Sea trials of ships after construction. Testing and commissioning of ships. Acceptance tests of ships

After completion of installation and outfitting works on the vessel, closing of construction certificates, mooring tests of the vessel are carried out in order to check in operation and determine the main characteristics of mechanisms, devices, equipment, instruments, systems, electrical equipment and the entire vessel as a whole for compliance with the drawings, diagrams, specifications of the vessel, forms and technical conditions for their delivery.

In order to save the motor resource of regular sources of electricity, the electrical equipment is powered from coastal sources of electricity.

According to the results of mooring tests, the readiness of the vessel for carrying out factory and sea trials.

Factory and sea trials are carried out for the purpose of adjustment, adjustment, testing technical means vessel, as well as determining the main characteristics of technical means and the entire vessel as a whole.

Upon completion of the tests, an audit of the technical means is carried out by means of a control opening and inspection of the internal cavities and rubbing parts.

After the revision of the technical facilities and the final finishing and painting of the premises and the entire ship as a whole, the acceptance certificate is signed and the ship is handed over to the Customer.

In order to save material and financial costs for serial ships, acceptance tests are carried out at the wall of the plant without the ship moving using simulation test methods. To do this, simultaneously with mooring and sea trials of technical equipment, their comparative tests are carried out in order to check the conformity of the loads and operating parameters of mechanisms and devices obtained by simulation methods of testing in the water area of the plant, the loads and parameters obtained under the conditions of sea trials carried out on the same vessel. same ship.

Simulation tests of the main ship power plant are carried out on parameters corresponding to the parameters obtained during bench tests of engines. The creation of these parameters on a ship located at the wall of the plant is achieved through the use of an unloading device. Simulation tests of the steering gear are provided using a loading device. Simulation tests of the anchor device are provided by the anchor chain tension method. The test parameters of the steering and anchor devices, in this case, must correspond to the test parameters in running conditions. Checking the anchor device at the working depth of the anchor is carried out at the control exit during the first operational voyage of the vessel.

Conclusion

The design technology and organization of the ship's construction was developed taking into account the production conditions of the builder and the structural and technological characteristics of the ship.

The main fundamental solutions of the design technology and organization provide for the reduction of labor costs and the duration of the construction of ships by performing the largest possible amount of work in workshop conditions, prioritizing the most complex work (forming the hull, and saturation of the III construction area, assembly and saturation of the superstructure) also in workshop conditions , performance of work by mechanized method, the use of advanced technological processes, reduction in the amount of work performed afloat, etc.

Metal pre-treatment is carried out on mechanized lines.

Cutting out parts, depending on the configuration and thickness, is performed on guillotine shears, press shears, presses or using thermal cutting on Kristall machines, the equipment is carried out in containers.

Assembly and welding of units and sections is carried out on assembly plates, individual and universal beds, conductors and a mechanized line for assembly and welding of flat sections with a wide use of semi-automatic and automatic welding. Editing of hull structures is carried out by a non-impact method.

The formation of the body as a whole is carried out from construction areas (enlarged blocks), construction areas - from sections. At the same time, construction areas are maximally saturated with mechanisms and equipment, with a high percentage of completion of completion work.

The production of pipes is carried out according to technological maps using group launches of pipes into production, downhole pipes - according to templates from the site, individually.

Installation work is carried out in workshop conditions and on board. Pre-assembly is carried out in the workshop for the assembly of units and mounting blocks. Installation work is primarily carried out in saturated areas of the vessel (engine room, superstructure).

Production of finishing products and equipment of ship premises is carried out on machine equipment as part of mechanized lines. The technology provides for the use of a modular system for the formation and equipment of residential and service premises, the manufacture of unified building elements, packages and insulation boards in workshop conditions, the use of normalized plastic furniture.

Painting work is carried out mainly using mechanized equipment at the hull structure assembly sites in the workshop, at the ship formation positions on the open slipway and afloat. Drying of the painted products natural.

Vessels are tested in the water area of the enterprise using simulation methods. This method is used to test main ship power plants, steering and anchor devices and radar equipment using a radio test site.

