When the engineers disconnected the cable, all the equipment powered by the Low Voltage (440V) Switchboard blacked out. These included lights throughout the vessel. The report says the system recovered making an automatic transfer and regained power after approximately 10 seconds.
Are FMEA common/required on all new vessels? (I’m only familiar with them on drillships)
I’m pretty sure FMEA are exclusive to DP vessels.
one engine
one rudder
its already failed
FMEA does not ONLY apply to DP vessels:
https://asq.org/quality-resources/fmea
But it is mandatory for any Dynamically Positioned vessel Class 2 or Class 3:
A five-yearly review is required thereafter:
Several companies offer their expertise to assist when performing FMEA Proving Test:
Have you ever seen a FMEA on a non DP commercial vessel?
I have attended several DP FMEA trials and checked the validity of FMEA as part of vessel inspections, but I have not heard to any other type of ship’s equipment being subject to FMEA requirements,or trial.
PS> That doesn’t mean that it doesn’t exist, though.
The REQUIREMENT for FMEA only applies to DP vessels and no one that isn’t required to do one is going to waste the time and expense.
Everyone else here knew what I meant, stop arguing just to hear yourself argue.
Doesn’t look like a single point failure though that’s what the article linked in the OP implies.
This is from the article in Maritime Ex :
"The report says the system recovered making an automatic transfer and regained power after approximately 10 seconds."
From the first article the op linked.
“…Checking hundreds or thousands of wires is a tedious and time-consuming process, he said, and there are any number of factors that could cause connections to loosen over time, including the constant vibrations on a ship.”
Not saying it’s the case with this catastrophe, just being the devil’s advocate & informing those who may not know. If an engineering team works an extremely long time on a root cause analysis & can’t find a smoking gun, one of a hundred thousand wires being loose is an easy go to to finish a report. Especially if the real reason was human error or so simple it should have been caught before & you don’t want someone to get written up or fired. Been there, done that.
The systems recovered in 10 seconds during that test because the power automatically transferred to the offline transformer. But the report specifically states that for that automatic transfer to occur, the offline transformer must be set to automatic switch mode.
I don’t see clearly where the report mentions whether that was the mode in use during the incident event in March.
One item I found interesting is the information that the owner modified the generator fuel system sometime after construction so that Gen 3 & 4 had pneumatic fuel supply pumps in the event of a power loss to the electric pumps. Perhaps that’s why they were running those two generators for departure.
(Also, thanks to those who answered my simple FMEA question with a simple NO)
As I said:
FMEA is widely used outside the maritime industries however:
Source: https://qualitytrainingportal.com/resources/fmea-resource-center/fmea-history/
Great. This is a maritime forum though, so why is that relevant?
Here’s the link to download the report.
Not true. According to @Heiwa it was sabotage.
Readers might enjoy refreshing memories of the early ( April 5th) thread about reports of power loss before Dali ever left the dock.
IIRC, and I very well may have misunderstood something, the incident alongside was #2 SSDG shut down because of an exhaust damper and #3 shut down on low fuel pressure while using transformer #2,
After the first incident the crew shifted from the #2 transformer to the #1.
It’s my understanding that when the Dali lost power and struck the Key bridge they were still on on transformer #1. The breakers for the transformer for the two running generators (#3 and #4) opened but both on-line generators continued to run.
From the report in the OP it seems that was where the fault lay, in the breaker for transformer #1 which opened during the test.
In the incidents alongside the on-line generator stopped running and in the second, when the Key bridge was struck, the generators were both still running but disconnected.
The headline of the original article is false. There’s no way to prove the UVR tripped the breaker because it was an unmonitored input. The relay will have no record of a trip. The event history on the relay will only show breaker open, leaving everyone scratching their heads. Not saying that wasn’t the problem though, it probably was. Really bad design oh HHI’s part.
I just troubleshot an almost identical situation a couple months ago on a very similar 6.6kV lineup.
The two differential trips on TR1 while they were testing is a hell of a coincidence though.
Looks like maybe more than just a loose wire. From the Washington Post:
“They retrofitted the transformer with anti-vibration braces, one of which had cracked over time, had been repaired with welds, and had cracked again,” Justice Department attorneys wrote. “And they also wedged a metal cargo hook between the transformer and a nearby steel beam, in a makeshift attempt to limit vibration.”
The Justice Department alleged that vibration problems on the ship were “not isolated.” A former chief officer reported that they were shaking loose the ship’s cargo lashings, and engineers reported they were cracking equipment in the engine room, according to the filing.
When the number 1 transformer failed on March 26 — plunging the crew into complete darkness — power should have transferred automatically to a backup, “number 2” transformer within seconds, Justice Department attorneys asserted. But that automated function, they wrote, had been “recklessly disabled,” leaving engineers struggling in the dark to manually reset tripped circuit breakers, a process that took a full minute as the ship surged closer to the bridge.