Mounting A Transducer

[gerg]

just got a new transducer and wanted some advice for mounting inside the hull of a glass boat.

The old transducer is a standard transom mounted transducer and is fixed to the inside of the hull with what looks like black sicaflex only much harder. I Did a google search and found some instructions that outlined the use of slow cure 2 part araldyte to glue to the hull.

Has anyone done this that could give me advice of a specific araldyte to use and also any pitfalls to watch.

I understand that the slow cure allows the air bubbles to rise to the surface which means they won't affect the transducer's performance. I also understand that this is one of the reasons that you don't use silicon or sicaflex to bond the transducer, but one issue I can see is that a slow cure araldyte will "run" until it sets reducing the surface area that bonds the transducer to the hull.

Any advice appreciated.

cheers, Greg

[pelican]

Hi greg

Was the old one performing OK in that position? If it was you might want to cut out a few steps.

2 choices, wet box or epoxy to the hull.

Wet box is basically a open topped box sealed to floor of hull filled with liquid silicon or oil. Tranducer is submerged in liquid and shoots through the hull.

Test run. In the spot you think the tranducer will work wipe down with acetone or metho and silicon a plastic container , milk bottle of 2 litre ice cream container both with bottoms cut out to the hull. Fill it with water and put the tranducer in with a small plastic bag filled with sand to hold it down. Try and get it to shoot vertically down. Go for a run over a bit of water you know and check it works. Ie you are checking there is no airbubbles in the hull lay up or metal, voids, wood or form or debri.

If it is all OK and you are happy that it is reading well then prepare for permanent installation.

Check for instructions on website of tranducer maker.

Was going o type out a long explaination but remembered there is a PDF on website below- sponsers will be able to order some epoxy from sounder suppliers.

We previously have created a small pool in the hull by using gaffer tape , pooring in mixed liquid epoxy and then placing in to it the tranducer attached to it's bracket to a lump of hardwood so it stays still while it cures

http://www.humminbird.com/pdf/transducer_faq/InsideHull.pdf

Inside the Hull Mounted Transducer

2

530509-4_B

2. Trial Installation:

You will not be able to adjust the mounting position after you install this Inside the Hull transducer. It is

best, therefore, to perform a trial installation first that includes running the boat at various speeds, in order

to determine the best mounting area before permanently mounting the transducer.

1. Plug the transducer into the control head, then power up the control head. When the control head

detects a functioning transducer, it will automatically enter Normal operating mode.

2. View the sonar signal at its best by holding the transducer over the side, immersed in the water, so that

it is pointing straight down over a known flat bottom. Use the display to benchmark against the sonar

signal that will be detected once the transducer is mounted inside the hull.

3. Place the transducer body face down at the identified mounting location inside the hull, oriented as

shown in the illustrations.

4. Fill the hull with enough water to submerge the transducer body. Use a sand-filled bag or other heavy

object to hold the transducer in position.

NOTE: The transducer cannot transmit through air, so the water is necessary to purge any air from between

the transducer and the hull, and to fill any voids in the coarse fiberglass surface of the hull.

5. View the sonar signal on the control head display and compare against what you observed in step 2,

making sure that the boat is in the same location as it was during your observations in step 2. If the

results are comparable, continue to step 6. Otherwise, locate a new position in the hull and repeat steps

3 through 5.

6. Run the boat at various speeds and water depths while observing the screen on the control head. If

depth performance is required, test the transducer in water at the desired depth. If the performance is

acceptable, continue to step 7. If the performance is not acceptable, repeat steps 3 through 6.

7. Once you have determined the best mounting location using this procedure, mark the position of the

transducer.

3. Installing the Transducer

1. Mark the location of the transducer and remove the water from inside the hull and thoroughly dry the

mounting surface.

2. Mix an ample quantity of two-part slow-cure epoxy and coat the face of the transducer and the inside

of the hull.

3. Press the transducer into place with a slight twisting motion to purge any trapped air from underneath.

If you are using a transom-style transducer, make sure that the pointed end of the transducer points

forward to the bow of the boat. Position angled-style transducers to transmit straight down and remain

in parallel alignment with the keel.

NOTE: Puck or round, circular-bottomed transducers have no directional bias, and therefore orientation of

these types of transducers is not as important. Rounded rectangular transducers, however, do have a

directional bias. Refer to the part of the illustration that shows orientation for transducers with directional

bias.

4. Weight the transducer so that it does not move while the epoxy is curing.

5. When the epoxy has cured, no water will be necessary inside the hull, and water or spilled gasoline or

oil will not affect the performance of the transducer.

[gerg]

Thanks Pelican - The PDF is the one that I have read, but the first part of your post is precisely what I wanted.

cheers, Greg

[pelican]

Forgot an even easier one for a test. Fill up a freezerbag with water, and stick tranducer in it with the bracket attached to a bit of ply or scrap wood. Place in hull where you want it and use another couple of freezer bags filled with sand or a brick or 2 to hold it in place . Hope that makes sense and you don't need much water just enough so there is no air between tranducer and bag and enough water so it has the weight to squeeze air from between hull and bag.

Don't wipe tranducer with acetone- we have melted one before but use metho or something to make sure there is no oil on it.

Areldite might be too thick to get teh air out of but if you warm it it will thin but cure faster. As long as it doesn't have air in it the cure rate isn't that important but they probably use slow cure as the reaction is exothermic ( puts out heat) so any tiny bubbles will expand with heat and leave viod. Just do a test between a couple of bits of glass ( jars) or clear plastic as you will be able to see if you are getting air.

We have done ours a little thick by putting it into a pool of epoxy 5mm thick so we have a way of getting it off without smashing tranducer if we have to.

Pel

[Dreamtime]

So me in my stupid D.I.Y frame of mind, drilled right through the hull. So, now there is a hole from the inside of the boat to the outside!!

The hole is only about 5mm in diametre.

Just be careful that you don't go this way.

[flatty hunter626]

lol sounds like somthing i would do drilling a hole in my hull:)