In article 6yage.73235$c24.21202@attbi_s72, says...

Most boats have a spot in the hull that is nothing but glass. Some paint
this area black so you can find it. Others leave it clear and it will show
up as a clearer area.

To make sure it will work at this spot - fill the bilge with enough water to
cover the area by about 1/4". Lay the transducer on this spot and check.

The transducer will not work thru any air pockets so you have to put some
water in there to try.

To install - I use silicone. People will tell you not to but I have always
done this with no problem. Build up a large area of silicone about 1/2"
thick. Take the transducer and push it down all the way pushing out all the
excess. Don't twist. This will remove any air bubbles. Take and wipe up
the excess w/ papertowels being careful not to move the transducer.

Problem w/ epoxy is you need a lot to push down and make sure there are no
air bubbles.


Thanks Tony, This is an old Four Winns (1985) Catalina open bow, and
the area I have been looking at just forward of the drain plug may indeed
be all glass the whole way through. I compared to the depth transducer
mounting on my brothers Stratos, and his is simply glued on exactly as
you have described. 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 went ahead and RTV glued the bugger in. I will launch tomorrow and
see what happens. I'll let you folks know the outcome, and hope it's
a positive one. As I said, if it even works down to 20 feet, I'll be happy.
I was guessing if there is core material, it is probably somewhat
water-logged anyway from 20 years of service, and that would actually be
an advantage in this case.

Bless all, Gummi.

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

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...

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