As one of many who have flown over water at night and out in a B206 in the Caribbean hopping from island to island well after dark. I can truthfully say it can sometimes be scary
.
Also one of the reasons most operators today want Helicopter drivers to have an IFR rating. Not because they will fly/file IFR but because it will be
IFR when VFR.
Besides all the other toys that folks will post here, try and get your boss to put in a good Radar Altimeter. It may be dark out and you have no horizon or be able to tell which is sky or water, but a Radar Altimeter will let you know your altitude all the way to the crash.