WHY NO Tugboats Dali Ship? Baltimore Bridge Collapse
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- Опубликовано: 16 май 2024
- Your questions on the Baltimore Bridge Collapse of the Francis Scott Key Bridge after being hit by the Dali container ship. If you wondered where were the tugboats, or why the Dali ship steered directly into the pillars of the Key bridge, this will all be discussed here.
00:00 2 NEW Alternate channels established at the Key Bridge collapse site
02:03 Controversy over new channel depth: 11 feet or 11 meters?
04:50 Why did the Dali ship turn into the bridge pillars?
08:42 Why were there no tugboats to guide the Dali ship past Key Bridge? 
Хобби
That's why you're an engineer. Engineers have to be accurate. . . . From a fellow engineer who has to be accurate.
Absolutely!
Just have to know what the safe side is and be on that one.
Really if I need to do 46 pillars i don't calculate every one of them. Just the one with the most load. Posibly one more ifnthe diffrance is large.
Even if I did calculate every one, the costumer would just be pissed that they are all diffrent
When I was designing the layout of British motorways, I had to work to an accuracy of 1/1000 of a millimetre - everything went fully metric on 1/1/1968, except for the distances shown on signs. Somebody thinks that’s hilarious - it wasn’t for me ! No computers back then.
thing is..... it was definitely more than a 15 degree turn per the video. Its a 45 degree turn from what i am looking at.
A ship that large cant kick out that quick in calm water
it was powered into the turn
@@ronniel5941 no one using metric ever actually uses metric.
57.3 mm ehh 60 mm is close enough send it off
People love to point the finger at anyone/anything before getting all the facts. Keep up the good work Jeff.
Great Info Jeff. Here is a little of my insight on big ships and what happens in events like this:- Ships steer like hospital gurneys with castor wheels. The stern moves to change course (that's where the rudder / propeller is) - not the bow. If the blackout occurred when the helm was to stbd (during minor course adjustment) the steering gear freezes without power. The stern moves to port (due to the 'hospital gurney' effect). If the Port anchor is dropped as the stern moves to port during this time it will drag beneath the keel further exacerbating the turn to stbd.
The helm is being constantly adjusted by the helmsman or the autopilot when is tight channels. However when the power goes out the steering pumps stop working and the rudder freezes at the last position until the emergency generator starts. Even if the helm was at a minor, say, 5 degrees to stbd momentarily when the blackout happened it will be a full minute before the power was restored. Without the propulsion engine providing enhanced flow over the rudders the ship will continue on the same course at 6 knots for some time even with the helm hard to port due to the 'sail' effect of the high containers .
The emergency generator starts about 1 minute after blackout I believe that is the black smoke as it will come "on full load" very quickly. It can power the steering gear but is not big enough to power all the propulsion engine auxiliaries. Therefore the main engine cannot start in reverse at this time. The main generators must be used.
To source and correct the initial blackout problem then get the main generators back "on the board" takes time. Only then can you re-start FW, SW, LO pressure, LO scavenge pumps and fans, blowers etc etc in sequence BEFORE you even can think of starting a four deck high, MAN B&W S90ME-C8-TII, 47,000 BHP, 2 Stroke diesel in reverse. The propulsion engine likely never restarted before the crash.
Hogwash …
Dropping either anchor while already drifting off course is going to eventually result in a pirouette, usually in the opposite direction to what was intended. For the first 90 degrees, the turning effect is increasing. The anchor is still in place, it will be easy to determine from the angle that it was turning the ship to stbd, not port. The question is, by how much?
@@justinsmith2363 it's not like those supports are that far apart. I would guess less than 1,000 feet, which only leaves a few hundred feet of clearance on each side if they stayed the correct course. If this power outage happened a minute later it would have been a few thousand feet farther ahead and beyond the bridge, instead of a few hundred off course up near the bridge.
The Emergency generator should still power the rudder commands. Rudders are much less effective when the amount of water going over it decreases (like a wing) with the propeller stopped it takes a lot longer for the ship to turn which they did not have.
@WilliamLHart Damn, it's so nice when we have educated people in the comments. Thanks for these informations =)
First discovered Jeff’s channel last summer while following the Oceangate catastrophe. You and Sal are the go-to guys on the Key Bridge. Thanks for all you do!
Same for me : came for the sub, then I subbed 😁
Great job Jeff! Thx for the update
Thanks for watching!
Jeff, Monty Python called they want their animation back.😂
Great update as usual!
