Ship Draughtsman Continued

COMPUTER AIDED DESIGN and Production

The use of standard calculations to determine the strength of structures was an early task for developments in computing. In a discussion on the use of Manchester University’s digital computer for analysing structures, P.L. James noted that the possibilities for shipbuilders ‘are really immense’.³¹ By the early 1960s it was suggested that, as various programs had been developed to cater for both structural and hull form calculations, shipbuilders would be able to send data to a computer service centre for processing. The author of another paper noted that ‘it is unlikely that any one shipyard could justify the purchase of a computer for purely technical work’.³² The British Ship Research Association (BSRA) was a prime mover in this work, and requested the Tyne Shipbuilders Association (TSA) to allow shipbuilding staff to join the BSRA Naval Architecture Department to develop a range of programs specifically for the industry.³³ Once the number crunching, or multiple calculation, aspect of computing had been developed, attention was focused upon the equations for curves used in the generation of a ship’s hull form.. Previous methods were described in a paper to the NECIES, and the author went on to show how these lines could be automatically faired by ‘high speed computer’.³⁴ The enormous significance of this was that it showed how various hull forms could be compared, together with their stability data, in a matter of hours, whereas the old method of manual drawing and calculation took many days for each hull form.

Developments in plotting technology, where the lines were drawn out by machine, were the subject of a number of articles in The Draughtsman Journal ³⁵ describing a system in use at General Motors. The major drawback with these developments was the physical size of the draughting machines. An account of BSRA’s research programme, while extolling the advantages of automatic ship’s lines fairing and calculation work, notes that the draughting machine had a plotting table 12 feet by 5 feet, making it completely unsuitable for drawing office use.³⁶

While programs for hull forms and structural strength were being developed, other aspects of shipbuilding were being examined to devise integrated control systems for ship assembly, and the procurement and fitting of the thousands of bought-in components necessary for each ship contract. In an article on ‘Scientific Shipbuilding’³⁷ the authors outline a series of computer programs based upon network techniques, where all aspects of a contract could be interlinked, thus providing a system of priorities for hour-to-hour control of work.

During the 1970s Swan Hunter and BSRA worked on a joint venture on behalf of the nationalized British Shipbuilders Corporation, developing the Britships 1 program for ship’s lines fairing and parts definition. By the beginning of the 1980s this had developed into Britships 2, which extended its scope ‘into the design and drawing office function and provides interfaces with other shipyard systems’.³⁸ With the aid of small computer terminals developed by the IBM Computer Aided Design (CAD) program, drawing offices began to be equipped with individual computer workstations for draughtsmen, linked to a central company network. Tyne and Wear shipyard drawing offices began converting to CAD workstations in the early 1980s, and by 1985 almost all drawing work was carried out by computer. By then much more compact plotting machines were available, and installed within the technical offices.

Outlines of decks, sections through the ship, and a range of standard details were available from ship files, and which could be called up and copied into each draughtsman’s files. Plans were drawn, on screen, in a series of coloured overlays, enabling other departments to select various information particular to their discipline. For example, an ‘Accommodation Arrangement’ would be drawn with one overlay showing the steel structure, a second showing the joinerwork bulkheads and furnishings, and a third with the sanitary fittings in their correct location. Once this drawing was underway the steel draughtsman copied the steel overlay for construction drawings, and the piping draughtsman took the sanitary fitting overlay to begin drawing the composite pipework arrangements, which also included cable trays and vent trunking. A detailed description of the system as used in the Tyne and Wear drawing offices was published in the NECJES Transactions in 1987, when the system had undergone numerous modifications.³⁹

The CAD workstation had a profound effect upon the work and craft skill of the draughtsman. With the hull form being available literally at the touch of a button there was no need to learn how to use curves or battens, nor was there a need to draw many of the standard items used — all were available on file to be placed anywhere on the drawing, at any required angle. Software programs for the design of hull forms, stability, and strength calculations were also available either in-house or bought-in, so there was no longer a need for the draughtsman to be closely involved with these traditional tasks. With the use of text in various sizes and styles, there was not even a need to be able to print neatly!

Although the job still required knowledge and experience there was no longer a requirement for the craft skill of draughtsmanship. Some draughtsmen, of course, by the selection of line and print type and other available graphics, did introduce a measure of aesthetic appeal into their drawings, although this was a minority activity. A number of senior draughtsmen, trained in the old ways but fluent on CAD, referred to the new CAD draughtsmen as ‘button pushers’. The fear was that as the standard files built up, there would be little need for the trained draughtsman and that they would, like the craft of tracer, largely disappear.

Finally we reach the Conclusion