Single or double hull? Real subs

[Wheelerdealer]

That diagram also makes that beast look like a lot of it was wet hull.

That's why Soviet/Russian boats sit so high out of the water.

[southern or]

Was the Papa (K-222) single or double?

[Covert Shores]

Double. The missile tubes were between the hulls. The large flood holes along the circular portion of the hull are also a giveaway.

[vasily]

What's the deal with the Typhoon escape chambers? Did those actually work? That diagram also makes that beast look like a lot of it was wet hull.

Yes, probably. I've seen pictures of twenty rows of four sailors (80 total, times two chambers) during a drill. There are no recorded incidents of a Typhoon needing the escape chambers to evacuate. Other Soviet subs had smaller escape chambers.
The earlier Soviet subs had "issues" with reactor, battery, and other gassing safety. That's probably the reason for the escape chambers, and why a red container for their gas mask was worn on their hip as part of their dress uniform.