1) Pour some water into a tub. Doesn't have to be deep, just as long as you can push something all the way along. 2) Get something that floats - empty pop bottle, for instance. Put it in the water so that it's floating. 3) Push it along a little.
Notice how difficult it is to keep it going straight? Now imagine doing that with a 150,000 ton cargo ship. You need to make constant course corrections to keep the ship on course. When the power went out, the ship went adrift. It was either going to turn port or starboard, no matter what, and given the relative narrowness of the channel, hitting the bridge was extremely probable.
Much appreciate your engineer’s report. I’m a retired civil engineer from Washington State.
Your videos are so interesting, thank you!!
Jeff, continued "thank yous" for your ongoing updates of this tragedy and recovery process. I never once doubted your 11' assessment. I knew you were right and even heard others later reporting the same fact. Keep up the good work. We know you have only accurate info for us!
Jeff thank you so much for bringing understanding to this tragic situation. Your explanations are simplified and detailed.
Thanks again Jeff - looking forward to the next update!
Hi Jeff,
this was the first time I've haerd and seen such a detailed professional analysis of this accident !
Thank you for it !
Thanks Jeff for doing a fantastic job reporting on this Mishap. You've always done your work on these engineering failures. Haters wil always open their pie holes about your great work. In the end, You're always right.
Thank you Jeff for the update information and the great news Nice work 👍👍👍💯
Thank you for covering this.
Truly excellent work. Thank you very much.
Bad maintenance trumped excellent shiphandling.
I remembering reading somewhere that the smoke you see right before the Dali turns was a full reverse input order but the rudder was stuck in the wrong direction from loosing power just before that. That caused the ship to rotate the wrong rotation. Every time the ship lost power the rudder input gets locked in that position. Great videos Jeff
Single screw ships tend to 'crab' their stern to the side when reversing the propeller. This can be more thrust to one side than even a working rudder can overcome.
Not one of these so called experts has brought up a possible rudder malfunction. Why is that? Are they really experts?
@@mikefochtman7164 then why would they order full reverse? Did they think they could stop?
@@keyjam9 The investigators will, I'm sure, be reviewing the pilot's and captain's decisions around just this sort of thing. The engine orders and helm orders given. But I'm sure if that smoke was from a 'full astern' order, the position of the rudder became pretty much irrelevant.
@@keyjam9The steering gear has a vast amount of redundancy. Certainly a loss of both normal and emergency power would stop it functioning. But there doesn't seem to be any reason to think it was far from amidship just before power failure (it would fail 'as-is'). And it's long recognized to be vital equipment so would have been restored just as quickly as the main engine. It may have failed, certainly investigators are looking into that as well. Just saying, full-astern can push the stern aside just as effectively as a hard over rudder.
Hi Jeff, i'm the guy that asked if it was the anchor. I watched a retired ships engineer @ Retro,On his bikes. His explnation is that when looking at the ship from the rear when the ship is under way the props turn clockwise, so when the Captain ordered full astern and because the ship was riding high the props would pull the rear of the ship to port. I also think that if when under way and the props tend to pull to sarboard the rudder would compensate and when full astern was ordered and the rudder wasn't adjusted that would just exacerbate the situation and move the ship even further to port.
your rudder doesn't do much when going in reverse. if your in a situation that you need to order full astern you are already Fu*****. You never need to know that information because you should never be in that situation.
I also think it was the anchor dragging and pivot point. If the stern beam crossed the anchor chain it would not matter if the anchor was to port or starbord.
At 8kts and 95,000 tonnes the momentum and achored chain could have turned the Dali starboard directly into the vertical column allision.
@@Carlos-im3hn AT 8 knots and 95,000 tons if you have to use your anchor to stop your ship, your screwed. You’re gonna hit. The difference in speed in this case was so negligible the ship was still going to hit the bridge. Just not enough time to stop the ship no matter what the captain or pilot ordered. This situation and all who have their theories can debate it for years and no solution given/recommended could a, or should have will prevent the ship from striking the bridge. Just not enough time between restoring power and getting speed back up to minimum steerage way. the Master/pilot just ran out of time to prevent the disaster.
Even if the tugs could do 20-25 kts which is way above commercial operating speed which can be disregarded in some cases such as this one but tugs are geared for torque not speed and all the engines have safety governors that are very hard if not impossible to override. Who said a tug who even manned and in service at that time. If it wasn’t it would take a minimum of 3-5 minutes to board the tug, start the engines, bring all systems online and get underway. These aren’t jet skis or small fishing/pleasure boats one person can’t hope on the boat cast the lines of a pray the engines start right up.