List of used literature

1 Fundamentals of shipbuilding technology: Textbook under the general. ed. V.F. Sokolova, - St. Petersburg: Shipbuilding, 1995.

2 Handbook of assembly and welding equipment for shipyard workshops. L .: Shipbuilding, 1983.

3 Handbook of process design for shipyards and workshops. A.K. Syrkov, L.: Shipbuilding, 1980.

4 Fundamentals of shipbuilding technology: Textbook under the general. ed. V.D. Matskevich, - St. Petersburg: Shipbuilding, 1971.

5 Guidelines for the course project on shipbuilding technology (electronic version).

6 Manufacturing technology of ship hull structures. V.V. Ivannikov, M.G. Shaidullin, P.L. Spekhov, B.R. Timofeev, - Gorky: Gorkov. polytechnic institute, 1988

Attachment 1

Sea trials are the technological stage of acceptance tests, the purpose of which is to check the operation of the equipment and its parameters in running conditions, as well as to check the ship's seaworthiness (buoyancy, stability, controllability, propulsion, maneuverability, wave strength). Sea trials are divided into factory and acceptance tests.

In the process of factory sea trials, adjustment and adjustment work is carried out and equipment is prepared for sea trials. At factory sea trials, the specification characteristics of the main marine engines are checked in terms of power, fuel and oil consumption, and full power development time. This check is made on various modes work: on the economic course, cruising, full and most at full speed with all engines running, in reverse. Simultaneously with the verification of the power plant, the speed and maneuverability of the vessel are determined. The speed is determined when passing the measured line, indicated by leading signs. At a speed of 18 knots, a ship must pass a measuring line of one mile, at a speed of over 18 to 36 knots - two miles, at a speed of over 36 knots - three miles. This achieves sufficient accuracy in determining the speed. The speed is determined as the average value of the measurements on several tacks.

The program of sea trials provides for the determination of the agility of the vessel at low, economic, cruising and full speed. Agility is characterized by circulation elements: circulation diameter (the distance between the lines of reverse courses when changing direction by 180 °), circulation duration, roll angle during circulation, loss of speed. The circulation diameter is determined in terms of the ship's hull lengths. The measurement is made by regular radar stations vessel or special equipment.

In the lengths of the hull, the run-out of the vessel by inertia is also determined. When checking inertia, the time from the moment the command is given to the complete stop of the vessel or reaching a certain speed is also determined.

Checking and final acceptance of the equipment during sea trials is carried out on the move of the vessel under conditions that ensure the receipt of nominal parameters. According to requirements normative documents equipment check is carried out under normal climatic conditions ( Atmosphere pressure 1.01 * 10 5 Pa, temperature 293 K, relative humidity 70%), with a wind strength of not more than 3 points on the Beaufort scale, taking into account the depth and speed of the current in the test area.

Upon completion of the acceptance sea trials of the vessel, an audit of the main and auxiliary mechanisms and devices is carried out according to the list compiled by the selection committee. The list includes those mechanisms and devices in which shortcomings are noticed. The audit consists in opening these mechanisms and eliminating the shortcomings noticed by the commission.

85 86 87 88 89 ..

9.2. ACCEPTANCE TESTING OF VESSELS

Acceptance tests are carried out in two stages: mooring

Tests; sea trials and acceptance.

In order to reduce the labor intensity of work and time for the delivery of ships after construction or repair, GOST 21792-76 allows simulation tests for the main marine diesel engines in running conditions at mooring lines. During simulation tests, mode mooring and sea trials of the diesel plant are not carried out.

Acceptance tests of the power plant and the ship as a whole are carried out according to the program developed by the designer or the shipyard, agreed and approved in the prescribed manner. The tests are supervised by a commission consisting of representatives of the plant, the customer and the USSR Register. The program of acceptance tests defines the objectives, scope and procedure for all stages of testing and acceptance of the vessel, establishes a list of documentation to be submitted before each stage of testing, as well as the volume of measured indicators and the range of measuring instruments used, the list of which basically corresponds to that indicated in Table. 9.1. For test modes lasting up to 1 hour, measurements are taken once, over 2 hours - every 2 hours.

