ETG,
>>>how long it takes to fly over the Atlantic Ocean
FWIW, if you are crossing from the Northeast/Canada area, your crossing should take about 3-1/2 hours, on average. That's from coast out/feet wet to coast in/feet dry.
Of course, going down in Canada or Labrador could be a real challenge, too!
JMHO,
Mamabear
(PS) The PFDs onboard the aircraft are pretty good. You might not need/want to carry your own. Or you could take a couple of heavy duty balloons as a field-expedient flotation device.