5 ship design

8/12/2019 5 Ship Design

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5 SHIP DESIGN

5.1 AIMS OF THE LECTURE

a) To describe the objectives of ship design

b) To outline the stages in ship design

c) To identify the expected products from each design stage.

5.2 THE OBJECTIVES OF SHIP DESIGN

Ship is a Made to order or Tailor made product, therefore every ship has its owned

assigned missions and has to be designed in accordance to the owners requirements and meetall the standards and regulations applied.

The main objectives of ship design are:

To obtain a ship that will fulfil all range of its performance criteria required by allstakeholders, these include operational performance such as speed, containment, fuelconsumption, safety, environment, accessibility and controllability; structuralperformance such as strength, vibration, noise etc.

To prepare a design that can be realised efficiently by the shipyard that will build itthrough its production processes, these include structural arrangement, materials to beused, definition of ship components, outfitting to be installed, etc.

To prepare a ship that will bring benefit to all parties concerned including the owner,the operator, the shippers, and the society at large, this is very much related to theperformance of the ship to be built include efficient and cost effective operation, easymaintenance, safe to the people and cargo, and friendly to the environment.

Figure 5.1 Ship Design Objectives


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5.3 DESIGN STAGES

The design process of an engineering product including shipbuilding can be described as theselection of the product identification from the design variables, which are very much dependon the complexity of the product. In shipbuilding the design process can be divided into three

distinct following stages: conceptual design, preliminary design, and detail design.

Preliminary design

Conceptual design

Detail design

Figure 5.2 Ship design stages


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a) Conceptual Design

The conceptual design wto the price of the shipperformance characterisqualification of human re

The purpose of conceptuships owner as to creatsteps:

Fig

Identify the needs

Since the ships econoso, therefore in orderpurpose and main opeusually based on the itype and size of shdevelopment of maritithe ship owner togetneeds for the ship, so t

Define the requiremen

When the needs haveowner, shipping consmust be fulfilled as tmission in both technthe containment capacdraft, and the cargo ha

Select the design crite

Design criteria are mmostly carried out by

ill influence much of the ships life cycle esand future operational cost including its ctics, types of technology involved, andsources required.

al design is to figure out the general ship ca feasible design and measure of merits

re 5.3 Conceptual Design Process

mical life time would reach up to around thito have a profitable ship it is worth con

rational tasks of the ship far in advance. Thenvestigation of the future shipping trends, tips, the advancement of technology appme rules and regulations etc. Upon considerier with shipping consultant and naval ar

hat the mission of the ship could be set up.

ts

been identified and the mission of the shipltant and the naval architect have to defin

he basis to ensure that the ship will be abical as well as economical aspects. Such reity, speed, fuel consumption, and number ondling system.

ia

re directed to the technical aspects of thenaval architects, designers, and engineers.

pecially in relationpacity, operationalthe number and

ncept given by thesing the following

ty to forty years orsidering the futureconsiderations are

he development oflied in ships, theng all these aspectshitect identify the

as been set up, therequirements that

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f crews, maximum

ship and these areThe design criteria


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include classification standards and rules to be adopted, materials of the shipsstructure, principal dimensions of the ship, main propulsion system, type and capacityof cargo handling equipment, structural system etc.

Develop the solution framework

In order to have a systematically flow of design process all the information,requirements, and design criteria should be integrated with the design procedures in asystematic framework of design planning, so that everyone concerned in the design ofthe ship can easily follow the design processes.

b) Preliminary Design

At the preliminary design phase the naval architects, designers, and other engineers translate

the agreed concept design into several technical and theoretical drawings for calculation andanalysis, ship modelling, and simulation purposes using iterative processes which in knownas design spiral introduced by Evans .

Figure 5.4 Design spiral


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In general preliminary design would include:

Hull form

Hull form is the hull shape of a ship, it is a central concept in floating vessel that provide

the buoyancy and is expressed by the lines plan, and body plan of the ship.

Structural arrangement

Structural arrangement is the design tasks dealing with choosing, calculating, andlocating the ships structural parts such as, hull and deck plating, framing system, webs,beams and stiffeners, bulkheads, floors, engine sitting, etc.

General arrangement

The general arrangement of a ship can be defined as the assignment of spaces for all therequired functions and equipment, properly coordinated for location and access.

Weights and centres estimation

This is to estimate the position of Centre , , .

Hydrostatic and stability calculations

Hydrostatic and stability calculations are undertaken to estimate the changing of shipsdraught, trim, and freeboard due to changes of weight and disposition of cargo.

Resistance and propulsion calculations

Resistance and propulsion calculations are undertaken to estimate the force that worksagainst the propulsion of the ship due to its speed, displacement, and hull form; and toestimate the required power to overcome the resistance in order to achieve the desiredspeed.

Auxiliary systems

Auxiliary systems are machinery and equipment beside main engine; they are rangingfrom electrical generator engines, motors and pumps, air compressors, boiler, turbocharger, deck cranes, mooring winches and windlass, inert gas plant, oily waterseparator, heat exchanger, ventilation and air conditioning machinery, etc.

Electrical systems

Electrical systems are the systems that are related to the distribution of electrical power,balancing the electrical load, and the arrangement of its control system.


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Outfitting system

Ship outfits are machinery and equipment that support the operational function of theship.

c) Detail/ Production Design

Detail design is carried out by shipyard, but usually there is a transitional design made by thenaval architects and the owner known as contract design, which is used as the basis forconstruction bidding and contract with the shipyard. The detail design phase is the final phaseof development.

During this phase, ships structural components and assembly drawings are created; steelsheets are nested and so on.

5.4 CONCLUDING REMARKS

a) The main objectives of ship design are: the ship will fulfil the performance criteria, theship can be built efficiently, and will be beneficial to stakeholders.

b) There are three stages in ship design process i.e. concept design stage, preliminary designstage, and detail design stage.

5 ship design

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