What are these three pillars with crank handles in the cockpit?

Posted by MisterGerry@reddit | sailing | View on Reddit | 25 comments

What are these three pillars with crank handles in the cockpit?

I've been watching The Mariner YouTube videos and his latest video shows a clear view of these three pillars in his cockpit. I've seen these on racing boats, but never knew what they did.
He operates them briefly in this video, but it's not clear to me what they do.