IMCA’s DP committee hosted a workshop in early March on the subject of DP system Network Storms. There were three presentations by individuals heavily involved in this subject and workshop sessions throughout to discuss and debate many specific points. In attendance at the workshop we had vessel owners and operators, 3rd party consultants, network specialists and OEMs from the IMCA Membership.
The focus of the workshop was on the complete DP system, not just the DP computers and associated networks but all systems and their respective networks from the position reference systems to the propellors and everything in between.
Why the focus on Network Storms? Well, the DP committee wanted to unravel the mysteries of network storms to ensure that industry has the knowledge and tools available to ensure our DP vessels are robust in terms of failure in this area, and ensure that any testing undertaken was fit for purpose and associated risks were understood.
The workshop addressed the belief that many network storms currently go unnoticed, manifesting themselves as a glitch or anomaly or doubtful human action. The discussion clarified that, although the effects may appear suddenly, they can build up over time and may represent themselves in the form of, for example:
- Crashed controllers
- Controllers becoming slow – position loss increases over time
- Equipment freezing
- Erratic behavior
- Or of course a combination of these effects
As a result of the manifestation of Network Storms being largely within the examples stated, perhaps the industry has not progressed in the pursuit of knowledge of this subject, and the potential risks posed.
Topics of discussion also covered what might cause a network storm and the risks of such a network storm affecting otherwise redundant systems. One of the presenters kindly provided a video of a Network Storm test being undertaken, the results demonstrating a complete loss of all thrusters from automatic DP control coupled with a loss of independent joystick on a DP equipment class 2 vessel.
The workshop concluded with arguably more questions than answers. Therefore a workgroup is in the process of being formed in order to take the subject forward in the form of industry guidance.