@@Carlos-im3hnI’m fairly sure the anchor had an effect… it did lose speed…
Good to see two channels, hopefully one will be open to recreational traffic soon.
I hope so too! But I doubt the Captain of the Port will allow it
Recreational traffic is the last thing they need. They don't need a bunch of amateur boaters screwing around the harbor or wreckage. On the list of 100 things to do, opening the port to recreation is number 98, they are currently on number 2.
If a ship has a single propellor, when it goes astern the propeller 'wash' moving forward against the hull will thrust the stern to the side, regardless of rudder order. A right-hand screw going in reverse while the ship is still moving forward (in an attempt to stop?) will thrust the stern to port (i.e. will turn the ship to starboard).
I think that plume of black smoke was the engine being restarted and put in full reverse. It may have slowed the ship, but it also swung it to the side, aiming it right into the southern support pylon. (IMHO).
The drive shaft and propeller together weigh over 100 tons for a 300 meter ship. They rotate at around 100 revolutions per minute. The drive shaft also has no gear and cannot be disengaged or braked. A brake would get way too hot with that weight. Basically you turn off the engine and turn it on again when the propeller stops. This time with a different direction of rotation of the motor. If you're half throttle there, it'll probably take around 4 min. take time until the engine stops. Also the propulsion slows down the stopping of the engine.
In my opinion, several factors came into play for the change of course. The drive and rudder failed for over 90 seconds and the current. Also it took a lot of time until the rudder, which weighed several tons, was moved after the blackouts. It also took some time until the engine had more thrust again after the blackouts. During this drifting phase, the underwater current from Curtis Bay caused the ship to turn. The anchor and bow thruster have no effect at this speed.
About 20 seconds before the impact, you can see the ship slowly turning back to its old course. But by then it was already too late. With the wrong rudder position and the propeller running backwards, the change of course at the end would not have been possible.
See this is actually a reasonable explanation. I wasn’t thinking it was some huge conspiracy. Definitely some r questions that need answered. This makes total sense though
@@muratti72mucway better explanation than this video that doesn’t address any of this…. I was thinking some thing seemed strange. But this actually makes sense
No it doesn't
@@muratti72muc
I think they were trying to restart the engine for forward movement to get the steering back which would be quicker than trying to reverse since this vessel is direct drive.
Why I love your channel Jeff, you always make sure you go by the facts given!! Much Love Keep up the good work!!
I appreciate that
Much love ? get a grip for god sake, this is Baltimore not San Francisco
I think too, that perhaps when the current from the other channel hit the stern of the Dali that perhaps a bit of momentum was generated which might have caused the stern to keep on swinging even after it was past the other channel. I love your videos!
Thanks for this informative video. Love the Hello Dolly clip!! Very good 😊
I have just recently discovered your channel and it never crossed my mind that any of your statements were questionable. I will continue to follow your channel very closely and appreciate what you are doing in accurately reporting on this tragedy.
Thank you
Thank you, nice job with good images and great resources. 🍻 from 🇨🇦
Thanks.
For telling us about the cross currents and tug boats.
Good explanations. Sticking to the facts is the only way.
One of the better more factual briefs I have heard. Thank you
What surprises me is that the tug situation was in the news the day after and it's still coming up.
Thank you for this explanation.
Thank you Jeff!!
Soooo glad that you're continuing coverage on this. Rest In Peace to all six who perished. They definitely SHOULDN'T build another truss In my opinion, I really like your suggestions on how they should rebuild
Great info thank you again!
6:00 The turn was because of the single screw propellor switching directions into full reverse. It works like a wheel. Called prop walk.
Jeff, you can look up the tides and winds for the time of the accident on the NOAA site. Winds at 143 degrees (on the nose) at 1-3 kn, and tide in ebb with a 1 foot change so if anything, advantageous. Neither an issue in any way. No way a cross current from the bay was acting against the tide…
PS: good early catch on the port log showing breakers tripping from the reefer units. E-Sysman now confirming, with an interview.
Funny that. E-Sysman also stated winds South Westerly, not North Easterly and clearly seen by the black funnel smoke, wind is more than 1-3 knots.
@@TA-wg9oi remember I’m citing NOAA observations, not trying to be an expert here… the dock electrical situation now has two sources. Nothing official nor publish/broadcast media.
@@markstevens1729 I just find it amazing that all of this was easily avoidable.
Most ports around the world have tug escorts especially where infrastructure as feeble as a steel arch continuous truss bridge is so close to a port anyway!
It's common that a ships vulnerability is at start up and leaving ports more so than at sea or entering ports after weeks at sea.
