So again, like I said, this was a spy boat. Usually has crew of 25.
“It is not an ordinary vessel, it is a research vessel,” the president said while meeting with the Russian Defense Minister Sergey Shoigu in the wake of the tragedy.
Putin referred to the vessel’s crew as “highly qualified professionals” and called the deaths of 14 sailors a “great loss for Russia and our fleet.”
He specified that two of those who died in the fire on board the research vessel were previously awarded the nation’s highest honorary title – the Hero of Russia – while seven were navy officers in the rank of 'captain 1st class' (Russian equivalent to NATO OF-5/US O-6 captain rank).
7 US Navy captain equivalents killed? In a crew of 25? Yep. SPY BOAT!
As to the cause of "the explosion" - well some Norwegian science guy claims that "unnamed Russian officials" told him it was a gas explosion. However the Russian Defense Ministry says Nyet! No Russian has informed any Norwegian officials about the incident.
Gas explosion? What gas? Normal subs don't have any flammable or explosive "gas" aboard. Yes, submarines do accumulate hydrogen as a by product of their O2 generators (which produce oxygen by splitting it from distilled water), but the hydrogen is not accumulated in any quantity but is pushed out into the seawater flow that runs through the outer loop that cools the inner loop (of distilled water) that absorbs the heat of the nuclear reactor to create steam in the steam generator (which turns the turbines which turn the generators for electrical power) and which is also used for the drive train which turns the screw or screws for propulsion.