How did you mount your depth finder transducer?

[AZ-Oldguy]

Originally Posted by chouliha

We did something similar with our fish finder. First we put the transducer in a baggie with fresh water and moved it around on the hull until we got a decent reading. Then just used a big glob of silicone to stick it to the hull. We often get reading in excess of a 100’. What we use it for besides determining depth is to see the bottom type. Especially to look for sandy section without any coral for anchoring

Good luck with your install

Chuck
Jacaranda

Chuck, are you saying that you just used silicone to directly cement the transducer to the hull? No oil or antifreeze no well just glue the transducer directly to the hall? For me to do that I would have to make a flat spot on the hull., or does the blob of silicon form a wedge so that the transducer is vertical?

[Mike OReilly]

On a previous boat I used a shoot-thru-the-hull transducer. On that boat I was able to find a fairly horizontal spot, and it had a solid hull. I used a pre-existing well, and simply filled it with water. I placed the transducer against the hull in the water bath, and then held it submerged in place with a sponge.

I always meant to silicon it into place, but the sponge/water bath worked perfectly for years.

The problem with your boat (and my current one) is the steep angle of the hull.

[AZ-Oldguy]

Originally Posted by Mike OReilly

On a previous boat I used a shoot-thru-the-hull transducer. On that boat I was able to find a fairly horizontal spot, and it had a solid hull. I used a pre-existing well, and simply filled it with water. I placed the transducer against the hull in the water bath, and then held it submerged in place with a sponge.

I always meant to silicon it into place, but the sponge/water bath worked perfectly for years.

The problem with your boat (and my current one) is the steep angle of the hull.

Steep sides is certainly the problem. I do have a solid glass Hull. I wonder if the silicone transmits the signal without any changes, the way the fiberglass does or water / oil / antifreeze does in a well? Essentially does the transducer not know that it is not directly in seawater?

[Copacabana]

Originally Posted by AZ-Oldguy

Chuck, are you saying that you just used silicone to directly cement the transducer to the hull? No oil or antifreeze no well just glue the transducer directly to the hall? For me to do that I would have to make a flat spot on the hull., or does the blob of silicon form a wedge so that the transducer is vertical?

I have 2 transducers (fishfinder and GPS) stuck in place with a blob of silicone. They both seem to read depth fine. The trick is the clean the area well, lay down a blob of silicone with no air bubbles (important) and then carefully and gently push the transducer into the silicone without getting any air under it. It should rest against the hull with silicone holding it in place. It's much easier than making a well to fill with water or oil.

[Mike OReilly]

While I did not use silicon, many have (or told me they have). The key seems to be to ensure there are no air voids in the seal. Many people also epoxy the transducer in place once they’re confident of the location. Again, the key is make sure there are no voids in the seal.

But none of this really matters in your case. Your issue (if I understand it) is the hull angle.

I’m just thinking out loud here, but if you really want to try this shoot-thru-the-hull approach, perhaps you can build an appropriate sized and angled wedge (using stiffened epoxy using high density filler) such that you can create a level space. Attach this to your hull using silicon, and then mount the transducer. If it works, then Bob’s your Uncle!

[AZ-Oldguy]

Originally Posted by Copacabana

I have 2 transducers (fishfinder and GPS) stuck in place with a blob of silicone. They both seem to read depth fine. The trick is the clean the area well, lay down a blob of silicone with no air bubbles (important) and then carefully and gently push the transducer into the silicone without getting any air under it. It should rest against the hull with silicone holding it in place. It's much easier than making a well to fill with water or oil.

Hi Chuck, just to make sure I've got this clear. Does your Hull have some dead rise, such that the transducer is only touching the hall on one Edge so that it can sit flat on a horizontal plane although the hull is not flat on a horizontal plane? Another words, is there more space under the transducer on one side than the other? I get it about no voids or air bubbles.

[Cheechako]

Cant you just pick a flatter part of the boat to mount it? I understand wanting it far forward, but realistically wonder how much that really gains you, vs maybe back a bit.. However if your old one worked where and how it is I imagine the new one will too.

