What have you been doing today?

[Nikhil Bhale]

Other aspect of the story is crew factor.
Commercial intrest demand reduction in crew size. Engine room crew will have 3-4 engineers (2 senior and 2 junior) and 1-2 ratings. At the time of incident the engine room will be manned by two engineers(1 senior and 1 junior)and one rating. Or the senior engineer will be on bridge and only junior engineer and rating in engine room. It depends on ship design.
This crew is sufficient during normal running of ship and ocean passage. But during restricted passage, in case of emergency you do not have enough people to run around. The duty engineer had to identify the problem and rectify it within minutes. You can always call off-duty crew for assistance but they will take time to arrive.

 

[GreenTwin]

My dad had a 118 foot river towboat, with twin diesels, I think they were 4 stroke.
They had shifting camshafts, and it took about 10 seconds for them to stop, get the cam shifted, and then restart running in reverse (there was no gearbox, just direct engine/propeller shaft connection).

Sometimes the engines would get on a dead-center, and they had to be restarted in forward, then stopped, then reverse attempted again.
They were air start, and there was a finite amount of compressed air for stopping and starting.

Approaching the dock would be rather concerning, especially when one of the engines got on dead center, and you knew there would be a delay in reversing.

And the hydraulic steering system on my dad's towboat actually failed one time, as he was approaching a major bridge (Murphy's Law I guess). The boat was going downstream with the current, but drifting towards the bridge, and the rudder did not respond.
Dad opened the throttles full, and missed the bridge by about six feet.

Rule No.01 of operating a towboat: Don't hit a bridge.

Dad rebuilt the steering immediately after that incicent.

Dad was not one to panick, and so that is what saved him.
He had his commercial riverboat liscense, and loved the river, and loved piloting boats on the river, and he did that his entire life.

A river with lots of commercial barge/towboat traffic on it is a dangerous thing.
I saw a pleasure cruiser go under the front of a barge when its engines stalled, which resulted in several deaths.

I learned to navigate the Mississippi River at night (frequently) with heavy commercial traffic present, lots of dikes, 7.5 mph current, etc. and lived to tell about it. I was a teen at the time.
It is a bit of an art. Sometimes it was a "thread-the-needle" situation between a large barge/towboat swinging around a bend in the river, and a dike, while avoiding the huge prop wash behing a towboat.
I had paper maps, and none of the modern electronics; just a spotlight which I occasionally used to verify a bouy.
There are no streetlights on the river.

Know thy maps as they say.

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[GreenTwin]

Other aspect of the story is crew factor.
Commercial intrest demand reduction in crew size. Engine room crew will have 3-4 engineers (2 senior and 2 junior) and 1-2 ratings. At the time of incident the engine room will be manned by two engineers(1 senior and 1 junior)and one rating. Or the senior engineer will be on bridge and only junior engineer and rating in engine room. It depends on ship design.
This crew is sufficient during normal running of ship and ocean passage. But during restricted passage, in case of emergency you do not have enough people to run around. The duty engineer had to identify the problem and rectify it within minutes. You can always call off-duty crew for assistance but they will take time to arrive.

As you mention, the engine and associated systems are not like an auto engine.
Everything takes time, and all the auxiliary systems generally must be functioning to support the engine operation/start-stop.

Problems may take minutes or longer to resolve, when you have seconds before things go wrong.

It does not pay to defer maintenance on boat equipment.

When electrical circuits start tripping, that takes time to resolve, and if the backup systems don't transfer correctly, that also takes time to resolve. Modern diesel generators can start and transfer in 10 seconds if all goes well.
A short in one generator could overload another one, and cause a cascading problem.

I got the opportunity to tour the interior of a 10,000 hp towboat engine room, and it is a marvel to behold, with a climate and noise-controlled control room, and a huge amount of equipment, piping, etc.

