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The Workboat Edition

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Back to the Drawing Board

Where are the Transportation

Macro Designers?

s naval architects and marine engineers we are famil- Really good designers, who have made many design spiral iar with the design spiral. While design is not truly trips, can draw a near complete design on the back of an enve- a spiral, we use the concept to remind ourselves that lope and never need to refer to the spiral. (The concept for the

A all pieces of a ship design interact. The design spiral LST was sketched out by John Niedermair on a scrap of paper is not a standard ? gure and can be simplistic or overcomplicated. and was incredibly close to its ? nal design. See page 16.)

A Google search image summary provides dozens of inter- The design spiral is actually a warning; if you skip a step, pretations, all investigating different variables, with the only you will likely get into trouble. Design is a system of check- commonality that all spirals start with the “mission” variable. ing boxes (the Sectors) and re? nement (the Spiral) and the

Figure 1 is an old and pretty one that is still being referred Design Spiral explains it graphically. Often a more concise to today. list of steps will suf? ce and Figure 2 is a simpler list of steps.

It is important to stress that real design does not really work In this spiral, which I will call Design Spiral 1, the ? rst step like the spiral indicates, it is both messier and more elegant, and is on the outer rim and the ? nal design is the point in the middle relies heavily on the experience of the designer. Some very clev- of the disk. While one can choose an almost limitless number er design theorists have provided alternative approaches, but as a of design considerations (sectors, variables), for the sake of design philosophy tool, the design spiral retains its core validity. this discussion I have provided the following design sectors:

A beginning designer pretty much has to start at step one and Mission, Size, Weight, Performance, Structures, Regulatory, go through every step, but experienced designers for a particular Human Factors, Construction Cost and Operating Cost. I made ship type can often jump in somewhere along the middle of the it modern and included Human Factors, which is a very im- spiral and pull the whole thing off in two trips along the disk. portant consideration and was omitted in the spiral in Figure 1.

Figure 1: Design Spiral, Evans, J. Harvey (1959), “Basic

Figure 2: Design Spiral 1 Circa 1980

Design Concepts,” Naval Engineers Journal, Vol. 21, Nov.

14 Maritime Reporter & Engineering News • November 2021

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First published in 1881 Maritime Reporter is the world's largest audited circulation publication serving the global maritime industry.