(https://en.wikipedia.org/wiki/Russian_submarine_Kursk_%28K-1...)

It was just 100m depth - a normal dive for professional divers - and i just remember how it was surprising that nothing was done during the next couple days. I mean such paralysis is typical for Russian bureaucratic machine, be it civilian or military (remember Rust?), yet these bangs were obviously easily heard by the listening anti-submarine posts of the Russian Navy ships idling right on top of it and nobody did nothing while waiting for the orders from "the top" and working around the clock trying to cover their a&&es.