The steering device is used to change the direction of movement of the vessel or keep it on a given course. In the latter case, the task of the steering device is to counteract external forces, such as wind or current, which could cause the vessel to deviate from its intended course.
Steering devices have been known since the appearance of the first floating craft. In ancient times, steering devices were large oars mounted on the stern, on one side or on both sides of the ship. During the Middle Ages, they began to be replaced with an articulated rudder, which was placed on the sternpost in the center plane of the ship. In this form it has been preserved to this day. The steering device consists of a steering wheel, stock, steering gear, steering gear, steering gear and control station (Fig. 6.1).
The steering device must have two drives: main and auxiliary.
Main steering gear- these are mechanisms, steering actuators, power units steering gear, as well as auxiliary equipment and means of applying torque to the stock (for example, a tiller or sector) necessary to shift the rudder for the purpose of steering the vessel under normal operating conditions.
Auxiliary steering gear- this is the equipment necessary for steering the ship in the event of failure of the main steering gear, with the exception of the tiller, sector or other elements intended for the same purpose.
The main steering drive must ensure that the rudder can be shifted from 350 on one side to 350 on the other side at maximum operating draft and forward speed of the vessel in no more than 28 seconds.
The auxiliary steering gear must be capable of shifting the rudder from 150 on one side to 150 on the other side in no more than 60 seconds at the vessel's maximum service draft and a speed equal to half of its maximum forward service speed.
The auxiliary steering gear must be controlled from the tiller compartment. Transition from main to auxiliary drive must be completed in no more than 2 minutes.
Steering wheel– the main part of the steering device. It is located in the stern and operates only while the ship is moving. The main element of the steering wheel is the feather, which can be flat (plate-shaped) or streamlined (profiled) in shape.
Based on the position of the rudder blade relative to the axis of rotation of the stock, they are distinguished (Fig. 6.2):
- an ordinary steering wheel - the plane of the rudder blade is located behind the axis of rotation;
- semi-balanced steering wheel - only a large part of the rudder blade is located behind the axis of rotation, due to which a reduced torque occurs when the steering wheel is shifted;
- balancing rudder - the rudder blade is so located on both sides of the axis of rotation that when shifting the rudder, no significant moments arise.
Depending on the principle of operation, passive and active rudders are distinguished. Steering devices are called passive, allowing the vessel to turn only while underway, or more precisely, during the movement of water relative to the hull of the vessel.
The propeller system of ships does not provide them with the necessary maneuverability when moving at low speeds. Therefore, many ships use means to improve maneuvering characteristics. active control, which allow you to create traction in directions other than the direction of the centerline plane of the vessel. These include: active rudders, thrusters
devices, rotary screw columns and separate rotary nozzles.
Active steering– this is a rudder with an auxiliary screw installed on it, located on the trailing edge of the rudder blade (Fig. 6.3). An electric motor is built into the rudder blade, driving the propeller, which is placed in an attachment to protect it from damage. By turning the rudder blade together with the propeller at a certain angle, a transverse stop appears, causing the vessel to turn. Active rudder is used at low speeds up to 5 knots. When maneuvering in tight water areas, the active rudder can be used as the main propulsion device, which ensures high maneuverability of the vessel. At high speeds the active rudder screw is turned off and the rudder is shifted as usual. 
Separate rotary nozzles(Fig. 6.4). The rotating nozzle is a steel ring, the profile of which represents the wing element. The area of the nozzle inlet is larger than the outlet area. The propeller is located in its narrowest section. The rotary attachment is installed on the stock and rotates up to 40° on each side, replacing the rudder. Separate rotary nozzles are installed on many transport ships, mainly river and mixed navigation, and ensure their high maneuverability.
Thrusters(Fig. 6.5). The need to create effective means control of the bow end of the vessel led to the equipping of ships with thrusters. The launchers create a traction force in the direction perpendicular to the centerline plane of the vessel, regardless of the operation of the main propulsors and steering gear. A large number of vessels for various purposes are equipped with thrusters. In combination with the propeller and rudder, the PU provides high maneuverability of the vessel, the ability to turn on the spot in the absence of movement, departure or approach to the pier with almost a log.
Recently, the AZIPOD (Azimuthing Electric Propulsion Drive) electric propulsion system has become widespread, which includes a diesel generator, an electric motor and a propeller (Fig. 6.6).
A diesel generator located in the engine room of the vessel generates electricity, which is transmitted through cable connections to the electric motor. The electric motor that ensures the rotation of the propeller is located in a special gondola. The screw is located on a horizontal axis, the number of mechanical gears is reduced. The steering column has a rotation angle of up to 3600, which significantly increases the controllability of the vessel.
Advantages of AZIPOD:
– saving time and money during construction;
– excellent maneuverability;
– fuel consumption is reduced by 10–20%;
– vibration of the ship’s hull is reduced;
– due to the fact that the diameter of the propeller is smaller, the effect of cavitation is reduced;
– there is no propeller resonance effect. 
