mercoledì 10 giugno 2015

Naval Science




The Entry of History in Naval Science



1Massimo Corradi
1Dipartimento di Scienze per l’Architettura, Scuola Politecnica - Genova, corradi@arch.unige.it


Abstract

The writings that most closely belong to the discipline of history, and in particular the history of shipbuilding, are papers containing arguments quite different from each other, or very informative or very specialized. The scientist is often embarrassed in reading these books because they are written from a humanistic, and they are not scientific-technical papers, sometimes they are complemented with mathematical formulas and diagrams written in obsolete languages, designed to discern the paths of history passed, and adjacent to a discipline that looks to the near future and not in the past, a history too often forgotten. The Scientia navalis or Naval Science, which Leonhard Euler (1707 - 1783) was a teacher and somewhat precursor, from time immemorial languishing on the shelves of libraries, neglected by scholars. This occurred because the discipline has come to self-awareness, especially in the contemporary age, when, following the example of the Galilean revolution, the community of surveyors and scholars of mechanics oriented his attention to the problems of shipbuilding and vessel operations, which at first seemed disciplines entrusted only to the skill of the shipwright, carpenters and the Masters and Shipmasters on board ships, as well as to the wisdom of tradition. History, however, is a fascinating and fruitful field of study for some guidance because by understanding what has been achieved in the past, has been able to establish a more consistent definition of science and technology to be used in applied in the design and construction. Even for shipbuilding, in fact, the sedimentation of knowledge of the past passed down orally by the shipwright to their students and then taught in the schools of Naval Engineering in France scrolls and founded by Jean- Baptiste Colbert (1619 - 1683) Secretary of the French Navy in the seventeenth century, has been able to point the way to address and solve static and structural problems, but also those related to material behaviour and then, thanks to the Enlightenment of the eighteenth century, those relating to navigation and manoeuvring of vessels. Only in this way it was possible to achieve those goals of technical and technological developments that have allowed the massive shipbuilding industry in the nineteenth century, following the same “logic” that guided the ancient builders and shipwrights, thus obtaining accurate and effective design and construction solutions.


1. Historical awareness in the science of shipbuilding


The writings most closely related to the discipline of history, and in particular the History of shipbuilding, are papers containing arguments quite different from each other, or very informative or very specialized.
The scientist is often embarrassed in reading these books because they are written from a humanistic, and they are not scientific or technical papers, sometimes they are complemented with mathematical formulas and diagrams written in obsolete languages, designed to discern the paths of past history, and adjacent to a discipline that looks to the near future and not in the past, a history too often forgotten.

