Many years ago I was on a jack-up drilling rig on the edge of the continental shelf in the Gulf of Mexico in about 200 feet of water.
Hurricane George, which turned and hit Mexico, blew across our rig.
All hands were evacuated by boat early in the day because of the lack of helicopters, but someone had to operate the crane to lower people to the work boat so the tool pusher, the mechanic and myself stayed to ride it out.
By nine that night the wave height measured from the legs on the jack-up was over forty feet.
The wind gauge in the wheel house showed gusts of over seventy miles per hour.
We had a sixty foot air gap, but some of the waves were hitting the bottom of our hull.
The giant LeTourneau jack-up was doing a Watusi dance, and cracks began to appear in the floors of the galley and living quarters.
The sweetest sound I've ever heard was the two-way radio when it crackled to life asking our location for an emergency evacuation by a big Puma flying on radar.
The Puma couldn't land; he could only hover for a short time.
We crawled across the landing mat and jumped up into the helicopter one at a time as he made successive passes trying to time a calmer period when he could approach.
The thing I remember most clearly was that the sea was not black; it was solid white!
When we got back to the rig several days later, we could see the damage the waves had done to the items on our upper deck which was forty feet thick.
In other words, the wave height had to exceed the sixty foot air gap plus the forty foot hull depth to reach our upper deck.
The wind gauge in the wheel house was broken at 110 miles per hour.
Amazingly, the rig itself was virtually undamaged except for cracks in all the floors.
A litte J-B Weld, a few sacks of paper and miles of duct tape and you were back to drilling in a couple of hours.