Page 50 - Practical Ship Design

Introduction, Methods and Data 21

on any other type of ship to which he may have access. Even if his concern is
entirely technical, he should note cost data and shipyard management techniques
against a possible change in the direction of his career.
Storing a mass of data in a way which enables the holder to find what he wants
quickly was always a matter of some considerable difficulty in the notebook era,
although even then it was well worth doing. Nowadays, those who have their own
personal computer can store an immense amount of data in small bulk provided
they can make time to input it.
Programs such as DBASE and ACCESS can be used to store vast amounts of
information and with a well devised retrieval system, access is almost immediate.
As well as collecting data it is important to organise its storage in a way that
enables it to be put to advantage - a way that facilitates interpolation against
scientifically chosen parameters. Quite frequently, there will be a need to extrapolate
beyond the field covered by the existing data and the use of a well chosen para-
meter may make this possible, although the dangers involved must be recognised.
Data should always be dated. Unfortunately much of it is liable to become out of
date as new developments occur and if it has to used after the lapse of some years it
is helpful to know its provenance so that the necessary corrections can be made to it.
Data to which a naval architect may want to refer can take many forms, but the
principal items which he should collect are:
- data on ship dimensions and dimensional ratios (see Chapter 3);
- data on ship’s lines, with block coefficient and LCB position, etc. (see
Chapter 8);
- data on powering (see Chapters 6 and 7);
- data on general arrangements (see Chapters 15 and 16);
- data on steel-weight, outfit weights and machinery weights (see Chapter 4);
- data on areas and volumes (see Chapter 5);
- data on the many rules applicable to ships (see Chapters 11, 12 and 13);
- data on the many different items that make up outfit with notes on their
capabilities, weights and the services they require (see Chapters 4 and 17);
- cost data of all sorts (see Chapters 18 and 19).

1.3.2 Datu sources

Pride of place amongst data sources must go to data on ships which have been
designed, built, or owned by the companies for whom the data collector works.
The calculations, plans, specifications, tank test results, trial trip reports, material
orders, man-hours and cost data, all or part of which will be available in these
companies provide a comprehensive data base covering all the items mentioned in
the last paragraph. The great point about this data is that its provenance means that
it can be used with complete confidence, whereas it is always wise to have some