…A FAIRLY COMPLEX SUBJECT.
Naval
Architecture, especially in its engineering sense - which is the harmonious
combination of those basic factors that produce seaworthiness, speed,
safety, balance, buoyancy, comfort and utility - is a fairly complex
subject.
Carl Lane, Penobscot Boat Works
…ATTITUDE
Naval
Architects – Shipwrights with Attitude!
Michael Gray
…THE
ORIGINATOR/MANAGER OF A SITUATION….
The
definition of shipwright is that of ‘an artisan skilled in one or
more of the tasks required to build ships,’ Michael Gray’s
description is, nevertheless, provocative and today’s Naval Architect
is much more than simply a descendant of Noah.
Naval
Architecture (Ship Design Engineering) of some years ago, could be
considered a euphemism, when shipbuilding was not an ‘exact
science’ but more of an art. Today, a ship design engineer is trained
to be the originator/manager of a situation, capable of promoting safety
standards based upon sound analysis, experimental testing and in-service
experience. He or she is far more than an “artisan.” The
application of computers in shipbuilding has replaced the cylindrical slide
rule, known at the time as the ‘barrel’ (now a museum piece),
and has made ship design and construction a mature technology.
Today’s
CAD/CAM systems not only enhance quality, they save time and costs. These
systems, together with extensive use of Computational Fluid Dynamics, which
solves complex fluid problems, and three-dimensional graphics, which are
computer generated visualisations of a ship’s structure, enable the
ship design engineer to integrate solutions, from conceptual stage of a
design to the fabrication of a ship/maritime structure, while the concept
is still on the design board.
Andrew G Spyrou FRINA
…CONCEIVE
OF, DESIGN, TEST, BUILD, AND OPERATE…
Engineering
is an open-ended process during which scientific knowledge is converted to
useful products for the benefit of society. In order to perform this
transformation, an engineer must be inquisitive and broadly educated, he or
she must be knowledgeable in the sciences and in the language of
engineering - namely mathematics, and he or she must be well educated in
the fundamental courses common to all engineering disciplines - courses in:
statics, dynamics, thermodynamics, fluid dynamics, materials, electrical
theory, and experimental techniques.
Naval architecture is that field of engineering which addresses how we can
apply our acquired wealth of knowledge to conceive of, design, test, build,
and operate all types of ships and boats - recreational to naval, small to
big, operating on or under the sea, sails to nuclear, etc.
US Naval Academy Annapolis
…COMBINES
IMAGINATION, ARTISTIC INSTINCTS, AND PROVEN SCIENTIFIC PRINCIPLES…
Naval
Architecture combines imagination, artistic instincts, and proven
scientific principles, tempered by basic engineering considerations, in
designing the means of ocean transportation of the future. The many types
of ships, boats and vehicles needed to operate on, under, or above the
ocean's surface provide the broad field in which the designer is to work.
The challenge to the naval architect is to convert the functional
requirements into an effective, workable, and cost-efficient design.
The Department of Naval Architecture, Ocean and Marine Engineering,
<i.
…A GENERAL UNDERSTANDING OF ALL ENGINEERING DISCIPLINES…
Naval
architects must have a general understanding of all engineering disciplines
because they generally start the process of designing a ship. After they
determine its basic size and shape, they address hull form and resistance,
propulsion power requirements, ship structure, weight distribution,
stability, and the efficient location of the many compartments throughout
the ship.
American Society of Naval Engineers
…ALL
ASPECTS OF LEARNING, DESIGNING, BUILDING AND SMOOTH RUNNING OF
VESSELS…
Naval
Architecture is a discipline, associated with other types of engineering
needed for vessels to be completely independent units of floating objects
in water, under various conditions of interaction of the wave and the wind
in all aspects of learning, designing, building and smooth running of
vessels; while a naval architect is a person who is fully and
professionally educated in this discipline.
Shyama Prosad Ghosh, FRINA
…SHIP
DESIGN ENGINEERING…
Naval
Architecture is ship design engineering. A Naval Architect is a ship design
engineer, responsible for the design of ships, ensuring structural strength
for the ship to remain afloat, and stability to remain upright, to survive
the forces of the seas and other hazards. The guiding principle of safety
is paramount.
Andrew G Spyrou, FRINA
…DESIGN,
CONSTRUCTION AND OPERATION ASPECTS…
May
I suggest that Carl Lane’s definition lacks certain essential
ingredients:
i.e. one who designs ships (Ca, 1885), extended to include other marine
structures,
i.e. one associated with one or more of their design, construction and
operation aspects,
strength is also rather important as are efficiency and economy in
performance, first cost and operational costs.