One example of the use of AZIPOD is a double-acting tanker (Fig. 6.7), which open water It moves like a normal ship, but in ice it moves stern first like an icebreaker. For ice navigation, the stern of the DAT is equipped with ice reinforcement for breaking ice and an AZIPOD. 
In Fig. 6.8. a diagram of the arrangement of instruments and control panels is shown: one control panel for controlling the ship when moving forward, a second control panel for controlling the ship when moving stern forward, and two control panels on the wings of the bridge.
Purpose technical means management
On ships of GDP and their types.
The basic requirements for technical controls for inland and mixed (river-sea) navigation vessels are determined by the rules of the Russian River Register (RRR), the Federal body for the classification of inland and mixed (river-sea) navigation vessels. These requirements take into account the type and class of ships.
Technical controls are designed to ensure movement, control and holding of the vessel on a given track. These include:
Propulsion system control system;
Steering gear;
Anchor and mooring devices.
One of the main elements of technical controls is steering gear.
The steering device is used to change the direction of movement of the vessel and keep the vessel on the line of a given path.
It consists:
From a control element (steering wheel, joystick);
Transfer system;
Executive elements.
The controllability of ships is ensured with the help of actuators of steering devices. The following can be used as actuating elements of steering devices on GDP vessels:
Ruli various types;
Rotary screw attachments;
Water-jet propulsion and steering devices.
In addition, on some types of ships the following can be used:
Steering devices;
Wing-shaped propulsion and steering devices;
Active and flanking rudders.
Ship rudders, their shapes and types.
Most widespread rudders of various types were received as an executive element.
The steering wheel may include: rudder blade, supports, hangers, stock, tiller, etc. auxiliary devices(sorlin, helmport, ruderpies).
The steering wheel, depending on its shape and the location of the axis of rotation, is divided into simple, semi-balanced and balanced; according to the number of supports - suspended, single-support and multi-support. For a simple rudder, the entire feather is located behind the stock axis; for semi-balanced and balanced rudders, part of the feather is located in front of the stock axis, forming a semi-balanced and balancing part (Fig. 4.1).
According to the shape of the profile, rudders are divided into plastic and streamlined (profiled). The most widespread on inland navigation vessels are balanced, streamlined rectangular rudders.
The steering wheel is characterized by: height h p– the distance, measured along the axis of the stock, between the lower edge of the rudder and the point of intersection of the axis of the stock with the upper part of the contour of the rudder; length l p steering wheel; offset Δ l p part of the rudder area forward relative to the axis of the stock (for semi-balanced rudder, usually Δ l p up to 1/3 l p, for balanced ones Δ l p up to 1/2 l p).
Fig.4.1 Steering wheels
The most important characteristic the rudder feather is its total area ∑ S p. The actual rudder area is characterized by the expression
S p f = h p l p (4.1)
The total required rudder area to ensure controllability of the vessel is expressed by the equation
∑S p t = LT (4.2)
where is the proportionality coefficient;
L – length of the vessel;
T – maximum draft of the vessel.
To ensure vessel controllability, the required total rudder area must be equal to the actual rudder area, i.e.
The steering device is the main means of controlling the vessel, ensuring its maneuverability and keeping it on a given course. Its main parts are:
control station (wheel or steering electric manipulator);
steering gear from the control station to the steering motor;
steering motor;
steering drive from the steering motor to the steering stock;
a rudder or rotary attachment that directly provides steering control of the vessel.
Main steering station located in the wheelhouse near the heading compass and gyrocompass repeater. The steering wheel or steering control panel is usually mounted on the same column with the autosteering generator. The rudder indicator is placed on the control column and on the left bulkhead of the wheelhouse so that the captain and the officer of the watch have the opportunity to constantly monitor the position of the rudder blade.
Steering wheel or manipulator. The steering wheel is a wheel with handles, with the help of which it rotates on a shaft placed in a special steering wheel cabinet.
By turning the steering wheel, the helmsman sets in motion the entire steering system. For ease of control, the steering wheel is designed in such a way that its rotation to the right corresponds to the rotation of the ship's bow to the right and vice versa.
The electric steering manipulator is a handle mounted on a special stand. Movement of the handle to the right or left through an electric transmission drives the steering electric motor, with the help of which the steering wheel turns in the appropriate direction. Steering wheels (manipulators) are installed in the ship's control posts (in the wheelhouse, in the conning tower, in the central control room and in the tiller compartment).
To ensure control over the position of the steering wheel, steering indicators are installed on the steering column or manipulator or next to them, indicating the angle of deflection of the steering wheel.
Steering gear. Turning the steering wheel sets it in motion steering gear, which serves to control the steering motor, which is usually located in the stern of the ship. There are several steering gear systems.
