A very important thing to remember about wave height. It is an average. The overall height is 2X the published height. In other words -- a 4' wave is really 8' trough-to-crest. Being an average, there can be much larger waves that roll through in sets and smaller ones also.
Brian's advice about dividing the height and frequency is a good rule. I've been on the ocean many times when there were 8 footers, but the wave timing was very long. I've also been on the Chesapeake Bay when the waves were only 4' and there was only 2-3 seconds or less in between waves --- That's a snotty ride
Just remember -----
There are many old sailors and many bold sailors --- But not too many old bold sailors!
Brian's advice about dividing the height and frequency is a good rule. I've been on the ocean many times when there were 8 footers, but the wave timing was very long. I've also been on the Chesapeake Bay when the waves were only 4' and there was only 2-3 seconds or less in between waves --- That's a snotty ride
Just remember -----
There are many old sailors and many bold sailors --- But not too many old bold sailors!