Mounting transducer outside of a glass bass style boat? (Pics added)

[sparkyaber]

I just purchaced a new lowrance gps/depthfinder combo with a transom mount transducer. My current depthfinder is a shoot through the hull design and is junk. (Doesn't work very well) I have polked around on some other forums and they seem to think that it is not a good idea to put it outside the boat. I have a Triton fs 190. Any thoughts?

[Capt. Don*]

I am curious to the reasons for not mounting on the transom. Is it the design of the boat? If you don't want to shoot through the hull, the only other option is to use a thru-hull transducer, I have used these on several of my larger non-trailerable boats over the years and they do the best job of all the transducers when it comes to deep (>200') water. These are large and expensive and require about a 1 1/2" hole cut into the bottom of the boat, they protrude about 2" below the hull and finding a mounting location is really tough when you consider strakes,chines and trailer bunks.

I would contact Lowrance and Triton and see what they recommend for your application.

[PerchJerker]

I have a Ranger (fiberglass) with 2 transducers running to my console. One is a transom mount transducer, the other is bedded in the hull. I use the transom mount one 99.99% of the time, the in-hull one works okay but the sensitivity and readings from the transom mount are much better. And the transom mount rarely if ever looses its reading on the bottom, even at 50+ mph.

[croixeyes]

Mounting your transducer to the outside of the transom is the best way to go.You will get far better readings from your graph.Drilling holes in your boat can be a little nerve racking,so you may want to have a boat dealer do it.Frankies in Chisago does an exellent job of rigging boats.

[sparkyaber]

I am not by any means going to drill a hole in the bottom of my boat. I was thinking of using the shoot through hull transducer that epoxies to the bottom of the hull (on the inside). I agree with what you guys are saying about the sensitivity readings being better outside the hull.

[croixeyes]

I was not saying to drill holes in the bottom of the boat,but in back on the transom.If your out on the Croix sometime and see riverdancer out there,check how they have there transducers mounted,She drives a white triton 198.I have mine mounted on my ranger tiller this way and its not that hard to do.But if fiberglass makes you nervous have a dealer do it,

[sparkyaber]

riverdancer- gotcha, I thought you were talking about mounting it in the hull, like stated farther above. Do all of you folks use bolts and nuts (8-32 or 10-24?) with epoxy or do you use just a machine screw with some epoxy. Oh, the last question is where to mount it? There is a lot going on back there with a lot of angles and such. If I get time I will snap a picture.

[delmuts]

if you are mounting on the outside of the hull; use stainless steel screws( you can buy these at marine dealers ) with a silicon sealer.( no epoxy!) you want to be able to change it if needed!

[PerchJerker]

What delmuts said. Just be sure it will be in a good place when the boat is in the water, and that you can't clunk it off the trailer when loading / unloading your boat.

[sparkyaber]

Here is what I am looking at, I really want to put the trasducer on the outside. Now the question is where? I am assuming point A is out of the water when I am on plane, maybe even point B. The second pic shows the only part that is in the water on plane, the part way down by the screen and the drain plug.

[sparkyaber]

anybody with any ideas?

[Ralph Wiggum]

Pick up a suction cup transducer mount (~$10). That way you can try out different positions till you find one that works well on your boat.

[castindad]

go to back bottom of boat sand a spot and adhere to boat inside much easierand very good reception castindad

[sparkyaber]

Whoh- hold the phone! Suction mount? Never heard of such a thing! Will it hold on at 70mph?, I think I know the answer to this next one, but will it work inside the hull?

Well that makes one northerner saying to put it inside, Most others say to put it on the transom, for reasons listed above. Also not to put it inside for reasons listed above.

I think I am going to mount it inside, and if that really doesn't work I will bite the bullet and just buy another transducer and put it on the transom, but where???????

I really like the suction mount idea!

[castindad]

use silicone marine type incase you want to change it castindad

[sparkyaber]

castindad- they make an epoxy that you can remove the transducer from? I thought it was a permanent installation when done?

[PerchJerker]

Some guys use silicone for shoot-thru-hull mounts so it's not permanent - that's what castindad is talking about.

Occasionally silicone mounts work almost as well as epoxy mounts but in general it is not nearly as good as using epoxy - loss of signal strength, loss of contact with the water, etc. I use epoxy. I think the majority of shoot-thru-hull mounts use epoxy.

I still prefer the transom mount for the best readings and the ability to adjust the angle if needed. I can't tell from your photos what I'm looking at though, so I can't help you with a transom location.