Roller transmission consists of systems of steel or bronze rollers connected to each other using bevel gears or hinges.
The roller transmission has significant shortcomings: the gears work quite quickly, deformation of the decks and deflection of the rollers can disable the entire steering device.
Hydraulic transmission is a system consisting of two cylinders connected to each other by thin copper tubes. One of the cylinders is located in the lower part of the steering wheel, and its piston is connected to the steering wheel. The piston of another cylinder, located at the steering gear, is connected to its spool. The entire system is filled with liquid (a mixture of glycerin with water or mineral oil).
Roller transmission diagram.
1 - steering wheel, 2 - bevel gears, 3- rollers, 4 - steering motor, 5 - steering wheel.
Hydraulic transmission diagram.
1 - steering wheel, 2 - manipulator part, 5 - pipelines, 4 - executive piston.
Sturroce transmission.
When the steering wheel is turned, the piston of the cylinder located in the steering column presses on the liquid and forces it to flow through the tubes, and since the liquid is not compressed in practical conditions, the piston of the second cylinder moves.
The hydraulic transmission has little durability, since if the tube is broken, the transmission fails and requires a lot of time to restore it.
Electric transmission should now be recognized as the most advanced system. It is carried out using electrical wires. The main element of these transmissions are controllers located in the helm cabinet and connected by a special electrical wire laid in the most protected parts of the vessel with an electric steering machine located in the tiller compartment. The controllers are turned by a handwheel, manual rocker or special handles and drive the electric steering machine
Sturroce transmission used on small vessels. It consists of steel cables or chains connected on one side to the steering wheel, and on the other directly to the steering gear. Main disadvantage steering cable transmission is significant friction in the rollers or pulleys along which the steering cable passes, as well as its rapid stretching, leading to the formation of backlashes.
Axiometer- a device for indicating the position of the rudder relative to the centerline of the vessel. It is installed on the helm stand or next to it. The arrow shows how many degrees the steering wheel is shifted to the right or left, and the green or red light turns on, respectively. signal light; When the steering wheel is in a straight position, the white light comes on.
Steering motor drives the steering actuators. There are many designs of steering motors, but most often ships have electric and electro-hydraulic machines.
In case of damage to the steering motor, it is equipped with a convenient means for turning it off from the steering system and switching to manual control.
Steering drives. Steering actuators are used to transmit the forces developed by the steering motors to the steering wheel. As steering motors The ships have electric and electro-hydraulic machines.
Steering gears provide transmission of steering motor forces to the stock.
Sector-tiller drive used on some modern ships of small tonnage. In such a drive, the tiller is rigidly attached to the rudder stock. The sector, loosely mounted on the stock, is connected to the tiller using a spring shock absorber, and to the steering motor - gear transmission. The rudder is shifted by the steering motor through the sector and tiller, and dynamic loads from wave impacts are absorbed by shock absorbers.
On modern ships steering gears are combined with steering drives, which allows achieving a high coefficient useful action the entire device.
The most widespread of such combined devices are electro-hydraulic machines.
In domestic shipbuilding they use plunger electro-hydraulic machines. There's pressure in them working fluid is converted into a translational movement of the plunger, which then through mechanical transmission is converted into a rotational movement of the tiller. It is used as a working fluid in such machines. mineral oil. The cars are available in two and four-cylinder versions.
In such a car with a steering stock 1 tiller tightly tied 2 and a slider is installed on it , connected to the plungers 3 of two cylinders 4. The cylinders are connected by pipelines to a pump 6 driven by an electric motor 5 . Oil pumped from one cylinder to another by means of a pump causes translational movement of the pistons, turning the stock through the tiller. The shock absorber is a bypass valve 7, which is connected to both cylinders through an additional pipeline. When the will strikes the steering wheel, excessive pressure is created in one of the cylinders. Then the valve opens slightly and the oil moves from one cylinder to another. On large-capacity ships, they are usually installed four-cylinder electro-hydraulic machines, creating large torques.
On the baller 1 tiller mounted rigidly 2, which is through the sliders 3 connected to plungers 4 hydraulic cylinders 5. Electric motors 6 Variable flow radial piston pumps are driven by 7. Control lever 8, driven by telemotors 9 from control station via traction 10 with shock absorbers 11, The operation of the pumps is being adjusted. When turning to the right, the pumps supply working fluid (oil) to the right bow and left stern cylinders. By oil pressure through the plungers, slides and tiller, the torque, as indicated by the solid arrows, will be transmitted to the stock and the rudder will turn to the right. The dashed arrows show the direction of oil flow when the steering wheel is turned to the left.
By switching the valves in the valve box, four or two cylinders (bow or stern pairs) can be activated. Two pumps or one of them can be switched on. Switching is done in the tiller compartment. On some ships, switching can be done from the bridge. As a rule, in cramped waters, in narrow areas, on approaches to ports, both pumps are turned on. On the high seas there is usually only one in action.
