This was a really fascinating read, but subs/maritime topics fascinate me in general.<p>The sub in question is 200ft long. Has only been seen by accident due to TopGear Moscow photoshoot that happened to capture it surfaced off the coast in the background.<p>The sub docks underneath a mother ship sub which allows it to be transported.<p>The sub can go deeper than any US sub due to a weird construction style of titanium vessels inside the hull.<p>All of this happened in relatively shallow waters while being docked to the parent sub (something that wasn't revealed until later in the story)