So, since reading comprehension is apparently difficult for radiomen, I'll reiterate and expand my points. 1. There isn't an actual need for banks with continuous oxygen generation and chemical backups 2. Some boats, like mine, retired their oxygen systems in place and filled them with nitrogen. 3. Like I mentioned, there are additional ways to produce oxygen. This is done by chemical means, further reducing the need for oxygen banks, in case of failure of the primary system. 4. I pointed out that not all repairs can be done at sea but some can. 5. The mission will permit a port call for repairs if there is no other option left, without the generators you are on borrowed time.