard (advantageshould be taken of any unassignedtime that may be available).



o Timing: The 25th of every month.


o Updating: Every month.

o Recovery: The actual situations (ad-vances or delays) at the end of eachmonth, regarding construction, draw-ing issues and material availabili-ties, are reflected in the monthlyscheduling for the ensuing month witharrangement for work force redistri-bution, overtime work, etc., as nec-essary to prevent escalation beyondanother month.

4.12 Weekly Scheduling

4.12.1 General


0 Purpose

To determine the work force distri-butions to the various activities.

To confirm prospects of finishingthe activities on schedule.

To coordinate hull constructionactivities with on-block outfittingand on-block painting within pro-cess yards.

o Prerequisites

Monthly Schedule

Determining and identifying draw-ings already issued.

Determining and identifying steelmaterials available.


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o Frames

- Subject Treated:which work is to

All ships forprogress simultan-

eously, except for erection workwhich is to be on a ship-by-shipbasis.

4.13 Daily Scheduling

4.13.1 General


0 Purpose


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Frame Size: Process Yard/ProcessStation/Trade.

- Time Period: Each workday for thenext two weeks.

4.12.2 Procedure

o

0

0

Distribute the daily work force tothe required activities by means ofthe formula:

Workers/day =

Budgeted Man-hours(Allocated Workdays) x 8

Compare the daily work force require-ments derived above with the dailyman-hours available, process stationby station and trade by trade.

Level any shortage of work force byarranging work force redistribution,

overtime work, and/or subcontracting.

4.12.3 Coordinating

Same as Part 4.11.3.



o Timing: Every Friday.


o Updating: Every Friday.

o Recovery: The actual situations (ad-vances or delays) at the end of theweek regarding construction, drawingissues and material availabilities,are reflected in the weekly schedulesfor the ensuing week with arrange-ments for work force redistribution,

overtime work, etc., as necessary,and never escalated beyond anotherweek.

p

- To determine daily job assignment

per worker.

- To coordinate progress includingprogress of on-block outfitting andpainting.

- To coordinate the sequence of dif-ferent types of work with drawingand material availabilities.

o Prerequisites

- Confirmed budgeted man-hours.

- List of workers' names.

o Frames

Subject Treated: All ships forwhich work is to progress simul-taneously, except for erection workwhich is to be on a ship-by-ship basis.

Frame Size: Process Station/Trade/Worker.

Time Period: Each hour for the nexttwo days.

o Procedure

- Assign individual workers to thedifferent activities based on thefinalized weekly schedule.

4.13.3 Coordinating

Same as in Part 4.11.3.


Output timing is at the start of jobsevery morning.


o Updating: Every morning.

o Recovery: Examine the progress ofwork made on the previous day andconsider possible improvements byredistribution of the work force. Ifrecovery of a delay is not possible


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5.0 ZONE OUTFITTING METHOD

5.1 General

Outfit scheduling is one of the inte-gration schemes which addresses outfitdesign and material procurement as well

as hull construction and painting. TheFlexible Production Scheduling System(FPSS) as applied to outfitting, alsoemploys the four supporting elementsdescribe in Chapter 2.0, i.e., FrameScheduling Method, IHOP Scheduling andTracking Operation, Decentralized Pro-duction Planning, Scheduling, and Engi-neering, and On-Schedule Availabilityof Information and Resources.

5.1.1 Frame Scheduling Method

The scheduling frames are successive-ly refined from large to small as ashipbuilding process advances from con-tract award (at which time outfitscheduling is already underway) todelivery. The outfit schedule in theearliest phase is limited to accumula-ting total man-hours for large framesthat are estimated to be required foreach duration between milestones, i.e.,

start fabrication (F), keel laying (K),)launching (L), and delivery (D . As theshipbuilding process further advances,frames are refined to enclose a groupof pallets and later to reach a statewhere each frame corresponds to a sin-gle pallet. At the same time, frames ofman-hour summary units are commensur-ately refined, i.e., to months, weeksand, days.

o

0

Outfit scheduling objectives are:

To determine that the timing of keymilestones (F, K, L, and D) are sat-isfactory for outfitting.

To determine the need dates for draw-ing issues and important material

o To schedule detailed outfitting oper-ations.

The refinement of frames is organizedto suit these different scheduling

objectives while maintaining accuraciescommensurate with phases of designdevelopment.

5.1.2 lHOP Scheduling and TrackingOperation

IHOP scheduling is performed to inte-grate, to an optimum practical extent,all hull construction, outfitting (on-unit, on-block, and on-board), andpainting processes. Improvement of

overall outfitting is sought by maxi-mizing on-block outftting when permit-ted by timing of block assembly and bylifting capacity. When blocks cannot beproduced in time or when lifting capa-city is not sufficient, outfitting isoptimized through a combination of on-unit and on-block outfitting. Completedunits are landed both on-block and"blue sky" on-board during hull erec-tion.

The process calls for close coordina-tion when dovetailing the inherentlydifferent types of work.

5.2 Organization

For properly executing the four sup-porting elements, traditional shipyardorganizations are too centralized inproduction planning, scheduling, andengineering. This prevents sufficient

coordination of schedules and schedulemonitoring. That is, centralizationprecludes sufficient communicationsbetween those who plan and schedule andthose charged with schedule execution.