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[Lloyd-ss]

From my experience as a marine engineer I can contribute to "free" knowledge on internet.
Ocean going ships generally have a single main engine to turn propellers. It is generally 2 stroke reversible engine running at low rpm. About 150.
Aux blowers are required during starting of engine and running of engine at low speeds. They are in auto mode and will cut in or cut off depending scavange pressure.
Ships engine are not like car engine. You cannot rev from zero to full by pressing a pedal. Think about all the momentum that needs to be overcome.
There is a crash astern mode to operate engine where engine at full ahead speed is stopped, cam position changed and engine start and run at full astern speed. I have never seen this tested other than during sea trials.
Boiler firing will also cause heavy black smoke initially. All ocean going ships are equipped with auxiliary boiler for heating purposes.
One bow thruster is not enough to steer the ship of this size. They are mainly use to berth the ship and not for steering. Bow thruster are effective at low ship speed and their efficiency decrease as ship speed increases. They stop being of any use above 5 knots of ship speed.
Extra generators are always running during manoeuvering and restricted passage.
All ships have an emergency generator which should come online within 45 sec of power failure. This will provide power to essential consumers only.
Rudder is used for steering. Its effectiveness increases as ships speed increases.
My thinking is that the ship lost steering system due to power failure and the crew was not able to avoid the bridge. There is emergency steering provided but it requires manual operations. Time was a constraint here.

Regards
Nikhil

Nikhil,
Thank you for your insightful observations and comments.
---------------
There is one additional piece of information that I read that the state of Maryland has been upgrading the physical protection of the bases of its bridges, but had not gotten to this bridge yet.
---------------------
But, back to your comments and those of Greentwin. It seems like there were multiple failures of systems and back-up systems, either because they didn't work properly or because they could not be activated in a timely manner.
It appears that the only thing that might have saved this situation would have been already having a tug lashed to the side of the ship to power it through this bad situation. Thoughts?

I worked where one of the products we built was the hydraulic steering system for a class of Navy ships. The tillar for the rudder was moved by an 8" hydraulic double-ended cylinder operating at up to 5,000 psi. The quality control of all the welding was extremely exacting. And the guys who did the Tig welding of the stainless steel piping were absolute artists.! The system also had a smaller back-up hydraulic pump to power the tillar at a much slower rate. The manually operated Acme threaded giant bolt that ran parallel to the hydraulic ram, was more of an emergency locking device to disable rudder movement. Trying to steer with it looked impossible. The momentum of so much mass is almost unstoppable.
Lloyd

 

[GreenTwin]

I wonder about having tugs on either side or end of the boat, and whether they could fit in the channel along side such a large boat, and whether they would have enough horsepower to effectively steel/guide a large ship.

Obvoiusly tugs are used around the world, and according to what I read, tugs were used to debark and get this ship out into the shipping lane.
Someone said that once the ship was underway, then the tugs depart.

And someone else said the ship accelerated to 7 knots, which would impart a very significant amount of momentum to that much mass.

I have heard about tugs having 10,000 hp, but I am not sure if that is standard or not.

And I have heard of tugs in front and back, one pulling, and one perhaps dragging a bit, but I am not sure if this is standard proceedure either.

The passage under the bridge seems a bit tight, with the transmission line base supports somewhat limiting space for tugs and such.

I recall the analysis that went on after the Challenger loss, and the rocket engineer in charge of signing off on the launch would not sign the launch-approval papers. NASA launched anyway, and the rest is history. That engineer said in a later interview that he is extremely proud that he did not get pressured into signing off on a launch that he did not think was safe.

I have had clients try to force me to do things that were not safe, and I told them "I don't work that way, and never will".
They fired me, but that was good for me since I don't do anything I feel is unsafe.

I look closely at all sorts of incidents, since I do design work on high-value infratstructure, and sometimes I have to write a report when things go bad. My report can and has resulted in multimillion dollar judgements against insurance companies ($20M in one case), and you can bet that an insurance company will challenge everything you write and say, with a multitude of lawyers. Writing accident reports is very risky business, and one had better be correct, else one's career is over immediately.

