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posted to rec.boats.electronics
DPFresh
 
Posts: n/a
Default Depth FInder Sensor

Hello all, so as oppossed to drilling a hole in my hull for a depth
finder sensor, I should be able to set it up inside the hull as long as
the sensor is in some type of liquid right? IT will be able to tell
depths through the fiberglass hull right?

Thanks,
David

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posted to rec.boats.electronics
Larry
 
Posts: n/a
Default Depth FInder Sensor

"DPFresh" wrote in news:1144040012.290616.216280
@i39g2000cwa.googlegroups.com:

Hello all, so as oppossed to drilling a hole in my hull for a depth
finder sensor, I should be able to set it up inside the hull as long as
the sensor is in some type of liquid right? IT will be able to tell
depths through the fiberglass hull right?



That depends on whether the hull is cored or not. Fiberglass conducts
sound energy just fine. Hull coring, like a Boston Whaler, is damned
near a perfect sound absorber in the foam core.

So, test it. Hook up the sonar, but leave the transducer loose so we can
move it around and find a hot spot, a spot where it sees through the hull
the best...away from the motor noise, if you please. Put a couple of
inches of water inside the hull so we can couple the sound from the
transducer to the hull inside the boat without mounting it. Take the
boat out into 50' of water.

Now, keep the transducer underwater any time the sonar is on......

Put the transducer, with the sound output surface pointing at the hull,
down we assume, under the water and hold it there against the hull. Turn
on the sonar and see what we gots. See the bottom? Move the transducer
around in this area and look for the best picture. Ok, we found a little
spot it works better than others. Have a second party start the boat and
drive full speed in a straight line while you watch the sonar. Can we
still see the bottom in 50' of water, or did the display go all crazy
because the engine noise and underwater bubbles or cavitation under the
hull right here got in the way? While underway, where we want the sonar
to work, of course, move the transducer around under the bilge water to
see if our hot spot is the "underway hot spot". Note the location of the
best place.

Take the boat home, pump it out and give our hotspot a good scrubbing in
Dawn, because Dawn "gets grease out of your way", like the commercial
says. Use Dawn to clean off the transducer, too. Ok, the hull is squeaky
clean at our hot spot. Dry out the bilge, fully and take a heat gun
(hair dryer) to our hotspot to make it perfectly dry and warm. Heat it
up but don't burn it. While it's still warm put a nice little blob of
epoxy on our hot spot and work the sound output surface, MAKE SURE IT'S
THE SOUND OUTPUT SURFACE, into the epoxy blob to work out all the air
bubbles in the epoxy. Notice I said EPOXY, not bathtub caulk or RTV or
Silicone sealer or any of those rubbery, sound absorbing, compounds like
3M 4200 or 5200 sealer or any of that stuff. EPOXY, 2-part, make-damned-
sure-you-get-it-where-you-want-it-before-it-hardens EPOXY. Epoxy hardens
into stone, a solid mass that transmits sound from transducer to hull.
It will also hold the transducer in place for life.

I had a Sea Rayder 16' jetboat that went about 60. The transom-mounted
transducer made the boat turn from its drag every time you dropped power
because it was jet powered, no rudder. So, I mounted my sonar just like
this and it's still working just fine since 1997.....(c;

Your sonar company, mine was Eagle, has a special transducer with a flat
face for mounting with epoxy. It even came with epoxy. This is the
transducer you want for this type of installation.....call 'em and ask
for it.

  #3   Report Post  
posted to rec.boats.electronics
Ed
 
Posts: n/a
Default Depth FInder Sensor

I have used silicon twice in the past for "temporary" testing in this
situation. (Figuring I would go back and fix it later once I found the
best spot). One was 4 years ago in my dingy and the other was 3 years
ago in my sportfish. Neither hull is cored. Both are still working
near perfectly for shallow water. (200ft) and high speed. I just cut
the caulking tube tip off at the widest point, made a pile of silicon
(no bubbles) and pushed the transducer down into the pile making sure
it was level to the world. I let it dry and tried it out. Since it
worked, I have not gone to back to "FIX" it... i have heard the evils of
doing this but I go back to the "if it ain't broke, don't fix it". I am
sure I am getting some attenuation but for what I am using them for
(SHallow water) I don't need all the power anyway. BTW... I do NOT
use this for my two 1500 ft sounders, those are thru hull with fairing
blocks, etc.

Using epoxy like larry suggested is a better solution but you better get
it right the first time.

Another trick for angled bottom boats.