[Copacabana]

Originally Posted by AZ-Oldguy

Hi Chuck, just to make sure I've got this clear. Does your Hull have some dead rise, such that the transducer is only touching the hall on one Edge so that it can sit flat on a horizontal plane although the hull is not flat on a horizontal plane? Another words, is there more space under the transducer on one side than the other? I get it about no voids or air bubbles.

Chuck is the other poster.

I just found a flattish spot to mount both transducers. There is no side that has more silicone under it.

Before you decide the hull angle is a problem, test the transducer in place. Get some children's modelling clay (plasticine or similar) and make a "pool" where you want to test the transducer. Then fill it with water. You can hold the transducer in the water and see if the hull angle affects your depth reading. If it works, then clean up the spot and mount it with silicone.

[Nanamuk]

On my DeKleer Endurance 35 I cut a piece of ABS (could use PVC) pipe with a diameter large enough to accommodate the transducer, bevel it to be vertical and fit close to the hull then glue it to the hull with thickened epoxy. I then melt some Vaseline, pour it in the tube, install the transducer at an angle so as to prevent bubbles getting trapped under it then shift it horizontal and support it while the Vaseline hardens. My old Lorence has both wide and narrow beam transducers. I regularly read 1000 ft with the narrow beam. My new Garmen fish finder craps out at 140 ft or less. The water temperature feature is accurate with the in hull installation.

[TheLastPirate]

I have mounted many thru hull transducers on steep angles. We would just make a fairing block out of teak,epoxy it then 5200 it to the hull, the transducer would be thru bolted also holding it on...I can't remember if we laid some glass around it after that...on the block to hull joint or not....I don't think it would hurt. You could make the fairing block out of juniper, mahogany, teak, even closed cell foam and glass over it. You can drill the hole after it's on there assuring it will be vertical...and you can always add a wedge of cabasil and epoxy if the block is off a touch. That was our standard operating procedure at the yard....I don't ever recall using a fairing block from a store, we always made them. And what someone mentioned was right...you have to have a long threaded shaft to lake it thru. I also have looked at the ...I think it's Minn Kota..they have a shaft minus the prop that you can mount your transducer to off the transom and raise it out of the water when you want to. I was looking at those for the forward looking sonars...cause I didn't like the idea of that little upside down parascope sticking out under my hull.

[Ken Z]

I have mounted transducers inside the hull and have made epoxy bases to level the hull shape to level then mount the transducer on the level base. You have to use slow set epoxy or you can ruin the transducer. You can make a form out of cardboard and duct tape and tape it to the hull and pour it, use slow set epoxy to bed the transducer.

[NorthCoastJoe]

Slightly off subject, but if I have a depth sounder and a fish finder. Depth sounder mounted forward of the keel. How far away should the fish finder be from it?
How close can I mount them? Will they create problems with each other if too close?

[Copacabana]

Originally Posted by NorthCoastJoe

Slightly off subject, but if I have a depth sounder and a fish finder. Depth sounder mounted forward of the keel. How far away should the fish finder be from it?
How close can I mount them? Will they create problems with each other if too close?

Good question. No answer...

My two transducers are mounted about 2 meters (6 feet) from each other. One is a Garmin fishfinder transducer and the other is for the Garmin GPS. They both work fine, but perhaps because they work on different frequencies and don't interfere with each other.

[Mike OReilly]

Originally Posted by Copacabana

Good question. No answer...

My two transducers are mounted about 2 meters (6 feet) from each other. One is a Garmin fishfinder transducer and the other is for the Garmin GPS. They both work fine, but perhaps because they work on different frequencies and don't interfere with each other.

That would be my only thought; as long as they operate on different frequencies, there shouldn’t be a problem.

[sailcrazy]

I mounted a P79 in an adjustable mount, and filled it with RV antifreeze....it worked fine for about 4 years, and has now stopped working. I'm guessing the antifreeze has evaporated and left a void under the transducer. Unfortunately, here in the /caribbean there is not a large supply of RV antifreeze! Please tell me more about the "oil" several have mentioned....just baby oil, or eng oil, or??? The melted vasoline idea is also intriguing. But I need something.