An accident waiting to happen.
I don't believe the 1-3 knot claim. That night they reported 7, and that seems more realistic, because we'd had quite a lot of wind in the week leading up to the accident.
I do believe them going into the wind, one of my speculations was a port side bow incoming wind which would cause the ship to turn harder the more the ship rotated.
@@Redslayer86 then take it up with NOAA. They have no reason to fudge any number.
Thank you for the update l was wondering about the Tug boats.
As a Captain, the vessel left around slack tide water, there was no current, the vessel turned for another reason that I'll cover in my next video 😊
Lmao!!!!
There had to be some current. And, the wind was blowing pretty good by looking at the smoke coming out of the ship and the way it goes sideways coming out of the stack.
I thank you sir for sharing your wisdom. You inform me with real love knowledge then most by your accurate assessment. Have an awesome and blessed day I do enjoy watching.
A 100,000 ton ship going at eight knots should have enough inertia to continue on a straight path, despite wind and currents. Per Newton's law of motion an object will continue in motion unless acted upon by an exterior Force.
One theory is that they should have just gone full speed ahead, instead of throwing it into reverse, which may have caused the rotation of the ship.
Yes, well, that ship was acted being acted on by wind, water, any currents, the force applied by the rudder being in any position but absolutely straight, so there were multiple forces acting on it. The ship was not on a frictionless surface in a vacuum.
"Assume a spherical ship on a frictionless surface..."
@@keith6706 the power of a 100,000 ton ship traveling at a speed of 8 knots is approximately 2,059,176 horsepower. I doubt whether the prevailing wind and currents at the time would have been enough to throw it off course.
Love your videos Sir. Started watching your content with the Titan disaster. Then went back and watched all your other videos. As a former Detective I love your investigations. Keep up the excellent work!
I read from several different news sites it was 11 feet. If it was 11 metres, it would be 36 feet. If I *did* think it could be 11 metres, there is no way I would leave you a comment without getting evidence from at least three other sources. Even then I could still be wrong, because we are all figuring out more every day.
I don't have the patience to fight with people online, especially when I have more experience than them. I have been watching your channel since the Surfside collapse, and then watched others as well, and you always put so much time and research into them that you are the best I have found. And funniest!
All USCG Maps are in ft so I don’t know why people are arguing that it’s meters… maybe non-US commenters?
The sources need to be independent, which is really difficult to get in this era of low budgets for reporting. This is a big enough event to have multiple independent sources, but many times, articles look strangely familiar, and then one sees wire services getting at least partial credit. We have a small advertising newspaper with a small amount of editorial content. They say that they are frequently the only news media covering a school board meeting in a large suburb.
I didn't believe a word you said about this until I saw your moveable Dali technology! I like to see you keeping some sense of humor! I started watching the condo collapse videos. thanks!!
Jeff this ship has 3 large main generators. Two must be online and in parallel when the ship leaves the dock. If one fails the other one will carry the load , there may be some load shedding of non-essential equipment intel the 3rd generator can be started and synchronized and put in parallel with the other. No blackout. the 4th generator is the emergency gen its not in the engibe room it has its own fuel supply #2 diesel its not large enough to run the main engine auxiliary equipment but can run the steering.
Super informative great job
Here on the rewatch crew. Thank you for your analysis🌸🌸💕
I assume very little coming from you, and your great videos another great video!
Thank you Jeff! Great video
My pleasure!
Like everyone I'm shocked at what happened. Your channel is superb. Your knowledge and the way you speak is very watchable. Thank you. Could you do a video on the future bridge design. It should be an international design competition.
I'm still thinking it was a combination of dragging the Port anchor and the cross-currents pushing the stern of the Dali to starboard and once the Port anchor line crosses under the centerline of Dali, its retaining force is no longer being applied to stop the vessel but to pull the Dali's bow (turning the bow) to the Port suddenly and into the bridge pier. Think about it.
I have not seen an underwater photo showing the position of the anchor or the position of the anchor chain that will tell the story. Had they not dropped the Port bow anchor with the ship's momentum it possibly could have still continued to turn to Port from the force of the current on the stern pushing it to starboard but somewhat slower and it most likely just would have missed the bridge abutment. I've Crewed and Captained Race Yacht for many years and although they have but one anchor forward to drop at the center line of the vessel when dropped while the vessel is still underway and depending on where that anchor finally digs in and holds determines which way the stern will pass the bow to Starboard or Port sides as the Yacht or ship would spins to a stop around the set anchor. Unfortunately, in this case, Dali turned to port.
