[icegreentea2]

Separate from the comments about pressure differential - even 2 atmospheres is probably enough to risk decompression sickness if they just popped the hatch at the end of the dive. So you'd need some way to reduce the pressure gradually. That either needs a way to vent gas out (which means adding a hole in the hull, which you'd really rather avoid having to deal with), or having a compressor inside the hull, or do the entire hatch popping in another pressure vessel. All of those options seem to odds with the 'go cheap and fast' approach.

[noduerme]

I'm not sure why it seems intuitive to me that the external to internal pressure ratio would be the measure of force exerted... i.e. that 2psi vs 1 would have the same net force as 100 vs. 50. I guess it's wrong, hence the responses, but it's still bothering me. Like, it seems intuitive that twice the mass in the same volume should exert twice the force on the inside of the container. I don't completely understand my error. Yes there's still 299 more atmospheres outside, but it's only 150x the inner pressure.

I'm not willing to concede this yet, I'll need to watch some youtube demos of why I'm a dumbass. hah.

As far as decompressing the hull on ascent, I was imagining that if they were testing it by pulling vacuum in it (as mentioned above) there must be some kind of auxiliary air release port...?

[BlueTemplar]

Pressure is Force / Area.

The materials must resist the net pressure, which is a vector addition, not division of vector's magnitudes one by another.