Figure 5-1 shows a decentralized


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Being product oriented, the outfit-ting department may be regarded asbeing grouped by problem area as fol-lows: manufacturing, fitting, and oper-ation. Usually, in the most effectiveoutfitting departments, manufacturingapplies only to the production of pipepieces, as in a Pipe Piece Fabrication

produced by the Material Section andthe Design, Hull Construction, andPainting Departments. Coordination isindispensable for scheduling on-blockoutfitting.

5.3.1 Flow


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p , pShop, as all other fittings are pro-cured from suppliers and subcontrac-tors. Fitting (assembly work) is subdi-vided so as to have sections specia-lized along product lines for deck,accommodation, machinery, and electrical(DAME). Operation applies to a sectioncontaining specialists for installa-tion, light-off, test, and operation ofcertain systems, especially includingmain propulsion systems and any otherlarge machinery systems of similarproblem category.

With reference to Figure 5-1, theMachinery Fitting Section is dividedinto F-groups for: on-unit (Ist assembylevel), on-block (2nd assembly level),engine casing special case of on-unit), and on-board (3rd assembly le-vel) . The F-group for on-unit and on-block is subdivided into AF-groups as:on-unit (1st assembly level) and on-block (2nd assembly level). The F-groupfor on-board (3rd assembly level) is

subdivided geographically, i.e, asabove lower engine-room flat and belowlower engine-room flat, and furthersubdivided into AF-groups, i.e., fit-

ting instrument and finishing, andrigging and scaffolding.

The Operation Section has only oneF-group which is subdivided intoAF-groups for installation (e.g., land-ing and aligning a main engine andoperation. The separation of this sys-tem-oriented section from the MachineryFitting Section is to coordinate allDAME zone-by-zone responsibilities in aconcerted effort to implement the finalphase of a ship construction effort ina system-by-system manner. Having noindependent operation sections, D, A,and E operational responsibilities areassumed by the D,A, and E Sections.

5.3 Frame Scheduling Method

The Outfitting Department preparesschedules per the sequence shown inFigure 5-2. Production engineers, fore-men, and assistant foremen, as shown inFigure 5-1, prepare schedules withintheir frames as tabulated in Figure5 3 Th O tfitti D t t i b d

The flow described in Part 4.2.1 for

hull construction is the same for out-fit scheduling.

In order to incorporate the backwardscheduling concept for outfitting, on-unit and on-block outfitting must becoordinated with the erection date foreach block as shown on the tentativeerection schedule. Also, on-unit andon-block outfitting must be coordinatedwith the Design Activities TimingSchedule and Important Material Pro-

curement Schedule per the PreliminaryIHOP Schedule.

On-board outfitting activities shouldbe coordinated among the outfitting andpainting sections by foreward schedu-ling from block erection dates. On-board operation activities, includingsea trials, should be scheduled bymoving backwards from the date of shipdelivery. The activities between theblock erection dates and the ship de-

livery date should be finally coordi-nated by both backward and forewardscheduling to prevent the activities ofboth groups from overlapping eachother. This concept is modeled inFigure 2-4.

5.3.2 Frames

The work and time frames for sched-uling successive phases of a construc-tion effort are presented in Figure

5-3. This figure illustrates how theframes are successively refined fromlarge to small mesh as a constructioneffort progresses. At each step offrame refinement the more accurate workvolumes for more precise scheduling arederived from the latest drawings andtheir material lists. These, in thefinal level of design development, areper the pallets which were tentativelydefined upon contract award and which

were finalized during the pallet meet-ing. Therein, design and field engi-neers for DAME outfitting reached mu-tual agreement on the definition ofpallets.

A pallet, i.e., a complete kit for


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5.4 Man-hour Cumulative Scheduling(Periodic)

5.4.1 General

The pertinent scheduling flow isshown in Figure 5-4.

Hb = total budgeted man-hours

Hei = accumulated man-hours ateach of the key milestones

o Superimpose the Shipyard Managersproposed K, L, and D dates for the


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0 Purpose

- To review the Shipyard MasterSchedule for the compatibility ofbudgeted man-hours allocated to aship contracted (or to be contract-ed) with the man-hours actuallyavailable to the Outfitting depart-ment.

- To serve as data on available pro-duction capabilities that is to beused by marketing people for soli-

citing new orders.

- To serve for adjusting the man-hours available on a long-termbasis.

- To serve the Shipyardlong-term adjustmentsaccumulations for thestruction, OutfittingDepartments.

o Prerequisites

Manager forof man-hourHull Con-and Painting

- Shipyard Master Schedule

- Outfitting budgeted man-hours.

o Frames

- Subjects Treated: All ships con-tracted or to be contracted.

- Frame Size: Ship/Outfitting.

- Time Period: Monthly for the nextthree years.

5.4.2 Procedure

o From the shipyard's history of simi-lar ships, choose the S-curve whichbest fits the circumstances beingconsidered.

o From the curve selected, determinethe man-hours accumulated at each ofthe key milestones as follows:

pi = Heir

p pcontemplated ship and by employing

the same percentages, plot the S-curve for the contemplated ship.

o Obtain the monthly man-hour distribu-tion (the derivative in mathematics)from the contemplated ship.

o Insert the monthly man-hour distribu-tion for the contemplated ship in themonthly man-hour distribution for allwork both contracted and contem-plated. Level excessive peaks by

comparisons with the available month-ly man-hours and shift dates withinwhatever limits existing contracteddelivery dates permit. Alternatively,the peaks may be retained providedadditional man-hours are budgeted.Obviously, t

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