At least the Jack-Up sits on the seabed. Wait until you're on a semi-sub and during bad weather the gangway swings back and fore and up and down.
During previous years of being an offshore engineer, top of the flare tower and the crown block level at top of the derrick are my usual places of visits when I ever I went offshore or bottom of the concrete legs on Cormorant A and the Brent Field.
Now based in the office
Summer offshore