Driving a small vessel at high speeds or with a powerful outboard motor becomes a real challenge if you use an outdated cable system. The jerks, backlashes and the need to put considerable physical effort into maneuvering are not only discomfort, but also a real threat to safety on the water. hydraulic steeringIt drastically changes the experience of piloting, making the boat run smoothly and predictably.
The principle of hydraulics is based on the transmission of force through an incompressible fluid, which allows you to instantly and accurately transmit commands from the helm to the engine tiller. Unlike mechanical cables, which have the ability to stretch, oxidize and create friction in turns, the hydraulic circuit provides uniform force in any position of the steering pen. This is especially critical for owners of boats with engines from 70 hp, where the load on the mechanics is already too high for comfortable control.
Choosing the right system is not just a kit purchase, it is an engineering challenge that requires considering the type of vessel, engine power and desired reaction speed. adaptive In this article, we will discuss all aspects of the transition to hydraulics, from the selection of components to the final configuration and maintenance.
Advantages of hydraulics over mechanical drive
The switch to hydraulic control offers the boatmaster the possibility that cables cannot operate, the main advantage being that there is no feedback from the engine to the steering wheel, which excludes impacts and jerks when the propeller hits a wave or underwater obstacles. Hydraulic pump It can dampen all vibrations, protecting the steering wheel's hands and mounting elements from damaging loads, and hydraulics can also allow the steering wheel and engine to be carried for a considerable distance without losing efficiency, which is true for boats with two control posts or a complex cockpit layout.
An important aspect is the durability and stability of the system in an aggressive marine environment. If steel cables are corrosive over time and require regular lubrication, then a closed hydraulic circuit requires little or no intervention for many years. Synthetic seals and special liquids ensure the operation of the unit at extreme temperatures, without losing their properties either in icy water or under the scorching sun.
⚠️ Attention: Using the wrong liquid or mixing different types of oils can cause the rubber seals to swell and the system to fail completely. Always check the manufacturer's specifications before refueling!
Another undeniable advantage is the ability to integrate with modern electronic systems. electrohydraulic pump The EHC, which allows for the connection of autopilot and greatly simplifies the operation of the vessel in long-distance passages, mechanical systems such capabilities are devoid or require complex and expensive alterations.
Design and operation of the system
Any hydraulic steering system consists of three main components: a steering pump (rule unit), a hydraulic cylinder (steering machine) and high pressure hoses connecting them. Steering pump It converts the rotational motion of the steering wheel into the forward motion of the piston, creating pressure in the system. Structurally, the pumps can be piston or bladed, the latter being considered more modern and providing a softer stroke without the characteristic "failures" in dead zones.
The hydraulic cylinder, mounted directly on the transom or in the tiller compartment, senses the pressure of the liquid and moves the thrust connected to the engine tiller. chrome-stack And the obal group, because it's the one that works in the most difficult conditions, in constant contact with water and dirt, and the hoses that connect the nodes must withstand pressures of up to 70-100 bar and have reliable protection against grinding and ultraviolet light.
The principle of operation is based on a closed loop: when the steering wheel is turned one way, the liquid is pressurized into one cavity of the cylinder, extending the rod, and from the other cavity it returns to the pump tank. The reverse valve prevents spontaneous flow of fluid by fixing the engine in a predetermined position. For systems with two control posts or complex geometry, additional expansion-tank and volume compensators.
Why is there two hoses in the system?
In the classic scheme, two hoses are used: one provides pressure fluid to turn one way, the other to turn the opposite way, which allows the cylinder to act two-way and return the steering wheel to its original position.
Criteria for choosing a kit for your boat
Selection of hydraulic steering components is a process that requires precise calculation. The first and foremost parameter is the power of the outboard motor. Engines up to 115 hp are usually small-cylinder systems that provide a quick response. Higher-powered motors, from 150 hp and up, require larger diameter cylinders that can exert more force on the rod, but they may require more rpm from stop to stop.
The second critical parameter is the type of hull and the location of the transom. On fast plane boats, the reaction speed is important, so you choose systems with a lower gear ratio. For heavy displacement vessels or trawlers, where speed is not a priority, force is more important, so you use high volume cylinders. outrigger Downriggers, which can create additional resistance when maneuvering.
And the brand of the manufacturer, which is traditionally considered the market leader. SeaStar Solutions (formerly Teleflex), HydraSport and YamahaThe products of these companies undergo strict quality control and have a wide service network. Cheap analogues can save the budget when buying, but at a critical moment their reliability can be questioned.
