Class Requirements
Based on IMO (International Maritime Organization) publication 645 the Classification Societies have issued rules for Dynamic Positioned Ships described as Class 1, Class 2 and Class 3.
- Equipment Class 1 has no redundancy.
Loss of position may occur in the event of a single fault.
- Equipment Class 2 has redundancy so that no single fault in an active system will cause the system to fail.
Loss of position should not occur from a single fault of an active component or system such as generators, thruster, switchboards, remote controlled valves etc., but may occur after failure of a static component such as cables, pipes, manual valves etc.
- Equipment Class 3 which also has to withstand fire or flood in any one compartment without the system failing.
Loss of position should not occur from any single failure including a completely burnt fire sub division or flooded watertight compartment.
Classification Societies have their own Class notations:
| Description | IMO Equipment Class |
LR Equipment Class |
DNV Equipment Class |
GL Equipment Class |
ABS Equipment Class |
NK Equipment Class |
| Manual position control and automatic heading control under specified maximum environmental conditions | - | DP(CM) | DYNPOS-AUTS | - | DPS-0 | - |
| Automatic and manual position and heading control under specified maximum environmental conditions | Class 1 | DP(AM) | DYNPOS-AUT & DPS1 | DP 1 | DPS-1 | DPS A |
| Automatic and manual position and heading control under specified maximum environmental conditions, during and following any single fault excluding loss of a compartment. (Two independent computer systems). | Class 2 | DP(AA) | DYNPOS-AUTR & DPS2 | DP 2 | DPS-2 | DPS B |
| Automatic and manual position and heading control under specified maximum environmental conditions, during and following any single fault including loss of a compartment due to fire or flood. (At least two independent computer systems with a separate backup system separated by A60 class division). | Class 3 | DP(AAA) | DYNPOS-AUTRO & DPS3 | DP 3 | DPS-3 | DPS C |
DNV rules 2011 Pt6 Ch7 introduced "DPS" series of classification to compete with ABS "DPS" series.
Read more about this topic: Dynamic Positioning
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