Mooring trials are carried out in order to check: the completeness and quality of installation of the main engines and auxiliary units with the mechanisms, systems and devices serving them; compliance of power equipment, systems and devices with technical specifications for delivery, operating instructions and drawings; serviceability of the power and propulsion installations of the ship; readiness of equipment, systems and devices for sea trials of the ship. Before mooring tests, the commission is presented with: technical conditions for supply of equipment, service instructions, forms, passports, drawings, descriptions, diagrams and other documentation in accordance with the list of reporting technical documentation, as well as a list of deviations from the approved technical documentation.

Auxiliary power equipment (boiler plant, pumps, separators, compressors, etc.) are checked in operation for their intended purpose. The operating parameters obtained during the tests should not exceed the values specified in the instructions, passports or forms. The modes and duration of their operation, as well as the list of measured parameters, are determined by their purpose and are established by the mooring test program. Mechanisms, systems and devices, the operation of which is not related to the course of the vessel, are finally accepted during mooring trials. Auxiliary DGs are checked both in single and parallel operation. Checking the operation of the main engines is carried out after checking the operability of the mechanisms, systems and devices serving them.

The load of diesel installations during the period of mooring tests in accordance with GOST 21792-76 should change:

For main diesel engines and diesel-geared units operating on a fixed-pitch propeller (FRP), - according to the mooring screw characteristic of the form А^р =, / (");

For main diesel engines and diesel-reduced units operating on a controllable pitch propeller (CVP), - according to the screw characteristic of the form N =.f(n), passing through the rated power mode, or according to the load characteristic of the form N =.f(H / D) when n = const;

For the main and auxiliary diesel engines running on the generator - according to the load characteristic of the form / V - / (L / kr) at n = const.

Mooring tests of diesel installations, the load of which varies according to the screw characteristic, are carried out in the modes indicated in Table. 9.2, according to the load - in the modes indicated in table. 9.3.

Sea trials and acceptance are carried out after the elimination of the comments identified during the period of mooring trials and the execution of technical documentation (tables of measurements, protocols or acts) based on the results of mooring trials. Sea trials are carried out in order to check: the operation of diesel engines on fuel grades provided for by the project documentation; main performance indicators of the power plant; reversible qualities of the main engines and CPPs; running and maneuvering qualities of the vessel.

The modes and duration of sea trials of ships with a change in the load of the main engines according to the screw characteristic are given in Table. 9.4, according to the load - in table. 9.5.

In order to save money and time, sea trials are replaced by simulation ones. Simulation tests in running modes at moorings are carried out for diesel engines powered by a propeller, if the running conditions of the latter and the running propeller characteristic of the diesel engine, passing through the rated power and speed mode, can be reproduced when the ship is stationary using means or simulation methods . The selected simulation test method should be verified by comparative tests with and without the ship moving. The results of comparative tests shall be approved by the Register, after which the selected method of simulation tests may be extended to the entire series of ships of this type. CRS is used as a simulation tool, which makes it possible to load the main engine in running conditions when the ship is stationary.

Diesel units of serial ships are allowed for simulation tests: after registration of acceptance documentation for the construction (repair) and mooring periods for mechanisms, systems and devices serving diesel; bench or ship run-in; adjustment and testing of the diesel engine in operation in shipboard conditions together with service mechanisms within 1 ... 2 hours to eliminate the identified defects and comments. Simulation tests of diesel installations should be carried out at the load conditions indicated in Table. 9.6.

During the period of simulation tests, the accuracy of reproducing

The howling of the screw characteristic passing through the modes of rated power and speed should be controlled according to the correspondence of the speed and main parameters of the diesel engine to the formulary or passport data obtained during the sea trials.

In view of possible deviations in the technical condition of engines on individual ships after construction or after they are out of repair, control of engine load conditions during simulation tests should be carried out according to a set of indicators, and not according to one of them. So, for the main engine 8 DR 43 / 61-V 1, a set of such indicators is given in Table. 9.7.

