A lane with no waves on the sea at Land's End

As we sailed past Land's End and out to Wolf Rock, we passed a long strip on the surface of the sea which had no waves. I've seen such before and had it in my mind that it was to do with the meeting of water of different temperatures. That seems possible in this location. Then I found this excellent synopsis https://earthscience.stackexchange.com/questions/10625/lanes-of-flat-ocean-surface-in-coastal-waters I am now interested in understanding the vertical component waves.