I had a lawyer tell me that I was wrong in my engineering conclusions, and the fault was with another party, not with his client.
I told him under deposition "Well, you would be wrong about that, and I can prove it in a court of law", and I did.

You can get sliced and diced in court if you don't know what you are taking about.
Its much like jumping into a tank full of sharks. One false move and it is all over.

There will be some lawyers that get very rich over this bridge situation.
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Edit01:
Apparently there are some very sophisticated tug designs these days.
This source lists one tug with 27,200 hp.
The larger the hp, the large the tug will be, and that could limit where it could be used, ie: a large tug may only be usable in the open ocean.

https://www.marineinsight.com/types-of-ships/what-are-tug-boats/


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[GreenTwin]

Apparently they rig tugboats in all sorts of configurations.

After watching this video, I think that if two or more tugs had been rigged to the ship, it could have easily been prevented from striking the bridge.



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[Lloyd-ss]

I want to mention a more mundane topic.
I changed the oil in my 2016 Tacoma yesterday. I used to do all my own automotive work but the dealer we were involved with always did good work at reasonable prices. But everything is out of warranty and last time (the only time) I went to one of those drive-thru oil change places it cost me over $100. And I didn't get any of the fancy extras they offer you with a big smile.

The Tacoma uses 6.25 quarts of oil and it is only changed once a year. I got the oil and filter (good quality) for $28. Again, the first oil change job for me in maybe 10 years. But I am 73. Vehicles don't go into the garage. Had some big sheets of cardboard and a dirt parking spot at the garden. My oil drain pan can't hold 6.25 quarts so I had to put the plug back in 1/2 way thru. Like stopping mid-flow at the Dr's office trying to not overflow the cup and pee on your hands. I peed on my hands. Most of the drips landed on the cardboard. But the dirt was uneven, everything was tighter than I expected. Blah, blah, blah. At least I didn't hurt myself, LOL.

Was it worth saving $80? Yes it was. But if I had had $80 to throw away, I would have probably paid somebody. It seemed like a good idea, but times change. I will be more prepared next time.
Lloyd

 

[Lloyd-ss]

Greentwin. That tug video was fantastic! Thank you! And I agree, a couple of tugs could have (definitely maybe) prevented that disaster yesterday. And that series of harbors has to be loaded with tugs. (But I hate armchair QB's, so I will shut up.)

 

[Nikhil Bhale]

Tug boats are primarily used for berthing/ unberthing operations only. They operate within port limits and are known as harbour tugs. Tugs that operate in open seas for towing or salvage operation are called ocean going tugs. They are of higher power and size.
Generally tugs will unberth the ship and clear it of the port limit. Ships will then proceed on their own under guidance of a pilot.
Pilots are only to guide the crew in navigation but they are not responsible for anything. Master is wholly responsible for the ship. There were two pilots onboard. I think one was a port pilot and other was a river pilot.
If the ship was running at 7 knots then rudder would be slightly less effective in steering the ship. It is not easy to turn a 100000+ tons of mass. Think about Titanic. They saw the iceberg well before they hit it. It was difficult to steer clear of it.
Whatever the cause the poor crew members will suffer the most now.

 

[GreenTwin]

I have to think that the crew members have to deal with whatever corporate does to the boat, ie: how much maintenance happens, and when.

If the ownership company does not or is not required to do enough maintenance, then systems will fail, and that is nothing the crew can compensate for.

I have to think the crew did the best they could with a series of system/power failures.

If the crew was responsible for the overhaul schedule, then they may have problems.

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[Nikhil Bhale]

Lloyd I don't think couple of tugs could make a difference.
If the ship was moving at 7 knots think about the momentum.
Another thing is I don't know how long the ship was underway after leaving the port. If it was a long passage at night then fatigue sets in quickly.
I remember coming to Tampa and New Orleans. Some 12-18 hours of river passage with constant maneuvering orders from bridge for engine speed change were tiring like hell. Luckily new ship the engine is directly controlled from bridge.