Cylinder volume (cc. cm)| Engine power (hp) | Type of cylinder | Recommended pump | |
|---|---|---|---|
| up to 115 | Front Mount (frontal) | 115-130 | Standard 0.9-1.2 l |
| 115 - 200 | Front/Rear Mount | 160-190 | Standard 1.5-1.8 l |
| 200 - 300 | Rear Mount (back) | 240-280 | High Output 2.0+ L |
| 300+ | Rear Mount / Dual Cylinder | 300+ | Heavy Duty |
When choosing hoses, always take a length with a margin of 10-15%. Laying on a complex route with the avoidance of obstacles and the design of smooth loops will require more length than the direct distance between the nodes.
Step-by-step instructions for installation of equipment
Installation of a hydraulic steering wheel requires precision and adherence to technology, because safety depends on it. Start with dismantling the old system and preparing the seats. stainless And the key is to ensure that the rod is parallel to the transom, so that you don't have to be skewed or snacked.
The hose is the next step, and you can't pull it into the string, you have to leave the loops to compensate for the vibration of the body and the engine, and you have to attach the hose to the sides with special rubber clamps every 40 to 50 cm, and you can't break it in a radius of less than 50 mm, because it causes the inner layer to break and the channel to clamp.
☑️ Checklist before launch
After the mechanical installation, the connection step follows: the high pressure hoses are connected to the pump and cylinder with the observance of the marking (usually "Port" and "Starboard" or color coding). Before the final fixation of the nuts, make sure that the thread is clean and free of damage. Puff moment must comply with the manufacturer's recommendations, the use of a dynamometer key here will not be superfluous.
System pumping and air removal
The pumping of the hydraulic system is the most important and critical step, on which the lack of steering is dependent. The air in the system is compressed, unlike the liquid, which makes the control nonlinear and dangerous. The procedure begins with filling the expansion tank of the pump to the maximum recommended mark. hydraulic fluidThe steering wheel is then slowly rotated from side to side several times, allowing air bubbles to escape through the liquid in the tank.
If you have a tube of air that doesn't go away, you use the pumping method through the plugs on the cylinder, and you put a transparent hose on the plug, you put it in a container of liquid, and you smoothly open the valve, while you press the steering wheel, and you repeat the operation until the bubbles stop coming out of the hose, and you keep monitoring and filling the fluid level in the tank.
⚠️ Warning: Never keep the steering wheel in its extreme position (stress on the side) for more than 5-10 seconds with the engine running or under load! this leads to a sharp jump in pressure, overheating of the fluid and possible extrusion of the glands.
After air removal, all pressure joints are sealed, and the joints of the hoses and cylinder rods are heated, and any leak, even a microscopic leak, must be removed immediately, because the loss of fluid on the move will lead to a failure of control.
It takes time to get the system up and running, so don't rush to finish the process after the first run of the fluid -- let the system stand for an hour, then repeat the procedure to ensure that the microbubbles are removed.
Typical malfunctions and methods of their elimination
There are a number of problems that can be experienced during operation, and the most common is the appearance of a backlash or a soft steering wheel, which almost always indicates air in the circuit or low fluid levels, and less often the wear and tear of the pump's internal seals, which requires bulkheading or replacement, and diagnostics begin with a visual inspection of the oil level and look for external leaks.
Heavy steering can be caused by the compression of the hoses, freezing of water in the system (if the wrong fluid was used), or mechanical damage to the cylinder rod (bolts, corrosion). If the rod is damaged, it will destroy the ossels every cycle of work, and the replacement of the cuff will only give a temporary effect. hydrocylinder.
Spontaneous steering of the boat to the side (" yaw") often indicates a skew when installing the cylinder or the presence of air in only one cavity of the system. Also, the cause can be different pressure in the tires (for a trailer) or asymmetrical loading of the boat, but first check the symmetry of the hydraulic rod. Regular maintenance, including hinge lubrication and tension check, prolongs the life of the system.
How often should I change the hydraulic fluid?
Manufacturers recommend a complete fluid replacement and system condition check every 3-5 years of use or 500 hours, but visual color and transparency monitoring should be done annually.
Can I use a liquid for automatic transmission instead of a special one?
In emergency cases, some systems allow the use of liquids such as ATF, but this is not recommended for permanent use. Specialized steering fluids have additives that protect against corrosion in marine conditions and have a certain viscosity at low temperatures.
Why did the wheel become tight after winter?
It's likely that the system has condensed, frozen, or thickened the old liquid, and it can oxidize the moving parts of the cylinder during the downtime, check the fluid level, heat the system at low speeds, and replace the oil if necessary.
Are the systems compatible with different manufacturers?
Generally, pumps and cylinders of different brands are not recommended to be mixed due to differences in the geometry of piston groups and seal specifications. However, hoses and fittings often have standard threads, which allows combining components under the condition that the working volume and pressure coincide.
What to do if a hose runs away from home?
If the leak is strong, exploitation is prohibited, and you can try temporarily to squeeze the hose with a special clip (if access allows) or use a high-pressure sealing tape for pipes as a temporary measure until you return to port, but this solution is only to reach the shore at minimum speed.