Page 331 - Introduction to Naval Architecture

6 SHIP DESIGN

(1) Many individual calculations are possible which otherwise*
could not be undertaken. For instance, ship motion predic-
tions by theory and the use of finite element analysis for
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structural strength. Design optimisation techniques are
increasingly being proposed and developed.
(2) A number of programs can be combined to form a computer
aided design system where the output from one program
provides a direct input into others. Revisions of the data base
as the design develops can be used to up-date automatically
the results of calculations carried out earlier. Thus changes in
scantlings occasioned by the strength calculations can up-date
displacement and stability estimates. The end result of the hull
fairing process leads to a tape which can be supplied to the
shipbuilder instead of the lines plan and table of offsets,
(3) Many more design options can be studied and compared and
these can be in greater detail.
(4) The computer can develop pictures of what the finished ship
will look like, internally as well as externally. These can be
used instead of mock-ups to assist in achieving efficient
layouts. The colours and textures of different materials can be
shown. An owner can effectively be taken for a walk through
the ship before it leaves the drawing board. 14
(5) In production the computer can help with routine matters like
stock control. It can control cutting and welding machines
ensuring greater accuracy of fit and facilitating more extensive
pre-fabrication and reducing built-in stress levels.
(6) On board it can control machinery and monitor its perform-
ance to give early warning of incipient failure.
(7) It can help the command with decision making. For instance
it can advise on loading sequences to eliminate the possibility
of overloading the structure. It can assist warship captains
when under enemy attack by suggesting the optimum actions
to take in defence.
(8) Computer based simulators can assist in training navigators,
machinery controllers and so on.

The outcome
Having dealt, albeit only in outline, with the factors involved in design,
and the design process, it is time to look at the end product, the ship.
Not surprisingly these differ considerably in look and size depending
upon the function they have to fulfill. Hence there is a need to look at
a number of ship types.