NTSB Preliminary Report M/V Dali

I just realized that maybe I have been incorrect all along in stating the main engine was started and that was the source of the black smoke. I think this must have been DG 2 coming on line at the second blackout. On April 16 on the subject “Dali engineering aspects” I had a couple of posts on the Dali modified funnel arrangement for the installation of the scrubber system. In looking at the engine room picture on the report, you will note that there are the 2 main engine uptakes from the exhaust manifold. The one on the near side is the original uptake terminating on the stbd side of the funnel. Think the one on the far side is the new outlet directed to the scrubber and then onto the funnel to the outlet on the port side.
There is one more much smaller one coming in between the 2 large uptakes. I think this is the exhaust gas outlet from DG2. The report also mentions ‘closing the exhaust damper’ from the DG2 causing a blackout in port. I think the design is for the DG2 is to discharge (in port) into the main engine exhaust manifold and travel up the large uptake through the scrubber to the funnel.
One 4000 kW engine coming on line and possibly fully loaded soon after it is on the HV board most likely is the source of the black smoke from the ‘large exhaust pipe’ in the funnel.
Jeez! Sorry!
image
Edit: Sorry again. I think the 2 uptakes are the main engine turbo outlets. Don’t think the little pipe is the DG exhaust. The DG exhaust must tying into the scrubber system must be higher up.

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So that HVR breaker is not really a breaker that can trip open thus blacking out the ship?

Old school
The HVR in this case is a real breaker. If for example you have 3 and 4 on line and feed to the LV board is through TR1, HVR opening will indeed blackout the vessel.

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Recent picture cropped from an aerial flyover video.

Picture cropped from 2017 ‘Shipping TV’ video of the Dali arriving at Felixstowe.

The stbd superstructure with just one uptake (new - possibly for the main engine bypassing scrubber?) is an add on - looks like sometime in 2019 or so.

The add on certainly does look like a scrubber exhaust to me as it is a typical add on.

From the preliminary report it does seem clear to me that the black smoke was not from an attempt to restart the ME. More like our engineering friends have speculated a generator coming on load.

I can only reiterate what I said earlier in this discussion that has been backed up by other experienced senior officers that the rudder could not have been in use as at that speed it would have taken some strong environmental forces to overcome the effectiveness of the rudder. I would have expected some rudder authority at much lower speeds than that even with just a single SG motor running.

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The NTSB investigators who wrote the report have access to heading and course data. Some of the data is in the preliminary report. Presumably that’s based on data from the VDR.

While the power was out and the wheel amidship the course was changing slowly to starboard. After that no info in the report except to say that with the wheel hard to port and engine stopped the rudder was ineffective.

That chartlet probably is based on AIS positions, it doesn’t include heading vectors.

It puzzles me that the preliminary report does not give more information about the rudder. The VDR must record the order and response of the rudder.

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Yes, says as soon as power restored the pilot ordered hard port. A little ambiguous.

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Unfortunately, it is possible to build, certify and operate a large ocean going vessel like Dali without enough redundancy to prevent this kind of accidents. The large majority of cargo vessels sailing out there are one failure away from a blackout and a total loss of propulsion and steering. The present statutory and class regulations do require some redundancy and reliability to be built into the vessels, but the continuity of service is not being considered. A loss of electrical power and subsequent loss of propulsion in open sea does not pose any major risks and a recovery time of few minutes is acceptable. But when this happens in confined and congested waters the recovery time is of the essence. A blackout recovery can be done in less than 45 seconds, but restarting all the auxiliaries and the main engine takes much longer. Under present regulations the blackouts happened on Dali are totally acceptable. To be fair to the industry, all major class societies have additional class notations regarding propulsion redundancy, but those notations are only voluntary and are coming with a higher price tag for the vessels.

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IMO - chasing down all the possible single point failures on modern slow speed diesels, and adding redundancy is not the answer.