Using the reserve control wheel, the rudder is shifted from the tiller compartment, where the gyrocompass repeater is installed. Such a system has an emergency hand pump installed outside the tiller compartment and having a separate pipeline, which is not shown in the figure. When a hand pump operates, only one pair of cylinders operates.
The advantages of electrohydraulic machines are: obtaining large forces and torques with small masses and sizes per unit of power, smooth, silent changes in speed over a wide range, high efficiency, reliable lubrication of rubbing parts with oil used as a working fluid, the possibility of reliable protection from overloads and durability when duplicating main components.
When operating electro-hydraulic machines, it is necessary to take into account that their operation depends on the quality of the hydraulic pumps. All noticed problems in the operation of such machines usually relate to pumps and control system elements. Thus, unfiltered oil in the system, scale remaining in pipes, metal shavings in the internal cavities of parts can cause failure of pumps and the machine control system. The plunger unit itself is reliable and durable.
In accordance with the requirements of the Register of the Russian Federation, the steering gear of sea vessels must have three drives: main, spare and emergency.
Main drive must ensure continuous shifting of the rudder from side to side when maximum speed forward travel, while the time for shifting the rudder from the extreme position of 35° of one side to 30° of the other should not exceed 28 s.
Spare steering gear must ensure continuous shifting of the rudder from side to side at a forward speed equal to half the maximum, but not less than 7 knots. A spare steering gear must operate independently of the main one, and it must be installed on all ships, except for ships with primary manual drives with an emergency tiller, ships with several separately controlled rudders and ships with one electro-hydraulic steering gear with two independent hydraulic pumps. Transition from primary to secondary steering must be completed in a time not exceeding 2 minutes.
Emergency steering gear must ensure shifting of the rudder from side to side at a forward speed of at least 4 knots. The emergency drive shall not be located below the bulkhead deck. Its installation is not required if the main and emergency drives are located in a room entirely located above the highest load waterline.
It is allowed that the main, spare and emergency steering drives or two main drive units have some common parts, for example a tiller, sector, gearbox or cylinder block, but on the condition that the structural dimensions of these parts will be increased in accordance with the requirements of the USSR Register.
Tiller hoists can be considered as a spare or emergency steering gear only for ships with a gross tonnage of up to 500 per. T; if they can be connected to an electric capstan or winch, they will be considered as a spare drive operating from a power source.
The steering device must have a system of steering wheel rotation limiters that allows it to be shifted to an angle of no more than 36.5°. The steering drive control system must be such that shifting the steering wheel stops before the steering wheel reaches the limiter, and in any case no later than the moment corresponding to shifting it to an angle of 35°.
Near each steering control station there must be a rudder position indicator. Such signs should also be in the tiller compartment. The accuracy of the readings regarding the true position of the rudder blade must be no less than: G - when the rudder is positioned in the center plane; 1.5° - at shift angles from 0 to 5°; 2.5° - at shift angles from 5 to 35°.
Steering wheels. The rudder is that part of the steering system that, under the influence of water flowing around the ship, forces it to make turns.
Rudders can be ordinary, balanced and semi-balanced.
Ordinary and semi-balanced rudders, consist of a feather 1 , ruderpnea 4 and ballera 2 . To make it lighter, the pen is made in the form of a sheet frame covered with steel sheets.
Ruderpiece has a number of loops 5 into which the pins are inserted 6 . The rudder post has loops with holes for hanging the steering wheel. The rudder stock passes through a hole in the ship's hull called the helm port. To prevent water from entering the ship, the helm port is sealed with an oil seal. 9 . The uppermost part of the stock is called the rudder head.
Ordinary steering wheel.
1 - rudder feather, 2 - stock, 3- steering head, 4 - ruderpiece, 5 - loops, 6-pins, 7- heel, 8 - ruderpost, 9- stuffing box.
Balanced steering wheel does not have ruderpis. It rests with special protrusions on hinges that fit inside the ship.
Steering action. When the ship is stationary, shifting the rudder to one side or the other will not have any effect on the ship. While underway, if the rudder is straight, that is, in the middle longitudinal (diametrical) plane, the ship will go straight. This happens because a stream of oncoming water flows evenly around the hull from both sides
The steering wheel is in forward position. a - to the right, b - to the left.
ship and rudder. But as soon as the rudder is placed in forward motion to the side, for example, to the right, then the streams of water running along the starboard side will meet the rudder feather on their way and begin to put pressure on it. On the left side the water will not encounter any obstacles. Under the pressure of water jets on the right, the rudder, and with it the stern, will begin to move to the left, the bow will go to the opposite side, and the ship will roll to the right.
When the steering wheel is positioned to the left, we will observe a deflection of the stern to the right, and the bow to the left.