Regards
Nikhil

 

[GreenTwin]

The ship had not travelled far after leaving the dock.

I would guess that it is not normal to have tugs escort large boats out of the harbor; there is really no reason to do that unless it is some sort of abnormal situation, such as moving a boat that does not have power.

From what I have read, a boat that size would have two main standby generators, and both would be running when leaving port.
I would guess one or two smaller critical load generators would also be running, but these would basically power critial lighting and navigation systems.

They are saying that to reverse the engine, it would require operation of the electrically powered auxiliary blowers for the main engine, with the aux blowers perhaps too large a load for a single generator.

So a trip on one generator could overload the 2nd generator.

In the video, the ship can be seen to blackout twice, which indicates to me both generators tripped offline, or stopped running.
It could be an alternator fault, diesel engine problem, transfer switch problem, or downstream power distribution problem.

To have both generators trip offline would seem to indicate that one generator fails, and that overloads the 2nd generator, and it also trips due to overcurrent protection.

They did appear to get the main engine reversed finally, which I think is the black smoke caused by by full reverse throttle.
Large diesel generators will also "blackstack" upon startup or large and sudden load changes.

All these ideas are mere speculation; not based on any know facts, but it will be interesting to compare these ideas with what comes out of the analysis that will happen eventually.

I design large diesel generator configurations for critical infrastructure, and there is a lot of thought given to reduncancy and critical paths.
I specify transfer switchgear with interchangeable drawout breakers, and bypass function, but those operations (drawout or manual bypass) occur over minutes, not seconds, and they require physical intervention.

100% reduncancy is important, as is duplication throughout the entire system chain, such as totally separate and isolated power sytems, wiring, transfer switches, etc.
I have had to deal with industrial processes like hydrogenation of oil, which involves injecting hyrogen under pressure and heat.
Loss of power can cause the process to go exothermic, with a catastropic failure.

Oil refineries are another area where redundancy is critical, since that process can also become unstable upon power loss.
Refineries typically use high-resistance grounding, to avoid a nusiance trip during production, along with a lot of redundancy, and some very reliable incoming power circuits, often fed directly from a large power supplier.
A power fault causes an alarm condition, but will not trip a breaker.

In power system design, you have to decide if more damage will occur with or without a breaker trip, and then you design accordingly.

The circuit breaker for fire pumps is designed to run the pump motor until it fails, because if the building is already on fire, then burning up the pump motor does not really matter.

A generator problem on a boat is going to trip an overcurrent device if a problem occurs, so you don't create a fire inside the boat.

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[Nikhil Bhale]

This is a container ship. Its normal electrical load demand is high because it carries several thousand refer containers. Generally these ships will have 3 or more generators of 1500-2000kW capacity each at 1000V.
Blowers for assisting main engine are big but I don't think they will exceed 100kW individually.
During port arrival or departure 2 or more generators will be running with atleast one generator on standby.
Ships run on 3 phase power with a floating neutral. Earth fault on any device will activate an alarm but no trip. All the machinery are duplicate with one running and other standby. Steering gear motors have no overload trip only alarm so that they can keep running in emergency situation. Heaviest consumer is generally bow thruster of around 1000kW.
Another problem may be fuel. It may be fuel quality or contamination or supply problem.
I had faced similar problems due to fuel contamination. Our ship was in Singapore straits coming from Japan to middle east. It is busiest shipping lane and we had a total blackout there. Problem was sea water contamination in our fuel tank due to leakage from ballast tank. Luckily nothing happened and we anchored safely.
Also now a days ships have to change over fuel when they arrive at port. They have to change over from heavy fuel oil or HFO to low sulphur diesel oil. These systems gives problems sometimes.

But these are all speculations and truth will come out after investigation.