During simulation tests, it is necessary to observe the following sequence of reaching the steady state: set the required speed; turn the propeller blades up to 3.5 divisions “forward” according to the remote pitch indicator and record the fuel consumption and exhaust gas temperature in the steady state of the engine. If they are below those indicated in Table. 9.7, then the turn of the CPP blades must be increased. Deviations should not be allowed Notes: 1. For diesel engines of ships with a power of 4000 kW

And above, tests in mode 4 are allowed to be carried out at a torque iio more than 85 nominal. 2. It is allowed to check the operation of the diesel engine in mode S during the period of control tests of the vessel in free water only

But the frequency is rotation.
rotation hour o i given more than +3 power in intermediate modes - ±5. In the modes of rated and maximum loads from -

The power declination must be 5% less than the nominal one.

After the end of the running or simulation tests and the completion of all the checks provided for by the program, a technical inspection is carried out and, if necessary, a control opening and inspection of parts and assemblies of the diesel engine and its servicing mechanisms and devices. The list of mechanisms and devices subject to control opening and inspection is determined by the selection committee and agreed with the Register.

Acceptance tests are completed with control tests. which are carried out when the ship is moving in free water or by simulation method (as agreed with the representatives of the customer and the Register, depending on the results of the control opening and technical inspection of units and mechanisms). Control tests are carried out in full speed mode at rated speed and in reverse mode. The duration of the test in full speed mode is: 1 hour for engines with a power of up to 150 kW, 2 hours - from 151 to 4000 kW, 3 hours - above 4000 kW. In reverse mode, the test duration is 0.25 h, regardless of engine power.

The materials obtained during the acceptance tests are subject to processing in order to: determine the average values of the measured parameters; design parameters and characteristics according to the measured parameters; decoding of all records on oscillograms and chart tapes; construction of reporting schedules; determining the degree of accuracy of the obtained measurement results. The results of acceptance tests are formalized by an act and a report on the tests of the ship, including sections: general data; EC test results; comments on the work of the EU; conclusions and recommendations. The appendix to the report contains summary tables of the main parameters, as well as graphs and diagrams that characterize the operation of the power plant during the testing process.

Maintenance of the ship's power plant after construction is carried out by the commissioning team of the plant, after repair - by the ship's crew.

When accepting a new vessel, the crew must familiarize themselves with: the propulsion system, auxiliary equipment, systems and technological equipment of the vessel; device and instructions for technical operation equipment and systems; grades of fuels and lubricating oils recommended for equipment operation; nomenclature and completeness of instrumentation; acceptance test program, test methods, list of measured parameters and instrumentation used; barrier parameters of power equipment specified in the operating instructions, passports, forms or technical conditions(THAT).

The ship's crew must: actively assist proper organization and carrying out all types of acceptance tests in full scope of the approved program; make proposals to the selection committee on the list of mechanisms and devices that require control opening; take part in inspections of mechanisms and devices during control openings; require checking the operation of engines and steam boilers on all types of fuels provided for by the design documentation.

Constant technical control products that are intermediate products of hull-processing, assembly-welding, mechanical-assembly and other shops are regularly produced during the construction of ships.

Permanent technical control of products that are intermediate products of hull-processing, assembly-welding, mechanical-assembly and other shops is carried out regularly during the construction of ships.

The scope of checks during construction is regulated by the list of mandatory acceptances, which is compiled jointly by the Executor-Shipyard and the Customer.

Technical control ends with testing and delivery of the vessel.

The purpose of the tests is to check the compliance of the technical and operational characteristics of the vessel with the characteristics specified in the design documentation.

Prior to the start of ship testing, the following works must be completed:

Installation of all pipelines

Systems of main and auxiliary mechanisms;

Room equipment;

Impermeability tests;

Installation of ship devices and practical things.

All works performed during the construction process, included in the list of mandatory acceptances, are issued with the appropriate documents - certificates signed by the quality control department and representatives of the customer.

