Smooth

During ocean gales, when very high seas are running, it has been observed that every few minutes a kind of lull, called a smooth, takes place in relation to the sea, and that these lulls occur after about every third sea. Vessels intending to heave to after running in a gale wait for one of these smooths, and when it comes to them they put the helm down and come-to in a much easier and safer manner than by manoeuvering the vessel so as to encounter the full force of the trough.