Seventeen Soviet Nuclear Sub Accidents Killed 266 Personnel Between 1960 and 1989
By Bruce Rule - Nov 6, 2014
See linked site for grim details including the loss of the K-8 NOVEMBER Class in there Bay of Biscay in 1970 when 52 personnel who already had been evacuated were ordered back onboard by higher authority.
As previously discussed by an archived article, only the first compartment was sealed when the K-8 sank. That compartment collapsed at a depth of 2020 feet. The implosion was detected by SOSUS at 04:04:44Z on 9 April.