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Ships on the sea don’t have brakes like cars, so how does a fast-moving ship slow down and stop? CE Approved Manufacturer of fabricating & metalworking
Generally speaking, there are four kinds of braking methods for ships. The first one is the familiar thrust reverser, that is, the propeller is reversed, which changes the direction of the water flow by 180 degrees, offsets the forward kinetic energy, and achieves the purpose of stopping the ship. The ship is driven by the propeller of the engine, and the speed of the propeller determines its speed. When the moving ship is about to stop, it is necessary to slow down and drive against the current for a period of time. This is because after the engine stops running, the ship will travel forward for a while under the action of inertia, so it is necessary to use the reverse current to help the hull “brake” faster.
This method is only suitable for all-electric propulsion ships. Now most ships are all-electric propulsion. At this time, there will be a motor on the main shaft, and it can be controlled to reverse. The reversal of the motor is much faster than the reversal of the steam engine! CE Approved Manufacturer of fabricating & metalworking
The second is kinetic energy attenuation or the use of the convective direction of the ship and the water to achieve the stop of the ship. Left full rudder, right full rudder, left full rudder and right full rudder, using the angle of the ship’s steering gear to decelerate, this mode can also play a partial deceleration role.
The third type is a steering device on a warship or a 10,000-ton giant ship. It can also be called an auxiliary brake. A propeller with a steering mechanism (fin stabilizer) similar to a ship under the bow of the ship, when the ship docks, and the ship The rudder is used in conjunction with lateral propulsion to achieve deceleration. (The anti-rolling fin is a bit like the fin of a fish. Its function is to reduce the shaking of the ship, but it can adjust the angle, just like the flaps of the aircraft, the full-open lift is also the largest, and of course the resistance is also the largest) CE Approved Manufacturer of fabricating & metalworking
ships with extended fins
The fourth is to break down. Personally, I feel that this should also be regarded as an auxiliary brake, just like parking the handbrake, and it will only be used in an emergency. The anchor of a large ship can exceed 100 tons, but it is ineffective to cast anchor if the water depth is too deep. After all, the length of the anchor chain is limited. Even the anchor chain of the Nimitz aircraft carrier is only about 1500 meters, and the average water depth in the Pacific Ocean is 4000 meters, so It is useless to break down in many positions!
However, it is still effective to anchor the ship in shallow water. After the anchor sinks to the bottom of the sea, it will be towed, which will play a great role in slowing down the ship. However, if it suddenly gets stuck, it is estimated that even the entire windlass can be pulled out from the ship ! CE Approved Manufacturer of fabricating & metalworking
Why do ships “go against the current” when they are docked?
If you take the ship many times, you will find an interesting phenomenon: whenever the ship wants to dock, always try to put the bow of the ship against the flowing water, use the deceleration effect of the reverse current to slowly slope towards the pier, and then Dive smoothly.
This is because when the ship is docked downstream, the speed of the ship on the other side is equal to the speed of the ship and the speed of the water; and when the ship is docked upstream, the speed of the ship on the other side is equal to the speed of the ship and the speed of the water. Obviously, the former is much larger than the latter, and the countercurrent landing speed is small, making it easier to land. CE Approved Manufacturer of fabricating & metalworking
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