II-BC7-2      Sea trial

2.1         Preparation before test

2.1.1    Sea trial is to check if the mechanic devices and maneuvering performance comply with the technical conditions of safe navigation and operation based on the mooring test. During a sea trial, the seaworthiness, machinery and electrical installations of a ship are to be tested and its general performance and equipment is to be surveyed for compliance with the requirements of the classification rules and regulations.

2.1.2    Before the sea trial, the Surveyors are to check the hull, machinery and electric installations in accordance with the requirements respectively. The completed survey items such as main and auxiliary engines together with associated equipment, boiler system, bilge system, anchoring, rudder, life-saving appliances, fire safety equipment, navigation equipment, signaling equipment, communications, ballasting, watertightness, inclining test report, load line marking, tonnage measurement, oil pollution prevention, alarms and safety equipment are to be checked for confirming that outstanding items are removed and will not affect the sea trial.

2.1.3    The sea area for the trial is to be as restricted for the maximum design service and to comply with the requirements for the watershed management/restriction of the local maritime administrations. Temporary life-saving appliances are to be provided for the number of test personnel as required for ships operating in corresponding sea areas.

2.1.4    The sea trial program is to be agreed with the shipyard and the Owner. Test items are to comply with the classification rules or recognized standards (e.g. GB/T3221Code for Dock and Sea trials of Diesel-driven Inland Ships) and to be approved. All instruments and meters used in the trial are to be provided with the valid qualification certificate issued by national metrological service agency or its recognized institutions.

2.1.5    The Surveyor is to carefully record test data and issues for specific items which he is to witness.

2.1.6       Confirm that the ship’s draught complies with the design requirements for sea trial and the run-in of main engines is completed. For the draught of ships other than tankers, the sea trial draft is the draft in a certain condition determined through model test and the parameters of main engines and the ship’s sea trial are to be examined in this condition, with the speed or pitch angle of main engines being increased accordingly for reaching their design load in full-load condition.

2.2        Test of main engine

2.2.1    The test time of main engine under prescribed conditions are listed in the table below.

2.2.2    During load test of main engine, where the stopping due to fault of main engine under 75% rated load condition or 100% rated load condition is 15 minutes or over or 30 minutes or over in total, the test time under such condition is to be recalculated. Where the test load needs to be decreased due to navigating operation or other causes, the intervals are to be compensated. In such case, the time is to be determined according to practical conditions for ships navigating in torrent waterways.

2.2.3    Each cylinder of main engines is to be balanced in normal output condition or rated condition. The deviation of main parameters of each cylinder from their mean values is in general to comply with:

Compression pressure ≤ ±2.5%, maximum combustion pressure ≤ ±3.5%, exhaust temperature ≤ ±5% (high and medium speed engines ≤ ±8%) Parameters of main engines in rated condition are to comply with the values specified by the manufacturer. The parameters unmeasurable due to the limitations of the main engine may be exempted.

2.2.4    Pumps, auxiliary equipment and sea chests serving the main engines are to be used alternately. The whole test process is to be continuous, with total downtime not exceeding 15 minutes, except for the situation when the standby pump needs to be replaced manually.

2.2.5     When the main engine is operating under rated load and the auxiliary engine is operating under normal condition, close the left and right sea valves alternatively to check the temperature of discharging of the cooling water of main and auxiliary engines. Where the fire pump and main engine or/and auxiliary engine share the sea valve, the function test of pumping water is to be carried out for the fire pump and to check the temperature of discharging of the cooling water of main and auxiliary engines, the function of fire pump and if any water scrambling.

2.2.6    After completion of the sea trial of main engines, crank deflection in hot condition may be measured and the deflection is to be not more than 3/10,000 piston stroke (mm) or the value specified in the main engine instructions. Remove the door and check the bearing temperature. Pay attention to the temperature inside the crank case. Where the temperature is too high, the door or observation hole is not allowed to open before the complete cooling of the inside of crank case after the diesel engine stops. The foundation bolts, through bolts and lateral supports of main engines are also to be inspected for securing.

2.2.7      For the requirements of checking the shafting and reversion test, refer to the requirements for checking and test of mooring test.

