Lesson four esign of a ship involves a selection of the features of form, size, proportions, and other factors are open to choice, in combination with those features which are imposed by circumstances beyond the control of the design naval architect. Each new ship should do some things better than any other ship. This superiority must be developed in the evolution of the design in the use of the most suitable materials, to the application of the best workmanship, and in the application of the basic fundamentals of naval architecture and marine engineering As sips have increased in size and complexity, plans for building them have became mare detailed and more varied. The intensive research since the period just prior to World War 2 has brought about many technical advances in the design of ships. These changes have been brought about principally by the development of new welding techniques, developments in main propulsion plants, advances in electronics, and changes in materials and methods of construction All ships have many requirements which are common to all types, whether they are naval merchant, or special-purpose ships. The first of such requirements is that the ship must be capable of floating when carrying the load for which it was designed. A ship floats because as it sinks into the water it displaces an equal weight of water, and the pressure of the water produces an upward force, which is called the buoyancy force is equal to the weight of the water displaced by the ship and is called the displacement. Displacement is equal to the underwater volume of the ship ity of the water in which it is gloating Whe weight of the ship, including everything it carries, is equal to the buoyancy or displacement. The weight of the ship itself is called the light weight. This weight includes the weight of the hull structure, fittings, equipment, propulsion machinery, piping and ventilation, cargo-handling equipment and other items required for the efficient operation of the ship. The load which the ship carries in addition to its own weight is called the deadweight. This includes cargo, passengers, crew and effects, stores, fresh water, feed water for the boilers incase of steam propelling machinery, and other weights which may be part of the ships international load. The sum of all these weights plus the lightweight of the ship gives the total displacement; that is One of the first things which a designer must do is to detemine the weight and size of the ship and decide upon a suitable hull form to provide the necessary buoyancy to support the weight that has been chosen Oner 's requiremen Ships are designed, built, and operated to fulfill, the requirements and limitations specified by the operator and owner. These owner's requirements denote the essential considerations which are to form the basis for the design. They may be generally stated as(1)a specified minimum deadweight carrying capacity, (2)a specified measurement tonnage limit, (3)a selected speed at sea, or a maximum speed on trial, and( 4)maximum draft combined with other draft limitations In addition to these general requirements, there may be a specified distance of travel without refueling and maximum fuel consumption per shaft horsepower hour limitation, as well as other items which will influence the basic design. Apart from these requirements, the ship owner expects the designer to provide a thoroughly efficient ship. Such expectations include(1) minimum displacement on a specified deadweight carrying capacity, (2)maximum cargo capacityLesson Four Ship Design The design of a ship involves a selection of the features of form, size, proportions, and other factors which are open to choice, in combination with those features which are imposed by circumstances beyond the control of the design naval architect. Each new ship should do some things better than any other ship. This superiority must be developed in the evolution of the design, in the use of the most suitable materials, to the application of the best workmanship, and in the application of the basic fundamentals of naval architecture and marine engineering. As sips have increased in size and complexity, plans for building them have became mare detailed and more varied. The intensive research since the period just prior to World War 2 has brought about many technical advances in the design of ships. These changes have been brought about principally by the development of new welding techniques, developments in main propulsion plants, advances in electronics, and changes in materials and methods of construction. All ships have many requirements which are common to all types, whether they are naval, merchant, or special-purpose ships. The first of such requirements is that the ship must be capable of floating when carrying the load for which it was designed. A ship floats because as it sinks into the water it displaces an equal weight of water, and the pressure of the water produces an upward force, which is called the buoyancy force is equal to the weight of the water displaced by the ship and is called the displacement. Displacement is equal to the underwater volume of the ship multiplied by the density of the water in which it is gloating. When floating in still water, the weight of the ship, including everything it carries, is equal to the buoyancy or displacement. The weight of the ship itself is called the light weight. This weight includes the weight of the hull structure, fittings, equipment, propulsion machinery, piping and ventilation, cargo-handling equipment and other items required for the efficient operation of the ship. The load which the ship carries in addition to its own weight is called the deadweight. This includes cargo, passengers, crew and effects, stores, fresh water, feed water for the boilers incase of steam propelling machinery, and other weights which may be part of the ships international load. The sum of all these weights plus the lightweight of the ship gives the total displacement; that is Displacement = lightweight + deadweight One of the first things which a designer must do is to determine the weight and size of the ship and decide upon a suitable hull form to provide the necessary buoyancy to support the weight that has been chosen. Owner’s requirements Ships are designed, built, and operated to fulfill, the requirements and limitations specified by the operator and owner. These owner’s requirements denote the essential considerations which are to form the basis for the design. They may be generally stated as (1) a specified minimum deadweight carrying capacity, (2) a specified measurement tonnage limit, (3) a selected speed at sea, or a maximum speed on trial, and (4) maximum draft combined with other draft limitations. In addition to these general requirements, there may be a specified distance of travel without refueling and maximum fuel consumption per shaft horsepower hour limitation, as well as other items which will influence the basic design. Apart from these requirements, the ship owner expects the designer to provide a thoroughly efficient ship. Such expectations include (1) minimum displacement on a specified deadweight carrying capacity,(2) maximum cargo capacity