The suction cup mount will work at slow speeds, it probably will not hold at high speeds. It's a temporary method of mounting to make sure you get the transducer in a good spot.

[SuddenlySummer]

No! No! No! Pick up the plastic 1" x 6" or any size mounting board for your transom. All you need to do is mount the board to the back of your boat. It will not hurt the perfromance of the boat.

You then can play with the mounting of the transducer to this plastic board without having to drill multiple holes in the back of your boat. If you change fish finders in the future, no problem.

Mounting the transducer near the center of the boat is not reccommended because of bubbles from the hull.

This set up will allow you to adust your tranducer with ease.

Simple.

[PerchJerker]

Quote:

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Pick up the plastic 1" x 6" or any size mounting board for your transom

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This probably will not work on a newer glass boat, most (or many) of them do not have a large enough flat surface on the transom to mount a board like this. Works great on aluminum boats though.

[sparkyaber]

perchjerker-I think that would be the whole idea of the silicone dealie-bobber, if it worked ok I could switch over to epoxy, if not I move it to the transom. Where would a guy find, or what exactly would a guy use for a silicone adhesive?

[sparkyaber]

I thought about the plastic board for the transom, but I think perchjerker is right as always. The place the transdcer would be located is actually concave so it is not flat as compared to the transom.

[Ralph Wiggum]

I haven't tried the suction mount at high sppeds, but I can tell you they stick on very well. I usually have a hard time getting mine off when I switch boats. If you got to the Cabelas site and do a search for "Suction Cup Mount" you will find what I'm talking about. It's $8 and well worth a shot, I'd say.

[PerchJerker]

The only 2 reasons I've heard of guys using silicone for bedded-in transducers is ....

1) So they can remove the transducer if they sell the boat or the depthfinder, or

2) If they want to try a transducer in the bow where you usually don't have flat surfaces.

You mention siliconing it in the bilge, then moving it to the transom if it doesn't work in the bilge. I use skimmer style transducers on my transom and puck style transducers in the hull, I've heard you can bed in skimmer transducers but I've never done it or seen it done. Also, I'm not sure that siliconing it in will give you that good of a representation of what it will do if it's epoxied in, as I think the epoxy is a much better mount for shooting through. I've never had a transducer that's been siliconed in, but this is what I hear from people that know what they're talking about.

For a shoot-thru-hull, if you want to know if it will work in a location you can have a little water in the bilge and hold the transducer against the bottom of the boat, if you can get a reading that way it will work after you epoxy it in (or call your boat manufacturer and ask them for info and suggestions). Try to get a flat level spot as far back in the boat as possible and as close to the center as possible (just make sure it doesn't interfer with your drain plug). I've put 2nd transducers in boats that already had a 1st transducer in them and have moved the transducer location by 12"-18" ---- point being it is not critical where you mount them as long as it is flat and in contact with the water.

I am considering doing another in-hull transducer in my boat for trolling, if I do it will be 4 feet farther forward from my other in-hull transducer. It might not read at planing speeds but it would be for a sonar I only use when trolling and then that part of the hull will be in the water.

One more consideration, a bedded-in transducer is not going to give you an accurate temperature reading of the water.

[foulpole18]

We used the 1"x 6" board on my dads warrior. Works really well. Like was said before then you can more your transducers around without adding holes to the boat. You only have the holes to mount the board.

[Valv]

I don't think you'll get good results where you plan to install it on transom. You have a lower section of boat (where your plug is installed) and it will give problems at hight speed. I had a Ranger 619 once and when installed on same spot (actually a little more to the right of your B point) it did work good until boat was on plane at good speed, then lost everything. I think the turbulence created by your lower transom/keel is the cause, I might be wrong, but that's why they install "shoot through hull"

[sparkyaber]

Valv, that is what makes sense to me also. The dealer told me that the place to install it was B, or maybe a little farther away from the motor but on the same level. I think I may silicone it in the bilge to give me an Idea of how it will work, and if it is even ok, I will cement it in and hope it is better with the epoxy. Now the question is when I install the through hull, how close can it be installed to a "wall" in the bilge. I have an accecsseble spot between my live well and wall that my batteries sit on. on the other side is a thicker piece of glass that the bilge pump is screwed into. The spot that the ducer would sit in runs the long way of the boat and is about as wide as if I would turn the skimmer 90 degrees (about 3" give or take) Is it ok to mount skimmer in that little channel?