? on round things in plow windows

a while back I was watching a program on discovery chanel about fishing boats and noticed that there was a round object in the window of the boat that was about 12 inches in diameter and looked like it was spinning. It reminded me that I saw the same thing on a track plow at the local rail yard. does anybody know what these are or what they are for?

Pike

Its a windsheild wiper, just used to clean a smaller spot and faster the the full wipers can do.

They are revolving panes of glass and their purpose is to maintain visibility for the operator by preventing the window from freezing over–as long as the pane is revolving then moisture cannot freeze. I think they have a technical name but I usually call them “those twirly doodads”.

On vessels we call them spinners, or slingers. They are expensive, but they are the most effective way I’ve ever come across to keep a window clear.
The outside ring usually has a heating element inside of it to melt any ice that tries to form around the edges. The ones without the heater element will sometines freeze up and get stuck. The hub has an electric motor in it.
I do believe you could throw a bucket of paint at one, and it would clear instantly.
I love them. Just wi***hey would put them on all boats.

Wasn’t the official name for those spinners “Kent Screens”? I seem to remember they were put into use on ships during WW II.

I seem to recall them being called “clear view”, but don’t know if that is an official name or a nickname.

Bob Boudreau
Canadian Coast Guard Retiree (shore based!)

Officially named “Aldis Glass” Was standard equipment on most HMS escort ships during WW 2