Official title: Dynamic positioning vessel design philosophy guidelines Reference: DNV-RP-E306 (formerly DNVGL-RP-E306, edition July 2015, superseding DNV-RP-E306 of September 2012) Issued by: DNV — recommended practice developed in cooperation with the Marine Technology Society DP Technical Committee
Why this recommended practice exists
DP class notation is governed by class rules that address DP equipment and redundancy requirements. Those rules do not address the industrial mission of the vessel, nor its overall performance and operational capability. A vessel designed only to obtain a DP class notation may therefore fall short of the post worst-case failure capability it could have achieved had sound design philosophies been adopted from the start.
RP-E306 sets out those philosophies. It is guidance, not a substitute for rules, regulations or class requirements — compliance with applicable class rules is still assumed.
What it covers
- Establishing the redundancy concept and worst-case failure design intent at the design stage, not after delivery.
- Design choices that minimise the loss of position-keeping capability after a failure and improve reliability, rather than merely satisfying the minimum single-fault criterion.
- Power generation and distribution philosophy, thruster arrangement, control system architecture and independence, and the auxiliary services the redundancy concept silently depends on.
- Documentation and verification: FMEA, capability analysis, proving trials, and how the design intent is carried forward into operations.
Centre of rotation — the clause operators quote most
If an alternate centre of rotation (other than centre of gravity / centre of vessel) is contemplated as a means to undertake the industrial mission, capability plots should be developed for this condition for both intact and post worst case failure scenarios.
This is the design-side counterpart to IMCA's DPE 01/25 warning on centre of rotation. Shifting the COR away from the COG introduces a lever arm, changes the yaw moment the thrusters must produce, and redistributes thruster utilisation — so the standard capability plots taken at the COG no longer describe the vessel the crew is actually operating. See the Dynamic Positioning entry for the COG vs COR discussion and the interactive explorer.
Where it sits among the other references
| Document | Role |
|---|---|
| IMO MSC.1/Circ.1580 | International guidelines and DP equipment classes |
| DNV-RP-E306 | Design philosophy — how to build in capability and graceful degradation |
| DNV-ST-0111 | Standardised assessment of station-keeping capability |
| DNV-RP-D102 / IMCA M166 | FMEA practice and verification |
| IMCA M 190 | Annual DP trials and testing practice |
Class rules set the floor. Design philosophy decides how much capability is left standing after the worst-case failure.
Related MTS guidance
RP-E306 shares its origin with the MTS DP Vessel Design Philosophy Guidelines, Parts I and II. Where a project follows the MTS documents, the RP indicates how the two compare, so a design team can work from either without losing the thread.