2.4        Disassembling inpection to main engine

            Main engine is to be disassembled for inspection after sea trial and subject to the operation test under 100% load after reassembling. The requirements for disassembling and inspection are as follows:

(1) for diesel engine with the piston stroke of 200mm or above, measure the variation of distance between the crank shaft and the cylinder wall and make records;

(2) for diesel engine with the piston diameter of 200mm or above, choose at least one cylinder to check the piston based on the practical situation of survey;

(3) for diesel engine with the piston diameter less than 200mm, disassemble and check if any abnormalities found during the test.

2.5        Measurement of torsional vibration of shafting

2.5.1    For ships with the power of single engine of 220kW or above, the Society may determine if the measurement of torsional vibration of shafting is to be carried out for ships based on the calculation method, stress due to torsional vibration and torque provided in the calculation sheet submitted to the Society. For ships required to be measured, the measurement report is to be submitted to the Society for approval.

2.5.2      Measurement of torsional vibration of shafting of ships of the same type. Where the measurement results of the first ship are approved by the inspection units, other ships of the same type are to be exempted.

2.5.3    Measurement of torsional vibration of shafting is to be carried out within the full range of working speed.

2.5.4      The qualification of inspection unit has been confirmed.

2.6       Test of lateral thruster

2.6.1    Test conditions: the ship is in stopping (zero speed) or low speed condition.

2.6.2    Preparation before test

(1)        The fixing and control position of lateral thrusters are to be examined.

(2)        “Zero” and “Maximum pitch” are to be adjusted in navigation bridge and both wings.

(3)        Thrust actions at all control positions are to be verified.

(4)        Thrust operation is to be examined at zero pitch for 30 minutes.

2.6.3    Test details and procedure

(1)        Ship is in zero speed:

            (a) Lateral thruster is started and changes of heading angle are to be measured and time recorded at maximum power, and the test is to last for 3–5 minutes.

            (b) Main and lateral thrusters are operated in combination, changes of heading angle are to be measured and time recorded at maximum power, and the test is to last for 3–5 minutes.

(2)   The rudder is to be kept at full rudder angel when the ship is at low speed to repeat the test of 6.3.1.

2.7       Anchoring test

2.7.1    The test is generally to be carried out at depths greater than 10m. Depths below 10m are acceptable for shallow waterways in dry season.

2.7.2　   Mechanic and free anchoring are to be carried for mechanic windlass. In the process of anchoring, check if any jumping, wrenching or vibration happens and the flushing effect of the flushing device of anchor chain. Check the moving parts for any abnormal heating or knocking. 

(1)　     Anchoring test for single anchor. To cast and hoist the left anchor and the right anchor alternatively and measure the hoisting speed. The hoisting speed for windlasses driven by motors is not to be less than 0.15m (9m/min). For ships engaged in services in category 3, the hoisting speed may be suitably decreased. For ships navigating in torrent waterways, the hoisting speed, if specially required, may be increased to over 0.2m/s (12m/min). Hand-operated windlasses are to be subject to function test for lightness and reliability.

(2)　     Anchoring of two anchors. To cast the anchors in turn into earth, then make the anchors come aweigh one by one, and hoist both simultaneously. This is not required for hand-operated windlasses.

2.7.3　  The windlass is to brake rapidly for two to three times after the anchor is casted but before touching the water stead to check the function of brakes.

2.7.4　  The chain controller is to secure the chain after anchor is casted. The main engine is operating at the minimum stable speed to back (not to back in torrent waterways) and the strength of chain controller and the partial strength of chains as deck are to be examined.

2.7.5　  Check the portability and reliability of the clutch of windlass.

2.7.6　   In anchoring of single anchor and two anchors, measure the starting current, working current and voltage of electric motor, rotation speed, oil pressure, oil temperature and rotation speed of oil motor. Check the function of brakes of prime motor in hoisting anchor. Measure the voltage of the system and the insulation resistance in heated state of controller and feeder lines.

2.8       Steering test.

Observe the transverse inclining of the ship when it is speeding up gradually and then determine if to carry out the test at full speed.

