@Khafee---that was sabotage---there is no way that hatch could stay open on a modern sub and it sinks---it is mechanically impossible---and then to have that much damage---.
Subs just don't nose dive into the ocean right from their position of parking---they slowly glide down a slope into the water---.
Plus subs have compartments that have doors that can be shut---and they are water tight---so maybe Joe Shearer may want to comment and bring out some truth.
IF a US$2.9bn sub can be sabotaged, OR as per their claim "left open by mistake" = incompetence. Either way who is to blame?