Eng-Tips is the largest engineering community on the Internet
Intelligent Work Forums for Engineering Professionals
Baltimore Bridge collapse after ship collision 125
- Thread starter Tomfh
- Start date
-
11
- #41
Pretty sure piers are NOT designed for a fully loaded container ship to impact them, regardless of speed. Let's be more judicious on the whole "defective design" folks. Find a referenced standard and know what you're talking about, please.
As a side note, if that Sunshine Skyway is the bridge in Tampa bay that fell due to a "tug impact" that tug impact was during a Hurricane. They blamed the pilot for a long long time until he finally prevailed.
As a side note, if that Sunshine Skyway is the bridge in Tampa bay that fell due to a "tug impact" that tug impact was during a Hurricane. They blamed the pilot for a long long time until he finally prevailed.
DAVIDSTECKER
Mechanical
Watching the Full Video from the 3rd post, I think the fatal error came after they regained electrical power the first time.
Two things to watch is that there was no smoke before the power outage and the ship appeared to be moving in a straight line.
The heavy black smoke didn't appear until a few seconds after power was first restored.
I think that when they regained control of the main engine, they put the drive in reverse and gave it full throttle.
This is a single propeller ship.
Besides the forward and reverse thrust there is a side force that come off of the propeller that pushes the stern to the side.
If you watch the hull closely, you can see it start to turn not long after the smoke starts.
I think that this is due to the side thrust, causing the ship to Dog Leg around the Dolphin protecting the bridge pier.
Two things to watch is that there was no smoke before the power outage and the ship appeared to be moving in a straight line.
The heavy black smoke didn't appear until a few seconds after power was first restored.
I think that when they regained control of the main engine, they put the drive in reverse and gave it full throttle.
This is a single propeller ship.
Besides the forward and reverse thrust there is a side force that come off of the propeller that pushes the stern to the side.
If you watch the hull closely, you can see it start to turn not long after the smoke starts.
I think that this is due to the side thrust, causing the ship to Dog Leg around the Dolphin protecting the bridge pier.
lex...not a tug, and not during a hurricane. It was the MV Summit Venture and was an old bulk carrier if I remember correctly and it happened in May. Hurricane season starts in June. A squal, yes, but not a hurricane. (As long as we're asking everyone to be accurate...)
I grew up in St. Petersburg, love the "new" bridge. I had a picture of it on my office wall for a long time.
I grew up in St. Petersburg, love the "new" bridge. I had a picture of it on my office wall for a long time.
Tug may be able to add something to this... but, I think that at that time, it was already too late.
-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates
-Dik
DAVIDSTECKER
Mechanical
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/raw/upload/v1711482445/tips/Doc1_bljcsu.docx[/url]
The ship appeared to be on a pretty straight course until something acted on it.
The ship appeared to be on a pretty straight course until something acted on it.
DAVIDSTECKER
Mechanical
Link to ship tracking site.
"Pretty sure piers are NOT designed for a fully loaded container ship to impact them, regardless of speed. Let's be more judicious on the whole "defective design" folks. Find a referenced standard and know what you're talking about, please."
Well, yeah. That's why they put fenders around them. The fenders around the San Francisco Bay Bridge protected the piers from the Cosco Busan, in 2007. A fully loaded container ship, as I recall. One could even think that they were NOT a defective design.
spsalso
Well, yeah. That's why they put fenders around them. The fenders around the San Francisco Bay Bridge protected the piers from the Cosco Busan, in 2007. A fully loaded container ship, as I recall. One could even think that they were NOT a defective design.
spsalso
- Thread starter
- #48
TugboatEng
Marine/Ocean
This ship is likely twice as heavy as the Cosco Busan. Ship sizes have increased astronomically over the last 10 years. Bridge fendering, even if present, would likely be obsolete.
Dik, it's possible a steering command was given and then the power failed. The rudder should hold its position for some time, moving slowly due to hydraulic leakage. Modern ships often use rotary vane steering gears which can be quite leaky vs the Rapson slide types.
If they did experience a steering gear failure it is possible they were attempting to use the bow thrusters to steer the ship with insufficient generating capacity on the bus. This could cause the brown out and black smoke.
Dik, it's possible a steering command was given and then the power failed. The rudder should hold its position for some time, moving slowly due to hydraulic leakage. Modern ships often use rotary vane steering gears which can be quite leaky vs the Rapson slide types.
If they did experience a steering gear failure it is possible they were attempting to use the bow thrusters to steer the ship with insufficient generating capacity on the bus. This could cause the brown out and black smoke.
-
1
- #51
dik, you also have to realize that, despite the size of these ships...the crew is really small. 20-30 people. So there's not a lot of man power to go around in a time sensitive casualty. In the Navy, we had a 'special sea and anchor detail' that would be set when entering or leaving port for situations just like this. But we had a lot of extra people. So we could spare an extra operator to stand next to the manual override to manual crank the rudder over if it came to it. I had to sit at one of the emergency switchboards to shift one of the emergency diesels onto the bus if needed. But we had more than 100 times as many people on board.
So yes, there are ways of correcting for it...but the crew on that ship probably wasn't in the right place to do it fast enough.
So yes, there are ways of correcting for it...but the crew on that ship probably wasn't in the right place to do it fast enough.
- Thread starter
- #54
Just Some Nerd
Structural
Completely unverified claim but I did read that smoke like that occurs when trying to start the engine. No idea if true
----------------------------------------------------------------------
Why yes, I do in fact have no idea what I'm talking about
GregLocock
Automotive
" Thus the pier structure has almost zero resistance against such impact." Your assignment is to design a concrete structure resistant to a the momentum of a 100000 tonne mass moving at 8 m/s. Let us know how you get on.
Statements like the one quoted do not belong on an engineering forum.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376
Statements like the one quoted do not belong on an engineering forum.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376
TheGreenLama
Structural
What are the harbor protocols when a ship of that size loses power within a harbor area? Are they immediately required to contact the harbor authorities?
LittleInch
Petroleum
Actually only moving at 7.5 kts = 4 m/sec.
But these vessels are just ginormous.
A bridge is always going to be at risk of being hit by a vessel. There were protection structures but the vessel turned just at the wrong moment. You can only deflect, not stop.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
But these vessels are just ginormous.
A bridge is always going to be at risk of being hit by a vessel. There were protection structures but the vessel turned just at the wrong moment. You can only deflect, not stop.
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
That's what I'm wondering. At the time of the power failure, was it already to late to avoid the collision? ... even if they were in the right spot at the right time?
-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates
-Dik
Fenders are not supposed to stop a ship. But that is the purpose of dolphins, a significant distance from the pier. The ship varied course quickly and missed the dolphin. The dolphin may not have held either. Current methods would be to build a subsurface island around the pier to ground a ship before it hits. But this channel is quite narrow. May not be room for the island.
Now is the time to reconsider tunnelling. The bridge is a write off, and may no longer be the best solution.
Now is the time to reconsider tunnelling. The bridge is a write off, and may no longer be the best solution.
Similar threads
