Pritchard, James; From Shipwright To Naval Constructor - Iowa State ...

18 James Pritchard
even though they may apply principles and use mathematics.78 Because
Duhamel, in seeking best practice, seems to have captured a similar
notion, it is worth elaborating on his ideas.
Introducing his students to the profession of naval architecture,
Duhamel, like countless engineers after him, pointed to the constraints
of the material and economic world. Necessary requirements must be
kept in mind-to find the shape of a ship's bottom, the height of the
primary gun deck above water, and the ship's speed, steering, sail
carrying, drift, and handling-all impose constraints. The "transcendent
geometers" treated some of these conditions. Some sought the
best curve to divide a fluid, but, though quite elegant, their methods
produced shapes that cannot be applied to ships because they fit only a
single condition. Others treated drift, but, since they supposed, in
order to facilitate the solution, shapes that ships do not have, the
exercise brought few benefits. Simple geometry, Duhamel wrote, is
insufficient to resolve these problems with exactitude, and a "transcendent
geometer" will do nothing useful if he is not a sailor. Constructors,
he concluded, have to abandon this route for the most part and confine
themselves to observation and experiment.79
Is this abandoning science? The short answer is, no. But as Duhamel
proceeds, he describes a mode of conduct that is less than applying
science and more in keeping with what engineers do. Observation and
experiment must supplement the way of the geometer, but this path
has as many difficulties. If a major defect is observed in a new ship, for
example, it is difficult to know whether it comes from stowage. And, if
not from stowage, it is difficult to learn the source of the defect. If ships
were not so costly, one could multiply tests and try out shapes, but
Duhamel adds that these approaches are impossible. One must be
content with the ships at hand. Engineers work in a world of economic
constraints.
Constructors have been both timid in their attempts and forced to be
content to observe ships already built. Until recently, a constructor
principally aimed to find a method to copy accurately the best ships in
existence. Some established all dimensions on keel length; others em-
ployed the midship beam. But, adds Duhamel, it is absurd to imagine
that constructors actually observed any relation between one part of a
ship and another. They could just as easily take the sternpost, wing
transom, or depth of the hold. Thus appeared the secrets and mys-
78Michael Fores, "The History of Technology: An Alternative View," Technology and
Culture 20 (October 1979): 853-60. Fores claims that engineering is not a system of
thought but "a process which makes useful artifacts and is most distinctive through the
type of output which it produces" (p. 856).
79Duhamel du Monceau (n. 71 above), pp. 52-54.