The Scientia navalis [Euler, 1749] or Naval Science, which Leonhard Euler (1707 - 1783) was a teacher and in its own way a precursor, from time immemorial languishing on the bookcases of libraries, neglected by scholars.
This occurred because the discipline has come to self-awareness, especially in the contemporary age, when, following the example of the Galilean revolution, the community of mathematicians and scholars of mechanics oriented his attention to the problems of shipbuilding and vessel operations, which at first seemed disciplines entrusted only to the skill of the shipwright, carpenters and the Masters and Shipmasters [Elias, 2010] on board ships, as well as to the wisdom of tradition.
History, however, is a fascinating and fruitful field of study and research for some guidance because by understanding what has been achieved in the past, has been able to establish a more consistent definition of science and techniques to be used in the design and applied in the shipyard.
Even for shipbuilding, in fact, the sedimentation of knowledge of the past passed down orally by the shipwright to their students and then taught in the schools of Naval Engineering in France desired and founded by Jean-Baptiste Colbert (1619 - 1683), Secretary of the French Navy in the seventeenth century, has been able to point the way to address and solve static and structural problems, but also those related to material behaviour and then, thanks to the Enlightenment of the eighteenth century, those relating to navigation and manoeuvring of vessels.
Only in this way it was possible to achieve those goals of technical and technological developments that have allowed the massive shipbuilding industry in the nineteenth century, following the same “logic” that guided the ancient builders and shipwrights, thus obtaining accurate and effective design and construction solutions.
Starting from the Architectura navalis [Furttenbach, 1629] by Joseph Furttenbach (1591-1667), continuing with L’Architecture Navale [Dassié, 1677] by François Dassie (XVII cent.), to get to the mature works of Bernard Renau d’Éliçagaray (1652 - 1719) [Renau d’Éliçagaray, Bernard 1690], Pierre Bouguer (1698 - 1758) [Bouguer, 1746; 1753; 1757], Charles Romme (1745 - 1805) [Romme, 1787], not to mention that some of the most well-known scholars, and finally arrive at the fundamental work of Henri Louis Duhamel du Monceau (1700 - 1782) on Architecture and construction of naval vessels [Duhamel, 1752], the treatises of Naval Architecture, construction and manoeuvring of the vessels, associated with the early studies of mechanics and hydrodynamics [Bernoulli, 1738], have traced the basics of the Arts of shipbuilding and seamanship.
Such a wealth of studies has opened the way for the founding of the Naval Science, as well as be formulated by Jean Bernoulli (1667 - 1748) first and then Euler, where the mathematics associated with the fundamentals of mechanics, has shown a new way of understanding the naval Architecture and shipbuilding [Corradi, 2011a]. In fact, Euler was «the first ... to express mathematically the resistance meeting a ship on its path through the water» e «Leonhard Euler first explained the role of pressure in fluid flow; formulated basic equations of motion and the so-called Bernoulli theorem; introduced the concept of cavitation, and the principle of centrifugal machinery» [Rouse and Ince, 1957].
In recent years, historical research has strongly developed in many disciplines of Mathematics, Physics, in areas such as mechanics of solids and structures in architecture, but little or nothing in particular in Engineering and Naval engineering disciplines, almost oblivious to the their rich heritage and sediment. This happened probably because the obsession of ever achieving new results has effectively forced their scholars to a frenzied run-up to the recent acquisitions of techniques and technologies, for an exciting race, which does not allow for breaks or critical thoughts turn to the future, and ‘ignorant’ and forget his past.
Today, however, it is desirable to happen a significant change of course; those who are paid more for frontier research should perceive that a genuine advancement of physical and mathematical sciences, as well as structural in the naval field, but perhaps especially in the nautical one, must not only be a unoriginal exercise das rechnende Denken, as Martin Heidegger cites (1889 - 1976), but require an intense effort to return to the speculative principles, and thus feel their deep meaning, their epistemological status, their unspoken or unmentioned values.
In this way the usual search expressed in the further processing of established theories, but still capable of refining, or the synthesis of more powerful, to better clarify the scope of validity of the technical solutions generally used, or in the realization of software for the numerical calculation more and more perfected, should not constitute the necessary routine that supports and reinforces a common basis of understanding among scholars, but it must be the study and knowledge of the past to guide future research.
The scientific horizon of discipline extends not only thanks to the discovery of new technologies, or to the increasing complexity of computing systems which for example the structural engineers are trained, though perhaps not always fully aware of the complex system of algorithms in that they are hidden content, as the machine becomes Deus (god / divinity) and not be disregarded by it and by its results.
The need to formulate plausible interpretations of the mechanical behaviour of structures and materials, research processes and methods of calculation, of which calls for a simplification of the designer’s intuition to bring awareness to calculate, must constitute the essential support that is needed combine with the historical knowledge in a continuous sedimentation of theoretical findings, technical developments and technological processes, which, however, is precisely the object of study of historians.
Suddenly it became clear, therefore, that the Naval Science modelled, since the scientific-educational ‘revolution’ occurred in the seventeenth and eighteenth centuries, as an aid to the problems of the new engineering and shipbuilding sectors, should provide appropriate tools and methods to the processes of design and construction, strong knowledge although remote and often associated with technical notes now only briefly, was to enable the engineer even more expert in his discipline to formulate design criteria and calculation tools beyond just one formal ‘analogy’ for ‘imitation’.
Today, the familiar with the laws of mechanics of solids and structures, capacity and care as much as possible in determining the exact boundary conditions beyond the margins of uncertainty permissible, the practice of rigorous calculus, should not be the only factors support in the design. The intuition that forces him to chase elementary concepts whose reasonableness can assure the technician, even in the absence of clear theoretical explanatory models must enter the fund of knowledge of the designer, as history has taught us and the Masters have handed down.
As Galileo cites in his Discorsi e dimostrazioni matematiche intorno a due nuove scienze [Galileo, 1638] «The constant activity which you Venetians display in your famous arsenal suggests to the studious mind a large field for investigation, especially that part of the work which involves mechanics; for in this department all types of instruments and machines are constantly being constructed by many artisans, among whom there must be some who, partly by inherited experience and partly by their own observations, have become highly expert and clever in explanation».
The engineer and naval architect and marine experts in science and engineering, must not only be blind performers of an imitative process, but sharing of meritorious experience, which are very disquieting, which belongs to the Socratic wisdom: awareness that their scientific knowledge is the best witness of their real ignorance.


