On Wed, 11 May 2005 14:45:17 GMT, Harry.Krause
wrote:

On Tue, 10 May 2005 19:40:29 -0000, (gudmundur)
wrote:

Hi folks, Just bought a Faria dash mounted depth sounder with a
'glue it inside the hull' transducer.

I used to be on the board for Faria. Nice company.

Will you cut this **** out? It's getting really annoying - this WAS a
good thread.

Later,

Tom

I have never had a problem on any of my boats.

--
Tony
my boats and cars at http://t.thomas.home.mchsi.com

-
"Shortwave Sportfishing" wrote in message
...
On Wed, 11 May 2005 03:19:14 -0000, (gudmundur)
wrote:

~~ snippage ~~

As for the silicone RTV glue, you are right on the money
there. I have glued ultrasonic doppler transducers to PVC pipes for many
years, and RTV is at least 90% as conductive to sound energy as any of the
lavishly expensive glues sold specifically for transducer mounting.

I was given to understand that silicone wasn't that transparent to
50Hz transducers. Any truth to that?

Later,

Tom

In article , says...

Hi folks, Just bought a Faria dash mounted depth sounder with a
'glue it inside the hull' transducer. Faria warns that it won't work
very good if my hull has core material in it. I am guessing it probably
has 3/4 inch plywood with the outer, and inner fiberglass body shell.

I only need to know when the water is perhaps less than 8 feet deep.
As long as it is deeper I have no worries.

What are the chances it will work o.k. out to perhaps 20 feet if I just
go ahead and glue it in anyway? I really don't want to remove the inner
fiberglass shell, and the wooden core, just to glue the transducer on
the inside of the outer skin.

Anyone currently running a half baked set up like I am going to try?
Do I have to just bite the bullet, and get out the Dremel?

Thanks all!



O.K. folks, It works like a champ! I had it in a local large
lake, and it was faultless down to 103 feet, the maximum lake depth.
It was accurate also, as I have been diving in this lake, and know
several points of depth reference. Don't know for sure if there is
a wooden core in the hull of my Four Winns Catalina, but if there is,
the transducer setup works fine. I did not use the deadriser or anything
special, just silicone RTV glued the transducer to the hull, and sat
a red brick on top to squish the glue.

Man, this will help me plan my dives in the lake much better now!
I know exactly where the sides of the channel are, at about 80 feet down.

Thanks all for thoughts and suggestions. Gummi.

In article ,
says...

On Wed, 11 May 2005 03:19:14 -0000, (gudmundur)
wrote:

~~ snippage ~~

As for the silicone RTV glue, you are right on the money
there. I have glued ultrasonic doppler transducers to PVC pipes for many
years, and RTV is at least 90% as conductive to sound energy as any of the
lavishly expensive glues sold specifically for transducer mounting.

I was given to understand that silicone wasn't that transparent to
50Hz transducers. Any truth to that?

Later,


I wish I could be helpful on the 50khz vs. silicone glue, but all
of our doppler 'fluid flow rate' transducers were higher in frequency,
at least 200khz and higher. With a higher frequency transducer, the
doppler shift is also higher for a given flow rate, and therefore, a
more accurate reading can be measured using the very same simple circuits.
In our case the silicone was both the mounting method, and the conductive
medium. When I first went to work for the company I saw this method being
used, and I insisted it was only half-assed at best, but the waveforms
on the scope, and the readings on the analog meters were rock solid!
To some degree, my career is based on "If I don't know it can't possibly
work, then it will probably work".

On Thu, 12 May 2005 16:14:47 -0000, (gudmundur)
wrote:

In article ,
says...

On Wed, 11 May 2005 03:19:14 -0000, (gudmundur)
wrote:

~~ snippage ~~

As for the silicone RTV glue, you are right on the money
there. I have glued ultrasonic doppler transducers to PVC pipes for many
years, and RTV is at least 90% as conductive to sound energy as any of the
lavishly expensive glues sold specifically for transducer mounting.

I was given to understand that silicone wasn't that transparent to
50Hz transducers. Any truth to that?

Later,


I wish I could be helpful on the 50khz vs. silicone glue, but all
of our doppler 'fluid flow rate' transducers were higher in frequency,
at least 200khz and higher. With a higher frequency transducer, the
doppler shift is also higher for a given flow rate, and therefore, a
more accurate reading can be measured using the very same simple circuits.
In our case the silicone was both the mounting method, and the conductive
medium. When I first went to work for the company I saw this method being
used, and I insisted it was only half-assed at best, but the waveforms
on the scope, and the readings on the analog meters were rock solid!

Interesting. I would have thought that silicone, but it's very
nature, would be a poor medium, but now that I think about it, it
makes sense.

To some degree, my career is based on "If I don't know it can't possibly
work, then it will probably work".

Trust me - a lot of brilliant careers are based on that simple, yet
somehow complex, principle. :)

Later,

Tom