(Also note that since he's not being charged with murder, they don't need to prove him guilty beyond a reasonable doubt.)
The burden of proof does not change with the crime. If the state is bringing criminal charges and an accused person’s liberty is at stake, it’s beyond reasonable doubt (probably some exceptions, but I don’t think so here). I know there are some strange twists in maritime law, but I don’t think this is one of them. If it is, please post a code reference or case or something so I can learn.
If the estate of the deceased files a civil suit for wrongful death, sometimes called manslaughter, then the burden changes dramatically to preponderance of the evidence.
Murder, manslaughter, what’s the difference?
Generally the difference between murder and manslaughter is the state of mind of the alleged killer. Note again, different in every state and the labels often conflict. In Title 18 the definitions are “unlawful killing of a human being with malice aforethought” for murder (section 1111), unlawful killing of a human being without malice. It is of two kinds: voluntary and involuntary“ for manslaughter (section 1112).
The crime section stated in the article is 1115. The title ought to get you attention: “
Misconduct or neglect of ship officers.” Which is defined as follows:
“Every captain, engineer, pilot, or other
person employed on any steamboat or vessel, by whose misconduct, negligence, or inattention to his duties on such vessel the life of any
person is destroyed, and every owner, charterer, inspector, or other public officer, through whose fraud, neglect, connivance, misconduct, or violation of law the life of any
personis destroyed, shall be fined under this title or imprisoned not more than ten years, or both.”
The article calls this seaman’s manslaughter.
“employed” probably does not mean what you think and in this case the captain probably will meet the definition of employed.
Read the definitions on your own:
https://www.law.cornell.edu/uscode/text/18/part-I/chapter-51.
Regrets on being pedantic, but ...
Disclaimers in my previous post are incorporated by reference.