Vitamin D.....created by the action of sunlight on the skin. See here if you care:
http://www.healthmart.com/supplements/vitamin-d-deficiency.html

Seemingly Tiny Tim had rickets because of a lack of sunlight and Vit-D. Smoggy industrial Lundun eh? Not saying I have rickets or any other disorders but hey, seismic life in the North Atlantic doesn't lend itself to tanning or even getting outside much. I think I've spent 4 minutes outside today and it was freezing.

The sea looks just like Angola was....big lollopping swells lazily rolling along minding their own business looking for a surfer on some distant coast. Difference is the temperature. It's way down there and then there's the windchill. The poor gunners on the back deck are wrapped to the last and run for their warm hut after meals.

I tied my chair to the desk in my cabin today. It went flying last night about 5:50 across the room on one of these. It must be one of the first surveys I've been on where we are taking the sea beam on. Now she doesn't roll much but every now and again there is a bit of a heave. I had my legs on another chair in the telly room last night and both chairs and myself went for a wee slide. I thought it was the table and went to grab my tea, but then remembered the table is bolted. I just waited for the return slide to get back to my tea. Those moments are kinda fun ;-)