Not a lot they could of done apart from drop an anchor.

The anchor is to stop a stationary boat from moving, not as a brake. Dropping it would either snap the chain or rip out part of the anchor handling mechanism.

Selling preventative engineering is hard work,

I can imagine.

In my field, obsolete kit is problematic. It’s a security risk and if it goes bang tomorrow then we’re screwed because manufacturer support is long gone. I used to harangue Sales to try and get customers to upgrade, they’d say the customer attitude was almost always “but why should we spend tens of thousands when what we already have just works?” And it’s a fair argument, everything works… right up until the day it doesn’t.

No it’s not.

It is also used as an emergency brake.

That’s why a ship’s crew will clear away anchors, when arriving or departing a port, removing all the fastenings that are used to secure them at sea, then have a couple of crew members with a radio standing by to drop them quickly in an emergency.

Dropping a large ships anchor straight from the hawse pipe is not for the faint hearted and it puts loads of strain on the equipment but it is designed to be used like that if really necessary. It’s not a routine operation.

There is an old saying “never go aground with your anchors in the pipes”.

I’m guessing making those supports bigger and stringer would make the space between them even narrower. Which was probably all fine when the bridge was built but not now that ships have grown so massive.

@gobuchul the Chinese barge took out a section of the bridge with similar results. Was just pointing out it’s not long since a very similar incident happened.

Dropping a large ships anchor straight from the hawse pipe is not for the faint hearted and it puts loads of strain on the equipment but it is designed to be used like that if really necessary. It’s not a routine operation.

Sounds like they got to test this on the Dali but it didn’t stop them. Im guessing it could have even contributed to the incident pulling them further off course.

It could of easily put them further off course but that might of made things better, ie aground but not hitting the bridge or not hitting it as hard.

I can’t see what action they could of took that would of made things worse?

I thought this was an interesting read.

https://twitter.com/cybergibbons/status/1772564868974915633

https://threadreaderapp.com/thread/1772564868974915633.html

Just saw on twitter that they did drop the anchors. At least they tried.

You can see the anchor chains hanging on the BBC photos.

Sounds like they got to test this on the Dali but it didn’t stop them. Im guessing it could have even contributed to the incident pulling them further off course.

How would it have done that? A ship swings round it’s anchor, if it was caught it would have turned on it.  Even if it was dragging it would swing. Probably, that’s certainly the picture of the dynamics I have in my head.

I wasn’t a deckie so have no idea what the procedure is but it could well have still been taking up slack in the chain when it hit. It if it was launched then the chain would have just flown out the locker until it hit the end. They’re long buggers.

It takes time for an anchor to bite (and that varies significantly depending on what the seabed is like) and then it also takes time for the massive chain to pull tight*. There might not have been anyone near the mechanism to actually drop it too, so (especially on something that size) add in more time for that too.

Safe guess is that the current (and possibly wind as even in calm conditions these things are huge sails) took them towards the bridge and the anchor was too little too late

*in normal use the chain would be fairly relaxed sitting on the bottom and actually doing a lot of the work

That video above on twitter/X/whatever looks like the ship was starting to initiate a turn under the bridge when it lost power. Assume this locked the rudder etc so the turn continued, past the point it should be straightening up. Power came back on, everything fired up, tried to correct it but too late and then the power went again…

@daveyboywonder read Cougars thread link, it explains it all. They would still have had emergency power but only once the blackout generator kicked in.

I’m amazed this doesn’t happen more often. The sheer volume of worldwide shipping and state of some boats is asking for trouble.

Also, you have to appreciate big ships can take a mile or so to stop!

Dropping an anchor like that, is an action of last resort.

You wouldn’t be keen to do it, it puts crew and equipment at risk.

I doubt anyone would make that call when the ship first blacked out, you expect the back up systems to restore power.

If you did it and the power came back on, then you would have very little control of the ship and the anchor would be controlling your movement.

By the time they made the call it was too late.

The Tay road bridge protection is detailed at https://www.icevirtuallibrary.com/doi/full/10.1680/bren.13.00010 – it only covers the main navigational channel which wouldn’t have helped when at out of control tanker tried to take it out in 1983 (https://www.reddit.com/r/dundee/comments/pdq2x8/tay_road_bridge_almost_hit_by_700_foot_oil_tanker/ and https://www.thecourier.co.uk/fp/past-times/2515193/oil-tanker-tay-bridge/).

Somewhat ironically, Perth Harbour was losing so much money it looks set for closure, and there is not a huge amount of traffic heading under the bridge anymore – the Dundee docks are before the bridge.

@jca
Thanks for posting,I had never heard that story before.
A proper near miss😲

in normal use the chain would be fairly relaxed sitting on the bottom and actually doing a lot of the work

This.  Most people think that it’s the anchor that holds a boat in position, but a lot of the work is done by the chain, which also means that a certain amount of chain needs to be let out for it to work.

Anyone thinking an anchor, even dug into clay, is going to stop a 90,000 ton ship travelling at about 14kph in short order is going to be very disappointed!

Anyone thinking an anchor, even dug into clay, is going to stop a 90,000 ton ship travelling at about 14kph in short order is going to be very disappointed!

Yeah, but they could have used it to change direction…

It wasn’t clear earlier in the day but fortunately they did manage to stop traffic before the collapse.

Yep, pretty much confirmed that the boat sent a mayday and the bridge authorities were able to stop traffic. Slightly less confirmed is whether all the traffic was off the bridge, but seems fairly likely that it was the maintenance teams on the bridge that were caught- big bridge, not quick for people on foot to get off it.

