In-hull transducer mount... Revisited!

[TBarCYa]

A couple months ago, I posted about mounting my transducer in a PVC ring filled with silicone. This worked perfectly for about 2 months until the silicone decided it didn't want to stick to the hull anymore.

Since silicone didn't work I decided to try polyester resin since I have it already and it's supposed to stick to the hull which was made (I assume) with polyester. This didn't stick to the hull either and I must have used too much catalyst for the conditions (very hot and humid) because I was able to easily break apart the chunk of resin to retrieve the transducer.

Yesterday, I used epoxy to mount a PVC ring that is threaded at one end to the hull then used silicone to make sure it was sealed. I placed the transducer in the ring and poured in enough mineral oil to cover the bottom of the transducer and screwed on a cap which has a hole drilled for the wire to go thru. Tomorrow, I'll find out if it actually works and hopefully it lasts longer than the previous two attempts.

 

[dingbat]

Re: In-hull transducer mount... Revisited!

The mineral oil is going to be a problem with silicon over time. Next time around try Propylene glycol

 

[fishrdan]

Re: In-hull transducer mount... Revisited!

I had a transducer epoxied in the hull of my old SeaSwirl for years, no problemo

 

[TBarCYa]

Re: In-hull transducer mount... Revisited!

I thought about antifreeze but if it does make it's way out of the ring, it's poisonous so I wanted to avoid it. I didn't think that the oil would affect the silicone but if it does, hopefully the epoxy made a good seal and it still won't leak.

I had considered epoxying the transducer to the hull but after the problems I had with the previous 2 attempts at getting this thing to work reliably, I figured the oil bath would be the easiest to undo if I needed to try again. I'm especially leery about it since it's a transom mount transducer that I'm using as a shoot-thru.

 

[dingbat]

Re: In-hull transducer mount... Revisited!

I thought about antifreeze but if it does make it's way out of the ring, it's poisonous so I wanted to avoid it. I didn't think that the oil would affect the silicone but if it does, hopefully the epoxy made a good seal and it still won't leak.

I had considered epoxying the transducer to the hull but after the problems I had with the previous 2 attempts at getting this thing to work reliably, I figured the oil bath would be the easiest to undo if I needed to try again. I'm especially leery about it since it's a transom mount transducer that I'm using as a shoot-thru.

Propylene glycol is non toxic. It's the stuff they use to winterize drinking water systems.

I too had issues with minerl oil. I changed to castor oil and didn't have another problem for the 3 years before I sold the boat.

 

[fishrdan]

Re: In-hull transducer mount... Revisited!

I had a transom mount transducer in my boat's bilge, the epoxy worked great.

I siliconed another transducer in the bilge and was not happy with the performance, void in hull, silicone problem, don't know. When I popped it off (which was a royal PITA) I found it had a good solid bond and no air pockets between the ducer and hull.

 

[dingbat]

Re: In-hull transducer mount... Revisited!

I had a transom mount transducer in my boat's bilge, the epoxy worked great.

I siliconed another transducer in the bilge and was not happy with the performance, void in hull, silicone problem, don't know. When I popped it off (which was a royal PITA) I found it had a good solid bond and no air pockets between the ducer and hull.

Transducers need a solid material to resonate the signal through. Using silicon to attach the transducers is like putting a rubber mat between the hull and the transducer. Ain't going to work worth a darn.

 

[fishrdan]

Re: In-hull transducer mount... Revisited!

Ain't going to work worth a darn.

I thought the same thing, but have heard several people suggest silicone for a bilge shoot-thru install. It didn't work for me and I can see your reasoning.

 

[TBarCYa]

Re: In-hull transducer mount... Revisited!

The silicone worked great for about 2 weeks until it lost it's hold on the hull. It never actually got hard tho and when I pulled the whole thing out, the silicone was still tacky and pliable.

I was out with the current setup today and it works great!! I use it more for navigation than fishfinding or bottom searching tho so as long as I got a reasonable depth number, it was good. Tomorrow I'll try looking at the sonar instead of the chart and see how it works.

 

[fishrdan]

Re: In-hull transducer mount... Revisited!

I think it also depends on the shape of hull and transducer, whether they will "mate" well. I had about 1/4" of silicone under the center of my transducer while the sides were flush with the hull, V shaped bilge and wide/flat transducer bottom. I can only imagine how bad this threw off the sonar pings and echos...

The epoxy installed transducer was narrower with a rounded bottom which conformed to the hull much better...

 

[dingbat]

Re: In-hull transducer mount... Revisited!

Finding bottom isn't going to be the problem. What you?re compromising are the details.

When I went to installed my P79 I left my transom mount installed for some comparison testing. I went out and anchored in 35' of water for some testing. First I hooked the transom transducer up to the FF and ran the unit in manual mode and adjusted the gains to get the best returns possible. I then did the same thing with the P79 in the bilge.

While I was able to get similar results with the P79 I had to increase the gains on the FF almost 20% to compensate for the signal derogation caused by the hull. This 20% was for a transducer in a ?live? media. Just imagine the signal loss when trying to shoot thru a layer of vibration deadening material such as silicon.

If you have a high powered unit and generally fish in ?shallow water? this isn?t such a big problem other than you have to jack your gains. Where it really will come home is when you get into deep water.

A 300W unit in 100? of water with a 30% signal loss is working with a handicap

 

[Boatist]

Re: In-hull transducer mount... Revisited!

All the manufactures I hve seen recomend SLOW CURE EPOXY and due slow mixing to keep air out. Still even on the best hulls you will loose at least 10 percent. The sound echo has to be strong enough to cause the hull to vibrate. Air in the resin or wood or foam and it will loose more.

 

[TBarCYa]

Re: In-hull transducer mount... Revisited!

I'm not sure that I'll get out today due to the weather but if I do, I will post back with some details. The big thing for me is not drilling holes in the brand new boat so sacrificing detail on the depthfinder is an acceptable solution for me. The gain is set to auto now so I'll mess with it and see what I can find.

 

[fossill]

...

 

[Capt'n Chris]

Re: In-hull transducer mount... Revisited!

Remember, the thicker or softer the adhesive medium is you are trying to "ping" through, the less it can be "heard" on the other side. By the same token, the more difficulty the "ping" is heard on the return sounding, the more difficulty your electronics have to interpret it, if at all. It's much like shouting through a pillow...the thicker and softer the pillow, the more difficult it is to recognize the sound on the other side. Also, remember this: when "shooting through" a fiberglass hull of one type and density substrate and then adding still another medium (epoxy, silicone, etc.) of even another thickness and density, compounds the issues now that you have entered 2 different materials the ping must sound through and return electronically unblemished.

 

[dingbat]

Re: In-hull transducer mount... Revisited!

Not to mention the frequency shifts that occurs when shooting thru ANY type of hull. Up to 7% of your resolution, is gone with the wind no matter what you do.

 

[chiroken]

Re: In-hull transducer mount... Revisited!

Wondering how it ended up working out TBarCYA??? I have a 2007 Maxum 1800MX and am trying to figure the same thing out. Where exactly did you end up mounting the transducer? I have been thinking of just starboard of the engine. I like the idea of a threaded pipe with cap.

How is the transducer held in position with this type of setup or in any other type of "water box".

Is the transducer pointed straight down even if the hull is angled?

Thanks for any info, this is confusing!!!