Chapter 3 Survey Requirements for Additional Systems and Services
3.4 Survey for Dynamic Positioning System (DP-system)
At each Annual Survey, the vessel is to be operated for a duration of at least two hours to demonstrate that the dynamic positioning system has been maintained properly and is in good working order. The operational testing is to be carried out to the Surveyor's satisfaction and the tests are to demonstrate the level of redundancy established by the FMEA (Failure Modes and Effects Analysis).
In addition, the following items are to be generally examined and tested so far as can be seen and placed in satisfactory condition:
(a) Documentation
The following accepted documents are to be confirmed onboard the vessel as applicable:
(i) DP FMEA
(ii) DP Trial Test Procedures/Results of Trials (iii) DP Operations Manuals
(iv) ESD (Emergency Shutdown) Operations Manual (b) Controls and alarms
Control system, including independent emergency shut-down facility for each thruster at the main dynamic positioning control station, position keeping redundancy, and alarms and instrumentation are to be generally examined and confirmed to be functioning satisfactorily.
(c) Position and environment sensors
All available position sensors, wind sensor(s) and gyro-compass(s) are to be generally examined and confirmed to be functioning satisfactorily.
(d) For DPS-I notation
The operation of the automatic control system and a manual position control system including manual transfer of control between the two systems is to be confirmed to be functioning satisfactorily.
(i) Verification that any DP-system hardware changes that may affect the DPS-I notation for the unit have been submitted, approved, and tested as required.
(ii) Confirmation that any software revisions since the time of last Survey have been tracked and tested as appropriate by Owner and suitably documented for record.
(iii) Any hardware or software changes that have not been tested since the last performance test shall have functionality proven and recorded by a supplementary trials program to verify the effect of the modifications with regard to the approved redundancy arrangements for the unit.
(e) For DPS-II notation
Completion of all items for DPS-I notation.
The operation of two automatic control systems and a manual position control system including automatic transfer of one automatic control system to another upon failure is to be confirmed to be functioning satisfactorily. Upon failure of the two automatic control systems, it is to be verified that the manual position control is possible. Also see 3.4.1(g) below.
Additionally the followings are to be confirmed or tested:
(i) General System
(1) Black out recovery test shall be conducted.
(2) The following redundant equipment shall be disabled or disconnected in order to demonstrate operational capability after such simulated failure/condition:
- Position reference systems
- Worse case failure (e.g. switchboard, transformer, engine, or thruster as applicable) - Network arrangements
(3) Demonstration of open bus power management systems.
(4) Demonstration of closed bus power management systems where such closed bus arrangements have been reviewed and accepted by the Society.
(ii) Standby and power redundancy
(1) Test thruster supply and generator feeder automatic transfer switches
(2) The tests will exercise the changeover functions as well as the redundant supplies.
(3) The standby and power redundancy tests may be combined with the tests of the Worst Case Failure Design Intent identified in the DP FMEA. Changeover to the standby DP control station is to be tested.
(4) Changeover to standby auxiliary services, such as seawater or freshwater cooling pumps and hydraulic pumps, shall be tested where these auxiliaries provide essential redundancy as identified in the DP FMEA.
(5) Test the switchover and isolation of redundant DC power supplies, such as in control power circuits. Where one DC power supply is failed or removed, voltage or current from the redundant DC power supply or any other source should not be present at the failed power supply.
(f) For DPS-III notation
Completion of all items for DPS-II notation.
The operation of three automatic control systems and a manual position control system including automatic transfer of one automatic control system to another upon failure is to be confirmed to be functioning satisfactorily. Manual transfer of control is to be verified possible at the third automatic control system located in the emergency back-up control station. Upon failure of the automatic control systems, it is to be verified that the manual position control is possible. Also see 3.4.1(g) below.
Additionally, the following items are to be confirmed or tested:
(i) The following redundant compartments shall be disabled or disconnected in order to prove operational capability after failure
(1) Main Control station
(2) Worst case failure compartment (e.g., engine room, switchgear room, thruster room, or other space)
(ii) Verification that no changes have been made to the watertight integrity and fire subdivisions of compartments containing elements of the DP and associated systems.
(g) Manual position control system for DPS-I, DPS-II, and DPS-III notations
The operation of the manual position control system using one joystick on the Navigation Bridge or DP control station and supplemented by an automatic heading control is to be confirmed to be functioning satisfactorily.