D. Faulkner FRINA
…DESIGNING
A SHIP AND PREDICTING ITS BEHAVIOUR…
The
definition of ‘naval architecture’ has changed since the term
first came into use. The earliest published use of the phrase ‘naval
architecture’ appears to date from 1629, when Architectura navalis by
Josephum Furttensbach, was published (in Latin) in Frankfurt, and
immediately translated throughout Europe. It was essentially a how-to book
on building various ship types (galleons, brigantines, etc.), and did not
include any scientific principles underpinning ship design. The meaning of
naval architecture was much different then, and encompassed a much broader
range of topics. For example, the book L'Architecture Navale by Sieur
Dassie, published in Paris in 1677, lists the following headings:
·
Dictionary of geometrical terms
·
Dictionary of nautical terms
·
Correct proportions (length/beam/depth/mast heights) of vessels of
various ranks
·
Inventory of articles aboard a war vessel
·
War maneuvers
·
List of officers and sailors aboard a vessel and their functions
·
Construction of a galley and a longboat
·
Tables of longitude, latitude and tides of principal ports
·
Description of ports and anchorages in the East and West Indies.
Only
a few chapters are devoted to what we would nowadays call ‘naval
architecture’; the rest deal with shipboard operations such as
victualling, navigation and naval tactics. More importantly, in the words
of an English naval architect, ‘it does not appear that there was a
single principle, deduced from science, employed to determine any of the
conditions stated in that work’.
The
first book that could be accurately called a work of scientific naval
architecture was Traité du Navire, published by the French astronomer
Pierre Bouguer in 1746. In it, he developed many of the fundamental
principles of naval architecture still in use today, for example, the
metacentric theory of stability, the use of beam theory in determining hull
strength, and the trapezoidal rule. The book was the first great synthesis
of naval architecture, as well - previous books concentrated on one aspect
such as maneuvering. It was roughly the equivalent of Newton's Principia
Mathematica in terms of its scope and effect on the world of ship design.
Traité du Navire was divided as follows:
BOOK
1: GENERAL IDEA OF CONSTRUCTION
·
Section 1- Shape of the Vessel and how to Trace it
·
Section 2 - Apparatus of the ship, including rudders, masts,
cordages
·
Section 3 - Strength of the Ship, including its Wood and Ropes
BOOK
2: THE VESSEL CONSIDERED AFLOAT, BUT NOT MOVING
·
Section 1 - Weight of the vessel, its buoyancy and loading
·
Section 2 - Distribution of the weight of the vessel, including a
description of the metacenter
·
Section 3 - Rolling and pitching of the vessel
BOOK
3: THE VESSEL CONSIDERED IN MOVEMENT
·
Section 1 - Examination of the shock of fluids; the wind on the
sails, and the water on the hull
·
Section 2 - General solution to the principle problems of maneuvering
·
Section 3 - Properties the vessel must have to steer well
·
Section 4 - Qualities the vessel must have to carry sail well
·
Section 5 - Properties the vessel must have to be fast and keep a
straight course.
This
format has remained essentially unchanged for naval architecture textbooks
for over two hundred years; the latest edition of SNAME's Principles of
Naval Architecture is also divided into three books, each of which covers
roughly the same topics.
Bouguer
unfortunately does not provide us a definition of naval architecture.
However, one quality of his book was its focus on modeling the ship in
mathematical terms and predicting its behavior prior to construction;
previous books mainly spoke of how to build the ship without attempting to
say anything about how the ships would behave once built. So, one element
of a definition of naval architecture should be the prediction of a ship's
behavior and characteristics before it is built. In this respect, naval
architecture is different from the art of the shipwright, which seeks to
build the ship (or boat) but does not necessarily aim at discovering how it
will behave once built.
The
aspect of science should play heavily in the definition. John Fincham's
book A History of Naval Architecture (1841) uses the phrase ‘The
Application of Mathematical Science to the Art of Naval
Construction’. Unfortunately, his book covered naval battles more
than it did science
It
also helps to look afield. Every issue of The Structural Engineer, the
journal of RINA's next-door neighbour, the Institution of Structural
Engineers, carries the following definition: ‘Structural engineering
is the science and art of designing and making, with economy and elegance,
buildings, bridges, frameworks and other similar structures so that they
can safely resist the forces to which they may be subjected." Ships
are more than just structural entities, of course, but the analogy with
respect to hydrostatics, hydrodynamics, etc., is clear. Thus, another part
of the definition should speak to the ability of the ship to safely and
efficiently respond to its element, the sea (this is a broad-brush term for
all navigable waters).
