Seems like it points towards some kind of fuel problem/issue.
To me, this a steering event, at 7 knots, 1000 yards from the bridge- you can stop the motor, sound all the alarms you want, if I have rudder control I am good.
So with all the talk of beefing up the bridge protection and adding tractor tugs.
Is there a better possible solution to maintain or get back rudder control in 2-3 seconds. Something better than the emergency generator
Seems something could be engineered to do that
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Well yes. There’s battery IPS gapped diesel powered systems, stupidly big pressure accumulators, and maybe even something practical. I want to have a discussion about it, but figured it might be good to let the noise die down first.
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Why not discuss this now?
A UPS to keep steering pumps running is worthwhile if big enough to keep those pumps going until the EDG starts.
A diesel to direct drive a steering pump would need to be running to be immediately effective
Pressure accumulator bottles would also be effective but as you say would need to be huge.
Regardless of what method was used, loss of steering needs to be reduced to such a short interval that a helmsman never senses a loss of steering and further it needs to be such that nobody take a particular action to regain it. All of this is very achievable but will cost the shipowners money to retrofit
At 7 kts. speed “though the water” you have steering control, but when you loose engine power the speed will drop below “steering speed” fairly rapidly. How rapidly depends on the type and size of ship, load condition, current direction and speed etc.
Since bridges tend to be across inlets or rivers currents varies greatly but in this case current was apparently following (rate not known) so the ship would have maintained a fwrd. momentum (SOG) of some velocity even without power.
To get back steering power in 2-3 sec. and/or engine(s) that can be restarted on EDG power only, MAY be possible to engineer.
How long before it could be made mandatory for all ships over a certain tonnage? (Starting with ship built after a future date TBA)
As I said in a earlier post; to mandate protection for bridges is a national (or even local) decision.
That can be based on local conditions and risk assessment for each bridge even.
To change how ships are built, equipped and operated is an international affair and will take decades to implement.
You can make rules for ships flying national flag, or even for foreign flag ships to be allowed to enter your ports, or territorial waters.
To be efficient such rules have to be accepted by shipowners worldwide:
I have no local knowledge but based on the tidal range in that area, the speed of the current wouldn’t be very high. Maybe yacht sailor can confirm this.
What may have happened here is that the data sources for the VDR stopped sending data due to the blackout and thus, the VDR recorded no data during the blackout of the data source(s) (controls and instruments). If that’s the case then, either those controls had no UPS/battery backup, or the UPS failed. It’s also possible that someone power cycled the controls in an attempt to get things online/restarted.
The current would normally be 0-2 knots or so at most.
For some reason my current display doesn’t show the harbor, but the Bay just outside was about at slack current. I would not think they had a current of more than 1 knot.
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Working from how aircraft are set up, the systems you all have described would be considered NUTS. Too many things that have to happen after the fact. I’ll admit the biggest engine I have ever dealt with was on an old tugboat, so lots I don’t know, but if I got put in charge of steering engine design it would have 2 totally independent systems that were ALWAYS on in pilotage waters, only physically jamming the rudder would disable steering. A steering failure would not even be noticed except for an alarm you were down to one system.
On the other hand making a better bridge and hiring some tugboats is easier than redesigning every ship on the planet.
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Good point, but how do you segregate them? Nothing on a ship is ever totally independent, in the sense that fuel is ultimately drawn from the same bunkers. In many ways a dedicated diesel pump for the steering gear makes sense, I think such an arrangement was even described above. Engines in this size range (up to a few hundred kW) can be brought online in a matter of seconds, and it could run off an almost-segregated fuel system with a day tank of known good dfo good for a few hours.
Simply having enough pressure available if a pump shuts down to take a rudder from being over to one side and bringing it back to center may very well have prevented this accident from occurring.
I still say that the absolute best way to prevent something like this is that ships of a certain size would be required to have an escort tug made up which could either steer a ship or stop it just like loaded tankers are required to have and screw the cost to the ship operators for such a requirement
Depends on the specific installation. I was on a ship that grounded in the Columbia River after part of the linkage of the steering gear became disconnected with the rudder hard right, the two simultaneously operating steering pumps effectively cancelled each other and we could not move the rudder from hard right.
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There is little current in Baltimore Harbor.
The Patapsco River is basically a drainage basin. A wind driven current is usually stronger during a WNW or NW blow.
Up the Ferry Bar Channel (Middle Branch) to the south and west is where the actual river starts making its way inland toward Ellicott City, the original Port of Baltimore during colonial times.
Heavy rains will cause a freshet out of the Inner Harbor (Northwest Branch) and the Middle Branch.
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Ships are affected by both wind and current. Container ships like the MV Dali (with high deck cargo) have quite a large windage area as well. (I don’t know the actual conditions at the time)
My point was that to maintain steering speed require engine power and a certain water flow across the rudder(s)
Even with engine stopped and “dead in the water” a ship may make speed over ground.
From the fuel side of things, it’s not likely that they were doing any sort of fuel change. They wouldn’t be able to run on VLSFO until they were 200 miles out unless they have a scrubber, then it’s 12 miles out. Unless they have an automated fuel changeover system and accidentally hit the button, I just don’t see this happening.
Additionally, the odds that the fuel in the EDG tank was the same as the fuel being used in the generators and main engine are pretty slim. While they do come from the same storage tanks, the EDG tank is usually kept full and topped off when it drops below a certain level.
So, a plausible situation that I could see involves the possibility that the quick close valves for the fuel system were tested during the port stay. I don’t know for sure what steps the crew would have followed doing so. I typically do one zone at a time and reset each zone once I’ve verified that each valve in the zone operated properly. I have seen valves that didn’t reseat properly. There are a couple of designs I’ve encountered where it’s difficult to visually confirm that the pin has fully reset and I’ve had one loss of propulsion where a pin that wasn’t seated fully allowed the valve on the ME day tank to drop closed.
A scenario where the EDG quick close valve wasn’t reset and the fuel tank supplying the generators vibrated off the pin and shut off fuel is possible. There’s usually enough residual fuel in the generator lines that you’d likely get a start and a short run before it starved itself.
On the topic of currents, wasn’t low tide at 0200?
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Thank you for sharing that profound analysis. My point was that there was insufficient current to affect the ship’s trajectory after losing power/steering.
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If the UPS was no good then how was the VDR recording bridge audio?
Also, IMO Resolution MSC.333(90) states that when both main and emergency power are lost then the VDR must be able to continue to record bridge audio. It seems to me like the VDR operated exactly as required.
The timeline of the audio only portion of the VDR recording lines up pretty close with the AuxGen power outage and actually provides evidence that the EGen never came on line.
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I find this VERY plausible. The ships anniversary date is March 4th so they may have recently done annuals (were they done in Baltimore?) where the quick closing valves would have been tested.
I have seen it very often where the EGen qcv is tested after the engine is run. The valve is reset and everyone leaves. How do they know it was reset right? You don’t until you run or test the qcv the next time. I took over a boat a while back and found every single qcv on the boat reset incorrectly. I have seen people reset them incorrectly right in front of me. I always test and reset the EGen qcv before I test the engine as a check.
When were the bollards that was supposed to protect the bridge pillars installed?
If not from when the bridge was new, was this done based on a risk analysis, taken increased size of ship calling at Baltimore Port into consideration?