Basic knowledge of application in propeller ships
The propeller is composed of several blades. The number of blades is usually three blades, four blades or five blades, and the angles between the blades are equal. Usually installed at the stern of the ship, the connecting part between the propeller and the stern shaft is called the hub, and the blades are fixed on the hub. When looking at the bow from the stern, the side of the blade seen is called the leaf surface and the back of the blade. The outer end of the blade is the tip, and the connection with the hub is called the root. The circular trajectory of the blade tip during rotation is the tip circle. This circle is called the paddle disk, the diameter is called the diameter, and its area is called the disk area.
The size of the propeller diameter is often limited by the ship's draft. The larger the diameter, the lower the speed and the higher the efficiency. There must be a good fit with the stern frame of the ship to prevent the tip of the blade from coming out of the water and affecting efficiency. The hull clearance should be appropriate to avoid causing severe vibration. When the forward car rotates, if the direction of rotation seen from the stern to the bow is clockwise, it is called a right-handed propeller, otherwise it is a left-handed propeller. The two-oar boat is installed on both sides of the stern. When it rotates normally, if it rotates toward the center line of the ship, it is called an internal propeller, otherwise it is an external propeller. The oar consists of several blades. The number of blades is usually three blades, four blades or five blades, and the angles between the blades are equal. Usually installed at the stern of the ship, the connecting part between the propeller and the stern shaft is called the hub, and the blades are fixed on the hub. When looking at the bow from the stern, the side of the blade seen is called the leaf surface and the back of the blade. The outer end of the blade is the tip, and the connection with the hub is called the root. The circular trajectory of the blade tip during rotation is the tip circle. This circle is called the paddle disk, the diameter is called the diameter, and its area is called the disk area.
The size of the propeller diameter is often limited by the ship's draft. The larger the diameter, the lower the speed and the higher the efficiency. There must be a good fit with the stern frame of the ship to prevent the tip of the blade from coming out of the water and affecting efficiency. The hull clearance should be appropriate to avoid causing severe vibration. When the forward car rotates, if the direction of rotation seen from the stern to the bow is clockwise, it is called a right-handed propeller, otherwise it is a left-handed propeller. The two-oar boat is installed on both sides of the stern. When it rotates normally, if it rotates toward the center line of the ship, it is called an internal propeller, otherwise it is an external propeller.