(h) Manual thruster control system
In addition to 3.4.1(c) to 3.4.1(f), the operation of the manual thruster control system using individual levers on the Navigation Bridge or DP control station is to be confirmed to be functioning satisfactorily.
(i) Alarms and instrumentation
The following audible and visual alarms including indicators at each control station are to be examined, verified operational and confirmed to be functioning satisfactorily, as applicable:
- 166 - CR CLASSIFICATION SOCIETY (i) Thruster power system
(1) Engine lubricating oil pressure – low*
(2) Engine coolant temperature – high*
(3) CPP hydraulic oil pressure – low and high*
(4) CPP hydraulic oil temperature – high*
(5) CPP pitch**
(6) Thruster RPM**
(7) Thruster direction**
(8) Thruster motor/semiconductor converter coolant leakage*
(9) Thruster motor/semiconductor converter temperature**
(10) Thrust motor short circuit**
(11) Thruster motor exciter power available**
(12) Thruster motor supply power available**
(13) Thruster motor overload*
(14) Thruster motor high temperature*
(ii) Power distribution system
(1) Status of automatically controlled circuit breakers**
(2) Bus bar current and power levels**
(3) High power consumers – current levels**
(iii) System performance
(1) Excursion outside operating envelope*
(2) Control system fault*
(3) Position sensor fault*
(4) Vessel target and present position and heading**
(5) Wind speed and direction**
(6) Selected reference system**
(iv) In addition, for DPS-II and DPS-III notations (1) Thruster location (pictorial)**
(2) Percentage thrust**
(3) Available thrusters on stand-by**
(4) DP alert through consequence analyzer*
(5) Position information of individual position reference systems connected**
Notes:
*：Alarm
**：Display
(j) Uninterruptible power systems (UPS)
The uninterruptible power systems (UPS) are to be operated and confirmed to be functioning satisfactorily.
The uninterruptible power systems (UPS) are to be operated without the normal main power input for 30 minutes to confirm that the batteries are capable of supplying the output power and are in satisfactory condition. The schedule of batteries is to be examined to verify that the batteries have been maintained.
(k) Communication
(i) A means of voice communication between the DP control position (navigation bridge), and the thruster room(s) is to be tested and confirmed to be functioning satisfactorily.
(ii) A means of voice communication between the DP control position (Navigation Bridge), the engine control position and any operational control centers associated with DP is to be tested and confirmed to be functioning satisfactorily.
Note: No back up required.
(l) Dynamic positioning system (DP-system)
(i) Confirmation of DP-system operations manual onboard. Verification that the manual is up to date with any modifications performed on the installation.
(ii) Verification that the failure modes and effects of any modifications or upgrades have been considered and incorporated in the operations manual.
(iii) Fail safe tests for thrusters
A single fault in the thruster system is to be such that a thruster fails to a safe mode so that the vessel's position and heading are not affected. Fail to a safe mode could be a failure to zero thrust or motor stop.
(m) The thruster installation using for DP-system
The thruster installation is to be generally examined so far as can be seen and placed in satisfactory condition.
The survey is also to include:
(i) Controls and alarms
Verification of effective means of control from both the Navigation Bridge and local control stations, including alarms and indicators. The following audible and visual alarms at each control station are to be visually examined, verified operational and considered satisfactory, as applicable:
(1) Engine low lubricating oil pressure (2) Engine coolant high temperature (3) Motor overload
(4) Thruster RPM
(5) Thrust direction (azimuthing type) (6) Thruster power supply failure
(7) Controllable pitch propellers hydraulic low oil pressure (8) Controllable pitch propellers hydraulic high oil pressure (9) Controllable pitch propellers hydraulic oil high temperature (10) Fire extinguishing systems
(ii) Communication
Means of voice communication between the bridge control station, main propulsion control station and the thruster room are to be tested and found satisfactory.
(iii) Thruster room
Thruster room arrangements, including adequate ventilation, bilge system and alarms for enclosed modules and firefighting systems are to be examined, tested and considered satisfactory.
3.4.2 First Bottom Survey in dry dock after delivery
At the first Bottom Survey in dry dock after delivery, thruster units are to be examined and confirmed in satisfactory condition including the followings.
(a) External examination including propeller, gear housing, bolting and their securing arrangements and for seal leakage.
(b) Internal gear train examination through inspection opening. Where inspection opening is not provided, at least one unit is to be opened for examination.
(c) Lubrication oil sample analysis.
(d) In addition, for controllable pitch propellers, blade seal leak check and functional test.
