Floating
It refers to the ability of a ship to float in water and maintain a certain amount of first and last draft and freeboard under various loading conditions. According to the balance of gravity and buoyancy of the ship, the buoyancy of the ship is related to the loading capacity and the safety of navigation.
Stability
It refers to the ability of the ship to be tilted away from the equilibrium position by external force, and the ship can return to the original equilibrium position when the external force disappears. Stability includes complete stability and damage stability, where complete stability includes initial stability and large dip stability. Generally, the stability of a surface vessel is mainly the stability at the time of heel. The ship width, the waterline coefficient, the freeboard, the height of the center of gravity, the size and height of the side area above the water surface, and the sealing performance of the hull opening are the main factors affecting the stability of the ship.
Anti-sinking
It refers to the ability of the underwater part of the hull to be damaged if it is damaged, and the tank can still float without sinking and not overturning. When the shipbuilding in the Song Dynasty of China was first invented, the watertight compartment was invented to ensure the ship's resistance to sinking. The rationality of the watertight subdivision of the main part of the ship, the freeboard value of the subdivision deck and the stability of the intact ship are the main factors affecting the anti-sedimentation.
Rapidity
It is the performance that characterizes the relationship between the ship's straight-line speed in still water and its required host power. It is an important technical indicator of the ship and has a great impact on the ship's use effect and operating expenses. Ship rapidity involves both ship resistance and ship propulsion. Reasonable selection of the ship's main scale, hull coefficient (especially square factor Cb and prism coefficient Cp) and line type is the key to reducing ship resistance.
Wave resistance
Refers to the degree of swaying of the ship in the waves, the stall and the degree of splashing on the deck (on the waves, splashing water). The wave resistance not only affects the comfort and safety of the occupants on board, but also affects the safety and operational efficiency of the ship.
The movement of the ship in the waves has six types: roll, pitch, head and tail, hesitation (heavy), swaying and swaying. Coupling motion is formed when several kinds of motions exist at the same time, and the most influential ones are roll, pitch and heave. Splashing is mainly due to the relative movement of the hull and the waves caused by pitch and heave. Increasing the freeboard, especially the first freeboard and increasing the floating of the first part of the water, is an effective measure to improve the splashing of the ship.
Manipulability
It means that the ship can maintain or change the performance of the speed, heading or position according to the driver's control, mainly including the two aspects of heading stability and rotation. It is to ensure that the ship is less steered during navigation, keeps the shortest voyage, and is flexible and convenient to avoid and avoid Timely and important links are related to ship navigation safety and operational economy.
Economic
Refers to the size of the ship's investment benefits. It is the most active factor in promoting the development and research of new ship types, improving the management of shipping and the development of the shipbuilding industry, and has received increasing attention. Ship economy is a part of ship engineering economics research, which involves indicators of efficiency, construction economy, operating economy and investment effectiveness.
The development of a ship depends first and foremost on the needs of the society for the ship. The rapidly growing bulk cargo (crude oil, mineral grain) transport vessels after the Second World War are quite mature in technology, and there is generally no significant increase or decrease in demand. There is a growing demand for finished packaged cargo carriers, product oil tankers, chemical tanker liquefied gas carriers, and oversized industrial equipment transport vessels. Ships and special-purpose high-speed vessels required for marine development will increase. Correspondingly, research on hydrofoil, hovercraft, catamaran and small waterplane ships will be strengthened.
The second factor in the development of ships is the improvement of economic and social benefits. High fuel prices and loading and unloading costs will encourage people to research new ship technologies, new energy uses, new models, automatic control methods and new energy from the aspects of energy saving, staff reduction and improved transportation methods (from the perspective of the entire transportation system). Ship type.
Ships in China's maritime law refer to seagoing vessels and other offshore mobile devices, except for ships used for military and government duties and small boats of less than 20 tons.
A ship is a means of transportation that relies on manpower, sails, engines, etc. to move on the water. In addition, civil ships are generally referred to as ships, military ships are called ships, and small ships are called boats or boats, which are collectively referred to as ships or boats.
