I had a friend whose sister had cystic fibrosis and she regularly got infections that turned her mucus blue. My friend went on to become an RN and later said that pyocyanin (PCN) was the cause of the blue colour, and that it always came on when her sister was infected with pseudomonas aeruginosa, and pseudomonas pyocyanea in particular. I think pseudomonas infections are fairly common.
ThankQ.
Her type of submarine most likely could not do (depths? other?) what would have to be done to cause one kilometer of damage by explosions.
Not that I know anything...