A couple of questions about drowning

[Lucilius]

How much weight in stone would be necessary to prevent someone weighting ca. 50Kg from keeping themselves afloat? How long does one last underwater before losing consciousness? I would guess 2-3m. Is that right?

 

[Worndown]

Humans barely float. It takes ten to fifteen pounds to sink you. You would need to google the time to pass out once you start drowning. Holding your breath makes the experience longer.

 

[AreWeWinning]

On some scuba diving forum someone says they can barely swim up 30 lbs, while their body weight is 200 lbs. That's 15% of body weight.

I think I would go for 30% of my body weight if I wanted to do this.

 

[Lucilius]

Another problem is how to evade triggering the sophisticated AI system monitoring the bridges here. How does one move and behave to be inconspicuous to the machine? Should I test the system by lingering on the bridge exhibiting different behaviors to get a sense of what gets flagged and what not?

 

[theboy]

In 10 minutes at the most you are dead

You can pretend to talk on the cell phone or draw the landscape from the bridge.

Don't attract attention

 

[AreWeWinning]

Another problem is how to evade triggering the sophisticated AI system monitoring the bridges here. How does one move and behave to be inconspicuous to the machine? Should I test the system by lingering on the bridge exhibiting different behaviors to get a sense of what gets flagged and what not?

I'm not sure what these are, but I think you should choose a location where there are no such systems rather than trying to evade them.

The last thing you want is to be rescued and live the rest of your life brain damaged.

Once you do it, eliminate any uncertainty or risk factors. Either go for the sure thing or don't do it. At least that's how I think about it.