Mounting A Shoot Thru Transducer

[CarinaPDX]

For temporary application for testing, or a season, just put it down with K-Y Jelly and use duct tape to hold in place. I have had a sender work for years this way. I finally put the sender down with silicone sealant, which lasted decades. It was a very close fit and came up with great difficulty using a chisel so I would not consider this a temporary solution.

As is so often the case, there are other threads on this topic so do some searching.

Greg

[Cheechako]

I've used silicone and have used epoxy, both worked well. Do it without air bubbles though. Maybe that's why slow setting epoxy..? Might help to warm the resin a bit so the bubbles can move in the thicker liquid...

[CharlzO]

[QUOTE=kclancy;2289977]

Originally Posted by Stu Jackson

toilet bowl wax ring

I've never had a chart plotter, but received one for Christmas. Did you put the transducer inside the ring on the hull and the massage the wax to cover the transducer? I'm trying to imagine how this works. I want to try this before other more permanent installations. Thanks!

Basically, you're going to use the wax like clay or putty. Squish it all into a big blob, and stick it to the hull, and then press the transducer into it, like sticking your finger into blob of gum or something. The general idea is that you need something without air bubbles between the transducer and hull, for the signal to not get lost or distorted by. The nice part about the wax, is it's very good at holding in place, easy to massage, and is still removable if needed, without having to break anything. It's quick, simple, cheap, and effective. Permanent mounting with epoxy is basically the same idea, but you lose the ability to remove it easily.

Something like:

[pmarble]

Garmin makes a shoot thru transducer (Airmar P79). I just installed one on my Tanzer 26 by using 4200 adhesive. Connected to my Garmin GPSMAP 74dv. Works Great!

[rwidman]

Originally Posted by cottonsail

I have a Raymarine I-40 sounder. I have it shooting thru the hull with mineral oil in the raymarine mount. I DO NOT recommend this unit. It curs out intermittently, going from an accurate reading down to zero. Just as suddenly it goes back to an accurate reading.. Does anyone have any ideas?

1) The oil level is too low. Add some oil.

2) Loose or damaged cable between the transducer and the unit it connects to.

[rwidman]

Originally Posted by CarinaPDX

For temporary application for testing, or a season, just put it down with K-Y Jelly and use duct tape to hold in place. I have had a sender work for years this way. ..............

I put KY jelly on mine and held it down with a zip lock bag full of water. It worked fine that way until I finally installed it with the antifreeze filled mount that came with it. That was a year or more.

[Beavereater]

Thanks for letting me know I'm not crazy Stu. Built a rectangle dam for the transducer this fall with West Marine 6 10 epoxy, planning on test shooting through water first before I melt the bowl wax. Have to wait until the weather warms we're walking on water for our fish right now. Hope it works, I would hate to find out I glued it in with air bubbles in the glue.

[kclancy]

[QUOTE=CharlzO;2290011]

Originally Posted by kclancy

Basically, you're going to use the wax like clay or putty. Squish it all into a big blob, and stick it to the hull, and then press the transducer into it, like sticking your finger into blob of gum or something. The general idea is that you need something without air bubbles between the transducer and hull, for the signal to not get lost or distorted by. The nice part about the wax, is it's very good at holding in place, easy to massage, and is still removable if needed, without having to break anything. It's quick, simple, cheap, and effective. Permanent mounting with epoxy is basically the same idea, but you lose the ability to remove it easily.

Something like:

Bingo Charlz! This is exactly what I needed. Thanks so much!

[ramblinrod]

Originally Posted by fishsail18

I bought a Garmin combo a few months ago that came with a transom mount trx, When I haul out the boat I plan on installing a thru hull trx. but for now thinking about just mounting this trx as a shoot thru as my hull is solid glass and not all that thick. what would be best to bed it down with? maybe silicone so I can remove it later. or is that not a hard enough substance?

I spent many years performing research on ultrasonic transducer bonding agents and methods in an acoustic research lab.

Depthsounder and fishfinder transducers are designed for maximum energy transfer into, and speed of sound calcs for, water.

So the best coupling medium to the transducer is water.

One method, is a still pipe, sealed to the hull and filled with water, that the transducer (face) is immersed in. If the water may freeze, then propylene glycol is a good transfer medium (but it tends to leak easier).

The one issue with this method, is that if the seal is lost or some kind of leak develops the medium is lost and the energy transfer ceases, rendering the system inoperative until repaired.

