Picture of the structure of the ship's steering gear: understand the inside of the steering gear in one picture

For every ten ship out-of-control incidents, four are related to steering gear failure. This is real data from the International Maritime Safety Report. You may think that the number is far from yourself. However, for people who sail at sea all year round, this probability falling on themselves is 100% huge trouble. Without further ado, today we will focus on that picture.Ship steering gear structure picture, explore the doorways inside step by step. We don’t have pictures, but you can describe them in your mind.

Don't scroll down in a hurry yet. We need to look at this physical work in reverse. What is the outermost part of the servo? It's an iron shell. But how do the pile of iron lumps inside convert tiny electrical signals into a force that can move dozens of tons of rudder blades? Have you thought about this? The key part of the steering gear is the pump station. If the pump station is not running, the rudder blade will be like a lifeless iron plate. Once the plunger pump in the pump station is started, the oil becomes active. Oil is sucked out of the tank, injected into the pipeline, and then flushed into the cylinder. Have you ever considered where this power comes from? Totally dependent on that oil pressure. Every time the plunger pushes forward, a little oil is squeezed out, and the pressure gradually builds up.

I have met many brothers who have just boarded the ship. When they opened the steering gear door for the first time and saw all the pipes and valves, they were immediately confused. If this is the case for you, don't panic. Let's not look at anything else first, but first identify which one is the oil inlet pipe and which one is the oil return pipe. The fuel inlet pipe is thick and the return pipe is thin. This guideline is the same everywhere. If you touch it with your hand, the oil inlet pipe will be warm to the touch, while the oil return pipe will cool down quickly, indicating that the oil inside has completed its work. It's that easy.

If you think the servo is just that, then underestimate it. The real power of the steering gear is not in the power it outputs, but in how it retracts the power. When you turn the steering wheel, a signal is sent to the steering gear. After receiving the signal, the pump station knows which side to pump oil to. When the left cylinder is filled with oil, the right cylinder must be drained. With this push and pull, the tiller moved. When the tiller moves, the rudder stock turns accordingly, and the rudder blades deflect. Look at this chain, do you understand? From the steering wheel to the rudder blades, there is a complete set of hydraulic operations.

When we talk about this hydraulic trick, we have to mention that smaller object - the valve. Valves are like traffic lights on a pipeline.In which direction the hydraulic oil travels and how fast it travels is entirely determined by the valve.. The relief valve is like a security guard. Once the pressure rises, it will open the gate to release the oil. The throttle valve is like a traffic policeman, controlling the speed of hydraulic oil. The reversing valve acts as a switch, and as long as it is switched back and forth, the direction of the rudder will change. If you couldShip steering gear structure pictureIf these three types of valves are identified, then about half of the secrets of the steering gear will be solved.

Speaking of this, you may ask, what are those thin tubes in the picture used for? Those pipes are used to control the oil circuit and exist specifically to serve the valve. The main oil line pipe relies on strong force to perform its function, and the control oil line pipe relies on precision to conduct command. If you think about it, when you drive the steering wheel, the wheels will rotate as soon as you move the steering wheel. The steering gear also follows the same principle. The oil pressure in the control oil circuit is not high, but the response speed is fast. Once the signal arrives, the valve will act immediately. After the valve moves, the powerful power of the main oil circuit will be revealed. This is the same as when you shout loudly and the people below take action.

But as for the steering gear, the more carefully you treat it, the more it will obey your control. It only works if we interpret this sentence in reverse. If you show indifference to the steering gear, it will definitely give up at the critical node when you most want everything to go smoothly. What's the most typical example I've seen? The pumping station was in good condition and there was plenty of oil, but there was no movement from the rudder. Can you guess where the problem lies? The problem lies in the small filter element at the oil suction port. The filter element is so clogged that even if you have power, you can't use it.The pump was idling there, the oil couldn't be sucked up, and the pressure couldn't be built up. How could the rudder respond?? you fromShip steering gear structure pictureLooking up, the filter element is only such a short section, but once it stops working, the entire system will be paralyzed.