So
- as a first cut attempt at a definition of naval architecture, pulling in
the historical and analogous constituents, I propose the following:
‘Naval architecture is the application of scientific and engineering
principles to designing a ship and predicting its behavior and
characteristics, so that it will safely and efficiently respond to its
element, the sea.’
Larrie D. Ferreiro FRINA
The
science of designing ships and other waterborne craft.
Random House dictionary,
A
designer of ships.
The Concise Oxford Dictionary
A
STUPID MECHANIC …..
If
we survey a vessel, what an exalted idea we must form of the ingenuity of
the carpenter, who framed such a complicated, useful and beautiful a
machine? And what a surprise must we feel when we find him a stupid
mechanic, who imitated others, and copied an art, which, through a long
succession of ages, after multiplied trials, mistakes, corrections,
deliberations and controversies, had been gradually improving? Many worlds
might have been botched and bungled throughout an eternity, ere this system
was struck out; much labour lost; many fruitless trials made; and a slow
but continued improvement carried out during infinite ages in the art of
ship building
‘Dialogues concerning Natural religion, Part V’
David Hume (Scottish philosopher 1711 – 1776)
…THE
USE OF THEORETICAL AND EMPIRICAL KNOWLEDGE WITHIN THE SHIP DESIGN
PROCESS…
A
study of the development of naval architecture during the Scientific
Revolution prompts the question ‘what is scientific naval
architecture?
In
focusing that study on the development of the theories and tools that
allowed for a more scientific basis of naval architecture, and how they
became incorporated into ship design, the important distinction between
‘naval architecture’ and ‘ship design’ must be made.
A shipwright can design and build a perfectly good ship without the use of
any theory and with little calculation or geometry, except for a few rules
of thumb based on past experience. Naval architecture is the process that
allows him to define and accurately predict the characteristics and
performance of that ship before it is built.
To
some extent, this split between naval architecture and ship design can be
seen in SNAME's two publications, Principles of Naval Architecture and Ship
Design and Construction. One deals with theoretical and empirical
knowledge, the other with practical implementation. In this regard,
‘rules of thumb’ and use of geometry is only a small part of
the picture - they are very good for giving a ship based on what has worked
previously, but do not serve to predict how an entirely new ship will
float, how strong it will be or how fast it will go.
Even
today rules of thumb is used on a routine basis. When I designed destroyers
and frigates, I used a set of L/B, B/T, etc., rules. Length-to-hull-depth
ratio (L/D) was kept at 10-15, on the grounds that over 15 gave unusually
high stresses and made the hull too flexible to maintain accurate weapons
alignment (there were other reasons, too). Under 10 meant that the
structure was not working efficiently, i.e., minimum thickness for local
loadings governed, so the hull steel was thicker (therefore heavier) than
what was needed for longitudinal strength. The ideal balance was a hull
thickness that adequately met both local loads & hull girder loads.
Now, shipwrights in the past also had these geometrical rules of thumb -
but all they knew is that if L/D was too big they would get cracking and
splitting in the wood.
‘Scientific’
naval architecture allows the designer to calculate the stresses and see
beforehand if he has an efficient structure - in short, it gives him the
rational basis for his gut reaction or experience. In this respect, modern
ship design is begun by using the kinds of rules of thumb known to the most
ancient shipwrights - but science and engineering ‘inform’ the
designer throughout the design process, and allow him to accurately predict
both the characteristics and performance of his ship before the first steel
is cut. This differentiates ‘naval architecture’ from
‘ship design’, in a sense making naval architecture as a part
of the ship design process.
A
naval architect is therefore someone who uses those principles in that
process (he/she is not necessarily a ship designer - lots of naval
architects specialise in hydrodynamics, structures, etc., and not in the
overall design). Therefore, another potential definition for naval
architecture is:
‘Naval
architecture is the use of theoretical and empirical knowledge within the
ship design process, to predict the characteristics and performance of the
ship before it is built.’
And
for a naval architect:
‘A
naval architect is one who uses theoretical and empirical knowledge as part
of the design process, to predict the characteristics and performance of
the ship before it is built.’
Larrie D. Ferreiro FRINA |
