TECHNICAL SUPPORT
Published 2026-03-25
When choosing the working pressure of a hydraulic steering gear, to put it bluntly, you are looking for the “just right” value. When the pressure is low, the steering gear cannot be pushed and the movement is soft; when the pressure is high, the system is prone to oil leakage, pipe collapse, and even the tiller is damaged. How much is appropriate? Don't worry, we will clarify this matter today so that you can have a clear understanding of it.
️Firstlook at the ship’s tonnage and rudder blade size. This is a hard threshold and there is no room for opportunism. Generally speaking, the hydraulic steering gear of a small boat or yacht has a pressure of 10 to 15 MPa (that is, 100 to 150 kilograms of force). If it is a work ship with tens to hundreds of tons, the pressure usually has to be raised to about 16 to 20 MPa. Don't use a small horse to pull a big cart, and don't waste resources. The most accurate way is to look directly at the equipment manufacturer's selection list.
️Italso depends on your steering system. Here's a tip: don't just look at the pressure at the pump station, but also pay attention to theservobore and valve group. If the bore is thick enough, it can rotate even if the pressure is low; if the bore is too small, you have to increase the pressure to make up for the thrust. When we are making plans, it is best to ask the designer to provide a pressure-thrust curve, which will be clear once we compare it.
1. The answer is yes, and the consequences are quite serious. Think about it, hydraulic oil is like human blood. If the pressure is too high, the first thing that cannot handle it is the oil seal and pipe joints. Once any sealing ring is broken, oil leakage will follow. Not only will the engine room be dirty, but the steering gear may fail instantly if there is less oil, which is a taboo during navigation.
2. What’s more troublesome is that high voltage is also a torture to the mechanical structure of the steering gear itself. If the tiller, bearings, and even the rudder stock work under a force exceeding the design for a long time, the risk of fatigue fracture will skyrocket. When we use it, we must install a well-adjusted safety valve in the system. It is the pressure "fuse" and is more effective than anything else.
1. The most direct feeling is that "the rudder is heavy", or "the rudder cannot be turned on". Especially on stormy days, when water hits the rudder blades, if the pressure is not enough, the oil pump cannot push at all. Once the rudder angle command is sent, the rudder blades will not actually turn in place, and the ship will start to yaw, which will make you feel panicked while sailing.
2. Another hidden danger is slow response. You want to avoid something in an emergency, but theservohas to grind for several seconds before it reacts. This will miss a big deal at a critical moment. Therefore, when we test, we must do a full rudder test to see whether the pressure gauge can be stable near the set value during operation and not lose the chain.
The easiest and most reliable way is to find design drawings. When each qualified hydraulic steering gear leaves the factory, the nameplate and instruction manual will clearly indicate "rated pressure". In practical applications, we regard this value as the ceiling. The pressure cut-off point of the pump station is set below this number. Do not adjust it upward based on your feeling.
You can leave some margin during actual operation. From experience, we generally set the system pressure at about 85% to 90% of the rated pressure. For example, if the nameplate says 20 MPa, you can adjust the pressure cut-off valve to about 18 MPa to ensure sufficient thrust and leave a safety margin for the system. This way, the equipment will last longer and you will have less worry.
The first step: first find out the "family background". Check the pipes and joints in the hydraulic pump station and steering gear compartment to make sure there are no obvious leaks or looseness. If this step is not done well, adjusting the pressure will be in vain, because the oil leakage will release all the pressure.
Step 2: Let the pressure gauge speak. Connect an accurate pressure gauge to the outlet of the pump station, and then loosen the locking nut of the relief valve. While having someone steer back and forth on the bridge, slowly tighten the relief valve and stare at the pressure gauge. When the pressure reaches the value you want, lock the nut. Remember, you must operate the rudder several times after adjusting to make sure the pressure is stable before it is complete.
️Myth1: The greater the pressure, the faster the rudder will be. In fact, the rudder speed mainly depends on the oil pump flow rate, that is, how much oil can be supplied per minute. Pressure only determines whether you can push or not. If you just increase the pressure, the flow rate will not change, and the rudder speed will still not increase. On the contrary, it will make the system very "strained".
️Misunderstanding2: The same pressure can be used universally. This pitfall is the one most people trample on. Hydraulicservos from different manufacturers may have completely different diameters of valve groups and cylinder materials, even if the standard pressure is 20 MPa. I have seen someone use the pressure value of boat A directly on boat B, and the result was that the oil cylinder was cracked. Pressure values must never be copied.
️Myth3: As long as there is no oil leakage, there is no need to worry about pressure. Hydraulic oil will deteriorate after being used for a long time, the spring of the relief valve will also become fatigued, and the pressure may drift away unconsciously. We recommend that you check with a pressure gauge every six months or every voyage. This is a good habit to spend a little money to ensure safety.
Speaking of which, I would like to ask you, among the hydraulic steering gear failures you have come across, were there any failures caused by improper pressure adjustment? Welcome to share your experience in the comment area. Let’s avoid pitfalls together and help more friends avoid detours.
Update Time：2026-03-25
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