Old Hat, the current thought is that they probably hit an uncharted undersea mountain, not another sub. That can only be characterized as an accident, not a mistake. Assuming, of course, that the mountain theory is correct.
We've now heard from at least two genuine sub experts in this thread, both of whom contradict your totally uninformed ideas. A wise man would now withdraw in silence.
I said nothing based on information. Remember, we don't know and will probably never know. Read more carefully. I pointed out the illogic in others reasoning.
What exactly is the relationship between accidents and mistakes. I mean don't mistakes sometimes cause accidents. Hmmm ...