Cut a piece of 3" pvc (or 4" if you have a big transducer) the approx
angle of the hull (about 2-4" long) glue it in with silicon to the hull.

Once it drys, fill it with water, test your transducer in the water at
all speeds. If the spot works, dry it out, fill it with epoxy, place the
transducer in the epoxy and let it dry. This allows more epoxy to
"flatten the surface"






Larry wrote:

"DPFresh" wrote in news:1144040012.290616.216280
@i39g2000cwa.googlegroups.com:


Hello all, so as oppossed to drilling a hole in my hull for a depth
finder sensor, I should be able to set it up inside the hull as long as
the sensor is in some type of liquid right? IT will be able to tell
depths through the fiberglass hull right?




That depends on whether the hull is cored or not. Fiberglass conducts
sound energy just fine. Hull coring, like a Boston Whaler, is damned
near a perfect sound absorber in the foam core.

So, test it. Hook up the sonar, but leave the transducer loose so we can
move it around and find a hot spot, a spot where it sees through the hull
the best...away from the motor noise, if you please. Put a couple of
inches of water inside the hull so we can couple the sound from the
transducer to the hull inside the boat without mounting it. Take the
boat out into 50' of water.

Now, keep the transducer underwater any time the sonar is on......

Put the transducer, with the sound output surface pointing at the hull,
down we assume, under the water and hold it there against the hull. Turn
on the sonar and see what we gots. See the bottom? Move the transducer
around in this area and look for the best picture. Ok, we found a little
spot it works better than others. Have a second party start the boat and
drive full speed in a straight line while you watch the sonar. Can we
still see the bottom in 50' of water, or did the display go all crazy
because the engine noise and underwater bubbles or cavitation under the
hull right here got in the way? While underway, where we want the sonar
to work, of course, move the transducer around under the bilge water to
see if our hot spot is the "underway hot spot". Note the location of the
best place.

Take the boat home, pump it out and give our hotspot a good scrubbing in
Dawn, because Dawn "gets grease out of your way", like the commercial
says. Use Dawn to clean off the transducer, too. Ok, the hull is squeaky
clean at our hot spot. Dry out the bilge, fully and take a heat gun
(hair dryer) to our hotspot to make it perfectly dry and warm. Heat it
up but don't burn it. While it's still warm put a nice little blob of
epoxy on our hot spot and work the sound output surface, MAKE SURE IT'S
THE SOUND OUTPUT SURFACE, into the epoxy blob to work out all the air
bubbles in the epoxy. Notice I said EPOXY, not bathtub caulk or RTV or
Silicone sealer or any of those rubbery, sound absorbing, compounds like
3M 4200 or 5200 sealer or any of that stuff. EPOXY, 2-part, make-damned-
sure-you-get-it-where-you-want-it-before-it-hardens EPOXY. Epoxy hardens
into stone, a solid mass that transmits sound from transducer to hull.
It will also hold the transducer in place for life.

I had a Sea Rayder 16' jetboat that went about 60. The transom-mounted
transducer made the boat turn from its drag every time you dropped power
because it was jet powered, no rudder. So, I mounted my sonar just like
this and it's still working just fine since 1997.....(c;

Your sonar company, mine was Eagle, has a special transducer with a flat
face for mounting with epoxy. It even came with epoxy. This is the
transducer you want for this type of installation.....call 'em and ask
for it.


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posted to rec.boats.electronics
David
 
Posts: n/a
Default Depth FInder Sensor

Thanks for the advice everyone... will letcha know how it goes....

- David


"Mys Terry" wrote in message
...
On Mon, 03 Apr 2006 10:21:25 -0400, Ed wrote:

I have used silicon twice in the past for "temporary" testing in this
situation. (Figuring I would go back and fix it later once I found the
best spot). One was 4 years ago in my dingy and the other was 3 years
ago in my sportfish. Neither hull is cored. Both are still working
near perfectly for shallow water. (200ft) and high speed. I just cut
the caulking tube tip off at the widest point, made a pile of silicon
(no bubbles) and pushed the transducer down into the pile making sure
it was level to the world. I let it dry and tried it out. Since it
worked, I have not gone to back to "FIX" it... i have heard the evils of
doing this but I go back to the "if it ain't broke, don't fix it". I am
sure I am getting some attenuation but for what I am using them for
(SHallow water) I don't need all the power anyway. BTW... I do NOT
use this for my two 1500 ft sounders, those are thru hull with fairing
blocks, etc.


I, and lots of people I know have used clear silicone and it works
great.

