[Caipirabob]

I'd like to know more about this ....

Me, too. The words "Violent and traumatic decompression" come to mind. I wonder how that works out from the depths these marvels run at?

I'm also hoping the words "pasty goo" aren't included in the manual.

[RoadGumby]

What decompression? Subs operate at atmospheric. That is purposeful, to negate need for decompression.

[rottndog]

The words "Violent and traumatic decompression" come to mind. I wonder how that works out from the depths these marvels run at?

No decompression would occur, because the air pressure in the boat remains approximately constant regardless of depth. I say approximately, because some air pressure differential will develop between the inside of the boat and sea surface air pressure (one atmosphere) over time while submerged, but it is only slight. Once the boat reaches PD or surfaces, it is required to 'equalize' before snorkeling or ventilating, but that will only result in minimal ear popping, similar to what is experienced on an airplane changing altitude.