Chapter 3 Survey Requirements for Additional Systems and Services
3.4 Survey for Dynamic Positioning System (DP-system)
3.4.1 Annual Surveys
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 s tation 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 in cluding 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:
(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.
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.