2. A “paradigm shift”

The history of Naval Science, certainly does not replace the knowledge of the Socratic docta ignorantia (learned ignorance), but rather should serve as a moment of reflection of the knowledge acquired to facilitate the development of new methods and analytical tools for design and calculus, and find in this way itself - juxta propria principia (according to its own principles) - the reasons for its growth.
Starting from the geometry to arrive at static, starting from mathematics to science of resistance, from the physical and chemical analysis of materials to the mechanics of solids and structures, the history of Naval Science can become connotative matrix of a weaving warp and weft, a cloth of empirical intuitions and scientific knowledge, in order to reveal the hidden reasons that pass through the design of a boat, vessel or ship, its structural dimensioning, its technologies and materials, to the shipyard that will lead to its construction.
History does not ignore the fundamental contribution by mathematicians and engineers engaged in research and study of topics related to the technical competences of the naval architect, but as can be seen from Mathesis Universalis pursued by the greatest scientists of the sixteenth and seventeenth centuries, the architecture and the art of building naval vessels, belong to the great mathematicians who founded a discipline, Naval Science, starting from its roots and its historical knowledge passed down from father to son, from master to apprentice in the shipyards and in the first naval establishments then, until the end of the twentieth century.
The acknowledgement of the important role fulfilled by scientists as one of the builders in the construction of a boat, a vessel, a ship, it is not a granted contribution, and unfortunately it is not enough to understand the intimate and essential process that led the shipwrights in shipbuilding. It is not, in fact, only a valuable contribution to certainly firmitas (“art of building”) of naval construction, although somewhat collateral, even when extrinsic design, but instead of a moment of scientific awareness of an act of intuitive design that brought to the project by imitation of the ship.
The integration between construction and scientific rationality exceeds the instrumental moment and aims for the meaning of the work as it was built. In this respect, to recall aspects of the history of science and construction techniques in the naval field, it properly belongs to the subject of the wealth of knowledge of the designer. Other views and perspectives overlook and intersect with each other, forcing even those involved in the project or in shape or design or construction of facilities or to awaken their attention on the act of the technical build, not intended as an intermediate when compared to a transcendent purpose, but as a profound dimension of the opening to the knowledge of man.
The relationship between art and science, between design and construction, becomes a means of interpretation of a design rationale that, as shown in the Schopenhauer’s text The World as Will and Representation [Schopenhauer 1819: III, § 43], belongs to the world of aesthetics, as well as the rational world. The structural aspect of the construction is anything but a side aspect and extrinsic act of design. Since it is based both the aesthetic essence of the work and science, according to the German philosopher, it is then the vehicle and message of beauty.
Is perceived as an astonishing historical truth that unites the science revolving around the shipbuilding: relating the history of Naval Science, caught in its essential moments, reveals issues relevant to the strength of solids, of Galilean memory, enhanced and transformed, in the search for physical-mechanical reasons that may explain the phenomenon of resistance, however themes developed in approximately three centuries of history.
The static forces and principles of composition and decomposition of forces from Simon Stevin (1548 - 1620), and then especially starting from Gilles Personne de Roberval (1602 - 1675) and Pierre Varignon (1654 - 1722), proved capable of erect a nouvelle mécanique, basic conceptual tools to interpret the static behaviour of the vessel at sea.
The structural mechanics and the definition of the laws of equilibrium, which gathers into itself the objective of structural design, becomes interpretive paradigm of the new Naval Science, because it leads one to suppose that the active and reactive forces, external actions and internal tensions are arranged in different parts of the structure in such a way that obey those laws.
«But there’s more: during the eighteenth century undoubtedly under the influence of philosophical and metaphysical conceptions guided by rational optimism, according to the principles of a cosmological and anthropological teleonomy, emerged the belief that the same laws “du repos et du mouvement des corps” were in their turn subject to a finalistic universal design, suitable to express the beauty and perfection of nature in the “best of all possible worlds”, track worthy of the Supreme Architect» [Benvenuto, 1988].
The great project of static and mechanical interpretation of the laws in terms of final causes, through the “method of maxima and minima”, fully developed with the help of the Variational method and calculus then gave clarity to the mathematical formulation of the theme inherent balance and stability will be the main topic of Euler’s Scientia navalis.
So, the historical study of Naval Science may be the way to penetrate the inner meaning enclosed in shipbuilding, because it is the tool to reveal the encounter between the mechanical science and techniques of construction, because the only observation of the object itself could not open that otherwise interpretive trails, and do not give explanations on the deep creative processes and design, but not even a vague foreknowledge of the laws of static and structural insights that underlie the construction itself.
The “paradigm shift”, according to Thomas Kuhn (1922 - 1996) Scientific Revolutions, that had begun to emerge in the aristocratic scientific circles, open to innovation of the Galilean science, and then in the European Academies, up to ebb slowly and not without opposition in the engineering practice at the end of the Enlightenment, finally explodes with the industrial revolution and it establishes its triumph.
In the seventeenth century before, and then in the eighteenth century, so we witness a deep and fruitful interweaving of scholarly and scientific academies, including the civilian and military schools, and corporations of master builders. Distinguished scholars compile and publish excellent texts on the subject of shipbuilding [Corradi, 2011b], almost simultaneously with what was happening in the history of mathematics and the mechanics as applied to the problems of the technique.
It is still a frontier land, not very stimulating for the students of the history of science, and somewhat difficult for scholars of the history of shipbuilding, but certainly critical to understand the paradigm shift that involved the world of technology, not relegated to only the most technical and design note of the shipyard, which as we have said, has for centuries based its manufacturing capacity in imitation, but open to education and to teaching, the definition of operational tools such as ‘plans construction’, with the birth of the Schools of naval engineering.