This seems pretty informative https://www.youtube.com/v/N39w6aQFKSQ

Video embed is no longer working “MV Dali Hitting Key Bridge in Baltimore – Track and Video Analysis”

As for pier protection, can anyone provide examples on bridges which span major shipping channels?

This is the newest of the two Severn Bridges, you can easily see the size of the caissons holding the supporting towers, and as the tide is out, how narrow the main channel is. The biggest ships negotiating the channel are car transport ships and container ships going into Avonmouth and Royal Portbury Docks, which may not be quite as big as the ship involved with the Baltimore collision, but the Severn and Bristol Channel are very difficult to navigate and very dangerous – it has the second highest tidal range in the world at 48 ft/15 m, it’s the longest river in Great Britain and has the greatest voluminous flow of any river in England and Wales by far 107 m3/3800 cu ft/sec.
It’s at this point the Severn becomes the Bristol Channel.
AFAIK, there’s only ever been one accident involving a bridge over the Severn, when two river barges collided in 1960 and hit the Severn Railway Bridge between Sharpness and Lydney, causing two spans to collapse into the river. Repair work was under consideration the following year when another similar accident occurred, so the bridge was demolished between 1967 and 1970.

I don’t think the channel upstream of Avonmouth (and downstream of the bridge) is deep enough for the container ships to drift up as far as the bridge if one  broke down entering or leaving the docks.

Here’s the first of the modern Severn Bridges, the caissons are a similar size, but the construction was unique, the decision was taken to use a completely new design and technique, it opened in 1966, and my dad took me down to Aust Ferry to see the bridge under construction.
There’s a footpath and cycle path across the bridge, and it’s well worth walking or riding across and back, especially when the tide’s on the run – you really get to see how powerful it is, and how dangerous, because of the large expanses of rock on both sides.

Forth Road Bridge a few months back.  Shipping channel beyond the tower.

By coincidence, I’m watching ‘Saving Lives At Sea’, and there’s a converted Dutch barge with engine failure drifting in the main channel of the Severn heading directly towards the Prince of Wales bridge at full flood tide, the barge is about 30 tonnes and a lot bigger than the inflatable life boat! They ended up having a Port of Bristol dredger take over the tow, the lifeboat was doing 1.1 kts into the tide, which gives an idea of how fast the tide flows, and how fast shit really does happen!

An aside – from the BBC

The cargo vessel, called the Dali, was built in 2015 and sails under the flag of Singapore. It can carry 10,000 shipping containers (standard 20 foot units). It was carrying 4,679 units.

Where the hell would the other 5321 containers go?

I’m looking forward to the  the whole “Today I am expert in (but not limited to) Harbour piloting, maritime navigation, and multi-span bridge engineering” vibe that this thread will descend into in short order. Don’t let me down.

convert
Full Member

An aside – from the BBC

The cargo vessel, called the Dali, was built in 2015 and sails under the flag of Singapore. It can carry 10,000 shipping containers (standard 20 foot units). It was carrying 4,679 units.

Where the hell would the other 5321 containers go?

I think what they’re saying is it has a nominal capacity of 10000 standard 20 footers, but the 4679 on board weren’t necessarily 20 footers, they come in 20 30 and 40 foot and also there’s a variant which is a foot taller

@jca, thanks for posting those Tay links – I’d not heard of that before, but then I was only 4 at the time it happened.

All those little mult-coloured boxes on the ship will be weighing 30 tonnes each if they are standard shipping containers.

Plus the weight of the boat, you can’t just put it into reverse gear… if it’s going in one direction, it’s going to keep on going in that direction.

Dropping anchor might slow it down, but not enough…not even close to make any difference.

To me, it seems like they were driving to fast for the conditions, at least, that’s how it appears on the surface.

If you’ll excuse the blunt ananogy.

“they were driving to fast for the conditions…”

Now if the bridge was wearing hi-vis, none of this would have happened…

Bloody bridges getting in the way of ships.. who do they think they are?

It’s not much, but there’s a little bit more background information to the story, which might clarify some points:

https://www.theautopian.com/heres-everything-we-know-about-the-container-ship-crash-that-destroyed-the-francis-scott-key-bridge-in-baltimore/

Dropping anchor might slow it down, but not enough…not even close to make any difference.

No, not with a ship weighing probably 100,000 tons. I could expect it to drop anchors to get chain out, as the chain is as important if not more than the anchor itself, as its the weight of chain resting on the bottom prevents the ship sliding just as much as the anchor.

But if its running out in an emergency, then its just running free and thats going to do nothing for momentum.

So they would have to run out chain, then brake it and hope theres enough out for a drag effect, al in the space of a few hundred meters.

But run out the anchor and hope it grabs ? thats not going to do anything other than snap the chain, or destroy the handling gear or even tear out the slates surrounding the fairlead

well excactly… it would make no odds. Any anchor would just snap the chain with that much weight and momentum, and cause more problems.

And, thats assuming flat water and no tide.

The boat came in too hot, simple as that.

negative – ghost rider- the pattern is full.

They appear to have just dropped the port anchor. Maybe they were hoping to just change direction enough to get through the pillars rather than actually stop. Most impressive in all of this so far is that during the few minutes it took for this to unfold they managed to get out the mayday call, it got to the bridge and they got the traffic stopped.  Doesn’t look like anyone was asleep