In reverse, the opposite phenomenon will occur: when the rudder is shifted to the right, counter jets of water will press on the left side of the rudder blade and push the stern to the right, and the bow to the left; when the rudder is shifted to the left, the stern will go to the left, and the bow to the right.
Reverse steering wheel position. a - to the right, b - to the left.
It follows that in forward motion the ship rolls in the same direction in which the rudder is positioned, and in reverse - in the direction opposite to the position of the rudder.
Reasons affecting agility. When controlling a ship, it is necessary to take into account the influence on the agility of the propellers, inertia, roll, wind, and waves.
When analyzing the influence of the propeller operation on the turning ability of the ship, you need to know the name of the propeller pitch. A propeller rotating clockwise, when viewed from the stern to the bow, is called a right-pitch propeller (Fig. 147); a screw rotating counterclockwise is a left-pitch screw (Fig. 148).
On single-screw ships they install right-pitch propellers, on double-screw ships so that they work outward, that is, on the right - a right-pitch propeller, and on the left - a left-pitch propeller (Fig. 149).
Under the action of a right-pitch propeller, a single-rotor ship tends to veer with its bow to the right: on forward travel a little, but in the back - a lot. Therefore, when turning around in a narrow area, it is best to turn to the right, if possible.
On a two-propeller ship, the action of the propellers is mutually balanced if they work with the same force.
The propeller attachment, installed instead of the rudder, significantly improves the maneuverability of the vessel. Its use also ensures an increase in the vessel's speed by 4-5% at constant power of the main engine. The nozzle represents
a ring placed on the screw and fixed to the stock, which unfolds in a horizontal plane. The jet thrown by the propeller creates a reactive force, ensuring the rotation of the vessel. In the tail part of the nozzle in the plane of the stock axis there is a stabilizer that enhances steering action nozzles
In addition to the basic controls, you can also install active control devices (ACS), and some of them not only improve maneuverability, but also ensure that the vessel moves with lag.
Control activation devices (ACS) have found wide application in the fleet, since they, firstly, ensure maneuvering of the vessel at low speeds, and, secondly, improve the maneuverability of the vessel when mooring.
The most common self-propelled guns on ships include: active rudders (AR), thrusters (PU), auxiliary propulsion and steering columns (VDRK).
The active rudder has an auxiliary propeller in an attachment on the trailing edge of the stern rudder. Electrical engine The auxiliary propeller is enclosed in a drop-shaped casing, power is supplied to it through a hollow stock, and the control is located in the wheelhouse. On some ships, this engine, mounted at the end of the stock, is located in the tiller compartment and is connected to the propeller via a shaft located inside the stock. When the auxiliary screw operates, a thrust force is created.
Turning the active rudder at a certain angle to the center plane creates a moment that turns the stern in the direction opposite to the rudder shift. In this case, the circulation diameter is greatly reduced, and the maneuverability of the vessel does not depend on the speed -
The propeller from the main engine may not rotate at all.
With the rudder in a straight position, the auxiliary propeller of the active rudder provides the vessel with a speed of up to 3 knots.
The thruster (PU) is a propulsion device enclosed in a transverse tunnel below the waterline and creating a thrust in the direction perpendicular to the centerline plane. The tunnel is usually located at the bow of the ship, but on some ships the thruster and tunnel are located both at the bow and stern; in this case, the ship can move with a log. The working body of the launcher can be propellers (single and paired), winged propulsors or pumps. The entrance holes of the tunnel are closed with blinds, and a gearbox and two screws rotating in different directions are placed in the tunnel pipe. A reversible electric motor transmits rotation through a gearbox to the propeller shafts of the launcher.
A retractable propulsion-steering column, which, together with the screw and attachment, can be rotated across the entire horizon, which makes it possible to create a stop in any direction. While the vessel is moving, the device is retracted into a special shaft in the hull and does not provide additional resistance to the movement of the vessel.
The steering device is designed to ensure controllability of the vessel (course stability and agility).
A general view of the steering device is shown in Fig. 6.20. The steering device includes a steering wheel, a steering drive, and a control drive.
The rudder includes a rudder blade and a stock. The basis of the rudder blade is a powerful vertical beam - ruderpiece. Horizontal stiffeners and loops are connected to the ruderpiece. According to their cross-section, rudders are divided into plate and streamlined. Streamlined steering wheel - hollow in cross-section has a drop-shaped shape, improves controllability, increases the efficiency of the propeller, having its own
Rice. 6.19.Main types of rudders: A– ordinary unbalanced; b– balancing; V– balanced suspended; G– semi-balanced, semi-suspended.
buoyancy, reduces the load on bearings. Because of these advantages, almost all marine vessels have streamlined rudders. According to the position of the axis of rotation, rudders are divided into: unbalanced, semi-balanced and balanced. According to the method of attachment to the ship’s hull - ordinary, suspended and semi-suspended (Fig. 6.19). In balanced and semi-balanced rudders, part of the steering wheel area (up to 20%) is located in the nose from the axis of rotation of the steering wheel, which reduces the torque and power required to turn the steering wheel and the load on the bearings.
