Been working the rigs for the past 25 years in the GoM, South China Sea, and Red Sea. Fortunately I've never had to endure the rough, cold North Sea. I have rode out some hurricanes in the GoM due to the operators piss poor planning and it can get just as scary rough as the North Sea.
While serving on USS Moosbrugger DD980 (destroyer) we were up there in the North Sea. We were told wave height was 30-40 ft, I believe it. 600 ft of destroyer moving around like a leaf in a hurricane. It was unreal. I can't imagine being on a stationary platform dealing with such extreme conditions.
How about 20' seas with a 110 ' Standby boat ? It was 2 days before we could eat or walk on the boat. Luckily the Sea Buoy & the rope held. Only 3 of us on board. Suuuckeed !
Just like the Bering sea, NO JOKE. Further from the equator so bigger seas. Been tossed around in it my self while in the Navy.
I'm with Jim, aka Realtor, wonder what they are on. I highly doubt that they have a production platform right beside a drilling platform but who knows. They do so strange shit in the oil business.
It's not a drilling semi sub, it's an accommodation rig. It houses workers while they build out platforms. there is no drilling derrick, but there is a large articulating gangway.