What's that on the fishing boat window?

I keep noticing on “Deadliest Catch,” and I’ve seen it elsewhere, that there is some device on the front window in the wheelhouse. It looks like a circle, maybe 18 inches across, with a cylindrical part in the middle. It’s forward facing and positioned such that it would be in the way of the captain looking out on the deck.

I’m guessing it’s some type of radar-related device. Anyone know?

No, it is the windshield wiper. The disk spins around fast enough to drive water off it, giving the pilot a better view through it.
(I have not seen the specific show but I have seen other fishing boats.)

Well, never would have guessed that. But yep, I even found a link that shows one: http://www.totalboatcare.com/store/index.php?main_page=product_free_shipping_info&cPath=318_482_504&products_id=2694&zenid=3fpc43e50pkeag14ufg00sq0t0

Thanks.

It also stops ice forming on that piece of window, or throws it off when turned on.

Because nothing is actually wiped, it’s usually known as a “clear view screen” or “clear vision screen”.