What's the round thingy,..??

[Bondo]

In the 1st scene in this video, there's a round thingy on one of this ship's windshields,.......
What is it,..??

 

[alldodge]

Clear View Screen

 

[Bondo]

Ok,..... So how does it provide a Clear View,..??
Is it like a windshield wiper,..?? Does it spin a wiper blade,..??
Does it work like a defroster,..??

 

[alldodge]

The window spins to disperse water and can also be heated

WIKI has best description

 

[Bondo]

Thank you Bob,.....

 

[Scott Danforth]

Cool, learned something today

 

[briangcc]

They're used on our machine tools. DMG 160/210. Clears cutting fluid from the viewing windows.

 

[QBhoy]

Yeah. Constantly rotates and doesn’t allow water to sit, obstructing view. Found commonly on commercial spec boats over the decades gone by. Pilot boats mostly all have these.