Baltimore Bridge

[Chuk_Chuk]

This is what you claimed:



I'd suggest you don't seem to understand if you think that bringing a ship to a halt is going to be harder than deflecting it - that's basic physics, it will require more force to bring to a halt, you know the rough direction of travel too. I don't need to know if it's 5 degrees to 10 degrees or 15 degrees to point out that deflecting it via a side-on impact is going to require less force than say colliding head-on into an object that isn't designed to deflect the ship and trying to bring it fully to a halt.

I've provided examples because this stuff exists, there are barriers built specifically to deflect ships.

Think about what you're saying re: motorway barriers "Motorway barriers are designed with a max impact angle of 20 degrees " - what happens if you crash perpendicular to one (i.e. it's not going to deflect the vehicle rather it's either going to stop it or the vehicle will fly over or pass through... that's going to require a lot more force! Reduce the angle so you're closer to perpendicular to it and there is much less force to absorb and the vehicle is deflated.

In the case of these barriers look at the design of them, they have pointed ends facing up and down the channel ships use or are circular, they want ships to deflect off them, they're not aiming to absorb all the force required to halt a ship, the idea that deflecting a ship would be "just as hard if not harder" than bringing one to a complete halt is false.

So we’ve gone from impact angle and direction of travel doesn’t matter to it does matter as long as it is a shallow angle. So we’ve made progress. You did actually understand my point. That’s good.

You’ve also repeated what I wrote in post 158. So I’m glad that you were paying attention.

 

[dowie]

So we’ve gone from impact angle and direction of travel doesn’t matter to it does matter as long as it is a shallow angle. So we’ve made progress. You did actually understand my point. That’s good.

No, I think you weren't paying attention in the first place, again we're talking about ships approaching a bridge and the point being that you can deflect them rather stop them!

You don't need to know the direction of travel (though you'd have a reasonable idea from both directions) it's still easier (requires less force) than stopping it.

Why do you think the barriers take the shape they do?

This is false:

I think deflecting would be just as hard if not harder, since you don’t know the direction of travel.

On the left hand side you need to handle much more force to bring the ship or boat to a complete halt, on the right-hand side the ship still maintains some momentum and is deflected, that inherently requires less force.

 

[BowdonUK]

I'm surprised the entire bridge collapsed. I thought it would have stopped at the other supports.

Also was there any cushions at the bridge foundations against accidental ship crashes?

 

[cu3ed]

Isn't the fact the multi-storey high overhang to the front the problem?..Seems the bow is fine its the mammoth front holding containers is what misses pretty much any "barrier" that would hit first.

 

[plasmahal]

I'm surprised the entire bridge collapsed. I thought it would have stopped at the other supports.

It didn't did it? The centre section collapsed. A lot of the bridge is still intact.

 

[Scania]

So the ship has a deadweight of 116,000 tonnes.

In 1969, the largest ship in the world was 29,000 tonnes.

I think your a little out there....

On 2nd May 1969 the first of the giant oil tankers to be built at the Swan Hunter shipyard at Wallsend was launched by Princess Anne. The Esso Northumbria at 253,000 tons was the biggest ship in the world at the time.

 

[CaptainRAVE]

Wonder how long it’ll take to clear that up. Doesn’t look like a quick or easy task.

 

[Chuk_Chuk]

Why do you think the barriers take the shape they do?

This is false:


On the left hand side you need to handle much more force to bring the ship or boat to a complete halt, on the right-hand side the ship still maintains some momentum and is deflected, that inherently requires less force.

Okay I’ll play along. We’re moving away from the original point but this looks like fun.

Take your image on the right and sweep the ships impact point across the entire frontal cross section of your barrier and explain to me how the component of velocity changes at the different impact locations.

Now sweep your ship so it impacts at different angles with your barrier and explain again how the component of velocity changes at different angles.

 

[dowie]

Okay I’ll play along. We’re moving away from the original point but this looks like fun.

Take your image on the right and sweep the ships impact point across the entire frontal cross section of your barrier and explain to me how the component of velocity changes at the different impact locations.

Now sweep your ship so it impacts at different angles with your barrier and explain again how the component of velocity changes at different angles.

No, this was the original point - tell me how deflecting a ship is going to be harder than bringing it to a halt..

Suppose a ship is just grazing the barrier - that is clearly not harder right? Now make it a slightly worse collision... becomes harder than grazing it right? And worse still and so on.. eventually, you come to a point approaching perpendicular where you're not going to be able to deflect and it's going to absorb all of the impact of the ship hitting it.

