Boats
Boats and Boatbuilding INTRODUCTION
BASICS OF BOAT DESIGN
Buoyancy and Weight
Trim and Stability
Structure
Watertightness

SKIN AND BARK BOATS

WOODEN BOATS
Lapstrake Construction
Carvel Construction
Plywood Construction

CANVAS-COVERED BOATS
ALUMINUM BOATS
FERROCEMENT BOATS
FIBERGLASS BOATS
MEASURING AND MODELING
The Half-Model
Lift Models and Lofting

BOAT PROPULSION
Inboard Motors
Outboard Motors
Water-Jet Drive
Surface-Piercing Propeller

Motor-Boat Racing
Rowing
Yachting

Ships
THE EARLIEST SHIPS
Earliest Sailing Vessels
Galleys
Biremes
Triremes
Roman Galleys
Dromons
Lateen-Rigged Ships
Junks
Viking Ships
Cog
Carrack
Caravel
Galleon
East Indiamen
Ships of the Line
Frigates, Sloops, and Brigs
Clippers
Last Days of Sail
FUEL-POWERED SHIPS
Paddlewheel Steamships
Innovative Ships of the Late 19th Century
The Screw Propeller
Iron and Steel Hulls
Double- and Triple-Expansion Steam Engines
Steam Turbines
Diesel Engines
The Great Ocean Liners
Cruise Ships
Cargo Ships
Container Ships
Roll-On-Roll-Off and LASH Vessels
Tankers
Crude Carriers
Product Tankers
Other Specialized Tankers
Tanker Safety
Fishing Vessels
Trawlers
Seiners
Long Liners
Research Vessels
Hovercraft
The First Nuclear-Powered Vessels
Naval Vessels
Aircraft Carriers
Battleships
Cruisers
Destroyers
Frigates
Mine Craft
NEW TRENDS IN SHIP DESIGN
SUBMARINES
Submersible Craft
Torpedo (weapon)
shiptravel.auuuu.com Index

BOATS: The Half-Model


The next development in boatbuilding was the use of drawings and the builders' half-model. Using drawings to delineate the shape of the hull apparently evolved slowly, but records are obscure. Similarly, little is known of the evolution of the half-model, but it appears to have developed along with the use of drawings. It is known that the use of such plans was common in 16th-century England, during the reign of Queen Elizabeth I, and Mediterranean builders probably employed crude drawings at least as early as the beginning of the 15th century. According to some authorities, the ancient Greeks and Romans also used drawings in shipbuilding and boatbuilding.

By the middle of the 17th century the art of designing boats by drawing plans was known throughout Europe. The sections were formed by compound curves made with the compass; the longitudinal curves were arbitrarily made according to the same principles that had governed the use of battens. The designers employed shifting molds based on the midsection form, so that one set of frame molds could be used by shifting butts to form all the frames; this system became known as whole molding. The boat design was drawn to reduced scale, and then, in a process known as lofting, a full-size drawing of the ship or boat was made. By 1800 drawing up the plans for ships and boats was fully developed, as was the lofting process.

The use of the half-model in lieu of the reduced-scale drawing appears to have originated in Europe at an early date; by the early 18th century carving a model from a solid block of wood was a popular method of design in commercial boatyards and shipyards. The shape of the model was determined by the judgment and art of its maker. The sections needed to form the mold frames controlling the hull shape of the boat were obtained by sawing the model at the desired transverse mold stations and scaling off these sections by drawing ordinates.
Boats
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