Hi Jon!
Sorry I am a bit late in answering, but I am presently in Africa and was last week in some remote area with no Internet connection. I am now in Accra and are able to communicate. Your question is not at all stupid, as you might know today it is an international standard for opening the hatches and connect a rescuevessel to same. Re the last action for trying a rescueeffort on the Kursk. In the days of VIICs there was of course no such system, but all the hatches could be opened from outside by a handwheel see the drawing below of the lower towerhatch. On photo of the tower tophatch it looks as on the museum U 995 they have removed the top hatch wheel, however you can see the a small part of the stuffing box for the spindle in the center of the tophatch. Thus apart from removing the outside handwheel the cover could only be locked by a catch inside. That catch was merely used to release the overpressure in the sub and preventing the hatch to be flung open which might have blown the CO overboard if the hatch was flung fully open.
Tore
