Lofting
Encyclopedia
Lofting is a Drafting
technique (sometimes using mathematical tables) whereby curved lines are drawn on wood and the wood then cut for advanced woodworking
. The technique can be as simple as bending a flexible object (such as a long cane) so that it passes over three non-linear points and scribing the resultant curved line, or plotting the line using computers or mathematical tables.
Lofting is particularly useful in boat building
, when it is used to draw and cut pieces for hull
s and keel
s, which are usually curved, often in three dimension
s.
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 lay out the grid, mark the Base Line along the length of the paper or plywood sheet. Then nail Battens 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
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.
Drafting
Drafting or draughting may refer to:* Campdrafting, an Australian equestrian sport* Drafting , slipstreaming* Technical drawing, the act and discipline of composing diagrams that communicates how something functions or is to be constructed. E.g.:** Architectural drawing** Electrical drawing**...
technique (sometimes using mathematical tables) whereby curved lines are drawn on wood and the wood then cut for advanced woodworking
Woodworking
Woodworking is the process of building, making or carving something using wood.-History:Along with stone, mud, and animal parts, wood was one of the first materials worked by early humans. Microwear analysis of the Mousterian stone tools used by the Neanderthals show that many were used to work wood...
. The technique can be as simple as bending a flexible object (such as a long cane) so that it passes over three non-linear points and scribing the resultant curved line, or plotting the line using computers or mathematical tables.
Lofting is particularly useful in boat building
Boat building
Boat building, one of the oldest branches of engineering, is concerned with constructing the hulls of boats and, for sailboats, the masts, spars and rigging.-Parts:* Bow - the front and generally sharp end of the hull...
, when it is used to draw and cut pieces for hull
Hull (watercraft)
A hull is the watertight body of a ship or boat. Above the hull is the superstructure and/or deckhouse, where present. The line where the hull meets the water surface is called the waterline.The structure of the hull varies depending on the vessel type...
s and keel
Keel
In boats and ships, keel can refer to either of two parts: a structural element, or a hydrodynamic element. These parts overlap. As the laying down of the keel is the initial step in construction of a ship, in British and American shipbuilding traditions the construction is dated from this event...
s, which are usually curved, often in three dimension
Dimension
In physics and mathematics, the dimension of a space or object is informally defined as the minimum number of coordinates needed to specify any point within it. Thus a line has a dimension of one because only one coordinate is needed to specify a point on it...
s.
Basic lofting
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 lay out the grid, mark the Base Line along the length of the paper or plywood sheet. Then nail Battens 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
Pythagorean theorem
In mathematics, the Pythagorean theorem or Pythagoras' theorem is a relation in Euclidean geometry among the three sides of a right triangle...
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 is a view of the boat from both dead ahead and dead astern split in half
- Plan view is looking down on the boat from the top
- Profile View is a view of the boat from the side
- Section View Cross section of the boats width
- BattenBattenA batten is a thin strip of solid material, typically made from wood, plastic or metal. Battens are used in building construction and various other fields as both structural and purely cosmetic elements...
long stick to help draw fair lines