How the CSS Hunley crew died

Maybe.

“(W)hen a torpedo blows something up underwater, it creatures pressure waves that reverberate in the water and through the body of anyone who happens to be in it. The instantaneous increase in pressure can squeeze oxygen out of the lungs and pop blood vessels in the brain. The effects are often deadly.

“But the damage occurs exclusively in a victim’s soft tissue, like the gut, lungs and brain - from the outside, it can be impossible to tell that the person has been harmed.”

http://www.theledger.com/news/20170824/science-may-have-solved-sunken-civil-war-sub

Link at http://knuckledraggin.com/2017/08/mystery-solved-by-the-whiz-kids/

The Hunley comes out of its shell

“A combination of rust, sand, rock and assorted ocean debris, concretions are hard as concrete. The concretion layer that coated the entire submarine, inside and out, was so thick, the original iron has been obscured since the Hunley was first raised from the harbor floor. Some areas of concretion were harder than the iron underneath them. In order for the sodium hydroxide treatment to leech the corrosive salt out of the iron skin effectively, the concretion had to be removed first. In May of 2014, the submarine was immersed in sodium hydroxide for the first time. That initial three-month soak was intended to loosen the concretions.”

http://www.thehistoryblog.com/

(Archaeologists still do not know why the submarine sank.)