Regards
Nikhil

 

[Steamchick]

Most Interesting! Having design circuit breakers for 33kV to 500kV (Main transmission line protection) I understand how they work, but know nothing of control systems around generation and usage of electricity. (Also designed and installed Busbars from 440V to 33kV, and Cables up to 1200kV DC).
So this was very interesting.
All I did yesterday was confirm my latest iteration of a boiler Safety Valve released fully at 30psi in my slave boiler. Confirming the valve design and spring setting. Next I have to change a dead weight for a valve, as I need a different setting on a boiler using a dead weight Safety Relief valve after re-working a boiler to latest design calculations. Slightly easier problems than Electric generation "safety trips"!
K2

 

[timo_gross]

Took day off from work today. Went to Taipeh to the Machine tool exhibition. "Expanding my whish list!"
Found some companies that make grinding discs in hobby workshop quantities of one.
Supplier for carbide blanks close to my home, is willing to sell to hobby guy.

Besided free catalogues everything seems to be expensive.
A sinker EDM in "hobby workshop size" . 60cmx80cmx150cm foot print plus cooling tank.
Work table 180x100 mm (7"x4"), table travel 5"x4". Cute machine. I wonder how much it will cost.

 

[anday1]

here's my Stuart twin launch 99% finished

 

[GreenTwin]

This is a container ship. Its normal electrical load demand is high because it carries several thousand refer containers. Generally these ships will have 3 or more generators of 1500-2000kW capacity each at 1000V.
Blowers for assisting main engine are big but I don't think they will exceed 100kW individually.
During port arrival or departure 2 or more generators will be running with atleast one generator on standby.
Ships run on 3 phase power with a floating neutral. Earth fault on any device will activate an alarm but no trip. All the machinery are duplicate with one running and other standby. Steering gear motors have no overload trip only alarm so that they can keep running in emergency situation. Heaviest consumer is generally bow thruster of around 1000kW.
Another problem may be fuel. It may be fuel quality or contamination or supply problem.
I had faced similar problems due to fuel contamination. Our ship was in Singapore straits coming from Japan to middle east. It is busiest shipping lane and we had a total blackout there. Problem was sea water contamination in our fuel tank due to leakage from ballast tank. Luckily nothing happened and we anchored safely.
Also now a days ships have to change over fuel when they arrive at port. They have to change over from heavy fuel oil or HFO to low sulphur diesel oil. These systems gives problems sometimes.

But these are all speculations and truth will come out after investigation.

Regards
Nikhil

The contaminated fuel is a very plausible explanation for having repeated total power failure.

An article yesterday mentioned that the ship was having electrical problems before it left the dock, such as perhaps breaker tripping problems? (not sure).

So another possibility is too many refrigerated containers were added, overloading one or more generators.

Often the problem is a cascading one, where one or more smaller issues combine into a larger issue, which dominos into a very large issue.

All just idle speculation at this point.

Edit01:
Reports of multiple alarms from the ship's blackbox.

One good feature that I am seeing (and specifying) more and more on electrical equipment is trending/event capture features.
This event capture is extremely important when one is trying to recreate the minor events that often lead up to a major event.
My clients specify smart controllers all the way down to individual motor control center buckets, and so you can figure out which motor tripped offline, and why, such as was it because of an overload situation, a short circuit, ground fault trip, etc.

Event capture is probably one of the most useful advances in electrical technology that has occurred since the advent of modern power distribution systems.

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[KellisRJ]

Looks very spify! Fun video, nice shop. Great set of successful subprojects!

here's my Stuart twin launch 99% finished

 

[Sprocket]

On my way to “work “. I Ski Patrol a couple of days a week, l guess we’re going to get some snow later today .
At least this time of year it doesn’t last long.
Doug

 

[Lloyd-ss]

View attachment 155090
On my way to “work “. I Ski Patrol a couple of days a week, l guess we’re going to get some snow later today .
At least this time of year it doesn’t last long.
Doug

Very nice. Beautiful sunrise. I understand the need to capture the moment. Looks a lot like where I live, but that is my sunset view. Do you have the firey sunsets to match?
Lloyd