For the delivery of the vessel to the customer, a commission is appointed, a test batch and a responsible deliverer. The commission includes assistants to the responsible deliverer for hull and electrical parts, a commissioning mechanic, foremen and workers from highly qualified fitters for main and auxiliary mechanisms, ship devices, systems, electrical equipment.

The test batch consists of specialists who monitor the operation of individual units during testing.

All deviations from normal operating conditions recorded by the test batch are reported to the responsible deliverer or chief mechanic. At the same time, a test log is kept, in which the test results are recorded.

The scope and sequence of tests are established special program, which is guidance document testing.

The acceptance of the ship is carried out by the acceptance committee, which consists of representatives of the customer and the Register.

Prior to the start of testing, the acceptance committee must be presented with a construction contract, a set of drawings of the general arrangement of the vessel, a book of installation certificates, a journal of the weight load of the vessel, a journal of alterations and approvals, acts of bench tests of the main and auxiliary mechanisms and other mechanical equipment, as well as instructions, diagrams, descriptions, forms of equipment and passports of control and measuring instruments (KIP). After reviewing all the submitted documents, the commission makes a decision on the readiness to perform acceptance tests.

In addition to preparation for testing, the testing period of ships includes the following stages:

Mooring trials;

sea trials;

revision;

control output;

Control tests.

Mooring trials

Mooring trials of ships (SHI) is a technological stage of acceptance tests, including Preparation for trials, Mooring trials, Sea trials, Revision, Control exit, Control tests.

Shi is carried out in a sufficient depth of the shipyard water area near the outfitting embankment, equipped with mooring shore facilities, without access to the sea.

The purpose of Shi is to check the quality of ship construction, installation and adjustment of equipment, preliminary testing under load of the main power plant at idle, auxiliary mechanisms, systems and devices that ensure the survivability and safety of the ship, preparing the ship for going to sea for sea trials.

By the beginning of the SI, the ship construction work must be completed to the extent stipulated by the construction certificates.

The verification of the main indicators of equipment operation during the period of SH and sea trials is carried out according to the methods developed by the Designer for the lead ships and the shipyard - for serial ships.

The methodology provides for the use of non-standard control and measuring equipment, as well as devices with established measurement scale limits and the required accuracy classes to check the parameters and create the required operating conditions for the equipment.

Shi is carried out separately for mechanical, electrical and body parts:

Tests of the mechanical part, starting with emergency systems and mechanisms that ensure the safety of the vessel during the test (fire system, flooding and water pumping systems).

Testing of auxiliary power equipment: turbogenerators and diesel generators, auxiliary boilers, evaporators, desalination plants, etc.

Tests of the main power plant are carried out last. Ship systems, pipelines, electrical networks, energy and survivability posts are tested simultaneously with the main mechanisms. Before testing the GTZA of a steam turbine plant, the operation of the turning and shaft-braking devices, as well as the forward and reverse movement of the turbines, are checked. In the process of mooring tests of a steam turbine plant, hydraulic tests of pipelines of all systems are carried out, including fuel, fire, steam; check the operation of auxiliary installations (ignition, feed, fuel pumps); oil is pumped through the engine room oil pipeline; produce hydraulic and steam samples of the steam pipelines of the engine room; carry out tests of circulation and condensate pumps, as well as pipelines directly connected to turbines; they check the power and lighting networks and start the turbogenerator, as well as start the GTZA to idle. Then, the operation of the GTZA is checked at a rotation frequency that is permissible according to the conditions of mooring reliability, according to the state of coastal structures and the depth of the water area.

Simulation tests

Simulation tests are tests in which the specification parameters of the ship's equipment are checked during mooring tests in the shipyard's water area, as close as possible to natural ones.

Simulation tests are carried out with the help of special unloading or loading devices - simulators that reproduce the running conditions of the ship's equipment.

An unloader is a special technological device used for simulation tests of the main power plant. The unloader serves to create easier conditions for the operation of the equipment. To unload the propeller at the stop and at the moment up to the calculated ones, a reduction in the propeller disc area is used due to the annular nozzle; a flow-directing chamber providing water inflow to the screw at a speed equal to its calculated axial speed; supply of compressed air to the propeller area in order to reduce the density of the water surrounding the propeller. The work of the propeller can also be facilitated by reducing the draft of the vessel and, consequently, by reducing the depth of the propeller.

