During the journey across the Atlantic, Olaudah Equiano describes what two of his "wearied countrymen" did which was to jump into the Atlantic Ocean because they preferred death than to be kept captive in such a manner and be treated less than dogs.
He described that the two men were chained together and thus decided to jump into the Ocean when there was a smooth sea and moderate wind. He also described that another chained person jumped in and many more would have followed suit if not for the intervention of the slave masters.