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Lofting is a drafting technique to generate curved lines. It is used in plans for streamlined objects such as aircraft and boats. The lines may be drawn on wood and the wood then cut for advanced
As ship design evolved from craft to science, designers learned various ways to produce long curves on a flat surface. Generating and drawing such curves became a part of ship lofting; "lofting" means drawing full-sized patterns, so-called because it was often done in large, lightly constructed mezzanines or lofts above the factory floor. When aircraft design progressed beyond the stick-and-fabric boxes of its first decade of existence, the practice of lofting moved naturally into the aeronautical realm. As the storm clouds of Lofting
melmoth2.com Lofting is the transfer of a ''Lines Plan'' to a ''Full-Sized Plan''. This helps to assure that the boat will be accurate in its layout and pleasing in appearance. There are many methods to loft a set of plans. Generally, boat building books have a detailed description of the lofting process, beyond the scope of this article. Plans can be lofted on a level wooden floor, marking heavy paper such as Red Rosin for the full-sized plans or directly on plywood sheets.
The first step is to layout the grid, mark the Base Line along the length of the paper or plywood sheet. Then nail
woodworking
Woodworking is the skill of making items from wood, and includes cabinet making (cabinetry and furniture), wood carving, woodworking joints, joinery, carpentry, and woodturning.
History
Along with Rock (geology), stone, clay and animal parts, ...
. The technique can be as simple as bending a flexible object, such as a long strip of thin wood or thin plastic so that it passes over three non-linear points, and scribing
A scribe is a person who serves as a professional copyist, especially one who made copies of manuscripts before the invention of Printing press, automatic printing.
The profession of the scribe, previously widespread across cultures, lost mos ...
the resultant curved line; or as elaborate as plotting the line using computers
A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations (computation) automatically. Modern digital electronic computers can perform generic sets of operations known as programs. These programs ...
or mathematical tables.
Lofting is particularly useful in boat building
Boat building is the design and construction of boats and their systems. This includes at a minimum a hull, with propulsion, mechanical, navigation, safety and other systems as a craft requires.
Construction materials and methods
Wood
W ...
, when it is used to draw and cut pieces for hulls and keel
The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. As the laying down of the keel is the initial step in the construction of a ship, in Br ...
s. These are usually curved, often in three dimension
In physics and mathematics, the dimension of a Space (mathematics), mathematical space (or object) is informally defined as the minimum number of coordinates needed to specify any Point (geometry), point within it. Thus, a Line (geometry), lin ...
s. Loftsmen at the mould lofts of shipyard
A shipyard, also called a dockyard or boatyard, is a place where ships are built and repaired. These can be yachts, military vessels, cruise liners or other cargo or passenger ships. Dockyards are sometimes more associated with maintenance a ...
s were responsible for taking the dimensions and details from drawings and plans, and translating this information into templates, battens
A batten is most commonly a strip of solid material, historically wood but can also be of plastic, metal, or fiberglass. Battens are variously used in construction, sailing, and other fields.
In the lighting industry, battens refer to linea ...
, ordinates, cutting sketches, profiles, margins and other data. From the early 1970s onward computer-aided design
Computer-aided design (CAD) is the use of computers (or ) to aid in the creation, modification, analysis, or optimization of a design. This software is used to increase the productivity of the designer, improve the quality of design, improve c ...
(CAD) became normal for the shipbuilding design and lofting process.
Lofting was also commonly used in aircraft design before the widespread adoption of computer-generated shaping programs.
Basic lofting
As ship design evolved from craft to science, designers learned various ways to produce long curves on a flat surface. Generating and drawing such curves became a part of ship lofting; "lofting" means drawing full-sized patterns, so-called because it was often done in large, lightly constructed mezzanines or lofts above the factory floor. When aircraft design progressed beyond the stick-and-fabric boxes of its first decade of existence, the practice of lofting moved naturally into the aeronautical realm. As the storm clouds of World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
gathered in Europe, a US aircraft company, North American Aviation
North American Aviation (NAA) was a major American aerospace manufacturer that designed and built several notable aircraft and spacecraft. Its products included: the T-6 Texan trainer, the P-51 Mustang fighter, the B-25 Mitchell bomber, the F ...
, took the practice into the purely mathematical realm. One of that war's outstanding warplanes, the North American P-51 Mustang
The North American Aviation P-51 Mustang is an American long-range, single-seat fighter aircraft, fighter and fighter-bomber used during World War II and the Korean War, among other conflicts. The Mustang was designed in April 1940 by a team ...
, was designed using mathematical charts and tables rather than lofting tables.melmoth2.com Lofting is the transfer of a ''Lines Plan'' to a ''Full-Sized Plan''. This helps to assure that the boat will be accurate in its layout and pleasing in appearance. There are many methods to loft a set of plans. Generally, boat building books have a detailed description of the lofting process, beyond the scope of this article. Plans can be lofted on a level wooden floor, marking heavy paper such as Red Rosin for the full-sized plans or directly on plywood sheets.
The first step is to layout the grid, mark the Base Line along the length of the paper or plywood sheet. Then nail Battens
A batten is most commonly a strip of solid material, historically wood but can also be of plastic, metal, or fiberglass. Battens are variously used in construction, sailing, and other fields.
In the lighting industry, battens refer to linea ...
every 12 inches (or more in some cases) where the station lines are to be set as a mark for the perpendicular line, which is marked with a T-square. The previous steps are followed in turn by marking the Top Line and the Water Line. Before continuing make sure to check the lines by using the Pythagorean theorem
In mathematics, the Pythagorean theorem or Pythagoras' theorem is a fundamental relation in Euclidean geometry between the three sides of a right triangle. It states that the area of the square whose side is the hypotenuse (the side opposite t ...
and make sure the grid is square.
The second step is to mark the points from the table of offsets. All measurements off the table of offsets are listed in Millimeters or the Feet, Inches, and Eighths. The points are plotted at each station then use a small nail and a batten to Fair (draw with a fair curve) the boat's lines.
Definitions
;Full sized plan: A 1:1 scale construction drawing of a boat and its parts ;Lines plan: A scaled-down version of a full-sized drawing often including the body, plan, profile, and section views ;Body Plan: A view of the boat from both dead ahead and dead astern split in half ;Plan view: A view looking down on the boat from above ;Profile view: A view of the boat from the side ;Section view: Cross-section of the boat's width ;Batten
A batten is most commonly a strip of solid material, historically wood but can also be of plastic, metal, or fiberglass. Battens are variously used in construction, sailing, and other fields.
In the lighting industry, battens refer to linea ...
: A long stick to help draw fair lines
See also
*Loft (3D)
Loft is a method to create complicated smooth 3D shapes in CAD and other 3D modeling software. Planar cross-sections of the desired shape are defined at chosen locations. Algorithms find a smooth 3D shape that fit these cross-sections. Designers ...
for the etymologically derived process used in computer-based 3D modeling
References
Books
*"The Evolution of the Wooden Ship", Basil Greenhill, Sam Manning, 1988 *"The Boatbuilder's Apprentice", Greg Rossel, 2007 *"Lofting a Boat: A Step by Step Manual" Roger Kopanycia, Adlard Coles, 2011 {{Shipbuilding-Footer Woodworking Technical drawing Shipbuilding Aeronautics