Keyword integration tips: hydraulic lock

If you continue to dig downward, you will notice that there is something called a hydraulic lock inside the steering gear.. The name sounds quite intimidating, but in fact after careful analysis, it is just two one-way valves working together. What exactly is its mission?When the rudder is rotated to the corresponding position, it will firmly hold the oil in the cylinder to prevent the rudder blade from being pushed back to its original position due to the impact of water waves.. You know how rough the waves are on the sea. Without this lock, the rudder blades will swing randomly like a windmill. How can the ship keep sailing in a straight line? So next time you check it outShip steering gear structure pictureWhen doing this, pay attention to the two small valves installed opposite each other near the inlet and outlet of the oil cylinder. That is the true body of the hydraulic lock.

Speaking of which, we have to talk about the things that servos are most afraid of. It's not the wear and tear of components or oil leakage, it's the air. Once air is mixed into the oil, the entire related system will be as if a person is suffering from asthma, making it extremely difficult to breathe, unable to breathe smoothly at all, and at the same time, unable to exert any strength at all. For example, when you push the rudder, it will vibrate, and when you return the rudder, it will be half a beat slower than normal. Then, how to determine that the system has entered the air? You can tell by listening to the sound. When the pump station is operating normally, it will make a dull buzzing sound. If the sound turns into a harsh rattling sound, there is a 90% chance that air has entered.In addition, you can also observe the reaction of the rudder blade. If it pauses for a while before starting to move when turning the rudder, then in all likelihood, the air is causing trouble.. It is not difficult to discharge the air. You need to find the highest position of the air release valve on the pipeline and unscrew it so that the oil comes out with bubbles. Once all the air comes out is oil, then tighten it.

You see, the problems with the steering gear are just a few situations. Among them, oil leakage is considered a condition, filter blockage is considered a condition, air intake is considered a condition, and valve stuck is considered a condition.An experienced sailor once said to me that 99% of steering gear failures are caused by oil problems.. The engine oil has become dirty, the oil volume has decreased, bubbles have formed in the engine oil, the temperature of the engine oil is too high, and the engine oil has become too thick. These are all problems with the engine oil. If you can treat the engine oil properly, then the steering gear will basically not cause you trouble.

At this point you must be wondering, how should I take care of myself? Good question.

Q: How often should the hydraulic oil be changed?

It must be replaced at least once a year, otherwise the decision should be made based on the results of the oil test. If the test finds that the acid value exceeds the standard or there is too much water, it must be replaced immediately. Don't wait until there is a problem with the rudder.。

Q: Does the filter element need to be replaced every time the oil is changed?

A: It must be replaced. The filter element is a consumable item. There is no way to clean the old one. Even if you wash it, it will be in vain. New oil must be matched with a new filter element. This expense cannot be saved.

Q: Why does the rudder move so slowly?

First, check the pressure at the outlet of the pump station. If the pressure is normal, then check whether the throttle valve is adjusted too tightly. If the pressure is low, then the problem mostly lies with the pump or the relief valve.

Q: Can I continue to drive the boat if the steering gear makes abnormal noise?

A: Definitely not. Making abnormal noises is the final warning. If you continue to drive like this, there may be a situation where it may get stuck at any time. Stop the car immediately for inspection and find out where the noise is coming from first.

Q: How often should the backup servo be tested?

A: An in-situ trial operation must be conducted at least once every month, and a real rudder test must be conducted every quarter. Never wait until the main steering gear fails to discover that the backup steering gear is also faulty.

Don't blame me for repeating it. These are all lessons learned at the cost of life. A few years ago, there was a bulk cargo ship. When it entered the port, the steering gear suddenly became stuck, causing the ship to rush straight towards the breakwater. After dismantling it and inspecting it, I found that the balls from the thrust bearing inside the steering gear were broken everywhere. So what exactly is the problem? It turned out that the grease had not been replaced for three years and had dried up long ago.The pilot inspected and signed before sailing, but no one opened the door of the steering gear compartment to take a closer look at the conditions inside.. You judge, who should be blamed for an accident like this?

