Posted by Herman and Gail Schiller (hschiller2@…>)
Many years ago I followed a Raymarine instruction to afix the DS
Transducer to the solid spot in the hull using silicone caulk. I did
this first in 1986 on an S-2 7.9 Meter which is a balsa cored hull
like Freedoms are. This installation always was less than perfectly
reliable in providing a depth reading all the time. I now have a
Freedom 28 Mull, and needed to replace the depth sounder in
mid-season. Therefore I glued the new DS’s transducer into the area
in front of the keel where the “transducer in water-filled baggie”
method indicated solid GRP. This too was also installed using
silicone caulk. The DS readings became more erratic this year, and I
purchased a new DS to replace it. The new DS instructions stated that
gluing the transducer to the inside of the hull should be done with
an epoxy glue, and definitely not silicone caulk.
Long story short, I decided to reglue the old transducer to the hull
with a Devcon Epoxy glue. The results were astounding. A dead-steady,
continuous reading is now available, with no more 0.0, or
fantastically large depth readings, from the old unit.
Lesson: Epoxy, which is much stiffer than silicone caulk, does a way
better job of transmitting the echo pulse from the bottom to the
transducer, and is the way to do this type of installation.
Herm
Yeah, but if you ever have to replace that transducer, maybe to get a different
depth sounder, tdon’t expect to get it off in one piece.
Steve Gaber
Sanderling, 1967 C-31 #77
Oldsmar, FL
---- Herman and Gail Schiller <hschiller2@…> wrote:
Many years ago I followed a Raymarine instruction to afix the DS
Transducer to the solid spot in the hull using silicone caulk. I did
this first in 1986 on an S-2 7.9 Meter which is a balsa cored hull
like Freedoms are. This installation always was less than perfectly
reliable in providing a depth reading all the time. I now have a
Freedom 28 Mull, and needed to replace the depth sounder in
mid-season. Therefore I glued the new DS’s transducer into the area
in front of the keel where the “transducer in water-filled baggie”
method indicated solid GRP. This too was also installed using
silicone caulk. The DS readings became more erratic this year, and I
purchased a new DS to replace it. The new DS instructions stated that
gluing the transducer to the inside of the hull should be done with
an epoxy glue, and definitely not silicone caulk.
Long story short, I decided to reglue the old transducer to the hull
with a Devcon Epoxy glue. The results were astounding. A dead-steady,
continuous reading is now available, with no more 0.0, or
fantastically large depth readings, from the old unit.
Lesson: Epoxy, which is much stiffer than silicone caulk, does a way
better job of transmitting the echo pulse from the bottom to the
transducer, and is the way to do this type of installation.
Herm
I can almost not believe my ears that the manufacture called for
gluing a transducer in with silicone! Anything that softens the ping
going out or coming in is going to degrade the performance of depth
sounders. You know you can also get very good results putting them in
a mineral oil but of course this involves building or purchasing a
tank for the oil and glassing that into the boat. The upside is that
you can eliminate the angle caused by dead rise in the hull form. Big
advantage is no more having to clean the transducer. In my opinion
the best of all is a retractable 'ducer with a flap in the fixture.
One thing for sure… you have certainly gotten to the bottom of that
problem! heh heh Good job.
Many years ago I followed a Raymarine instruction to afix the DS
Transducer to the solid spot in the hull using silicone caulk. I did
this first in 1986 on an S-2 7.9 Meter which is a balsa cored hull
like Freedoms are. This installation always was less than perfectly
reliable in providing a depth reading all the time. I now have a
Freedom 28 Mull, and needed to replace the depth sounder in
mid-season. Therefore I glued the new DS’s transducer into the area
in front of the keel where the “transducer in water-filled baggie”
method indicated solid GRP. This too was also installed using
silicone caulk. The DS readings became more erratic this year, and I
purchased a new DS to replace it. The new DS instructions stated that
gluing the transducer to the inside of the hull should be done with
an epoxy glue, and definitely not silicone caulk.
Long story short, I decided to reglue the old transducer to the hull
with a Devcon Epoxy glue. The results were astounding. A dead-steady,
continuous reading is now available, with no more 0.0, or
fantastically large depth readings, from the old unit.
Lesson: Epoxy, which is much stiffer than silicone caulk, does a way
better job of transmitting the echo pulse from the bottom to the
transducer, and is the way to do this type of installation.
Herm
-BTW You can now buy liquid filled transducers that are ready made
for install inside the boat and they compensate for the deadrise.
Also canted element transducers that get you in the ball park for thru
hull ones without using a fairing block. We used to make two trips
and cut the block back at the shop but when we were pressed for time
we sometimes would haul the whole table saw out to the job… heh heh
Posted by Herman and Gail Schiller (hschiller2@…>)
To determine a spot on the bottom of a hull where there is solid GRP
(not balsa, foam, or air bubble void) one sticks the transducer in a
water-filled baggie, and places it over prospective sites.
Someone must monitor the DS display to see when you get a solid
reading (not interspersed with 0.0 or other invalid displays). Then
mark that spot as OK with a magic marker. After cleaning up that
spot, one can either glue the transducer to the hull with epoxy
glue, or glue a piece of 3" PVC pipe suitably beveled to fit the
hull. This PVC pipe must be glued to the hull to be watertight and
then can contain the transducer, immersed in fluid, and capped so
that it doesn’t lose the fluid therein.
Herm
At 03:59 PM 4/28/2008, you wrote:
Does the transducer really have to be in some kind of water filled
bag and what is supposedly achieved by this?