Where deemed necessary by the Surveyor, non-destructive testing may be required.
In case the first Bottom Survey in dry dock after delivery is the first Special Survey after delivery, the items specified in 3.4.3 below will also apply.
- 168 - CR CLASSIFICATION SOCIETY 3.4.3 Special Surveys
In addition to the requirements of the Annual Survey specified in 3.4.1 above, complete performance tests are to be carried out to the Surveyor's satisfaction. The schedule of these tests is to be designed to demonstrate the level of redundancy established in the FMEA for DPS-II and DPS-III. In those cases where a Continuous DP Testing Program has been accepted in 3.4.3(d) below, this may be considered by the Surveyor for acceptance in lieu of conducting the complete performance test.
(a) Thrusters are to be surveyed as part of the Special Survey in accordance with 2.3.4 of this Part.
(b) Full power tests of thrusters and generators are to be conducted.
(c) The prime movers of thrusters are to be examined as applicable in accordance with 2.7.2 of this Part.
(d) Annual DP Testing Program
If the vessel is on Machinery Continuous Survey (MCS), the Owner may submit a Continuous DP Testing Program to conduct the required FMEA and performance testing throughout the survey cycle. The program may schedule approximately 20% of the FMEA and performance testing, along with the requirements specified in 3.4.1 above for the Annual Survey each year. This Annual DP Testing Program is to be submitted for review. The testing program shall be kept on board the vessel for reference at each Annual Survey.
Appendix 1
Loading Computer System (LCS) for Stability and Longitudinal Strength
A1.1 General Requirements
A1.1.1 Application(a) The requirements of this appendix apply to ships equipped with computer based systems for calculation and control of loading conditions for compliance with the applicable stability, longitudinal and local strength requirements.
A1.1.2 Class Notation
(a) Ships equipped with loading computer systems designed, manufactured and tested in compliance with the requirements of this appendix, for calculation and control of stability, longitudinal and local strength, may be assigned the additional class notation LCS.
A1.1.3 General requirements
(a) The Loading Computer System is regarded as supplementary to the Loading Manual and Stability Booklet and if relevant the Grain Loading Manual which are always to be provided on board.
(b) The user's manual is always to be provided for the loading computer.
(c) The user's manual and the computer software must be prepared in a language understood by the user. If this language is not English, a translation into English is to be included.
(d) If the software includes on-line interface, for instance remote tank sounding or draught reading, it is assumed that the remote system is maintained and calibrated as recommended by the manufacturers.
(e) On-line computers are to be connected through a gateway if connected to the ship 's network serving main functions. The gateway shall have read only possibility unless the computer is approved for two -way communication.
(f) The software may be type approved or approved on a case by case basis for a specific ship.
(g) The software may be type approved, the validity and limitations of the type approval are to be carefully noted. If a type approval is found not to cover all parts of relevance for a specific ship, addition testing and documentation as for a case-by-case approval may be required.
A1.1.4 Documentation
(a) Hardware documentation
If the hardware is not type-approved, the concerned documentation is to be submitted.
(b) Documentation needed when software is type approved
In case of type-approved software, the following documentation is to be submitted:
(i) Preliminary test conditions (print of input and output data).
(ii) Stored characteristic data. (e.g. hydraustatics, cross curves, VCG or GM limit curves, lightweight definition, tank data and associated limits to still water shear force, bending moments and torque, as applicable, and with explanation as found necessary.)
- 170 - CR CLASSIFICATION SOCIETY (iii) Number, position and limits of read-out points. The shear force limits are to be specially considered
for ships sides and longitudinal bulkheads. The loading computer is to take into account the local correction of the shear forces for conditions with greater pressure differences on the ship 's bottom structure.
(iv) Final test conditions (print of input and output data)
In case the user's manual is tailor made for a specific ship, the manual is to be submitted as well.
(c) Documentation needed for case-by-case approval of the software
With a case-by-case approval of the software, the following documentation is to be submitted:
(i) Software description and specifications, including flow chart.
(ii) User's manual, including flow chart.
(iii) Preliminary test conditions (print of point and output data).
(iv) Stored characteristic data. (e.g. hydrostatics, cross curves, VCG or GM limit curves, lightweight definition, tank data and associated limits to still water shear force, bending moments and torque, as applicable, and with explanation as found necessary.)
(v) Number, position and limits of read-out points
The shear force limits are to be specially considered for ships sides and longitudinal bulkheads. The loading computer is to take into account the local correction of the shear forces for conditions with greater pressure differences on the ship's bottom structure.
