“Oil on troubled waters” has been an idiom since forever, I think.
Works great on a lake with ripples on it, and it doesn’t take large quantities – a tablespoonful to half an acre of water according to one of the clips below. You end up with a molecule-thick layer with the molecules all lined up so their watery tails are in the water, and their oily heads stick up and tend to move en masse with the wind instead of generating individual ripples.
I don’t know how this scales to the sea with breaking waves. Imperfectly, I imagine. IIRC Knights was advocating it with a bag fore and aft to make a smooth to leeward for launching boats.
Here’s an 1892 NYT article quoting twelve or so masters who wrote to the H.O. giving reports on oil effectiveness. All but one of them reported good results.
Benjamin Franklin famously investigated the calming properties of oil during his visits to England in the mid-18th century, demonstrating the effect on lakes such as Derwentwater. Communications between Franklin and William Brownrigg show that Franklin had first encountered the phenomenon aboard a ship in 1757 and investigated it several years later alongside Brownrigg and Sir John Pringle.[7] This led to the discussion of the topic at the Royal Society on 2 June 1774.[8]