 
Fig. 1. Left: image taken from the English manuscript Fragment of Ancient English Shipwrighty by Matthew Baker (c. 1530-1613), c. 1586; Right: School of Shipbuilding of Brest (1680), illustration of Pierre Ozanne (1737-1813), professor of drawing.

Here the contribution of the engineer-mathematician, or mathematician- engineer, master of his discipline, and therefore ready to penetrate between the old maps bristled with calculations and discouraging geometric constructions has proved invaluable. Exploring the science of “build vessels” of Galilean memory, as stated in his opening words to Discorsi [Galileo 1638] before, through and after the “paradigm shift” of which we have mentioned, is no longer a marginal contribution to the history of shipbuilding, as far as the heart of a crucial event that has changed the face of the “arte del fabbricare navigli” (“art of build vessels”).
For this reason it is believed that the interest in the history of shipbuilding should be more than a moment of mere scholarship for scholars enthusiasts but becomes an instrument of basic knowledge among students of architecture and shipbuilding: the history of both disciplines in itself, and for the history of shipbuilding itself, especially when you are working with projects of restoration, refitting or transformation, who is required to make a diagnosis and a prognosis for their best re-use. Maybe not so much an objective historiography what sustains this interest, but rather the awareness that thorough knowledge and careful reconsideration of the past are now a necessary condition for real progress of the research.


3. “A perfect intelligence”