The baller serves to transmit torque to the rudder blade and turn it. The stock is a straight or curved rod, which is attached at one end to the rudder blade using a flange or cone, and the other end enters the ship’s hull through the helm port pipe and oil seal. The baller is supported by bearings and is mounted on its upper end tiller– single-arm or double-arm lever.
The steering drive connects the steering stock with the steering gear and consists of a tiller and a corresponding transmission to it from the steering gear. The hydraulic plunger drive fig. is most widely used. 6.21 and steering gear with oscillating cylinders fig. 6.23. Gear-sector drives (outdated type), tiller and screw drives are used (Fig. 6.22).
Rice. 6.20. Steering gear.
1 – rudder blade; 2 – ruderpis; 3 – stock; 4 – lower bearing; 5 – steering gear;
6 – helport tube. The safety of the vessel depends on the steering device, so it is required that in addition to the main drive there is also a spare one. The main drive must ensure that the steering wheel turns by full speed ahead
of the vessel from 35° of one side to 30° of the other side in 28 seconds (mechanical steering wheel limiter at 35°, and limit switch at 30°). The spare drive must ensure that the rudder can be shifted at half speed (but not less than 7 knots) from 20° to 20° on the other side in 60 seconds. An emergency drive must be provided if any waterline extends above the tiller deck (the room where the steering gear is located).
Given the special importance of the steering gear for the safety of the ship, modern ships usually install two identical drives that meet the requirements for the main drive (Fig. 6.21). This significantly increases the reliability of the steering device, since in this case mutual replacement of components is possible. With a hydraulic drive, the steering wheel is turned by oil supply high pressure
into one of the hydraulic cylinders and under the action of the plunger the tiller and steering wheel rotate (oil drains freely from the opposite hydraulic cylinder). Rice. 6.21. General form (a) and operation diagram of the electro-hydraulic steering machine (b): 1-baller, 2 – tiller, 3 – cylinder, 4 – plunger, 5 – electric motor, 6 – oil pump
, 7 – control station. A Rice. 6.22. Steering gears: b– tiller; V– screw;
– sectoral.
1- rudder feather; 2- baller; 3- tiller; 4- steering cable;
5-tooth sector; 6- spring shock absorber; A) is used on boats. Since the cables are wound on the drum in opposite directions, when the steering wheel with the drum rotates, one cable lengthens and the other shortens, which causes the tiller and steering wheel to rotate.
Screw drive (Fig. 6.22. b) is used on small ships. Since the threads on the spindle in the area of the sliders are in the opposite direction, when the spindle rotates in one direction, the sliders move closer together, and when rotated in the other, they move away from each other. This causes the tiller and rudder to turn.
The gear-sector drive was previously widely used (Fig. 6.22. V). Driven by an electric motor through a gearbox. In this drive, the tiller, as always, is firmly mounted on the stock, and the gear sector rotates freely on the stock. The tiller is connected to the sector by a spring shock absorber, which softens the shock of waves transmitted from the rudder to the gearbox
The steering gear control drive connects the steering wheel located in the wheelhouse and the steering gear. The most common are electric and hydraulic drives.
Rice. 6.23. Steering gear with oscillating cylinders
In narrow spaces at low speed, the ship does not listen well to the rudder, since the low speed of the flow impinging on the rudder sharply reduces the transverse hydrodynamic force on the rudder. Therefore, in these cases, they usually resort to the help of tugboats or install active control devices (ACS) on the ship: thrusters, retractable rotary screw columns, active rudders, rotary nozzles.
Thrusters (Fig. 6.24.a) are usually installed in the bow of the ship, and sometimes in the stern. To ensure that the niche in the hull does not create additional resistance while the vessel is moving, it is closed with blinds.
The retractable steering column provides support in any direction, so it is often used on small boats and watercraft to keep it in one place at great depths. At shallow depths, the column may be damaged.
An active steering wheel (Fig. 6.25) is a small propeller installed in the steering wheel and driven by an electric motor or hydraulic motor located in a capsule built into the steering wheel. In some cases, the propeller is driven by an electric motor located in the tiller through a shaft that passes through a hollow stock. When the main engine is not running, the steering wheel can be rotated up to 90° and create a thrust in the desired direction when the auxiliary propeller is operating. Sometimes this version of the self-propelled guns is used when it is necessary to ensure a low speed of the vessel of the order of 2 - 4 knots
Rice. 6.24. Thruster (a) and retractable rotary propulsion and steering column (b).
