Blackout Start Troubleshooting

We had the privilege of boarding Viking Diamond a couple months back. What was technically interesting was the opportunity to tackle problems of distinctly different nature.

The vessel was well managed and operated. Technical superintendent was up to speed on all issues and ship crew had in-depth knowledge of the onboard systems. Documents were cataloged in an organized fashion too.

There was this MSB blackout start problem that was observed onboard. While it's not the most difficult of problems, its universal applicability makes this problem highly share-worthy.

This vessel uses a Valmarine (l3) PMS. Upon a blackout, the PMS should attempt to remotely and connect any available DG (sequence is based on priority). There was no problem in remotely starting the DGs (which ran without a glitch), but the show ground to a halt there. None of the DGs could be connected to the busbar.

Thanks to my super colleague onboard, and our very capable ship electrician, the devil in the detail was exorcised without exasperation. They discovered that even though the DGs started, the PMS was unable to determine if the DGs started successfully. Why? Because there was no frequency and voltage feedback to the PMS. (even though there was rpm info from the tacho) And why not? Because the transducers providing such feedback had no power...

We eventually traced the root cause to a defective UPS .

What factors contributed to the quick resolution of this problem? Good documentation to trace the possibilities, competent minds to narrow down these possibilities, supportive crew to permit unpopular blackout tests to verify our deductions.

With those conditions onboard, you know you have a perfect receipe for problem solving.