40' waves
Unfortunately, in the open ocean, if the breeze blows above 40-45 knots for long periods of time, you will see waves in the 40 foot and higher range fairly often. They are routinely seen in the North Atlantic and North Sea-I spent 3 days in a NE gale of the East coast of the Bahamas and saw lots of them-some bigger (in a Tartan 37).
And yes, off the Pacific Coast of the US and Gulf of Alaska they can get as big-In the Sydney Hobart Race several years ago- many of the boats encountered waves in the 70-80' range at the height of the storm...Imagine racing-never mind sailing, in that weather!!
And there was the famous rescue in the Single Handed Round the World Race (Vendee Globe) by the British guy (Pete Goss) of the Italian guy (Raphael Dinelli).
Goss (who was ahead and downwind of the sinking boat) turned around (alone, mind you) and sailed UPWIND (alone, mind you) in 60-70 foot seas and 60+ knot winds for over 120 mn!!! Alone. Then, he managed to find a guy in a life raft-floating around in those Gynormous waves and low visbility. Alone. In a 60 footer. And then picked him up and nursed him back to health..amazing feat...
"And there be Kraken, too"
S