Transducer Inboard Installation

[gbendaly]

Hummingbird states that their fishfinder transducer can be either transom fixed or installed inboard using a slow curing epoxy mix as long as its located on the centerline of the hull and facing downward at 90 degrees
so I chose option 2 but kept reading a depth of 1.6 feet !
I wonder if this will change when the epoxy sets ?
since I did not want to risk waiting for the epoxy paste to cure and lose the transucer altogether I removed it and thought I'd ask for your opinion and advice
any thoughts ??
thanks
George

[Minggat]

I believe you did the right thing. If it does not work with the epoxy uncured, I have serious doubts it all of the sudden believe you have followed the rules and reward you for it.

I met a guy who violated the rules and tried silicone to test his transducer in different spots until he got a proper reading. Then let the silicone set up because he can pop it off if he wants, even if to just use the recommended epoxy.

I tried it. Could only get a reading in one spot. Then I couldn't repeat it!! Gurrrrr.

I have redundant (3 fixed mounts and a handheld) depth units. This has worked for me.

If the "tansducer in the bag'o water" trick does not work for you, try plumbers putty or modeling clay to find the sweet spot. When you find the sweet spot and want to use the epoxy, make sure you STILL get a reading you're happy with.

One of my units is still stuck in place... with the clay. Stupid thing has no idea why it's so happy.

[gbendaly]

thanks minggat, you confirmed my fears , I am presently designing a device that can hold both the paddle wheel of the speedo and the depth transducer below the waterline at the transom , it will have a pendulum motion to counter the heeling angle at all times..will post some pictures if it works..
george

[Captin_Kirk]

Is your hull cored where you are trying to put the transducer? If so you have to remove the core and put the transducer on the last layer of fiberglass.

Very scary stuff, but that is what the directions for mine said.

[GordMay]

A hard adhesive transmits sound best. However, winter temperature extremes and flexing on trailer rollers can cause it to delaminate.
Soft adhesives absorb sound and will greatly reduce performance.

To compromise, use a viscous slow-cure epoxy or a fairly rigid one-part adhesive sealant.

In cold climates, a one-part polyurethane adhesive, such as Boat-Life’s ‘Life Seal’, may be best.
3M’s ‘4200' would also be ok.
Caution: Do not use “5 minute” epoxies because they are too brittle.
Do not use RTV (silicone) adhesives because they absorb most of the sound energy.

Mounting In-Hull Transducers ➥ http://www.cruisersforum.com/forums/f55/mounting-in-hull-transducer-42702.html#post474506

➥ http://airmartechnology.com/uploads/.../17-452-01.pdf

➥ http://airmartechnology.com/uploads/.../17-467-01.pdf

➥ http://airmartechnology.com/uploads/...ide/17-010.pdf

[idpnd]

Nasamarine publish inhull installation instructions for their transducer on their website

[osirissail]

Yes as CaptinKirk stated - the hull material must be solid FRG and not cored or have voids. Since it is "sound" that is being transmitted you need a "solid" medium to allow the passage.
- - However, epoxy or glue or whatever is not necessary. I had a left-over little round depth finder from a small speed boat which I got rid of. I went to a plumbing supply place and purchased a PVC "clean-out" adaptor that the transom mount transducer would fit into. It was for 6" diameter pipe. Then I removed the hull paint in the areas I was going to use; ground the area as flat as possible and then used epoxy to attach the PVC clean-out adaptor to the hull.
- - The adaptor has a screw-in "lid" which I cut a notch into to allow the cable to pass through. Then you fill the interior of the adaptor with mineral oil (otherwise known as "baby oil") and placed the transducer inside and screw down the lid to hold the transducer tightly to the hull. You may need to adjust the "height" of the PVC clean-out adaptor to fit the total height of the transom transducer.
- - The unit works better than when I had it mounted on the speedboat and it is currently "shooting" its signal through 1.5 inches (35mm) of FRG. And if/when the transducer/depth sounder fails or dies, I just unscrew the "lid," lift out the transducer and replace, it if I want, with a new unit.

[svcambria]

I met a guy who violated the rules and tried silicone to test his transducer in different spots until he got a proper reading. Then let the silicone set up because he can pop it off if he wants, even if to just use the recommended epoxy.

