Page 41 - Practical Ship Design

12 Chapter 1

In addition, formats have been suggested elsewhere which it is hoped will assist
readers in developing programs for a number of other design calculations.
An example showing how to develop a special-purpose spreadsheet has been
included because the author has found most handbooks on computer programs
singularly difficult to follow (a criticism not particularly directed at the Lotus 123
system which the author used, as this handbook is better than most) and wondered
whether writing programming instructions which would be readily intelligible to a
computer novice was as difficult as these books made it seem. At the end of this
section readers will be able to judge whether he has succeeded!
Incidentally, almost the only computer books which the author has read that he
would exempt from this criticism are the entertaining series with the general title
“Computing for Dummies” which deal with a number of well known computer
programs and are a delight with their clarity and wit.
Table 1.1 originally set up to produce data for Chapter 3 is used here to illustrate
the development of a spreadsheet. If readers can follow these instructions and
create their own versions of this spreadsheet, they should have little difficulty in
writing other spreadsheet programs to speed up their ship design calculations.
Some of the instructions which follow are applicable to all spreadsheets but
some are specific to Lotus 123.

- Before starting to use the computer, prepare a draft of what you intend to do;
assess the width which each column needs to be, the number of decimal
places which are appropriate and collect all the equations it is intended to use.

- At the MS/DOS prompt A> put the Lotus 123 system disc in drive A and enter
123.

- After an interval, an outline spreadsheet generally as shown in Fig. 1.3 will
appear, but without the menu which is discussed later. The spreadsheet has a
top line with alphabetic labels to identify the columns, and the first column
gives numbers to identify the lines. Neither of these identifications appear
when the spreadsheet is printed unless the print screen key is used as has
been done for the illustration. As this alphanumeric index can be useful for
descriptive purposes it has been repeated in the third line and second
column respectively of the example.
- The next step is to title the columns. Position the cursor and type the required
title - this will first appear in the top right of the screen and will transfer to
its correct position when “enter” is pressed.

- If it is desired to centre the title within a column the word should be preceded
by A. If the word is required to start at the left of the column it should be
preceded by ‘.