NTSB Preliminary Report M/V Dali

I tried to point you guys to this before but shipowners have the ability to specify the kind of bridge you speak of.

Or are you saying the time has come to make it mandatory rather than an extra class notation? Now that would be interesting.

A post was merged into an existing topic: BAM - Bridge Alarm Management


The captain also, in this situation, has to trust, (but verify) that the pilot is doing their job. @244 posted about this dynamic.

Captains and pilots are accustomed to splitting duties so presumably that would reduce the chaos a bit.

1 Like

Texas, KP and KC

I agree entirely with your recent posts above.

I just think our collective jobs could be made much easier if the use of deafening alarms was controlled .

I got distracted last night into a discussion on aviation which is totally off topic for which I apologise, but while on the subject of accident reports I think it would be beneficial to look at The Emma Maersk accident approaching the Suez Canal.

I’m afraid I can’t link it, I am sure someone can.

What I took from it was.

The stern thruster shed one or more blades which punched through the tunnel. This should have been contained by watertight doors but the bulkhead penetrations failed and the generators were in imminent danger of being flooded.
The vessel berthed at an adjacent container terminal and grounded.

From my interpretation of the accident the crew performed magnificently during the entire event.

One of the notes from the crew was that communication was hampered by the constant sounding of loud alarms.

This incident occurred sometime in the 2000’s

It seems to me a shame that lessons have not been learnt with regards to alarms.

1 Like

There is something very odd in the PR.

Referring to PR page 9, it is clearly mentioned that “Most bridge equipment also lost power,…”. This would only be possible if both DC UPS (Uninterruptible Power Supply) and AC UPS would have both failed as the 1st blackout occurred.
DC central UPS and AC central UPS are powered by batteries, they supply without any interruption mission-critical devices and those include various bridge equipment.

Referring to Page 11 there must be inaccuracies, emergency bridge equipment is supplied by UPS power and unless there were very serious issue with the UPS’s, a failure of both DC and AC uninterruptible power is quite unlikely and would have caused a whole series of problems and also there would be no records of RADAR nor ECDIS or other displays without local battery.

The VDR captures either vectorial screen image data or frame-grabber-acquired screen image data.
Typically the VDR will record for both X-band and S-band RADAR’s as well as the ECDIS one image every 15 seconds and, if there are multiple displays for the same function, the acquisition will be interleaved though X-band and S-band are counted as separate (i.e. one image sampled every 15 s for both frequency bands).

The VDR records a lot of various data but many devices stopped working as the 1st blackout occurred until either emergency or regular power was restored.

Some critical controls remain powered by local batteries. The partially redundant ME controls must be able to manage the emergency lubrication as the ME will be windmilling for some time before stopping though here the speed was low (the main ME controllers are redundant but not the cylinder control units though the engine can be run without all cylinders operating).

Without UPS power, only data from devices with internal batteries could have been recorded by the VDR but overall I still doubt that the UPS’s failed. Sure is that the wording of the PR is not clear.
I am not referring to the wording about the EG, as the NTSB has not formally established if and when the EG came online, the conditional form must be used in the text. It simply means that for now no details are confirmed about the EG; the crew mentioned that the EG came online but the NSTB is not confirming that for now as the investigation is obviousy not complete.

The VDR itself never stopped working as it remained powered by the internal 12 V 24 Ah sealed lead-acid battery of the Recording Control Unit (lasts about 2 hours depending on the load).

There is still the question about the black smoke but unfortunately no one who knows well that type of engine replied.
Several previous replies in this thread do not make much sense as they refer to much smaller ships. Unless I specified it otherwise, I was specifically referring to either M/S Dali or other large container ships. For example MV and LV breakers are often not operated the same way, also C/O (Closing/Opening) cycles with a single spring charge may vary, also delays within a cycle depend on the used breaker.

The retroffited scrubber can require enough power to require a 2nd DG to be run for the base load (reefer container excluded).

Another point is the sequencing of DOL-started motors. Many motors are started DOL (and yes, I know softstarters, I designed enough controls using them, especially pumps, including also designs with emergency DOL start of larger pumps).

On a large container ship there are many larger pumps as well as some larger fans, those motors are often DOL and if they are not sequenced they can overload the power distribution.

Oh jeez, silly me, I thought the AI thread abuse was finished.

1 Like

Maybe you have something constructive to add. For example where the windmilling of the ME would have allowed to reverse the ME or something about the black smoke. And please make sure to refer to the type of ME and DG’s in use, some made generic comments which do not apply to the installed ME, DG’s or steering gear.

The PR is not clear about the consequences of the 1st blackout: Either the AC UPS and DC UPS did not fail in which case most bridge instruments would not have stopped working, or both UPS failed which would mean that nearly all data from external sources would have been lost and one emeergency power available there whold have been some reboot delay (and some devices require a heat up time to stabilize or must be realigned).

The bridge and wing audio ist acquired directly by several microphones though depending on their number and locations the recordings will be more or less valuable. It also depends on the background noise.

ME data has been recorded by the redundant engine control system powered by local batteries.

Hi 244
I just downloaded the incident report prepared the Danish Maritime board. Will give it a good read later. The section on the alarm distraction is spot on. In the O&G industry the alarm and monitoring system has about 25 to 35k I/O points as opposed to about 2-5k in vessels.
Alarm rationalization and prioritization exercise (not a minor exercise) is usually conducted with the vessel crew and engineers. Perhaps shipowners should consider this as part of the delivery package.
PS: Had an unfortunate experience with incorrect setting on the main engine slow down. Slow down was set to Full Ahead rather than DS. Piston cooling ‘no flow’ alarm, ME slow down from sea speed to Full, all engineers turn to in the CR, 2 engineers go down to see if oil was flowing into the glass cover and a crankcase explosion with both engineers getting hurt. One much more the other - he was wearing a polyester coverall and it just melted onto his body with the hot oil.

Thar she BLOWS … again … in its words ‘after a re-boot delay’. :slight_smile:

If all external power is lost, without internal battery (like e.g. the VDR Recording Control Unit), or supercapacitor (only for short backup times)) a device shuts down and when external power is restored if it’s based on microprocessors it must reboot, this can take from a fraction of a second to several minutes though in most cases it’s just a few seconds for small devices and somewhat more for more complex microprocessor-based systems (like a PC and many devices are based on embedded or usualyPC’s).
In some cases you can chose to skip some internal self tests to reboot faster and perform some sequential tests while already running.

For now it is not fully clear if DC UPS power and AC UPS power both failed as statements are contradictory if you read carefully. It would be surprising and mostly the result of a poor design but OTOH I doubt the UPS’s are modular and redundant without any single point of failure.

I know the GMDSS and Gyro have battery back-up, what other bridge instruments are on battery back-up?

Modern integrated bridge pretty much everything except steering.
Even Standalone, Radars ECDIS ect everything except steering.

This particular ship is relatively new so my guess probably all the bridge equipment except steering gear. I don’t actually know.
Even the Nav lights usually have at least two circuits one of which is designate emergency and has a 24 volt battery back up. The other just regular supply.
( Have a long running difference of opinion with my oppo, I always run on E JIK we have a blackout so we don’t have to remember to switch over. He always runs on regular JIK he wears out the back up, The lights don’t care they are on both circuits)
And yep the Nav light panel has an alarm.
As do all the UPS.

UPS nice to have, You don’t have to go reset everything like the old days, it just keeps going