Exactly what I did with the same results. Please don't tell my transducer that it's not supposed to work...
You will not get any results on center line if you attach it above the keel. On mine, I measured the offset from center line of the fixed transducer - just ahead of the mast - and duplicated it on the other side. Set with a tuna can, both top and bottom removed, set transducer in, filled with silicone, waited a couple of days, and voila! depth information. The transducers don't need to be exactly 90 degrees down, they have some aperture just like any other antenna, and you can test that by holding it by hand in water and see how far you can tilt it and have it work.
The epoxy method definitely makes it a permanent part of your hull until you grind it off - ugh. And the transom position lets you know what you have already passed over...
I should mention mine is a fish finder type, nice as it can display a nice big number for depth - good for rivers, bars, shallow anchorages - or a profile to get a trend on the bottom, and an intimation of bottom conditions - or ID some fish.

Michael

[hugosalt]

"For what its worth"
Years ago on my solid fiberglass hull, I installed a thru hull transducer inside the hull using silicone...it worked when silicone was wet, it worked when it dried...and its still working now.

[gbendaly]

quoting Osirisail :"Then I removed the hull paint in the areas I was going to use; ground the area as flat as possible"
is this inside the hull ?? what about the antifpouling paint outside ?? does it affect in any way the signal

[osirissail]

Originally Posted by gbendaly

quoting Osirisail :"Then I removed the hull paint in the areas I was going to use; ground the area as flat as possible"
is this inside the hull ?? what about the antifouling paint outside ?? does it affect in any way the signal

It is the inside of the hull below the "floorboards" - The inside of my hull is painted with two-part epoxy paint both to stop water from getting to the FRG and to make cleaning and storing of things easier. The two-part epoxy paint is rather thick and "softer" than the FRG. So removal was necessary to present clean FRG surface to epoxy the clean-out adaptor securely.
- - This technique of using an outboard/transom mount depth sounder inside a boat has been written up periodically in the various sailing/cruising magazines which is where I got the idea. It is a good non-destructive way to mount the transducer and be able to remove it for repair or replacement.
- - For those contemplating installing a fixed thru-hull transducer for the normal sailboat depth sounders - spring for the extra bucks and get the model transducer that is removable - just like the speed/log paddle wheel sensor. Being able to remove the unit while in the water can save big bucks and avoid an early haul-out should the permanent depth transducer fail.

[Minggat]

Originally Posted by osirissail

- - For those contemplating installing a fixed thru-hull transducer for the normal sailboat depth sounders - spring for the extra bucks and get the model transducer that is removable - just like the speed/log paddle wheel sensor. Being able to remove the unit while in the water can save big bucks and avoid an early haul-out should the permanent depth transducer fail.

I went that way. Spent a lot of money to get it mounted and a lot of money to get it unmounted.

[Minggat]

Originally Posted by gbendaly

what about the antifpouling paint outside ?? does it affect in any way the signal

You're way overthinking this.

[Chrisc]

The thing to remember is that the transducer beam doesn't zoom straight down - it flares out as a cone-shaped pulse. If the transducer is mounted amidships and close to the keel, it is possible that the 1.6 foot constant reading you are getting is from one side of the the pulse intersecting with the bottom of the keel. Happened to me, and I had to shift the darn thing a little more out board.
I have one transducer mounted internally on silicone and one internally on epoxy. I cannot detect any difference between the two.

Chris

[stevensc]

I have mounted one using silicone it worked fine for years. be sure to get all the bubbles out of the space between the transducer face and the hull (must not be cored) inside surface. you may have to try different places to get a good reading.
Last year I set one in wax, it has worked very well with the advantage that I could have moved it if it had not worked well the first try. I used wax from a toilet ring wax seal bought at a hardware store. I made a ball about the size of a billiard ball, I set it in a likely spot and pushed the transducer down into it holding the transducer level.
It also worked the first time so I left it like that, over a year now no problems. The was is still pliable, it has to be in an area out of the way where it won't get bumped as the wax will not hold it firmly as silicone or epoxy would.
Steve