I'm putting a fish finder in my boat and would rather silicone the
transducer to the inside of the bottom of the hull. Do I need a special
transducer or will any one work?

They make shoot-thru-the-hull transducers for this. Not to be confused with
"thru-hull" transducers
that actually get mounted through a hole in the hull. The
shoot-thru-the-hull types need:

- To be stuck down to the inside of the hull with the supplied sealent.
- Or be emersed in an oil.
- Both of the above are so there are no air bubbles between transducer &
hull
- The hull must be fiberglass as the transducer won't work through materials
with voids
- The location under the hull (outside) still must be one where water is
always covering
that area when the boat is moving. And where no air-bubbles will
collect.



"Randy" wrote in message
.. .
I'm putting a fish finder in my boat and would rather silicone the
transducer to the inside of the bottom of the hull. Do I need a special
transducer or will any one work?

Hi Randy,

I asked around and most are still mounting the transducers outside on the
rear of the transom at water line on aluminum and fiberglass hulls.

I thought through the hull on fiberglass was the big deal, but when I asked
around resecently with my marine soarces they said it was not as popualar as
outside?

I think the comment was that the through the hull method reduced the
accuracy of the fishfinder/bottom sounder.

What do others think about this?

--
Bill Kiene

Kiene's Fly Shop
Sacramento, CA
www.kiene.com

"Randy" wrote in message
.. .

I'm putting a fish finder in my boat and would rather silicone the
transducer to the inside of the bottom of the hull. Do I need a special
transducer or will any one work?

On Thu, 07 Aug 2003 14:48:44 GMT, "Bill Kiene"
wrote:

Hi Randy,

I asked around and most are still mounting the transducers outside on the
rear of the transom at water line on aluminum and fiberglass hulls.

I thought through the hull on fiberglass was the big deal, but when I asked
around resecently with my marine soarces they said it was not as popualar as
outside?

I think the comment was that the through the hull method reduced the
accuracy of the fishfinder/bottom sounder.

What do others think about this?

Hi Bill,

First, let's sort out the difference between "through the hull", and
"shoot through the hull".

"Though the hull" means that a hole is drilled through the hull. It
may be the most accurate method, but I will never drill a hole through
the bottom of any of my boats. My choice, I guess.

"Shoot through the hull" works on fiberglass, steel, and aluminum
hulls. The transducer is adhered to the inside of the hull, with a
"bubble free" adhesive. It works well, may be a little less accurate
than "through the hull", but not enough to matter. I've used a tape
measure to check mine, and it read 100% accurate at full stop. This
method is "iffy" for wood hulls.

"Transom mount" means you attach a bracket to the wet side of the
transom, and mount the transducer there. The wire is exposed, which
some people don't like, but it is quite accurate if installed
correctly. The most important thing with this method is to get it off
to one side of the engine where bubbles aren't a problem, but not so
far that it lifts out of the water at speed.

For a wood hull, I would recommend a transom mount, primarily because
I am old, and I think it is sacriligious to bore the bottom of a wood
hull. )

Regards,
noah

Courtesy of Lee Yeaton,
See the boats of rec.boats
www.TheBayGuide.com/rec.boats

Does not work on aluminum hulls.
Bill

"noah" wrote in message
...
On Thu, 07 Aug 2003 14:48:44 GMT, "Bill Kiene"
wrote:

Hi Randy,

I asked around and most are still mounting the transducers outside on the
rear of the transom at water line on aluminum and fiberglass hulls.

I thought through the hull on fiberglass was the big deal, but when I
asked
around resecently with my marine soarces they said it was not as popualar
as
outside?

I think the comment was that the through the hull method reduced the
accuracy of the fishfinder/bottom sounder.

What do others think about this?

Hi Bill,

First, let's sort out the difference between "through the hull", and
"shoot through the hull".

"Though the hull" means that a hole is drilled through the hull. It
may be the most accurate method, but I will never drill a hole through
the bottom of any of my boats. My choice, I guess.

"Shoot through the hull" works on fiberglass, steel, and aluminum
hulls. The transducer is adhered to the inside of the hull, with a
"bubble free" adhesive. It works well, may be a little less accurate
than "through the hull", but not enough to matter. I've used a tape
measure to check mine, and it read 100% accurate at full stop. This
method is "iffy" for wood hulls.

"Transom mount" means you attach a bracket to the wet side of the
transom, and mount the transducer there. The wire is exposed, which
some people don't like, but it is quite accurate if installed
correctly. The most important thing with this method is to get it off
to one side of the engine where bubbles aren't a problem, but not so
far that it lifts out of the water at speed.

For a wood hull, I would recommend a transom mount, primarily because
I am old, and I think it is sacriligious to bore the bottom of a wood
hull. )

Regards,
noah

Courtesy of Lee Yeaton,
See the boats of rec.boats
www.TheBayGuide.com/rec.boats

On Sat, 9 Aug 2003 17:45:04 -0700, "Calif Bill"
wrote:

Does not work on aluminum hulls.
Bill


Partially true. Transducers with speed and/or temp sensors don't work
well through aluminum. Otherwise, it's "do-able".

"Puck" style transducers can normally be used through an aluminum hull
if mounted in a small oil or water box (i.e. sealed Tupperware
container with the bottom removed, siliconed to the hull). Silicone
has been used to directly adhere the puck to the hull, but the results
aren't consistent- works for some, not for others. Epoxy will usually
break loose when the hull flexes, or due to different thermal
expansion rates.

Bronze body transducers should never be mounted directly to a
dissimilar metal. It causes corrosion. Use plastic bodied pucks.

Here are just a few links to illustrate:

http://www.wmi.org/bassfish/bassboar...ors/T62325.htm
http://www.vexilar.com/help/tips/tip003.html
http://www.vexilar.com/help/tips/tip015.html

I intend to experiment with alternative adhesives in my 14' jon boat
(more dense than silicone, more flexible than epoxy).
I'll let you know how it works out.
noah

Courtesy of Lee Yeaton,
See the boats of rec.boats
www.TheBayGuide.com/rec.boats