Return to the picture of the ship's steering gear structure. If you look at it now, the feeling should be different. Pump station, oil cylinder, valve group, pipeline, oil tank, filter element, hydraulic lock, relief valve, reversing valve, throttle valve, thrust bearing, rudder angle feedback device...these names are no longer as difficult to understand as a bible, but each one has its own personality, lively and flexible existence. You know what their respective tasks are, and you also know how they will toss if they are unhappy. That's enough.

Keyword Inclusion Tips: Feedback Organization

The marine steering gear has a rather ingenious feature called a feedback mechanism. This thing is similar to a thin connecting rod. One end is connected to the tiller, and the other end is connected to the control valve. Its job is to convey the position of the rudder blade to the pump station in real time. When you perform a steering operation, the valve will open and the rudder blade will begin to rotate. When it rotates to the angle you want, the feedback mechanism will pull the valve back to the neutral position. Once the oil line is disconnected, the rudder blade will stop. Think about it further. Without this thing, you need to hold the steering wheel with your hands all the time. Once you let go, the rudder will go off on its own. Wouldn't that make people extremely tired? So inShip steering gear structure pictureYou should pay more attention to the thin connecting rod, it is the key to closed-loop control.

Let’s talk about a common thing. Sometimes the rudder rotates, but the angle displayed by the rudder angle indicator does not match the actual rudder blade angle. This is because the feedback link is loose or bent. If you just look at the indicator to repair it, that is It can't be repaired even after dark. The correct way is to first climb into the steering gear compartment and check where the tiller is actually turned, and then return to the bridge to compare the indicators. If the two sides are inconsistent, adjusting the connecting rod is more effective than repairing anything else.

Look, the knowledge about steering gears is quite profound if you say it is profound, but it is fairly simple if you say it is simple. You don't have to be an expert in the field of hydraulics, you just need to understand where problems are particularly likely to occur, what signs there are before a problem occurs, where to check first and where to check after a problem occurs. This is the same as treating a person's illness. You don't need to learn how to perform surgery, but you must know that if you have a fever, you must first measure your temperature. If you have a stomachache, you must first think about what you have eaten.

Now is the time to say goodbye. Having said so much, the key point is just one sentence:Ship steering gear structure pictureIt is not for taking exams, but to help you save your life at critical moments. I will give you three action suggestions. If you can achieve them, the steering gear will basically not conflict with you midway. First, open the steering gear compartment door and look at it for a quarter of an hour every month. Not only look, but also listen, touch, and smell. Listen for any abnormal sounds, feel whether the temperature of the pipes is appropriate, and smell whether there is any smell of oil coke. Second, create a maintenance record form. Record the oil change date, filter element model, pressure reading, fault phenomenon and solutions. Do not just rely on your brain to remember. Third, find an old valve that has been scrapped, disassemble it and take a look. If you have personally seen the small holes and springs inside, you will know why the valve jams when the oil becomes dirty.

Keyword Inclusion Tips: Follow Organizations

Next, add a following mechanism in the steering gear. Don't be fooled by this name. The follower organization is actually another name for the feedback organization mentioned earlier. Its essence is to cause the movement of the rudder blades to always follow the instructions of the steering wheel. When the instruction arrives, the action immediately follows; when the instruction stops, the action stops. An excellent follow-up mechanism will have a reaction time of no more than two seconds. You turn the steering wheel until the rudder blades start to move. If the interval exceeds two seconds, the steering gear needs to be overhauled. So inShip steering gear structure pictureThe pull rods, cams, and springs that connect the tiller and the valve group are inconspicuous. Without them, the steering gear would be like a stupid big guy, with strength but used in the wrong place.

Life at sea is not easy, and it is even more difficult for those who make a living in the wind and waves. You have to remember that even if the boat can be old, the steering gear cannot be messed up. If you add just one drop of sweat in the steering gear compartment, the sea will play one less life-threatening joke on you. The next time you open that thick and heavy steering gear door, don't just stand at the door and watch. Go inside, squat down, and reach out to touch the iron bumps. They have temperature, and that temperature is where your confidence in safety lies.