(vi) Final test conditions (print of input and output data) A1.1.5 General software requirements
(a) Software
(i) The software and the stored characteristic data must be protected against erroneous use.
(ii) The software design is to be such that it limits possible input errors by the user, for instance t ank volume input is not to exceed maximum tank volume, or negative volume input to be accepted.
(iii) The software is to be user-friendly, preferably with graphic presentation of loading conditions and on-line user's task help.
(iv) The software is to include loading limitations. A warning is to be given if these limits are exceeded.
Note:
Loading limitations should include minimum/maximum draught, maximum trim, shear force and bending moment limits, minimum/maximum metacentric height (GM), cargo tank filling height as a function of cargo density, limits to distributed loads on deck, filling of ballast and cargo tanks etc.
(v) The software is to present relevant parameters of loading conditions, such as displacement, draughts forward, midship and aft, trim, center of gravity, metacentric height, free surface correction, shear forces, bending moments, torque and local strength as well as the limiting values for those parameters and an overall judgment whether all loading parameters are within the limiting valu es.
(vi) If intended for stability calculations, the software must include effect of free surface from slack tanks on the initial metacentric height (GM) and the righting lever (GZ) as well as the effect of external heeling moments, if applicable.
Note:
If the software is based on interpolation on even keel hydrostatics only, the limiting trim will be considered as maximum 1% of the ship's length.
(vii) If the software calculates damage stability, a list of damage cases is to be included. Any intended loading condition must be checked for these damage cases. The results are to include the equilibrium position and the GZ curve after damage, as well as criteria control.
Software is to give an overall judgment whether all the damage cases were found comply with the applicable requirements, within an acceptable time.
(viii) If the software includes on-line interface, for instance remote tank sounding, or draught reading, a warning is to be given in case of line interface failure. Further, it is to be possible to give the on-line input manually.
(ix) In case of discrepancy between calculated and actual displacement, the software is to use the actual value and correct the center of gravity in a satisfactory manner. The normal procedure is located in the center of gravity of the deadweight.
A1.2 Approval and Testing Requirements
A1.2.1 Approval principles(a) The requirements of hardware is to be complied with the Rules.
(b) The software can be either type approved or case-by-case approved. The latter case is only in condition with system installation on board a specific ship. In either case, relevant requirements stated in section A1.1 are to be complied with.
(c) Approval and certification.
(i) Documentation according to A1.1.4 including preliminary test conditions in accordance with A1.2.2 is to be submitted for approval.
(ii) Final test conditions according to A1.2.2, are to be tested on board in the presence of a surveyor as described in A1.2.3.
(iii) Certificate of the loading computer system will be issued after checking of final test conditions on board.
A1.2.2 Test conditions (a) General
(i) Preliminary test conditions are based on estimated lightweight data. Final test conditions are those conditions which are based on lightweight data obtained from the inclining test or the lightweight survey.
(ii) Special or additional test conditions as specified in (vii) may be required by the Society in case the standard test conditions do not fully expose critical aspects of software, e.g. limitations which need to be demonstrated in particular.
(iii) The units and reference system of the test conditions are to be the same as used in the loading manual and the stability booklet.
(iv) At least 4 preliminary test conditions are to be submitted. The corresponding final test conditions are to be submitted after satisfactory result on board in the presence of a CR Surveyor.
(v) The selected test conditions are to be representative of the service conditions and the same as the conditions presented in the approved loading manual or the stability booklet. The 4 standard test conditions are to be as follows:
(1) Light ship condition.
(2) Ballast or partly loaded condition.
(3) Fully loaded condition.
(4) Arbitrary loading condition given extreme values.
(vi) Documentation of test conditions is to include input and output data for each condition.
(vii) Additional test conditions, if required, are to be tested of limiting loading parameters, such a s maximum draught, maximum trim or maximum KG. Further, they are to include extreme loading conditions, with varying loading parameters such as tank filling heights as a function of cargo density, limits to distributed loads on deck, shear force limits, bending moments and torque as far as applicable.
A1.2.3 Testing and certification (a) General
(i) At least 4 of the final test conditions are to be tested on board in the presence of a CR surveyor, before the loading computer certificate is issued.
- 172 - CR CLASSIFICATION SOCIETY (ii) The results from the test conditions must not deviate significantly from the results in the approved
- 172 - CR CLASSIFICATION SOCIETY (ii) The results from the test conditions must not deviate significantly from the results in the approved