Load devices create an additional load to check the health of the equipment. For example, when testing diesel generators and turbogenerators, the shore network serves as a load device, where excess electricity is transferred from the ship under test.

Simulation tests of the anchor device on the mooring lines are carried out in several ways: by fixing the anchor chain on the shore when the main engine is operating at design conditions in reverse or by hanging loads on the anchor chain section. The most promising method for simulation testing of an anchor device is the method using a universal loader located on a pontoon and representing a hydromechanical brake with remote control. This method has a number of advantages in terms of versatility, independence technological process tests, accuracy of reproduction of natural conditions.

With the help of simulation devices, navigation and radar equipment, a gyrocompass, a hydrodynamic log, and hydroacoustic equipment are also tested.

To adjust the radars, special polygons are arranged, taken out of the plant and equipped with special reflectors. The direction and distance to the reflectors are known. Radar stations detect reflectors, determine course directions and distances to reflectors. The data is compared with the true values and adjusted according to station deviations to the required accuracy in determining the desired parameters.

Hydroacoustic equipment is checked using a measuring device installed under the bottom of the vessel - a hydrophone, which measures the sound pressure of the vibrator of the hydroacoustic apparatus. Based on the measured sound pressure, the range of the hydroacoustic equipment is recalculated.

Simulation tests reduce the duration of the delivery period by about half, allow you to create stable test conditions, improve the quality of testing and reduce the consumption of fuel and energy resources.

Sea trials and delivery of the vessel

Sea trials - a technological stage of acceptance tests, the purpose of which is to check the operation of equipment and its parameters in running conditions, as well as to check the ship's seaworthiness (buoyancy, stability, controllability, propulsion, maneuverability, wave strength). Sea trials are divided into factory and acceptance tests.

The speed is determined when passing the measured line, indicated by leading signs. At a speed of 18 knots, the ship must pass a measuring line of 1 mile, at a speed of 18 - 36 knots - 2 miles, at a speed of over 36 knots - 3 miles. This achieves sufficient accuracy in determining the speed. The speed is determined as the average value of the measurements on several tacks.

The program of sea trials provides for the determination of the agility of the vessel at low, economic, cruising and full speed.

Agility is characterized by circulation elements:

Circulation diameter (the distance between the lines of reverse courses when changing direction by 180 °);

The duration of circulation;

Bank angle during circulation, loss of speed.

The circulation diameter is determined in terms of the ship's hull lengths. The measurement is made by regular radar stations of the vessel or special equipment.

Checking and final acceptance of the equipment during sea trials is carried out on the move of the vessel under conditions that ensure the receipt of nominal parameters. According to the requirements of regulatory documents, the equipment is checked under normal climatic conditions (atmospheric pressure 1.01 105 Pa, temperature 293 K, relative humidity 70%), with a wind force of no more than 3 points on the Beaufort scale, taking into account the depth and speed of the current in the test area.

After the audit, the ship goes to the control exit. If the commission has no more comments, then the certificate of delivery and acceptance of the vessel is signed.