In addition to possible side channel cross currents, vessels experience a phenomenon known as “prop walk” depending on wether the ships propeller is right or left handed, the stern of the vessel will move laterally port or starboard and is particularly noticeable when backing astern.
Then why did they go full reverse if it would turn them at such a critical location?
Poor choice? Who knows what happened in the moment, but yes going in reverse while moving at 8 knots will dramatically change the heading and quickly.
Current or wind at 8 knots is highly unlikely. It would first push the bow, then the whole ship and then it would affect the stern. I have worked in restricted waters with currents up to 6 knots and yes the effect is quite notable. This is especially notable in river bends.
Propeller walk applying astern propulsion is more probable.
Prop walk is not instantaneous on a vessel that size. It can also be counteracted somewhat with the rudder. When a vessel that size loses power at low speed, the rudder is practically useless.
Great. Content.... current flowing from the side channel or wind can make ship turn..... Tugs would have been a great idea to escort the ship under the bridge... but we have to remember that a an additional cost
An additional cost to who? Clearly the bridge costs more.
Tug escort would be additional cost to the shipping company & the cost of shipping. I do know that the bridge is a great cost
They have to physically turn on each system by hand once the main power goes out. And they have a procedure to follow about which systems get turned on in a certain order.
One thing I seen said the ship had 3 seconds to manually steer it so it wouldn't have hit the bridge. They can steer it in the engine room if the bridge can't.
A tug boat guy who knows that port said they only can use tugs to get them docked and to get them pointed in the right direction if they need that. At very slow speeds. But that huge ship is just too big to lead out of port once it gets under way on its own power. They do make some really big tug boats but they're rare and not used in that port. This is all information you can find just from searching around the internet. They asked for tugs because they were freaking out from the power loss but tug boats would have been useless with a ship that large going 7 or 8 knots.
Another bang up job great video keep ‘‘em coming
Legal eagle also just released a video on the legal side of the collapse, but one thing that he pointed out there is a state law that requires all cargo ships to have a bay pilot on board to navigate the ship out of the bay.
They had a bay pilot _and_ a harbor pilot on board.
Excellent factual report Jeff. Well done for calling out the critics who need to go back to their books, if they can read that is.
I believe the propellers starting up can cause lateral forces which can alter ships heading.
So your story is the current of Curtis Bay channel was strong enough to push the stern (back) of the Dali and therefore somehow specifically cause the bow (front) of the ship to turn to the starboard (right) n exact collision course for the worst place to turn to, the vulnerable support. However if you roll back time and Dali position to before the Dali interacted with current of Curtis Bay channel was strong enough to push the stern (back) the bow (front) of the ship would also be affected by the channel and logically the Dali would turn the port (left) potentially avoiding the support as it would now be point away from support and towards open channel and the support on the other side. Short theory: The Dali would get first affected by current of Curtis Bay channel on the bow of the ship first turning it to the port side (left) away from the course to hit the support.
Exactly Jeff. Generators don't supply power straight away. Even if they have an automatic switch over they still take time to load up and produce power.
Prayers from the UK xxx
Excellent run down on the potential chain of events. Curious to your thoughts on redundancy systems in place for a ship that large or any vessel with the secondary source of power that can assume upwards of 85%, if not more, of routine navigational and housekeeping functions. Point I'm trying to get to is, as you addressed the "wind up time" needed for ICE backup systems; traditionally, there would be batteries/Uninterrupted Power Supply (UPS) to carry the minimal load needed to support critical systems until voltage could be generated by the back-up generator. Not knocking anything, just curious if anyone has thoughts that I could be missing. However, now that I'm typing this it leads me to believe there was a potential master breaker failure that prevented all downstream redundancy/ATS's, etc. to not engage. Again, great detail, enjoyed the presentation. Just my thoughts and not leading to any direction one way or the other. Thanks for entertaining the comment.
Great video and coverage Jeff. If the side channel influenced the ship, it would the entire ship. It would have pushed the bow to port as well as the stern. My conclusion is that the rudder still had 7-8 knots of water flowing past it and it was the rudder that turned the ship, not a headwind, ebb tide or side current. Why do we not now the steering commands or the engine (ahead or astern) if running?
As the ship moves through the narrow channel it is pushing water in front of it in the channel so there is higher pressure built up around the bow. As the bow passes the channel intersection, the water pressure built up in front of the ship will decrease on the side of the bow facing the intersection as the pressure gets released into the side channel. The pressure on the side of the bow opposite the intersection is still high though, so it will push the bow towards the side channel. This would only happen at the bow. There are many forces acting on the ship like this, so boats usually have to make steering inputs all the time just to travel in a straight line without drifting.
