Clear view screen
From Wikipedia, the free encyclopedia
On ships, a clear view screen or clearview screen is a glass disk mounted in a window, usually on the bridge, that rotates at high speed to disperse rain, spray, and snow. A clear view screen is typically driven by an electric motor at the center of the disk, and is often heated to prevent condensation or icing.
A picture of a modern clear view screen can be found at http://www.speich.it/htmlEN/cvs/cvs.htm.