2.1. DP Classes – Redundancy Levels
Classification societies set the standards for DP system classes. In general, the rules set by the main classification societies (DNV-GL, ABS, LRS) are similar and are based on IMO MSC 645 guideline. According to DNVGL-RP-E306, there are three DP Classes:
Class 1: Automatic and manual position and heading control. No redunancy =>Loss of position can occur in the event of a single fault.
Class 2: Automatic and manual position and heading control. Loss of position should not occur from a single fault of an active component or system such as generators, thrusters, switchboards, remote control valves etc. However, loss of position can occur after failure of static components such as cables, pipes, manual valves etc.
Class 3: Automatic and manual position and heading control. Loss of position should not occur from any single failure including a complete burn fire subdivision or flooded watertight compartments. Redundant and separated components.
2.2. Codes and guidelines
Classifications societies offer classification standards and guidelines. Most common are:
|DNV:||Dynamic Positioning Vessel Design Philosophy Guidelines, DNV-RP-E306|
|Dynamic Positioning Systems, Updated July 2013|
|ABS:||Guide for Dynamic Positioning Systems, Updated July 2014|
|IMCA:||IMCA M 103 Rev. 1, December 2007|