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Comment by junaru | Hacker News Reader

> Two years ago a Navy destroyer was ripped open by the nose of a Liberian tanker. Ten sailors were crushed or drowned as their sleeping quarters filled with water after the collision. At the heart of the tragedy is a single checkbox on a touchscreen.

No, this is crew incompetence, the checkbox is just covering the fact the crew has no idea how the vehicle works or how to operate it.

> The crew believed they had lost control of the ship because they were relying on the main steering controls, the rudder, without realizing that the ship was turning because of the secondary steering method, propellors set at different speeds

Let that sink in (no pun intended) - the crew is not aware the propellors can spin at different speeds... for three minutes... with what appears to be two giant sliders on the screen.

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> Let that sink in (no pun intended) - the crew is not aware the propellors can spin at different speeds

This isn't a very good take. Every mariner is aware of using differential throttle to manoeuvre. It is a primary means of control below the speed where the rudder is effective.

You've completely missed the human factors element. When what you are seeing doesn't match your expectation then it can quickly lead to issues. It's practically the exact same as AF447. The urgency of being about to crash into something can make it very hard to step back and understand what is actually happening.

Not to forget, the same problem has happened before with aircraft pilots.

Someone doesn't notice that the the wrong engines are running, or someone forgot to power down one of the engines.

Or there was an engine failure. And in the confusion, someone powers down the wrong engines.

Usually in these cases, fatigue or information overload is a major factor.

The pilots were fully qualified. They were simply overworked, and too tired to realize their mistake.

I wouldn't assign all the blame to lack of training. The navy is very famously overworked and understaffed, and not just in the USA.

The air industry is very good at blame-less post-mortems and finding root causes. I think the Navy could benefit from some things from their playbook. I think one major contributing factor is that Navy ships are so bespoke compared to airliners.

The Nuclear Navy is also excellent at post-mortems (though they’re called critiques – it is still quite possible and reasonable to blame someone if indeed it was personnel failure) and finding root causes. It wouldn’t surprise me to learn that the conventional fleet did things completely differently.

Unfortunately, the conventional US Navy has an incredibly bad history when it comes to post mortem investigations.

They have very consistently used scapegoats to hide systematic issues, or problems caused by people higher up the chain.

Someone needs to polish their brass before that happens.

You are both right and wrong. A competent crew wouldn't have failed.

But given the operating conditions (lack of sleep) and recruiting (lack of personnel) a competent crew couldn't be assembled on the McCain.

The crew did their best under the conditions, and failed.

Sounds like they shouldn't have left port, then.

An engine order telegraph wouldn't have this problem. So IMO it is very much a design problem, a problem that was already solved but needed to be created again so we can learn those lessons again.

The design looks pretty terrible. If the same UI can do very different things based on checkboxes and controls can be spread out over multiple stations non-obviously, that's about recipe for causing the problems above.

It sounds like they had a button for reverting all controls to a single station, if that wasn't used to recover obvious control that's on the sailors, imo. The fact that such a button is necessary to recover from a run of the mill situation is however a serious design failure.

This is nonsense. It's the same argument that people use against memory safe languages "it's possible to write memory safe code in C, you just have to not be incompetent". The truth is, all people are various levels of incompetence, and varies according to many different parameters that are all perfectly expected (like sleep deprivation).

You design a system to be as robust as possible to all operating conditions, which includes human fallibility.

Did you read the part where control over each propeller is passed separately to different station?

This does look like a very error-prone design to me

I'm very curious about that. It sounds like the kind of thing which is done just because it can be done. But in doing so adds a wast amount of complications and makes everything very error-prone (as you say).

What is the purpose of passing separate parts of the control to separate stations? When is that useful?

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