Swimming with Sharks: Navy Physician Remembers the Indianapolis Disaster
navymedicine.navylive.dodlive.mil
navymedicine.navylive.dodlive.mil
Staying together in a big, tight group might have been key.
In Harm's Way: The Sinking of the U.S.S. Indianapolis and the Extraordinary Story of Its Survivors by Doug Stanton (Mass Market Paperback)
Sounds like the reports of shark attacks on the living were greatly exaggerated, but its no wonder if men were hallucinating from dehydration and fever.
https://www.amazon.com/dp/B01M0ULKCM
Also this survivor has a website of the event
I hope we never have such a war again.