Page 38 - Practical Ship Design

Introduction, Methods and Dutu 9

There are such a mass of symbols and abbreviations in use in naval architecture
and ship design that it was thought best to define these in close context to the
formulae in which they are used.
The author has tried to write this book in as plain English as possible as he has a
strong dislike of some of the modem words with which a number of today’s
technical papers seem to be inflated. In keeping with this policy, the book tries to
describe practical ship design methods and not to “elaborate the systems method-
ology of the design of marine artifacts”!
One of the aims of this book is to help naval architects to co-operate closely and
harmoniously with marine engineers and other specialists whose expertise is
required in ship design and construction, which seems preferable to indulging in
“synergetic integration”.
The author has tried to follow the one acronym he really likes, “AAEFTR’ -
“all acronyms explained first time round’ and hopes that his readers will appreciate
this.

1.2 DESIGN CALCULATION METHODS

1.2.1 General discussion
It is perhaps worth emphasising that this book deals primarily with initial design,
although it also looks forward to the detailed design development which follows
once the initial design is accepted. Whilst many of the methods given were origin-
ally used on slide rules or calculators, they can equally well be developed into
computer programs and in a number of cases this development has been outlined in
the book. The author hopes that readers will write their own computer programs
using some of the other methods suggested.
To bring himself up-to-date with modem computer methods the author wrote to
several firms who offer computer-aided ship design programs and received a
number of helpful replies. In general these showed that there are a number of good
programs covering what the author would call “design development”.
Although these programs, which are discussed in § 1.2.3, can also contribute to
initial design, none of them seem to deal with the first, and arguably the most
important, step in initial design - the determination of suitable main dimensions,
block coefficient and the arrangement concept. That this should be the case is not
altogether surprising as these aspects of initial design (at any rate as the author has
practised it) do not require any considerable mathematical treatment but do need
quite a bit of lateral thinking, which is not easy to program.
As soon as these initial design steps have been completed CAD (computer-
aided design) can come into its own with many of the programs discussed in § 1.2.4