The rotary nozzle (Fig. 6.25.b) is a streamlined ring-shaped body within which the screw rotates. When the nozzle is turned, the jet of water thrown by the propeller is deflected, which causes the vessel to turn. The rotary attachment significantly improves agility at low speeds and especially in reverse. This is explained by the fact that the entire stream of water is deflected by the nozzle both in forward and in reverse, unlike the steering wheel. In addition, in some cases, the nozzle can increase the efficiency of the screw.
TO
Fig.6.25 Active rudder (a) and rotary attachment (b): 1- rudder blade; 2- auxiliary screw; 3- electric motor; 4- stock; 5- electrical cable; 6- propeller; 7-rotary nozzle.
Azimuthal complexes “AZIPOD” are becoming increasingly popular, which I install on passenger ships and even on Arctic vessels. A typical layout includes: two aft-mounted rotary rudder columns holding nacelles containing electric motors adapted for rotating “pulling” propellers (PPP) (Fig. 6.26). The power of each speaker is up to 24,000 kW.
Fig.6.26.
Steering columns type “AZIPOD”
“A special hydraulic drive ensures that each of the gondolas rotates 360° with an angular velocity of up to 8° per second. Controlling the rotation of the screws makes it possible to select any operating mode in the range from “full forward” to “full reverse”. It is important that the “full reverse” mode can be provided to the vessel without turning the nacelles by 180°. Driving mode"
“-used when the vessel is moving at a relatively high speed; In this case, the gondolas rotate synchronously (the angles of joint transfer are within ±35°). The high hydrodynamic efficiency of such a steering complex is noted: the controllability of the vessel remains acceptable even when the rotation of the propellers stops. The driving mode allows emergency braking (due to reverse - without turning the columns); Maneuvering mode” (soft form)
“– used when the ship is moving at a relatively low speed. In this mode, one of the gondolas retains the function of a “marching” device, the second is rotated 90°, forcing it to work as a powerful stern thruster;) – propellers shifted to the right and left sides (+45° and –45°) force them to rotate “forward” or “backward”. If the propeller of the right gondola works “forward”, and the left one works “backwards”, a transverse control force arises in the direction of the starboard side; in a symmetrical situation - in the direction of the left side.
The steering device is designed to keep the vessel on course or change the direction of its movement. It ensures the controllability of the vessel.
The following rudders are used on ships: ordinary, balanced and semi-balanced.
Ordinary steering wheel- this is a rudder, the feather of which is located aft of the axis of rotation.
By design, there are 2 types of rudders: 1-layer or flat, resting on ribs connected to the rudderpiece, and 2-layer, or streamlined, in which the rudder blade consists of a frame covered with steel sheets. The empty space is filled with wood or harpius to prevent corrosion.
To hang an ordinary steering wheel, loops are made on the rudder pier and rudder post. The holes in the loops on the ruder pierce are conical, while on the ruder post they are cylindrical. The lower loop on the rudder post does not have a through hole and is a support that takes the weight of the steering wheel. In the thrust bearing, a “lentil” is placed under the pin. During operation, when worn, the lentils are replaced. To prevent the steering wheel from being lifted up and torn from its hinges by the impact of a wave, one of the pins, usually the top one, has a head. This design allows you to remove the steering wheel without entering the dock.
To prevent the rudder from shifting to an angle greater than 35°, limiters are installed: protrusions on the rudder pier and rudder post, chains, protrusions on the deck.
The upper part of the ruder pierce is connected to the stock. Connection methods may be different, but one indispensable condition must be met: the steering wheel must be removed without vertical shift of the stock. The most common is the bolted flange connection. Top end The stock is brought out to the deck where the steering gear is located.
In order to prevent water from entering the ship's hull through the cutout for the passage of the stock, it is placed in a helmport pipe, the connection of which with the outer plating and deck flooring is made watertight.
The use of streamlined rudders allows you to reduce water resistance when the vessel is moving. Thanks to this, the controllability of the vessel is increased and the power spent on shifting the rudder is reduced.
The hollow handlebar frame consists of a rudderpierce, an outer rim and several ribs. The sheathing sheets are connected to the frame by welding.
Hanging an ordinary 2-layer rudder is done in the same way as a 1-layer one, but there are 2 pins, which allows you to bring the rudder blade as close as possible to the rudder post (it is also made streamlined). It is a fixed part of the rudder blade - the counter-rudder. This design allows you to increase the speed of the vessel by 5-6%.
a) Ordinary flat steering wheel has an axis of rotation at the leading edge of the steering wheel. The rudder blade 9, made of a thick steel sheet, is reinforced on both sides by stiffening ribs 8. They are cast or forged integrally with the thickened vertical edge of the rudder - the rudder pierce 7 - with hinges 6, in which the pins 5 of the rudder are securely fastened, hung on the hinges 4 of the rudder post 1 . The pins have a bronze lining, and the rudder post hinges have backout bushings. The lower pin of the ruderpierce fits into the recess of the heel of the sternpost 10, into which a bronze bushing with a hardened steel lentil at the bottom is inserted to reduce friction. The heel of the sternpost absorbs the pressure of the rudder through the lentil.