The boat is also not symmetrical from bow to stern, so the drag on the boat underwater is different from bow to stern. Even if there was one even and consistent force from the wind pushing the boat in one direction evenly, it would still turn the boat as the center of pressure from the wind is not in the same location as the center of drag from the hull. Furthermore, the wind is always changing and is basically never consistent from one location to another. It will increase a few knots, decrease a few knots, change direction a few degrees and sometimes change back and forth quite dramatically.
This guy is smart great video
Movable Dali! Love it, former SMPTE.
I don't think they made a course change but the Voyage Data Recorder would reveal that
Out going tide would have a effect from side channel currents pushing the ship to the left away from pillar ..was the ship dragging anchor pulling the front to the right hitting the pillar ? does the data show rudder position ? and throttle position from the time the ship started turning
Look at the water surface - calm, no wind. Dropping the port bow anchor and dragging it may have changed the direction with holding the bow and the stern swinging to port.
I absolutely agree with mikefochtman. I am a now retired, Ship Master, previously with Maersk. My last ship was also almost identical in dimensions to the Dali.
During the last 40 years I have 'Done' Chesapeake/Baltimore numerous times. Like Mike , I think the following happened.....
- Just prior to the bridge the ship blacked out, maybe twice. Generators and Main Engine were restarted.
- after M/E was confirmed OK,the telegraph was put full astern.
Propeller turning anticlockwise when viewed from behind the ship.
- the phenomenon known as 'transverse thrust' kicks the bows to starboard and stern to port.
- Dali turns directly towards the bridge tower.
So it wasn't spooks, Martians or terrorists.
Only possible cause was what we learnt at navigation college back when ships were made of wood and men were made of steel -
'Shiphandling #101' Transverse Thrust!!!
Greetings from South Africa. Baltimore has always been one of my favorite port - and I've been to a lot!
Kudos 😊
If you look at the smoke, it was quite windy too. What about the torque factor of the spinning screw against a rudder that requires power in order to operate? Ever let go the steering wheel on an outboard ? You mention current, but what about tide? There is also a witness account that the ship had electrical issues WHILE loading in relation to the refrigerated containers with many power failures pre embarkation. Thankfully you being an engineer understand how all these factors can combine to produce this accident. Thank you.
Jeff, it might help to understand the "Paddlewheel Effect" on ships.
The ship's starboard bow didn't turn to starboard until the engine restarted (as noted by the thick black smoke), when the engine restarted they likely engaged the propeller shaft into reverse, that will cause the stern to move to port while pivoting the bow to starboard. The opposite is true for forward drive.
Look up "Paddlewheel Effect" on ships.
Hi Thank you for your Videos . There is A video going around showing small like fires at different points . Is that the power transformers catching on fire . You might know .how was the pilot on board going to get off the ship . was there a small boat going with it. so he could get off .thank you for your time .
Thank you Jeff for another informative video. A question, were tugs going to be useful as the ship was travelling at 8 knots and tugs can only operate safely around big ships at about 3 knots? Am I correct with this assumption? All the best from Sydney Australia 🇦🇺
Sal also mentioned that when a ship transits a channel, there is an underwater "wake" that generates pressure against the sides of the channel. The ship lost power lost power just as it reached the junction with the Curtis Bay Channel at which time the pressure from the starboard side would disappear and the pressure from the port side would push the ship to the right.
I feel certain that soon, the discussion will turn to a port side prop walk after full astern propulsion was engaged.
From my experience, that is most likely the cause of the turn to starboard.
Timing,... Smoke from the stacks>full Reverse>PROP WALK pushes the stern out turning the ship>lose power>allision with the bridge support.
major effort to start running gear astern when running at 8 Knots. it reduced speed to around 6 knots at point of collision. ordering anchor drop and anchor to take effect are two different things
In the NTSB videos, it appears as if the top portion of one of the bridge supports is sitting on the bow deck of the Dolly. This column, either the port side or ocean side of the bridge, is probably the column that was struck first. Any thoughts on that?
When you talk about the turn before the the bridge at the Curtis bay Channel. It seems to me that that area is about the same time the ship lost power. That would allow the wind and current to push the vessel to a slight right hand turn. We are back to cause and effect
Tugs are effective only at slow speeds for mid and large size ship. For 8 knots which the ships are moving when around the bridge, a tug will only be tagging along and not an effective tug. Remember the tug will use its power to keep up with the 8 knots speed and then whatever will be left after that it can apply as force to try do something to the ship. There is hardly any power left for that at 8 knots.
