Dont know about FAR, but in the UK, rule 20 of the Rules of the Air prohibits VFR flight at night.
I really think that VFR ops overwater at night in an aircraft without automatic height hold acting through a fast-acting input to the collective channel of a 4-axis autopilot is asking for trouble. And using NVG is not a way to convert night to day. The RAF operates a variety of helicopters with an assortment of APs using NVG. All of them, without exception, require two crew in the cockpit for such an operation. That includes the SAR crews who can choose any combination of NVG and white light that gets the job done.
Sven