Here's another tip: Don't swamp your boat with water as some idiot
suggested. The way to test for a good location is to simply fill a
zip-lock plastic sandwich bag with water and seal it closed. Place the
transducer on top of the water bag and move that around your DRY boat.
A breast implant can be substituted for the water filled baggie if you
have one handy.




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posted to rec.boats.electronics
Lynn Coffelt
 
Posts: n/a
Default Depth FInder Sensor


"David"
Thanks for the advice everyone... will letcha know how it goes....

- David


My experience (as if anyone cared) is that plastic faced transducers
work well in an epoxy bed, but rubber faced ones have a tendency to develop
a separation after a time, and if there is enough moisture around, may not
affect operation. But the rubber faced ones work even better in either a
liquid bath or a silicone bed.
For real fish finding, and bottom evaluation purposes, there is no
substitute for hole-in-the-bottom, or a well placed and finely tuned transom
mount transducer.
The zip-lock, water filled bag is a rewarding test method, but I always
put the transducer IN the bag. Never thought of just shooting through the
whole, closed bag! Great idea!
Old Chief Lynn




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posted to rec.boats.electronics
external usenet poster
 
First recorded activity by BoatBanter: Jul 2006
Posts: 31
Default Depth FInder Sensor

This seems like a good time to interject my problem. I had originally
posted a thread explaining that my LX-201 Datamarine depth finder
wouldn't work. The problem was traced to a faulty thru-hull
transducer.
Although I considered many solution alternatives (with the help
of the fine folk on this group) I settled on trying an Airmar P79
in-hull because they told me it would be compatible with the LX-201.
Also, I preferred not to mess with the old thru-hull as it needed to
be pulled from the bottom and appeared to be epoxyed in place.
Initial tests have shown that the Airmar will work well as it
will be used on a non-cored Grady White with a solid hull thickness
of less than one inch.
The problem has been the mounting of the transducer. Airmar
uses a bottomless base (ring) with a flange that is secured to the
inside of the hull with adhesive. The base is then filled with either
mineral oil or propylene glycol (their instructions), and the
transducer snaps on over that such that its bottom face "floats" on
the liquid. Obviously whatever adhesive is used must make a permanent
seal between the hull and the base flange as the base itself has no
bottom.
Here is the problem. Airmar specifically states that epoxy,
or the previously recommended Boatlife LIfe Seal or 3M 4200
are *not* to be used. Only GE Silicone II is allowed! With an area
perfectly cleaned with 409 (the area has a gloss), I have tried to
mount the base three times, each with many hours of cure time.
Each time when I have added the glycol, it leaks out after a few
seconds as if it were reacting with the silicone. When the base is
removed, the silicone on the flange is a sticky mess.
It really doesn't make sense to me that silicone would work at
all in this application. So why not use epoxy? Is it just that it
would be permanent and if the transducer base had to be
moved or removed you couldnt get it off? Surely Airmar sells
replacement bases. (I will check tomorrow.)
Your counsel is much appreciated. Am I just doing something
wrong in applying the Silicone II? (Otherwise known as "Kitchen
and Bath.") Or am I correct that this is a bad idea for a permanent
installation and epoxy should be used?
Thank you.
Frank







On 2 Apr 2006 21:53:32 -0700, "DPFresh"
wrote:

Hello all, so as oppossed to drilling a hole in my hull for a depth
finder sensor, I should be able to set it up inside the hull as long as
the sensor is in some type of liquid right? IT will be able to tell
depths through the fiberglass hull right?

Thanks,
David


  #7   Report Post  
posted to rec.boats.electronics
external usenet poster
 
First recorded activity by BoatBanter: Jul 2006
Posts: 97
Default Depth FInder Sensor


