Design Spiral 6i685q

SHIP DESIGN Different types of phases in design spiral

DESGIN SPIRAL  The design spiral is a methodology for developing ship designs.  This is an iterative process.  Each successive iteration is referred to as a 'spin' of the spiral.  The four phases in design spiral are

1. 2. 3. 4.

:

Concept design phase Preliminary design phase Contract design phase Detail design phase

DESGIN SPIRAL

A basic design

Concept design + Preliminary design

Basic design includes the selection of • Ship dimensions • Hull form • Power • Arrangement of machinery etc.

In overall design process, basic design is followed by contract design and detailed design.

A concept design :  Determination the fundamental elements of the proposed ship (ship type and its L , B , T , D , V etc.)  Includes light-ship weight estimates  Used as a talking paper for obtaining approximate construction costs

preliminary design :  Determination of the main hull dimensions and of some form coefficients  Sketch of the General Arrangement, defining the compartment configuration  Preparation of preliminary Body Plan, sufficient to allow the evaluation of the stability and of the cargo capacities  Prevision of the propulsive power  Estimation of the lightship weight  Estimation of ship cost

A contract design :  Ship Specification(faired lines, power based on model testing, sea-keeping and maneuvering characteristics etc.)  Final general Arrangement  Body Plan, with enough detail to allow the manufacture of scaled models for testing in hydrodynamic towing tanks  Classification drawings of the structures (mid-ship section, typical bulkheads, shell expansion, bow & stern structures)  Stability and longitudinal resistance computations/calculations  Diagrams of the main piping systems (cargo, ballast, bilge, firefighting, etc.)

A detail design :  Total fairing of the body plan, defining all the structural frames, decks, seams and butts of the shell plates  Production drawings of the structures detailed to the block level  Material Specifications  Information for cutting, bending and assembly of plates and stiffeners (drawings, cutting tapes or files, moulds , pin-jigs ,etc.)  Isometric drawings of the piping systems (for manufacture)  Arrangement of the piping systems (for assembly)

A For a moderate size vessel: Concept Design Preliminary Design Contract Design Detail Design

: 20 work-days : 300 work-days : 5,000 work-days : 60,000 work-days

1 work-day= 8 hours of work/day

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