2.8.1　  Test of main steering gear

(1)　     The ship is required to be under the condition of the design draft and design speed during the test. The test procedure is:

0o→Hard port;

Hard port→0o

0o→Hard starboard;

Hard starboard→Hard port;

Hard port→Hard starboard;

Hard starboard→0o

For steering gear with the steering gear of ±35°, when the rudder is turned from 35° on one side to 30° on the other side: refer to the time measured from 35° on one side to 30° on the other side of 9.1.4.6 (1), Rules for Construction of Inland Navigation Steel Ships 2009. For hand-operated steering gear, the force of steering lever is to be measured and the requirements in the following table are to be complied with.

For steering gear with the rudder angle of ±45°, the rudder it turned from 45° on one side to 40° on the other side: refer to 9.1.4.6 (2) , Part 2 of Rules for Construction of Inland Navigation Steel Ships.

For hand-operated (mechanic and hydraulic) steering gears, refer to 9.1.4.7, Part 2 of Rules for Construction of Inland Navigation Steel Ships.

For additional requirements for ships navigating in torrent waterways, refer to 9.1.6, Part 2 of Rules for Construction of Inland Navigation Steel Ships.

For ships navigating in Three Gorges Reservoir Region, refer to 9.1.7, Part 2 of Rules for Construction of Inland Navigation Steel Ships.

The time of rudder movement of ships navigating in Three Gorges Reservoir Region at the maximum operation speed is to comply with the following table.

2.8.2　  Test of emergency equipment

To examine the capacity of accumulator, stop the operation of oil pump at 60% of the ship’s design speed and measure steering in full rudder from one side to the other side for at least six times.

Steering gear supplied by emergency power source is to be subject to emergency steering test for 60 minutes.

2.8.3　   Examination during the steering test. The conversion of main steering gear from the control system of main power supply to that of emergency power supply is to be quick and reliable. The conversion of main steering gear to auxiliary steering gear is to be quick and reliable. The operation of steering gear.

2.9        Navigation performance test

Navigation performance is to be conducted in a good weather with the wind not stronger than Beaufort scale 3 and in a water area with mild current, less traffic and enough depth of water. The ship is to be in the designed draft as far as possible.

2.9.1　  Speed test

(1)　     Speed test is generally carried out in the speed test area by range beacon method or GPS.

(2)　     Testing area is to be in a water area with the depth five times than the draft of the ship. The width of the course is to enable the ship or fleet to turn with full rudder at the rated rotation speed.

(3)　     In the test, the main engine is to operate at the rated rotation speed. Carry out the test for at least three times and the track lines are to be the same on the whole. Calculate the average speed by using the average method with the navigation speed each time.

　　     Average speed of three tests:

　　　 V＝（V1＋2V2＋V3）/4

Average speed of four tests:

V=（V1＋3V2＋3V3＋V4）/8

where：V——speed, km/h;

　　　  V1——downstream (upstream) speed,  km/h;

　　　  V2——upstream (downstream) speed, km/h;

　　　  V3——downstream (upstream) speed, km/h;

　　　  V4——upstream (downstream) speed, km/h.

(4)　     In addition to the methods above, other efficient methods may also be used for speed testing.

2.9.2　  Turning test

(1)　     Turning test is to be carried out with the 85% of the maximum power output for circling for one round with hard port and hard starboard respectively. Measure the steady turning diameter, dynamic heeling angle, static heeling angle and the turning time of the ship.

(2)　     For ships with double propellers, the turning diameter and turning time with full rudder of going ahead and backing for one time respectively.

            Note: the turning test may be started from a small rudder angle. Increase the angle gradually and observe the heeling of the ship then determine if the full rudder test is to be carried out.

2.9.3　  Stopping test

　　     Measure the length of track line and sliding time when the ship stops in downstream and upstream for one time respectively.

(1)　     Full speed ahead→stopping

　　     Measure the length of track line and sliding time from the stopping order is given to the ship stops.

(2)　     Full speed ahead→ full speed backing astern

Measure the length of track line and sliding time from the order of backing is given to the turning point of reversing (the point where the ship stop going ahead for backing).

2.9.4　  Course stability test

　　     The test is to be carried out without cross wind or transverse flow and for one time in downstream and upstream respectively to measure the steering frequency and yaw.