I cannot remember the video I saw this in, but the gentleman was speaking on some authority that the direction of the screws imparts A turning torque on the ship. Apparently most ships screws turn the same way in such a manner that when they apply power, the ship has a bias to turn to Port. Conversely, if you stop the screws or if you reverse the screws, then there is an opposite torque that pulls the ship to starboard. This gentleman was advocating that upon power loss or upon power, restart the pilot, or captain applied reverse power, which then rotates the screws in the opposite direction, and that would have pulled the ship to starboard, resulting in the turn, that we see and the collision with the bridge pillar. Again, sorry, I do not recall the video proper, but if you look at some of the earlier videos, particularly from the ship channels, it might be one of those. Seems to me to be a very plausible explanation for observed turn
Jeff the meter vs. ft confusion originate from some videos, showing maps with depth in meters...
And yes by not using one system international, it will cause accidents... something to think about.
The turning at the last moment has many hypothesis. Current could be a reason. but current from that channel would have pushed onto the entire side of the Dali, making it turn, but also pushing it more to the middle of the main sailing channel. Wind would have similar effects. The other hypothesis is the Dali turning suddenly while temporary regaining power. A ships propeller doesn't have forward trust from the very start. Anyone who tried to maneuver a motor vessel knows when turning on the prop, it will push the ships stern to the side. Which side is depending on the direction of rotation.
As these all are just hypothesis, we better wait until the investigators release information on this change of direction. Speculating only leads to fantasy tales...
Thanks for putting the latest info on RUclips. I'm following you guys from Denmark.
If I remember correctly, the wind was basically dead calm at the time. So there was no wind to affect the M/V Dali. My best guess is that dropping the port side anchor likely affected the turn counter to its intention. And yes, I really am just guessing. Of course the intention was to turn it left, but obviously somehow had the opposite affect. The other effect is if they lost track of the rudder and when power returned they didn't know where the rudder was. Even though you mention that the M/V Dali did not turn much as far as degrees of trajectory, it actually is a lot of turn in a confined area over a short distance.
Another guess on my part is that if they had done absolutely nothing once they initially lost power, they could have drifted safely under the bridge. They were doing 8.7 knots at the time they lost power, which is enough to maintain stearage.
Sal said recently that wind and currents probably were too weak to have an effect. What would have an effect, is the bank effect which would pull the moving vessel towards the side of the shipping channel, and the lack of the bank effect where the other channel comes in.
Another factor in it turning is channel suction. On one side, you have the main channel. On the other, you have the other channel coming in. Bernoulli is sucking on the main channel side, but once you cross the other channel, suction on that side goes away. Sail area in wind can play a factor, too.
Emergency generators would have been lined up for the maneuvering watch because of how long they take to start. My guess is they had a switchboard / distribution fault. So even with the emergency generators running, power couldn't get where it was needed. Pumps feeding the main engine would have shut off, and those lights that came back on initially were probably an emergency buss. Even if it was the main busses coming back online, the engine was starved of lube oil and fuel while it was down.
I heard "meters" mentioned on another channel here so i think thats where that came from. On the ships turning issue. Once the ship started drifting outside the channel and taking up in the mud/sand. Everything changes concerning how the ship reacts and handles. Lack of water under the hull could have contributed to the sudden course change.
Sal at what going on with shipping has a video showing the tugs routes before, during, and after
You're right a ship this HUGE acts like a SAIL, all the more reason to ALWAYS have a tug boat escort out to sea and into the harbor, especially AT NIGHT and especially if there are no concrete barriers protecting the supports. Instead of using common sense in the first place, it takes a disaster like this to change. Just like 9/11 we were so naive to think hijackers would never fly the jets into buildings. Thanks for the update.
Love the Hello Dolly clip. You had me laughing.
I am curious. Could dropping the port anchor have had any effect on the ship’s turning.
I heard another explanation for the turning of the ship - that the turning of the propeller imparts a rotational force to the ship and the direction of that force is dependent on the direction the propeller is turning. So if the ship was switched to full astern the opposite rotational force would come into effect, potentially contributing to the turning of the ship.
Overlay the ais position data over the chart of the channel. I think the dolly rubbed the side of the channel on it's starbard side. The drag of grounding the side of the ship would have slowed the right bow swction and caused a slew to the right and probably a port side move to the left. That yawing motion is pretty clear when watching the video.
11m is about the draft depth of a Nimitz Class aircraft carrier and about 37ft.
If I remember correctly the main channel hat 51ft which is 15,5m. Big ships don't have that much draft compared to their heigt.