More to the point - try explaining why absorbing some of the momentum of the ship is going to be "harder" than absorbing all of it?

Answer - it isn't - this is basic conservation of momentum. I don't need to know whether the ship is going to just graze the barrier at a very slight angle or whether it's going to be a hefty-ish impact at a larger angle that is still deflected, the fact that there is still some momentum conserved when deflecting it vs bringing it to a complete halt already negates your claim that deflecting it could be harder.

 

[arknor]

If they want to prevent it in future, then just have a rule that any cargo container has to be escorted though a bridge by 1-2 tug boats.

can't be that many bridges cargo container vessels go under surely.

 

[Goksly]

Followed by "food and goods prices to rise by 10% due to additional transport requirements..."

 

[cu3ed]

Followed by "food and goods prices to rise by 10% due to additional transport requirements..."

Nestly and Unilever and getting the lube out once again.

 

[plasmahal]

If they want to prevent it in future, then just have a rule that any cargo container has to be escorted though a bridge by 1-2 tug boats.

can't be that many bridges cargo container vessels go under surely.

What if the tug loses power like the ship did?

Not saying its a bad idea, it is sensible, how do you mitigate against all possible scenarios.

 

[tom_e]

Nestly and Unilever and getting the lube out once again.

I think they ran out of lube a couple of years ago and have just been ramming it in dry since.

 

[Terminal_Boy]

This might explain the ship veering to starboard after losing power where it did…

How Did A Ship Destroy Baltimore's Key Bridge?

â©ABOUT THIS VIDEOâ©On 26th March 2024, the container vessel, Dali, hit Baltimore's Key Bridge, leading to its complete collapse. This video is an explanation ...

youtu.be

 

[Chuk_Chuk]

No, this was the original point - tell me how deflecting a ship is going to be harder than bringing it to a halt..

Suppose a ship is just grazing the barrier - that is clearly not harder right? Now make it a slightly worse collision... becomes harder right? And worse still and so on.. eventually, you come to a point where you're not going to be able to deflect and it's going to absorb all of the impact of the ship hitting it.

More to the point - try explaining why absorbing some of the momentum of the ship is going to be "harder" than absorbing all of it?

I said “just as hard if not harder”. The harder bit was in reference to extreme conditions were you’re expecting to absorb a significant amount of kinetic energy but must transfer the kinetic energy back to the ship to change its velocity so that you can “deflect the ship” or whatever you actually meant by that statement.


Now then Do the question I asked. Go on since it’s just basic physics you should be able to easily do the maths to calculate the component velocity of the ship at different approach angles and frontal collision points. It’s just trigonometry. We need to make sure the barriers work in all conditions right?

Also please explain how you’re going to control the point of impact of the ship to ensure you only get the shallow graze angles you are talking about and not any of the worst case conditions where you have to absorb significant amount of kinetic energy.

After you can explain how you’re going to build your barrier to not plastically deform (or how the ships hull won’t just plastically deform) under the immense kinetic energy load and how it will remain rigid enough to allow for this “deflection” you are talking about?

 

[dowie]

I said “just as hard if not harder”. The harder bit was in reference to extreme conditions were you’re expecting to absorb a significant amount of kinetic energy but must transfer the kinetic energy back to the ship to change its velocity so that you can “deflect the ship” or whatever you actually meant by that statement.

Which is completely wrong as already explained - you're still conserving some momentum in the direction perpendicular to the bridge if you're deflecting the ship vs bringing it to a compete halt.

That it can be a "significant amount" of kinetic energy doesn't matter, it's still going to be an even more significant amount and thus even harder if you want to halt the thing!

After you can explain how you’re going to build your barrier to not plastically deform (or how the ships hull won’t just plastically deform) under the immense kinetic energy load and how it will remain rigid enough to allow for this “deflection” you are talking about?

I don't need to explain that at all, these things already exist. Nor did I claim that a ship wouldn't deform or would be deflected in every scenario. It's your claim that deflecting a ship is as hard or harder than brining it to an immediate halt that is falty here.

 

[Hagar]

What if the tug loses power like the ship did?

Not saying its a bad idea, it is sensible, how do you mitigate against all possible scenarios.

Build a tunnel.

 

[StriderX]

A tunnel will take far longer no? Having to move massive borers that are either not built or already doing other jobs seems unlikely to be feasible versus getting steel orders going that could be done immediately. That's ignoring how long it would take for the planning process itself.

Also it would mean you couldn't transport hazardous materials through in trucks which is partly why the bridge was important.

 

[plasmahal]

Build a tunnel.

It's an option. Going to take longer and cost more.