"frank1492" wrote in message
...
This seems like a good time to interject my problem. I had originally
posted a thread explaining that my LX-201 Datamarine depth finder
wouldn't work. The problem was traced to a faulty thru-hull
transducer.
Although I considered many solution alternatives (with the help
of the fine folk on this group) I settled on trying an Airmar P79
in-hull because they told me it would be compatible with the LX-201.
Also, I preferred not to mess with the old thru-hull as it needed to
be pulled from the bottom and appeared to be epoxyed in place.
Initial tests have shown that the Airmar will work well as it
will be used on a non-cored Grady White with a solid hull thickness
of less than one inch.
The problem has been the mounting of the transducer. Airmar
uses a bottomless base (ring) with a flange that is secured to the
inside of the hull with adhesive. The base is then filled with either
mineral oil or propylene glycol (their instructions), and the
transducer snaps on over that such that its bottom face "floats" on
the liquid. Obviously whatever adhesive is used must make a permanent
seal between the hull and the base flange as the base itself has no
bottom.
Here is the problem. Airmar specifically states that epoxy,
or the previously recommended Boatlife LIfe Seal or 3M 4200
are *not* to be used. Only GE Silicone II is allowed! With an area
perfectly cleaned with 409 (the area has a gloss), I have tried to
mount the base three times, each with many hours of cure time.
Each time when I have added the glycol, it leaks out after a few
seconds as if it were reacting with the silicone. When the base is
removed, the silicone on the flange is a sticky mess.
It really doesn't make sense to me that silicone would work at
all in this application. So why not use epoxy? Is it just that it
would be permanent and if the transducer base had to be
moved or removed you couldnt get it off? Surely Airmar sells
replacement bases. (I will check tomorrow.)
Your counsel is much appreciated. Am I just doing something
wrong in applying the Silicone II? (Otherwise known as "Kitchen
and Bath.") Or am I correct that this is a bad idea for a permanent
installation and epoxy should be used?
Thank you.
Frank







On 2 Apr 2006 21:53:32 -0700, "DPFresh"
wrote:

Hello all, so as oppossed to drilling a hole in my hull for a depth
finder sensor, I should be able to set it up inside the hull as long as
the sensor is in some type of liquid right? IT will be able to tell
depths through the fiberglass hull right?

Thanks,
David



If you are going to contact Airmar regarding the availability of a
replacement base why don't you ask them why you can't use epoxy or 4200? I
would think 4200 would glue this down with no problem. Silicone is a
sealer, not an adhesive. I don't think it produces a very strong bond and
consequently any impacts on the base are likely to break the seal.


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posted to rec.boats.electronics
external usenet poster
 
First recorded activity by BoatBanter: Jul 2006
Posts: 100
Default Depth FInder Sensor

Frank,

I dicked around with an Airmar P79 for quite a while. Used Life Caulk,
used silicone, used 4200, used 5200, and each time, the mineral oil
caused the adhesive to lift from the hull after a week to a month.
Finally ordered a new base ring (they are available, $12 IIRC), cleaned
everything well and used JB Weld (basically just epoxy) to glue the ring
down. Filled with mineral oil and have had no problems for over a year now.

Keith Hughes

frank1492 wrote:

This seems like a good time to interject my problem. I had originally
posted a thread explaining that my LX-201 Datamarine depth finder
wouldn't work. The problem was traced to a faulty thru-hull
transducer.
Although I considered many solution alternatives (with the help
of the fine folk on this group) I settled on trying an Airmar P79
in-hull because they told me it would be compatible with the LX-201.
Also, I preferred not to mess with the old thru-hull as it needed to
be pulled from the bottom and appeared to be epoxyed in place.
Initial tests have shown that the Airmar will work well as it
will be used on a non-cored Grady White with a solid hull thickness
of less than one inch.
The problem has been the mounting of the transducer. Airmar
uses a bottomless base (ring) with a flange that is secured to the
inside of the hull with adhesive. The base is then filled with either
mineral oil or propylene glycol (their instructions), and the
transducer snaps on over that such that its bottom face "floats" on
the liquid. Obviously whatever adhesive is used must make a permanent
seal between the hull and the base flange as the base itself has no
bottom.
Here is the problem. Airmar specifically states that epoxy,
or the previously recommended Boatlife LIfe Seal or 3M 4200
are *not* to be used. Only GE Silicone II is allowed! With an area
perfectly cleaned with 409 (the area has a gloss), I have tried to
mount the base three times, each with many hours of cure time.
Each time when I have added the glycol, it leaks out after a few
seconds as if it were reacting with the silicone. When the base is
removed, the silicone on the flange is a sticky mess.
It really doesn't make sense to me that silicone would work at
all in this application. So why not use epoxy? Is it just that it
would be permanent and if the transducer base had to be
moved or removed you couldnt get it off? Surely Airmar sells
replacement bases. (I will check tomorrow.)
Your counsel is much appreciated. Am I just doing something
wrong in applying the Silicone II? (Otherwise known as "Kitchen
and Bath.") Or am I correct that this is a bad idea for a permanent
installation and epoxy should be used?
Thank you.
Frank







On 2 Apr 2006 21:53:32 -0700, "DPFresh"
wrote:


Hello all, so as oppossed to drilling a hole in my hull for a depth
finder sensor, I should be able to set it up inside the hull as long as
the sensor is in some type of liquid right? IT will be able to tell
depths through the fiberglass hull right?

Thanks,
David




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