"Beyond a reasonable doubt" is not "beyond all doubt," of course. Juries routinely apply their collective wisdom to the evidence to decide whether any doubts as to causation are reasonable. The final jury charge in the Conception case hasn't been made available yet, but it will be interesting to see how the Court squared the causation circle. In brief, the defense claims line up with your thought, Wookie; his jury-instruction brief urges a finding, beyond a reasonable doubt, of "but for" causation as to at least one decedent: That is, regardless of whether it was grossly negligent not to follow applicable maritime law, the failure to have a proper watch must also have (beyond a reasonable doubt) actually caused a death. The government's proposed instruction is that "the defendant’s misconduct, gross negligence, or inattention to his duties was the proximate cause of the death of a victim. A proximate cause is one that played a substantial part in bringing about the death, so that the death was the direct result or a reasonably probable consequence of the defendant’s misconduct, gross negligence, or inattention to his duties."And that’s really what it comes down to, isn’t it?
Had the person responsible for following the regulations followed the regulations, would those 34 people have died?
To me, there's not really much difference; if the death was "the direct result or reasonably probable consequence" of the breach, then without the breach, the death wouldn't have occurred. I'll post the final charge if it comes available, but it is often only in the transcript, which is unlikely to be available anytime soon, and not at all if there's no appeal (i.e., if the government loses).