(1)　     The ship sails on a stable direct course at the full speed for 5min, measure the number of steering operations and maximum steering angle necessary for keeping the course unchanged is to be measured for propulsion by left and right single screw. Normally steering is carried out for not more than ten to twelve times every minute and the angle is not greater than 2o～3o.

(2)　     The ship is going ahead with rudder amidship at full speed for 3min to measure the angle of deviating from the original course.

(3)　     For twin-screw ships, the maximum steering angle necessary for keeping the course unchanged is to be measured for propulsion by left and right single screw.

2.9.5     Z-shape maneuvering test 

Z-shape maneuvering test means the test of determining the ability of course changing of the ship with the steering gear changes in a Z-shape as time goes.

(1) Application: 9.1.1.1, Chapter 9, Part 5 of Technical Regulations for Statutory Survey of Inland Navigation Ships.

(2) Test conditions: 9.1.3.2, Chapter 9, Part 5 of Technical Regulations for Statutory Survey of Inland Navigation Ships.

(3) Test requirements: ships navigating in torrent waterways can be tested according to the requirements of GB/T3221Code for Dock and Sea trials of Diesel-driven Inland Ships, and the Z-shape steering test for ships not navigating in torrent waterways can be carried out with reference to the requirements.

2.10　   Radio communication equipment

2.10.1　  Very high frequency telephone is subject to the test of calls from ship to ship and shore to shore, as well as DSC call and receiving. The voice on the telephone is to be clear.

2.10.2　  Medium-high frequency single side board transceiver is subject to the function test of radio telephone and radio telegraph on each working frequency. The voice on telegraph and telephone is to be clear.

2.11　   General inspection of electric installations

           In the sea trial, in addition to the items for the test of hull and machinery such as rudder, anchor, fire protection and remote control of main control, following general inspections are to be carried out to check the working conditions of each system.

           (1)  emergency (provisional ) power supply;

           (2)  auxiliary electric motor system;

           (3)  lighting and navigation signal light system;

           (4)  commanding telephone and automatic telephone system;

              (5)  fire alarm and alarm bell system;

             (6)  broadcasting inboard and out broadcasting.

2.12　   Power station

2.12.1　  In the sea trial, power generators work alternatively and to observe the normal working condition of generators and distribution board.

2.12.2　  The power station can work normally when the generator of highest power onboard is started.

2.13      Test of remote control system of main propulsion device

            Remote control system is to be used at the auxiliary control station of the bridge and main control station of engine room to test various controls within the range of operation conditions. Test methods are listed in Figure 1 and Figure 2. Diesel engine propulsion is to be tested according to the procedure as shown in Figure 1, and powered adjustable pitch propeller propulsion is to be tested according to the procedure as shown in Figure 2. At least two rounds of controls are carried out at the auxiliary control station of bridge based on the figures and one round of controls are carried out at the main control station of engine room.

Figure 1 Test Procedure for Control System of Main Diesel Engines

 

            Figure 2 Test Procedure for Single-Handle Control System of Powered Adjustable Pitch Propeller

Notes of Fig.1 and Fig. 2

(1)  numbers mean time, in min;

(2) when ahead running at the dead-slow speed, the rudder is to be turned to full at the position of “”;

(3) operate as quickly as possible at ‘―→’;

(4) the power supply (electricity, compressed air, oil pressure) for remote control system is to be shut down for 2 minutes where the symbol ‘→→’‖— is marked, so as to examine the main engines for any danger or abnormality due to loss of control power.

(5) Main engine is to be stopped by operating the emergency shutdown device at the position of ‘→→→’.

(6) Tests are carried out for the pumps and standby devices serving the main engine to converse and start automatically.

(7) Where the symbol × is marked, the running of shafting is to be stopped.

Note: For the control system of multi-engine single propeller ships and the nonsingle-handle control system of adjustable pitch propeller ships, the test method and time may be adjusted as necessary according to the above Figures.

2.14     Test of centralized control and monitoring equipment

The test of centralized control and monitoring equipment is to be carried out during voyage in accordance with the regulations in mooring test.