For this reason, my favourite solution, is to use polyester resin (what the hull is made of so a perfect acoustic impedance match to that) to adhere the transducer face in as intimate of contact with the hull as possible.

So here is my process.

1. Scout the best mounting location (forward of the keel, close to centreline, etc., etc,)

2. Dangle the transducer over the side of the boat, pointed at the sea bottom, and record the single strength, grayline density, or whatever means there is to determine how strong the echo is.

3. Place the transducer face down on a sealed sandwich baggy filled with water, against the inside of the water wetted hull.

4. Verify the signal strength is close to that recorded. Try some different locations to find one that gives best results.

5. Dry up the mounting location and sand it to bare FRP.

6. Make a little dam around the mounting location with a silicone sealant bead.

7. Rough sand the face (by hand) of the transducer.

8. Wipe the mounting location and transducer face with acetone to remove residue.

9. Pour a thin (1/4" deep) pool of polyester resin in the mounting location.

10. Wipe the transducer face with polyester resin.

11. Immerse the transducer face, (rocking it back and forth to get out any air bubbles) into the polyester resin pool.

12. Apply tape (or some other means) to the transducer to hold it in place.

13. Turn on the system and verify the reading is still good. If so, let it cure, if not clean it up and find out why not.

14. Remove power from the unit until cured to avoid adding heat to the transducer and resin, assuming the water (inside of hull) is above 10 C.

15. Retest the unit when the resin is fully cured.

Note that there are all kinds of materials that can be used to adhere a transducer to a hull, but the best is one that will represent the best acoustic impedance match.

Silicone and wax is actually terrible for this. It will likely work, but not as well as polyester resin.

When one can easily assure maximum energy transfer (and hence performance) why not?

Temporary methods of adhesion are not prudent. They may become unadhered when least desired. And yes, I have been hired to repair depth equipment where the sole cause of failure was poor transducer adhesion, (silicone, wax, various sealants including Silly Putty (I $#!+ you not), and liquid transfer medium escaped).

So what about later moving the transducer?

First a permanent install is definitely the most reliable and when it comes to instruments you may rely on, reliability is important. Second, I have successfully removed countless polyester resin adhered transducers by simply placing the tip of a wood chisel at the transducer/resin interface, and giving it one sharp whack with a mallet.

Certified Raymarine Installer and Service Provider

[ramblinrod]

Originally Posted by Cheechako

I've used silicone and have used epoxy, both worked well. Do it without air bubbles though. Maybe that's why slow setting epoxy..? Might help to warm the resin a bit so the bubbles can move in the thicker liquid...

While I don't recommend using epoxy, (I prefer polyester resin for a whole bunch of reasons), slow setting epoxy won't get so hot that it catches your boat on fire, or cooks the transducer, while curing.

[ramblinrod]

Originally Posted by fishsail18

I bought a Garmin combo a few months ago that came with a transom mount trx, When I haul out the boat I plan on installing a thru hull trx. but for now thinking about just mounting this trx as a shoot thru as my hull is solid glass and not all that thick. what would be best to bed it down with? maybe silicone so I can remove it later. or is that not a hard enough substance?

Just a question....

If you mount a transducer to the inside of the hull, and it works flawlessly, why would you want to add a hull penetration?

[ramblinrod]

Originally Posted by ramblinrod

I spent many years performing research on ultrasonic transducer bonding agents and methods in an acoustic research lab.

Depthsounder and fishfinder transducers are designed for maximum energy transfer into, and speed of sound calcs for, water.

So the best coupling medium to the transducer is water.

One method, is a still pipe, sealed to the hull and filled with water, that the transducer (face) is immersed in. If the water may freeze, then propylene glycol is a good transfer medium (but it tends to leak easier).

The one issue with this method, is that if the seal is lost or some kind of leak develops the medium is lost and the energy transfer ceases, rendering the system inoperative until repaired.

For this reason, my favourite solution, is to use polyester resin (what the hull is made of so a perfect acoustic impedance match to that) to adhere the transducer face in as intimate of contact with the hull as possible.

So here is my process.

1. Scout the best mounting location (forward of the keel, close to centreline, etc., etc,)

2. Dangle the transducer over the side of the boat, pointed at the sea bottom, and record the single strength, grayline density, or whatever means there is to determine how strong the echo is.

3. Place the transducer face down on a sealed sandwich baggy filled with water, against the inside of the water wetted hull.