It should be part of the voyage plan to identify the places where losing the plant/steering for 2-3 minutes would be un-acceptable and identify ways to mitigate that. ( maintaining tugs, slower speeds, increased communication with ER that they are in a critical spot ).

This should also carry through to the pilot organizations in ports, to do the same, more general passage planning and identify where additional steps are needed to prevent momentary losses of propulsion and steering from causing major events.

Ships loss the plant occasionally, we have all been on ships that go dark. And not saying more can and should be done to minimize that. I don’t think chasing that to zero is the answer. The answer is understanding that it can happen and to add additional links in the error chain where needed to prevent that event from becoming a more serious event.

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I agree, it is not possible to completely eliminate the risk of propulsion loss. However a lot can be done to minimize that risk.

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AV2013,

In design, operationally or both?

KC
Sorry disagree
At that speed at rudder hard a port it would have been effective.

In my pilotage Carrer I regularly run speeds down until the rudder lost authority then transitioned to either kicks ahead or tug power.

For some reason the rudder was not functional.

Retired engineer has put forward a theory of hydraulic lock which as a non engineer I don’t really understand but sometimes you just have to trust your engineering department .

Is it possible that the #3 steering gear motor was not coupled to the emergency generator?

Do the bridge crew have to manually start the #3 steering gear motor?

As a ships master I knew these things but as a pilot I had to rely on the bridge crew.

As an anecdote.

During routine simulator training one of the comments I heard during my latter years from the instructors was, ’ it doesn’t matter what we throw at you ,as you just deal with it" , a bigger compliment I can’t imagine.
The biggest challenge, as a senior pilot I/ we found was a loss of steering

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I had originally thought the stern going to port causing the ship to hit was the result of full astern. From the report that did not happen.

Wonder why the report did not mention wind /current at the time. Or was bank suction something usually expected passing under the bridge. The auxiliary channel opened to the north is shallow main channel deep, big ship recipe for bank suction. Or starboard anchor could have caused her to turn.

It’s possible power and rudder control lost she could have gone straight enough for a glancing blow instead of full on. Why she turned never mentioned

Because it’s the preliminary report.

That’s true but I wrote many situation reports in the Coast Guard and all required weather conditions. Sea state, Wind, Current etc. Its simple basic information, can have effect on liability though, complication out of operators control.

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Both. During the design stage a FMEA is prepared by the builder and a fault simulation test carried out during trials. For example, one of the failure modes is the loss of a HV switchboard due to internal short-circuit on bus bars. And here we have also an operational requirement, there needs to be at least one generator connected on each HV switchboard. And the vessel is provided with an Operating Manual explaining the redundancy features. Again, all this is voluntary, you may have a look at ABS rules, Propulsion Redundancy R1 and R2 notations. Or DNV RP notation. They cannot be applied to vessels with only one propulsion machine but at least the requirements regarding the electric power generation and distribution could be used to minimize the risk of propulsion loss.

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Got it and thank you for the explanation. You clearly know your stuff.

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But the DALI did not leave the dock with her generators configured such. Two online gens feeding only one side of the HV buss and then the connected LV transformer connected to the opposite HV bussbar. Any issue with the HV busstie and you have a black ship.

However I am aware that the ship did not go black because of an inadvertent opening of that breaker and the tripping of the breakers both supplying and exiting the transformer feeding the LV buss yet the ship was fitted to be operated with two independent HV busses feeding the LV board bur wasn’t.

The ship’s I worked on, with the engine stopped had bare steerage at around 3 kts. I think rudder force is approximately a function of the square of ship’s speed so I’d expect even with no engine the Dali to have steerage at 7 or 8 kts.

What I’m saying is presumably the NTSB has position, heading, speed and rudder angle data from the VDR. This is what it says in the report after power was restored the second time.

At 0127:23, the pilot ordered the rudder hard to port (35°). At this point, the
main engine remained shut down and there was no propulsion to assist with steering.

Somewhat ambiguous, doesn’t say they had control of the rudder but seems like mentioning that they had no steering would have been more relevant than saying there was no propulsion.