After mooring are carried out sea trials associated with going to sea. Tests are carried out in a specially equipped water area called "measured mile" ("measured line"). This is a track of a certain length (for example, one mile), the beginning and end of which are indicated by secant alignments - a pair of coastal wooden shields with a vertical black stripe painted on them. When for an observer on board the lanes merge into one, the ship is in alignment. One alignment marks the beginning, and the other marks the end of the measured section. The direction of the vessel's movement is set either by the guide lines, or by the course indicated on the map.
A commission is formed to conduct tests, all the results of its work are drawn up in the form of protocols, where, in particular, the names and positions of the commission members, the time and conditions for testing, information about the measuring instruments used, and measurement results are entered.
Certain requirements are imposed on the vessel at the time of testing, the measured mile itself, test conditions and measuring instruments.
The vessel must be freshly painted (no more than 15 days, and in cold water - 30 days after leaving the dock), must not have a heel and trim. During sea trials, the displacement is usually less than in full load, which is taken into account when processing the results. For this purpose, it is recommended to measure the drafts at the extremities and from both sides amidships, which will make it possible to take into account the list and general bending of the vessel. During docking, the condition of the protruding parts is examined and, if necessary, their damage is repaired. Special requirements are imposed on the condition of ship propellers. Check the geometric characteristics of the propellers, in the presence of damage to the blades, they are eliminated.
The tests are carried out in calm weather: wind force is allowed up to approximately 3 points (for small ships - up to 1000 tons - up to 2 points, for large - over 20,000 tons - up to 4 points), and excitement - up to 2 points (also for small ships - less, and for large ones - more), and the leading signs should be clearly visible. There should not be a strong current in the area of the measured mile, especially in the transverse direction, which distorts the results of the speed measurement. It is very important that the depth per measured mile be deep enough to avoid the effect of shallow water on drag. Recall that a sharp increase in resistance begins at the Froude number in depth

Where H is the depth of water per measured mile. It is believed that the depth of water per measured mile should be greater than the greater of the two values calculated by the formulas

Where B and T are the width and draft of the vessel, respectively; v- top speed vessel during testing. Thus, at normal transport ship speeds of 15-16 knots, the required depth is approximately 25-30 m (if the ship's draft is not very large). With increasing speed, the required depth increases rapidly.
The errors of speed measurements should not exceed 0.5%, the time of passage of the measured section - 0.2 s, the number of revolutions of the propeller shaft per minute - 0.2%, the torque per propeller shaft- 3% of the torque at rated power, fuel consumption - 0.5%, wind speed - 2%, wind direction -5%, vessel draft - 2 cm, water and air temperature - 1 degree, start and end times of the run - 1 min.
The program of sea trials provides for the movement of the vessel in several modes corresponding to the speed of the main engine from minimum to maximum, including nominal ones. For lead transport vessels with internal combustion engines, the following modes are mandatory: n = nom, n = 1.03 nom, n = 0.91 nom, n = 0.80 nom, n = 0.63 nom. In each mode, the ship makes three runs (the movement pattern is shown in Fig. 11.1; the curve that the ship describes when turning in the opposite direction is called the “coordinate”). To do this, it falls on a given course, which must be exactly maintained, the desired speed is set, and a steady speed is gained. There are observers on board with stopwatches, the number of which must be at least three. When passing the first alignment, the stopwatch starts, the second - stops. The results are recorded in the protocol; if one of the three results is significantly different from the others, it is discarded. The ship's speed during the run is calculated as the quotient of the length of the measured mile divided by the average time. The average speed for three runs in one mode is calculated by the formula:

Rice. 11.1. Scheme of the movement of the vessel on a measured mile

Thus, the possible flow velocity is taken into account, which will be taken into account twice with a plus and twice with a minus. Moreover, if during the test the speed was gradually changed by approximately linear law, the formula eliminates the influence of the flow. This is faster and more accurate than determining the average speed over four runs.
Modern navigation systems allow high precision to determine the position of the vessel at any point of the World Ocean and at any moment of time, which makes it possible in principle to conduct high-speed tests in places not specially equipped for this purpose. However, the possible flow must be taken into account.
Another important measured characteristic is the engine speed. On ships under operating conditions, it is measured by tachometers, but for test conditions their accuracy is insufficient. A tachoscope is used here - a mechanical or electrical device that has a revolution counter and a stopwatch in one housing. The tachoscope roller rests against the engine shaft at the nose end, when pressed, both the stopwatch and the rev counter start working, when released, they stop.
There are pulse tachoscopes operating on various physical principles. They are also used in cases where it is not possible to connect a tachoscope to the end of the shaft.
It is highly desirable to also measure engine power and propeller thrust or thrust. These measurements are technically more complex and less accurate. One way to measure the power of diesel plants is by fuel consumption. To do this, a measuring tank is included in the fuel pipeline, at the inlet and outlet of which there are transparent tubes with risks. At some point, the fuel pipeline is blocked, fuel from the tank begins to be consumed. At the moment when the fuel level is equal to the input risk on the tank, the stopwatch is started, and at the output it is stopped. Knowing the specific fuel consumption in g / kWh and measuring the actual consumption in g / h, the power is calculated. But the specific fuel consumption is not a completely stable characteristic and does not guarantee accuracy. The error of this method is about 4-5%.
Diesel power can also be measured by an indicator diagram - a record of the pressure in the engine cylinder as a function of piston displacement. There are special devices for this purpose. The sum of the powers of all cylinders gives the indicated power; the effective power of the engine is less due to losses in the engine (for friction), which is taken into account by the mechanical efficiency, the value of which can be determined during bench tests of a diesel engine at the manufacturer's plant, but is also not quite stable.
The power of steam and gas turbine plants is determined in other ways, which we do not consider. On ships with electric propulsion, power can be determined from the current parameters.
There are other, more complex ways. Since the power PD is uniquely related to the torque Q transmitted by the shafting (PD = 2pn * Q),
using torsiometers, it is possible to measure the torque through the angle of twist of the shaft φ on a certain base 1. In this case

Here Ip is the polar moment of inertia of the shaft section; for continuous round section diameter D

According to the principle of operation, electric and acoustic torsiometers are distinguished. To convert the angle of twist into torque, knowledge of the shear modulus G is required, which is not a completely stable characteristic of the material. If you first calibrate the measuring section of the shaft to determine the shear modulus, the error in determining the moment is 2-3%.
Using strain gauges glued at an angle of 45 degrees to the shaft axis, it is possible to measure the shear stresses in the shaft (strictly speaking, the deformation of the shaft from torsion), which can be easily converted into torque and power on the shaft. But here there is a serious problem of signal transmission from a rotating shaft to a stationary measuring equipment. Metal deformations are measured in hundredths of a percent, the same order of change electrical resistance sensors that need to be measured with high accuracy. If readings are taken using slip rings and brushes, a resistance arises in the contact, the fluctuations of which can be of the same order as the measured signal. To reduce this resistance, firstly, the pressing force of the brushes is selected, and secondly, attempts are made to use low-melting metals, such as gallium alloys (the melting point of pure gallium is 30 C). These errors can be avoided if a preamplifier and a radio transmitter are also placed on the rotating shaft, and a receiver and the rest of the measuring equipment are nearby. Note that an additional error with this method arises from inaccurate knowledge of the shear modulus of the shaft material.
Prop thrust or thrust measurements are even more difficult. For example, the thrust of the propeller on the moorings can be determined by the tension of the cable connecting the ship to the shore, for which powerful dynamometers or metal plates with strain gauges glued to them are used.
The most accurate results can be obtained by replacing one of the intermediate shafts with a special insert equipped with instruments for measuring both thrust and torque. Such an insert is made specifically for a certain series of vessels. The thrust gauge (hydraulic or electric) can also be installed in the thrust bearing. The stop measurement error usually exceeds 5%.
Test results are processed and analyzed. To convert from displacement at the time of testing to full, the Admiralty formula is usually used. It is desirable that the ship develop the design speed at the nominal engine operating mode. Sometimes the test speed is less than the design speed. Perhaps this is due to insufficient depth per measured mile or to the roughness of the skin - these cases should be excluded during preparation for testing. As we noted, errors may be due to the insufficient level of development of science and the features of the built vessel. There are also cases when the test speed exceeds the design one.
If during the tests the speed of the vessel, the rotational speed of the propeller shaft and the power were measured (the thrust often cannot be measured), then according to their results, the coefficients of the associated flow and the effect of the non-uniformity of the velocity field at the moment, which were previously known from the data of model tests, can be corrected. Further, having calculated the resistance of the vessel, it is possible to correct either the resistance or the suction coefficient in case of discrepancy with the results of model tests.
Sometimes, according to the test results, the elements of the propeller are adjusted.