Tugs cannon safely work on a ship at 8 knots. At 2-3 knots they begin to lose their effectiveness. While 5 knots doesn’t seem like a lot, it’s enough to trip the boat and kill the crew. The dead slow ahead speed of these ships is faster than what a tug can safely be along side. The slower the ships go, the harder they are to steer so they will have a planned transit speed that gives the best control at the slowest safe speed. If you watch an arrival, the tugs do meet the ships farther out because as the ship slows down they will maintain direction by giving a helm command then pulsing the main engine to stay drifting down the channel. They have to slow down in a controlled drift to get to that minimum speed where the tugs can work along side. On departure they want to get the ship pointed outbound and get the tugs away so they can get up to departure speed and have control. Best case scenario on a tug you can expect 12 knots out of it, and even that’s a lot. They are designed to have high thrust a low relative speed through the water so just to have a tug running with a ship at 8 knots it’s being pushed pretty hard just to keep up with it.
Great video Jeff! I am confused about some things though. The position that is shown in the video when the ship has problems is .39 miles from the bridge. Max speed in the harbor is 8 knots. It takes 2 minutes 54s to travel that distance at 8 knots. But the ship starts turning about 45 seconds before it hits the bridge…. Is this just something over looked? Would love to hear your input on that.
your numbers are off. When I see the original video that shows the collision, the power goes off at time stamp 1:24:33, right at 1:25:31 in the video, the power comes back on, and the ship has already started to skid with the bow pointing to the right. By 1:26:20 the turning to the right is more pronounced, until 1:28:43 it strikes the pillars. So the ship was turning for 3 minutes before impact, not 45 seconds as you stated.
11:11 I live a mile from that bridge , I've fish under it yes your right about the the depth of the channels, our tugboats only dock and launch the ships in the right direction the channels is wide enough where they don't need assistance, under the bridge was wide enough for two ships
For reference, on the Mississippi River, the Corps of Engineers maintains a minimum of a 9 ft channel for barges.
There's a bow thruster 3,000KW/4,000HP in front and anchors that could've been dropped. It'll all come out in time and the conspiracy stuff will continue no matter what. Thanks for everything Jeff!
No conspiracy but lots of silt on bottom of channel. I don't believe an anchor would of had much effect. However I don't understand why pilot wouldn't of kept the Dali straight sincepowwr was lost meaning rudder would of been straight. Better question is who greenlighted the Dali as seaworthy? It had unresolved electrical issues at dock. Coincidentally all powwr was lost after tug escorts disembarked
@@user-co7fb6qe5wAs a "theorist" (I'm really not) I've been right about a lot. Plenty of people are starting to notice
While in know very little about shipping. Getting someone to the bow, relessing the achorchain. Get sufficent clain out in 4 minutes.
Sounds kind of impossible to be.
@@user-co7fb6qe5w Why do you think the rudder would be straight when the power is lost? The pilots are constantly adjusting the rudder just to travel in a straight line to compensate for the various forces acting on the ship. The rudder could have been stuck at 10 degrees to port or something when the power was lost.
Hi. I’m an actual naval architect, and I know more about ships than you do or ever will. The anchor was dropped, but anchors are intended to hold stationary ships in place, not stop moving ones. At 8kts, she would have just dragged her anchor. That Pirates of the Caribbean trick doesn’t actually work in real life. As for the bow thruster, those don’t really have any significant impact above 5 knots. They may have actually tried to use it anyway, and the enormous power demand may have been why the ship lost electrical power the second time.
The anchor. Jeff, it is a common strategy to release the anchor on loss of steerageway... I recall this order might have been given by the pilot, but do we know if the anchor actually deployed, and if so, which side, aka might that have contributed to the swing to starboard?
The port anchor was deployed (this was confirmed early). Anchors can be deployed without power, and if it had an effect it would have pulled the ship to begin turning to port.
Am trying to understand how these depth-cards work, i assume the water level can be low or high in a river, so how do you know the depth of a channel at any given moment? Is 10 feet the minimal depth with low water level? If the water level is high, could deeper ships pass through these 10 feet channel?
I don't know much about ships, but could they have dropped anchor? or would that have been electronically controlled?
Should there be a 3kl speed limit around all bridges ? At 3kl less damage happens & bow thrusters work better .
People forget that rivers have currents
Can you please indicate length on meters too? Please.
8:37 seem to recall Sal mentioning that the port anchor (11:41) was dropped (power issues prevented starboard?), wouldn't that torque the ship towards that side (+ wind & currents)?