4. Verify the signal strength is close to that recorded. Try some different locations to find one that gives best results.

5. Dry up the mounting location and sand it to bare FRP.

6. Make a little dam around the mounting location with a silicone sealant bead.

7. Rough sand the face (by hand) of the transducer.

8. Wipe the mounting location and transducer face with acetone to remove residue.

9. Pour a thin (1/4" deep) pool of polyester resin in the mounting location.

10. Wipe the transducer face with polyester resin.

11. Immerse the transducer face, (rocking it back and forth to get out any air bubbles) into the polyester resin pool.

12. Apply tape (or some other means) to the transducer to hold it in place.

13. Turn on the system and verify the reading is still good. If so, let it cure, if not clean it up and find out why not.

14. Remove power from the unit until cured to avoid adding heat to the transducer and resin, assuming the water (inside of hull) is above 10 C.

15. Retest the unit when the resin is fully cured.

Note that there are all kinds of materials that can be used to adhere a transducer to a hull, but the best is one that will represent the best acoustic impedance match.

Silicone and wax is actually terrible for this. It will likely work, but not as well as polyester resin.

When one can easily assure maximum energy transfer (and hence performance) why not?

Temporary methods of adhesion are not prudent. They may become unadhered when least desired. And yes, I have been hired to repair depth equipment where the sole cause of failure was poor transducer adhesion, (silicone, wax, various sealants including Silly Putty (I $#!+ you not), and liquid transfer medium escaped).

So what about later moving the transducer?

First a permanent install is definitely the most reliable and when it comes to instruments you may rely on, reliability is important. Second, I have successfully removed countless polyester resin adhered transducers by simply placing the tip of a wood chisel at the transducer/resin interface, and giving it one sharp whack with a mallet.

Certified Raymarine Installer and Service Provider

Forgot one little tidbit.

Before whacking the chisel with a mallet, disconnect the transducer and short the wires (else a significant voltage could be developed that could damage the transceiver input).

[brianlara 3]

My new Simrad Go 7 XSE plotter came with a really ugly oblong shaped transducer which was meant to be transom hung of the supplied brackets.
Instead, I selected a spot along the centreline about 700mm from the back of the keel. I gave the glass a good clean with acetone, mixed an eggcup full of Araldite 5 minute clear epoxy and wiped it, free of bubbles, onto the surface. Held it in place for two minutes 'til it gelled.
Five minutes later and not even warm the sounder reads well enough to satisfy the most demanding professional fisherman. Just brilliant. Job done in 15 minutes or less.

[sailjumanji]

Originally Posted by Copacabana

I used silicone on my two depthsounder transducers and they have been working fine for years. Just a few quick tips before you install...
Choose a place on the hull and then test the depthsounder with the transducer sitting in a pool of water (I used plasticine putty to make a well which I filled with water). Test it with the boat sailing and also motoring to make sure it gives soundings at angles of heel and with prop turbulence as well). Once you've found the right spot on the hull, clean it well, sand it and carefully squeeze out the silicone so that there are no air bubbles. Then just carefully push the transducer into the goop and wait for it to set. I believe you lose a little sensitivity by mounting the transducer inside the hull, but that is more than compensated, in my opinion, by not having another hole in the hull!

This is exactly what I have done in two boats. No issues. And can be removed if the transducer fails.

[ramblinrod]

Originally Posted by brianlara 3

My new Simrad Go 7 XSE plotter came with a really ugly oblong shaped transducer which was meant to be transom hung of the supplied brackets.
Instead, I selected a spot along the centreline about 700mm from the back of the keel. I gave the glass a good clean with acetone, mixed an eggcup full of Araldite 5 minute clear epoxy and wiped it, free of bubbles, onto the surface. Held it in place for two minutes 'til it gelled.
Five minutes later and not even warm the sounder reads well enough to satisfy the most demanding professional fisherman. Just brilliant. Job done in 15 minutes or less.

Yes, epoxy resin will work.

The energy transfer through epoxy may not be quite as good as through polyester resin.

One of the key reasons I avoid epoxy use is the risk of becoming sensitized to it. I know people who have become so sensitized to epoxy that now (and presumably for the rest of their lives) can't go anywhere near it (several hundred feet) without severe reaction.

There are very few applications where polyester resin can't be substituted for epoxy, and certainly where epoxy doesn't need to be substituted for polyester. There are certainly applications where epoxy CAN'T be substituted for polyester.