Back in the 1960s and 70s, there loads of powerboats with headlights. They worked great. I know of a dozen charter fishing captains that have them and would not leave the dock without them. Contrary to popular belief, they actually do act just like car headlights, and they're far superior to a spot light because they were mounted below the bow and did not reflect on any portion of the boat - just the objects in front of the boat. They were wonderful for navigating in tight quarters with lots of unlit buoys and day markers, as well as locations where there are lots of anchored boats that choose not to turn on their anchor lights because it runs the battery down.
Many of the powerboats that had them were high-speed boats that zipped along at speeds in excess of 40 knots. When I had my store, I custom installed them on some Chaparral, Donzi, Pro-Line, Boston Whaler, Mako and Starcraft boats. Back then, a pair ran about $400, one for each side of the bow. And you had to cut a hole in the bow to insert the light fixture into. They would sure make life a lot easier when navigating through a maze of crab and lobster pot markers at night in New England and Chesapeake Bay. I wish I would have had them on my boat the night I nearly slammed into a massive stake net more than a mile off Tilghman Island. I can still hear my wife screaming "we're gonna die."
Gary