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Depth sounder w/through-hull transducer....

8K views 19 replies 10 participants last post by  CaptainForce 
#1 ·
I recently finished up a major refit on my Catalina 30, which included a rebedding of my depth sounder's transducer. It required a little heat gun action to get it out, and now that the boat is in the water, the sounder isn't receiving a signal from the transducer. Since the boat's back in the water, it would require a haul-out to get a new transducer installed.

So.... anyone have any luck with in-hull, or on-hull transducers -- the kind that adhere to the hull rather than fit in a thru-hull? Any brands/models work for you?

Sailor with the best answer wins a prize!
 
#2 ·
I've seen a couple of references to people who bedded their transducer inside the hull using a wax toilet ring.

Google "transducer wax ring" and you'll get a bunch of examples.

Here's one: SailboatOwners.com - Transducer

Hope this helps,
Jim
 
#3 ·
I think they can work quite well with in-hull mounting, though you'll necessarily lose a bit of range. There are various methods used here. Also note that Airmar does produce a version that is meant to accommodate the deadrise of the hull (ie point straight down even if the hull in that area is not level - which may not be a huge deal because our boats aren't level much of the time anyway!!)

btw good to see you here... I trust your move to Florida has ultimately gone well?
 
#4 ·
Hello,

As previously mentioned, you can use a toilet bowl wax ring to test the location of a depth transducer inside the hull. I did that on my boat and found a good location in front of the keel. I planned on removing the wax and using epoxy. However, the wax has worked so well that it's still there 5 years later.

Maybe I have lost some depth performance, but I don't care about SHALLOW water, not deep water.

Barry
 
#5 ·
So no special transducer is needed? That's good news....

Thanks for the replies, gentlemen!

Ron,
How are you, Cap? Moving the wife and kids went well. However, I had the boat laid up in Jacksonville for most of a year, due to the Deepwater Horizon event last summer, which was followed by storm season. While dry docked, I had serious water intrusion through the stb. coachroof rail and mainsheet wench.... I checked on the boat in April, and it was fine. I came back in early December and found eight inches of water in the cabin.... it got in the engine crankcase.... unbelievable.... It was the apocalypse....

Anyway, I got the mess cleaned up, rebuilt the engine, worked on teh steering quadrant, did a ton of epoxy work on the bottom, painted the deck, etc. Between work, family and all, I've one busy S.O.B. The engine (an A-4) runs like a sewing machine, and all is well once again. They have a DIY boatyard nearby. I was there for three months and had them replace the cutlass bearing, rebed a couple of thru-hulls, and prime the bottom.... and the bill was $860! And that included a gallon of Micron bottom paint....

Anyway, I'm of half a mind to do a quick haul and properly install the transducer. Then again, I am so dang sick of boat maintenance right now....

Anyway, good to chat, my friend! Looking forward to pestering/ridiculing the Wombat!
 
#6 ·
Hog,

Great to hear from you!

Sorry about the boat mishaps, though.

Me personally, I'd just live without the depth sounder until the next scheduled haul-out. But that's me -- I'm thrifty.:)
 
#7 · (Edited)
Thanks for the update, Dwight.

While you don't need a special transducer, they do produce versions intended for in-hull installations.(like this one)
P79 In-Hull - Airmar Marine Transducers

Btw Airmar makes most of the transducers regardless of who else's name is on it.

Any idea why you're not getting a signal? Have you checked all the wiring connections?
 
#8 ·
I will be installing the transducer for my new system inside my hull. I have read of people using epoxy to mount the transducer and also silicon. If using silicon you need to get the air bubbles out. I'm not sure how this is going to work as I dont get good signals back when holding the unit against the hull.
 
#9 ·
I've got 12V to the device, but it gives a blinking 18.8 signal, which the manufacturer (Signet) says is an indication of no signal between the trans. and the device. However, at times it will give a reading of, say 183, and it doesn't blink. As per the Signet, this indicates that there is a signal, but that indicates a previous reading. Does that tell you anything?

Thanks again....

John, how are you!

They've got some very skinny water around here. Getting to and from the Gulf can be a challenge, even when you're in a marked channel. I may wait, as I've got to move it to a new marina, which I'm hoping has fewer depth issues than where I am presently.

The water is unbelievably clear here. Can't wait to get some pictures and videos.... Hope you're well, my friend!
d
 
#10 · (Edited)
I've got 12V to the device, but it gives a blinking 18.8 signal, which the manufacturer (Signet) says is an indication of no signal between the trans. and the device. However, at times it will give a reading of, say 183, and it doesn't blink. As per the Signet, this indicates that there is a signal, but that indicates a previous reading. Does that tell you anything?
Did you re-use the existing cable when you changed transducers or did you re-run the cable that came with the new one? This sounds like a poor connection somewhere between the transducer and the sounder. Are we talking the DS172 old style LCD indicator Signet line? Sounds like it. That's a coax line that gets soldered into the disconnect fitting at the sounder itself. I'd be looking for a cable fault/break/short... these are pretty simple setups and it sounds like the sounder itself is powering up OK.

The only other thought I have now is that the transducer you installed is not actually compatible with that older sounder..... did you get if from Signet?

EDIT _ sorry.. just re read your OP... I gather you simply R&R'd your old transducer... check cable/connections anyway but I suppose it's possible the heat damaged the tranducer itself???
 
#11 ·
I didn't change transducers or the sounder. They're the same. To be honest, I don't know what line of Signet it is. I'll check that out. But I believe you're right about the solder at the disconnect fitting. The sounder powers up just fine. Is it possible/advisable to swap out coax cable on these things? It's my understanding that you don't mess with the cable.... but I'm not 100% on that....
 
#12 ·
I'd be checking that that connection at the sounder is fully plugged in, maybe even disconnect and reconnect it and have a look at it... You can thread the cover off and check the connections inside easily enough... Beyond that try to visually inspect the coax where you can looking for nicks or breaks in the cable.

It is usually best not to disturb this type of cabling but it's not working now so maybe there's not so much to lose by attempting to replace the cable as a check.
 
#13 ·
I'll check the connection. If I had to guess, I'd say the heat gun may have zapped the transducer. Then again, one of the yard hands was certain that it wouldn't, and he's been pulling these things out of hulls for years now.

I'll report back...
 
#16 ·
I'm another successful shoot-through transducer user. Like BarryL, I was going to just test with the wax, but the transducer was stuck in so well with it, I left it alone. In my case, the transducer was meant to shoot through and not be mounted in a thru-hull.
 
#20 ·
A zip-lock bag of water is easily used to test the location an effectiveness of sounding through the hull. Simply place the bag against the clean inner hull surface and nest the transducer against it for the test. After finding our good location we epoxied our transducer in place. Take care and joy, Aythya crew
 
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