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Big round thingy in boat windows - is it an antenna or what
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Stefan Trethan
Sat, 04 Jul 09 17:58:15 +0000
Ok, so i keep seeing this thing on TV, and i want to know what it is.

Sometimes when they show boats there is a round thingy in one of the
front windows. The boats usually have several rectangular windows, and
one has a large circular frame set inside the glass. The frame is a
couple of centimeters wide and almost fills the entire glass in
diameter. There also seems to be a smaller knob like item right in the
center of the frame.

I suspect it is an electrical device like an antenna?

It seems so very odd to place it right in a window where it surely
obstructs the view. Or maybe it serves some navigational purpose? Or
maybe it's just a hatch to let fresh air in (this one seems
exceedingly stupid)?

Anyway, google couldn't help me, so maybe one of you can explain a
landrat like myself what purpose this strange thing serves ;-)

If it isn't immediately clear to someone what I am talking about I can
probably figure out how to make a screenshot of moving pictures and
show it to you.

Thanks

ST

7 replies folowing
Dave Mucha
Sat, 04 Jul 09 18:14:05 +0000
http://www.luminous-landscape.com/images-40-antartica/bridge.jpg





--- In Electronics_101@yahoogroups.com, Stefan Trethan wrote:

>
> Ok, so i keep seeing this thing on TV, and i want to know what it is.
>
> Sometimes when they show boats there is a round thingy in one of the
> front windows. The boats usually have several rectangular windows, and
> one has a large circular frame set inside the glass. The frame is a
> couple of centimeters wide and almost fills the entire glass in
> diameter. There also seems to be a smaller knob like item right in the
> center of the frame.
>
> I suspect it is an electrical device like an antenna?
>
> It seems so very odd to place it right in a window where it surely
> obstructs the view. Or maybe it serves some navigational purpose? Or
> maybe it's just a hatch to let fresh air in (this one seems
> exceedingly stupid)?
>
> Anyway, google couldn't help me, so maybe one of you can explain a
> landrat like myself what purpose this strange thing serves ;-)
>
> If it isn't immediately clear to someone what I am talking about I can
> probably figure out how to make a screenshot of moving pictures and
> show it to you.
>
> Thanks
>
> ST
>



dicsEE
Sat, 04 Jul 09 18:29:39 +0000
 
Stefan Trethan
Sat, 04 Jul 09 18:29:39 +0000
Exactly! And it's even got two of them darn things!

So what's it do?

Thanks

ST


On Sat, Jul 4, 2009 at 8:14 PM, Dave Mucha wrote:

> http://www.luminous-landscape.com/images-40-antartica/bridge.jpg
>
>

leon Heller
Sat, 04 Jul 09 18:46:56 +0000
----- Original Message -----
From: "Dave Mucha"
To:
Sent: Saturday, July 04, 2009 7:14 PM
Subject: [Electronics_101] Re: Big round thingy in boat windows - is it an
antenna or what?


> http://www.luminous-landscape.com/images-40-antartica/bridge.jpg


Wipers so that the helmsman can see out when it's raining.

Leon

Dave Mucha
Sat, 04 Jul 09 18:48:56 +0000
IINM, it is a windshield wiper sorta device.

the 'glass' spins fast so water is swept away from the spinning.

I could be wrong.

google clear view screen


Dave




--- In Electronics_101@yahoogroups.com, Stefan Trethan wrote:

>
> Exactly! And it's even got two of them darn things!
>
> So what's it do?
>
> Thanks
>
> ST
>
>
> On Sat, Jul 4, 2009 at 8:14 PM, Dave Mucha wrote:
> > http://www.luminous-landscape.com/images-40-antartica/bridge.jpg
> >
> >
>



leon Heller
Sat, 04 Jul 09 19:58:09 +0000
----- Original Message -----
From: "Mike Payson"
To:
Sent: Saturday, July 04, 2009 8:40 PM
Subject: Re: [Electronics_101] Re: Big round thingy in boat windows - is it
an antenna or what?


Interesting. So is the clear portion only the inside of the disk, or
does it create enough force to blow the water off the outside of the
windshield as well? Seems like old-fashioned windshield wipers would
be just as effective.

They are usually operated by an electric motor and belt.

Leon

jongkung01
Sun, 05 Jul 09 00:43:11 +0000


> Interesting. So is the clear portion only the inside of the disk, or
> does it create enough force to blow the water off the outside of the
> windshield as well?


I saw on a movie, the circular portion spins. There's a STATIONARY wiper that the glass passes under. I don't believe the idea is to spin it so fast to blow the water off. But hey who know?

Think of an old record player being the circular glass and the pickup arm being the wiper.

I don't know why they do it that way on boats / ships.


Jong

P.S. When I was a private pilot student, I was shocked to learn that my Cessna 152 didn't have a windshield wiper AT ALL !!!

Howard Hansen
Sun, 05 Jul 09 02:06:59 +0000
Three links to clear view screens:
The first says they rotate at 1500 RPM
http://en.wikipedia.org/wiki/Clear_view_screen
The second shows one type of construction.
http://www.speich.it/htmlEN/cvs/cvs.htm
An alternate type of construction
http://www.frenchmarine.com/Product.aspx?PID=826&CID=150

Howard


jongkung01 wrote:

>
>
>
>
> > Interesting. So is the clear portion only the inside of the disk, or
> > does it create enough force to blow the water off the outside of the
> > windshield as well?
>
> I saw on a movie, the circular portion spins. There's a STATIONARY
> wiper that the glass passes under. I don't believe the idea is to spin
> it so fast to blow the water off. But hey who know?
>
> Think of an old record player being the circular glass and the pickup
> arm being the wiper.
>
> I don't know why they do it that way on boats / ships.
>
> Jong
>
> P.S. When I was a private pilot student, I was shocked to learn that
> my Cessna 152 didn't have a windshield wiper AT ALL !!!
>
>