Re: adult life vests
Big boats sink slower than small ones. But I'm not agreeing with 5, or even 15 seconds, and it doesn't matter; the officer wins.
Agree...
But it is the judge that always wins.

I would have my day in court.
The law says "Readily Accessable" and a "Reasonable amount of Time", That opens the "Reasonable Person" legal theory.
I would argue that you should reasonable have it in your hand in 5 seconds.
And completely doned in under 60.
And, if the prosecuter doesn't see it a valid case, or the Officer doesn't show for the trial .... You win by default.
Been there, Done that!
And, boats under 20 feet don't sink at all, They just swamp.
(That's the Law!)
But the issue here is not how fast boats sink, or capsize, or how fast you can be thrown overboard.
I totally agree with the good judgement of wearing one.
The legal argument is what would be reasonable.
If there is nothing in the law that states 5 seconds, and no one can do it in 5 seconds ...
That is "Unreasonable!"
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NOTE:
We just held a life jacket drill in the living room.
Type III, Three Buckles, seated, jacket at your feet.
Timed from "Go" to last buckle snapped.
Best time ... 17 seconds. Worst time ... 21.
This was after a trial run, with "Reasonable Adults".
At 5 seconds, nobody even had it over their shoulders.
Add some confusion, panic, and a pitching deck and 40 second looks barely reasonable.