To prevent the steering wheel from moving upward, one of the pins, usually the upper one, has a head at the lower end. The upper part of the rudder pierce is connected to the rudder stock 2 with a special flange 3. The flange is slightly offset from the axis of rotation, so it forms a shoulder and makes it easier to turn the rudder blade. The displacement of the flange allows, during repair of the rudder blade, to remove it from the hinges of the rudder post without lifting the stock, by disconnecting the flange and turning the blade and stock in different directions.
Ordinary flat rudders are simple in design and durable, but create great resistance to the movement of the vessel, so it is required great effort for their transfer. Modern ships use streamlined, balanced and semi-balanced rudders.
b) Feather streamlined steering wheel It is a welded metal waterproof frame covered with sheet steel.
The feather is given a streamlined shape and sometimes additional special attachments are installed on it - fairings. Ruderpost is also made streamlined.
V) U balance steering wheel part of the feather is shifted from the axis of rotation to the bow of the vessel. The area of this part, called the balance part, is 20–30% of the total area of the pen. When shifting the rudder, the pressure of counter flows of water on the balance part of the feather promotes the rotation of the rudder, reducing the load on the steering machine.
d) Semi-balanced steering wheel differs from the balancing one in that its balancing part has a smaller height than the main one.
Balanced and semi-balanced steering wheels- these are rudders in which the rudder blade is located on both sides of the axis of rotation. These rudders require less effort to shift. The part of the area located in the nose from the axis of rotation is the balancing part of the steering wheel. The ratio of the area of the balancing part to the rest is the degree of balancing and is expressed in %. On modern ships, the degree of balancing is 20-30%
The steering wheel is called balancing, if the height of its balancing part is equal to the height of the main part of the steering wheel. If the balancing part has a lower height along the axis of the stock than the main part, then such a steering wheel is semi-balanced.
The balance rudder is mounted on a sternpost that does not have a rudder post. The steering wheel is hung on 2 hinges in the upper part and the thrust bearing, but there may be a different design: the steering wheel is held by a stock, which has a thrust bearing in the lower part of the helm port. A balanced pendant rudder is often found. The feather of such a rudder has no supports at all and is held only by the stock, which in turn rests on thrust and support bearings.
Active steering It is a streamlined steering wheel equipped with a small propeller. When shifting the rudder, the thrust force of the propeller is added to the force generated by the rudder. To increase efficiency, the screw is placed in a guide nozzle. The propeller rotates from an electric motor placed in a teardrop-shaped fitting on the steering wheel. The power of the installation ranges from 50 to 700 hp. In the event of an accident of the main engines, you can use the tail rotor, the ship will maintain a speed of 4-5 knots.
Bow thrusters. In the bow of the ship, transverse tunnels are made in which small propellers. The diameter of the thrusters reaches 2 m, the engine power is up to 800 hp. To change the direction of the jet, a system of dampers is used, as well as reversing the propeller.
Thrusters provide controllability at low and reversing, allowing you to move even with a lag. Can be used on a wide variety of vessels.
Sector drive with steering cable transmission. A sector is fixed to the stock instead of a straight tiller. Each branch of the steering cable runs around the sector along a special groove and is attached to its hub. With this design, the slack in the non-working branch of the steering cable is eliminated. The size of the central angle of the sector should be such that the steering cable does not have large kinks. Usually it is equal to double the rudder angle, i.e. 70 o.
When repairing a rudder at sea, it must be secured in a certain position. For this purpose, there is a brake on the steering gear. A brake arch is installed on the sector, to which the brake pad is pressed using a screw drive.
IN sector drive with gear transmission the teeth are located along a sector arc and mesh with a gear connected to the steering drive. The gear sector sits freely on the stock and is connected to a straight tiller, rigidly attached to the stock through buffer springs. This connection protects the sector teeth and gears from breaking when waves hit the rudder blade.
Currently wide application get hydraulic drives , which are a type of tiller drive. A slider is installed on the straight longitudinal tiller, which is connected by rods to the cylinder pistons. The cylinders are connected to a pump driven by an electric motor. When pumping liquid from 1st cylinder to another, the pistons move and rotate the tiller. Included in the drive system bypass valve. When a wave hits the rudder feather, a overpressure, the liquid flows through an additional pipeline through a bypass valve into another cylinder, equalizing the pressure. This softens the jerking of the tiller.
To activate steering actuators, use steam engines and electric motors. On large ships, as a rule, they use manual drives, installed in the wheelhouse. To make it easier to shift the steering wheel, a gear or worm gear is included between the steering wheel and the steering drum.
=Sailor II class (p.56)=