Awareness, as Aristotle wrote [Aristotle, Pol I, 2, 1252 24], that “considering things in their genesis, you get a perfect intelligence” comes from deep reasons who invest the fundamental principles of the disciplines of interest the naval engineer; disciplines ranging from mechanics to hydrostatic and to hydrodynamic, shipbuilding, science and structural engineering, mechanics of materials, mechanics of solids and structures, etc.
Is not it wrong to imagine the pre-judgment (in the sense of Gadamer’s thought) according to which, for example, in only the structural calculation, each shipbuilding - can be regarded as a physical object completely describable and explicable by the scientist, if - and only if - is known unequivocally its design configuration, i.e. the geometry of the whole and of each of its parts, the nature of the external and internal action which is subject, as well as the equations that govern the relationship between actions and reactions, efforts and stress, strain and deformation in different materials.
The structural analysis belongs by right to the riverbed of the Naturwissenschaften and therefore is based on data currently ascertained experimentally. It then makes use of the laws that govern the mechanical behaviour of the bodies, and you do not see what role can exercise the knowledge of the past history that can govern the design of the present object, if not as useful, but accidental support.
In no way, this implies the introduction of the history of scientific analysis, nor assumes strange interweaving thinking “nomothetic” characteristic of the natural sciences and the intention “idiographic” always shielded by the veil of interpretation, which concerns the historical sciences out, in the Geisteswissenschaften. More simply, it is better to fix instead of the initial data which, together with the boundary conditions, define the physical-mathematical problem, so as to ensure the existence and uniqueness of the solution.
Nevertheless, this solid scientific approach, undoubtedly successful in many applications of mechanics of solids and structures and engineering in general, can be critically revisited and applied even when it comes to designing the new, in order to connect intimately analysis, purely scientific analysis, of the physical object, an analysis of another kind, this time to trace the history of structural design that guided the shipwright and the first engineers of the time.
For example, just behind the Industrial Revolution in the nineteenth century, which introduced in shipbuilding the use of iron and the steam within cultural horizons and traditions no longer familiar to us, but also in the long evolution of shipbuilding in nautical field, where the calculation is arrived late and the structural design, the construction idea was made by the master for decades.
Among the essential principles of scientific disciplines that are a priori of ship design is in fact a convincing image “asymptotic” of the structural description and explanation, according to which, any answer offered by the engineer is valid since he enrolled in the narrow path of achievements approximate, because that is how you present prolepsis anticipation of a perfect solution whose existence is ensured by the universal principle of physical determinism.
But the questions that arise are the following: who could say with absolute accuracy to possess all the necessary data of the problem? Who ever would declare to know the “constitutive equations” of materials especially those that meet current shipbuilding? And who would know never to play with the precision of an intricate calculations congeries, as is required by the strongly non-linear nature of the complex mathematical problem that must be addressed?
In this sense, it would take ... a demon obliging, or rather one of those angels who, at the time of the second Scholastics of the seventeenth century, inhabited the Treaties of physical scientists most loyal to the Aristotelian tradition: because these incorporeal entities could serve as ideal actors to some daring experiments to break some laws of the peripatetic cosmology, without fear of incurring the censure of the Inquisition [Giattino, 1653], indicating the existence of a solution, however, is not known with certainty be excluded at the actual calculation. Still, the idea behind these figures is paradoxical that we have mentioned converges to the image “asymptotic” of scientific knowledge mentioned.
Suppose the objective existence of a perfect solution but unattainable within a design process, which can be more “secularly” define infinite laboratory, able to go from the beginning to the end of a route can only descriptive-explanatory sight distance and wholesale the solution searched, trying to make sense and measure the results actually achieved by the limited cognitive instruments of our knowledge, interpreting them as approximations, more or less accurate, the true solution.
In this way it is found and accepted the convergence of some iterative procedure, with any a priori assessment of the margin of error associated with each iteration, it is proved analytically that numerical results obtained by a finite-difference methods (FDM) or finite elements methods (FEM) are much closer to the correct ones, the more it thickens the solution, according to one or more laws granted at the discretion of the designer.


4. Conclusions

The question that therefore arises is what is the position of the designer when they are asked to forecast the structural behaviour of a design idea, but he pretends to be an objective assessment of the behavioural characteristics of the vessel in its entirety.
The answer perhaps is clear: the indefinable number of factors that are put in place, the insurmountable difficulty of the experiment, the uncertainty that remains in any theoretical model designed to represent the inherent non-linearity of the materials, the incidence of aspects may be captured only by considerations of probability, lead us to think that not even in principle be apparent via a “ontologically” determined, after which shines forth the true goal of the solution.
In this sense, our case is not much (or only) complicated, but rather complex. The first term is appropriate for those intricate problems and perhaps unattainable, but for which you can configure, at least in the abstract, solving paradigms, while the second term is applied to those other problems that defy any paradigm.
The solution thus remains contained in the un-decidable act of design, be it aesthetic and engineering, but the act of design is the history of the time that has been designed and built, and over the years will be slowly forgotten. But the solutions proposed, designed and implemented should not belong to the world of the past, but as solutions to problems or comprehensive answers to the questions asked should be collected and narrated as a key tool for growth and development of the knowledge of the discipline.

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