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A lot.
(lemm.ee)
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this post was submitted on 26 Mar 2024
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So cars these days have anti-collision systems. One would think a million dollar boat, with millions of dollars in cargo, approaching a multimillion dollar bridge would have some sort of active sensing system to prevent a collision. That video shows the Dali strolling right into the support. It wasn't a glancing blow, rather it was a direct hit. Either somebody f'd up big time, or major act of sabotage on US territory.
I wouldn't think anti-collision systems would be feasible on a container ship: they're too big with too much inertia. It can take miles to slow to a stop or execute a turn. It's not like a car, where you can just hit the brakes and have immediate results. All that extra braking and re-accelarating would burn a bunch more fuel, too.
A good anti collision system here could be a dude with binoculars lol!
Don’t need binoculars. As the ship drifted out of control, they had a clear view of the bridge they had no power to avoid.
If it takes miles to slow to a stop or execute a turn, that just makes me think the ship’s future position is easier to know with certainty, giving any collision detection system more lead time to alert to expected collision.
To alert to, sure. It makes car-like automatic braking infeasible though, unless we're looking exclusively at stationary objects like bridges, which are only present for a miniscule fraction of a container ship's travels; they won't have time to react when a sailboat suddenly tacks across your bow, for example. And it certainly won't help when the ship is without power and drifting, like the one that hit the Key bridge.
Yes it would be only for stationary obstacles. Unless maybe other ships were broadcasting their anticipated paths too, but that’s a whole new level of complexity.
For avoiding these stationary obstacles, it would help more with more distance predicted. As in, it could have predicted the collision path before the engines cut out.
Like, if the ship was in a turn when the power died, it would continue on a curved path due to the rudder being fixed in place.
So with a far-out predictive collision system, in a situation where cut power would result in a collision, that warning would be signaling the collision before the cutout. Loss of power would not change the path of the boat through space.
So that means (unless I’m misapplying some assumption here) this ship was on a collision path before the power cut out; their plan must have been to directly approach the bridge support, then turn away from it later.
(Unless the rudder fails to straight, which seems to me like it would be a bad design decision, specifically due to how it would cause power failure to result in a new travel path)
Having that kind of tracking for other ships is actually something I remember from twenty years ago or so: it was called AIS, and you could use it to very easily tell if you were going to get close to another ship with it; pretty much all the big ships had it at the time. It was particularly nice because it would tell you the name of The ship, which made it a lot more likely that you could raise them in the radio.
One interesting note is that steering will actually change when you lost engine power even if the rudder remains in place (which I believe it does) because the propellers are no longer driving the water across the rudder, which lessens its effect..
The effects of wind and current are another factor to consider, especially closer to shore. I'm sure it's possible to model the course of a vessel, but it's a big and constantly changing problem.