Someone here implied that yachtsmen are reckless and foolish. Very very few don’t know what they are doing and the experienced have a very heathy respect for the sea and value their safety!
Not all small craft are equal however. Motorboats have no chance of surviving high seas, some yachts fair much better, others are designed to take a pounding. It’s all about keels and hull design. EG A 26ft Contessa with her long keel hull would be vastly better than say a modern Bavaria 32. The Bavaria is twice the volume of the Contessa with little low down weight, so would be far more prone to getting knocked down, but would feel much more uncomfortable/dangerous. When the tired a nd scared crew of the Bavaria would be seeking a port of refuge, the Contessa would be coping well.
Sustained very high winds with a very long fetch will.produce phenomenal wave heights.
The Atlantic swell is often quite big because of the fetch, but it’s less pronounced offshore.
Depth affects wavelength, hence steeper sided more dramatic looking (and dangerous) waves form in the shallow waters by the coastline.
Given that it would take a long time for these waves to form and high winds were being experienced, it’d only be a suicidal blind idiot who would put to sea in such conditions. The warning signs are obvious and abundant!
Only yachts that are on long passages with no port of refuge would be affected, but I’d hazard a guess that transatlantic skippers heading to and from the UK would be giving such voyages a miss at this time of year due to the general weather trends of winter, especially given the sustained windy weather of late. When making long passages and the inevitabke bad weather approaches, yachts often reroute to avoid weather systems. The skippers who sail the Atlantic are usually far better qualified than the majority, who make short coastal hops.