Transducer Installation Questions and Answers

[cbadmin]

From: C-LionRay (Original Message) Sent: 3/25/2003 8:19 AM
I am starting this thread to provide a resource for folks who want or need information regarding installing transducers. Please feel free to share information and your experience here.

From: C-LionRay Sent: 3/25/2003 8:24 AM
I am replacing my current GPS Fish Finder with a better model and I need to remove the old transducer ans install the new one. It doesn't look like the old one was sealed and I am concerned about water migration in the transom since it is below the water line and I know the boat was moored.
The old and new transducers are both transom mount and look identical except that the new one has two more pins on the connector. That means it is better huh
Should I be concerned about this or am I just parenoid?
What should I use to seal the screws when I install the new one?
How far below the water line should I set it?
Thanks in advance,

Ray on Sea Lion

From: Jim F Sent: 3/25/2003 10:40 AM
Ray - I think it's healthy to be paranoid abouts lots of screw below the waterline. The transducer need to be right in line with the bottom of the boat if you want it to work while you're runnung. The solution I like is to mount a piece of 1/2'' or 3/4 " poly sheet material (like Seaboard) on the transom down to the waterline, and then screw all the accessories (transducers, bait pumps, etc.) to that. I think they sell them at West Marine or Cabelas, but you can get the same material at a plastics place like Tap Plastics. To really do it right, I'd get a piece long enough that all the screws to attach it are up above the waterline. That way, if you want to change something, there's no worries about sealing the old holes.

My $.02 - Jim F

From: Sea Deuce Sent: 3/25/2003 11:30 AM
I highly recommend using 3M 5200 for sealing anything under the waterline. If it is determined that you have dry rot, contact the Rot Doctor for a complete line of materials that will assist in correcting the problem. They are out of Washington state and are a great company to deal with.


From: stevej Sent: 3/25/2003 6:08 PM
Ray checkout this Lowrance link for a transducer install guide doubt that the brand matters much
http://www.lowrance.com/Manuals/Files/skimmer_xdcr_0147-581_091302.pdf

5200 is the stuff to use as Sea Deuce said, while your at it pull every screw on the transom above and below the water line and seal also make sure that any thru transom cables covered by a clamshell or whatever have the exposed balsa in the hole sealed with 5200.

stevej


From: C-LionRay Sent: 3/29/2003 12:26 AM
Thanks guys, good info.

From: Mike Sent: 4/14/2003 4:23 PM
Here's my question: Is there any problem with having two transducers on the transom? I didn't get the sounder module for the new GPS yet, but I hope to soon. Right now I am using a low-end Humminbird fish finder with a single frequency transducer. The Garmin will be a dual frequency. I would like to relocate the Humminbird so it can be seen thru the window from the cockpit. I am wondering if the two transducers will confuse each other?

Thanks,

Mike

From: Mike Sent: 4/14/2003 11:08 PM
And another question. Is the water speed sensor worth having? It nearly doubles the price of the transducer kit. It would be kind of cool to know the speed of the river current, but not really necessary. The GPS gives the actual speed the boat is traveling, and it's easy to tell how swift the current is by cruise speed/rpm comparison. The current does determine the needed fishing tackle, but just pitching it out there once tells you if you need more or less weight. So, what do you think?

From: Redƒox Sent: 4/15/2003 12:39 AM
Yup! you can not run two at the same time, they will cause MUCH interference.

From: tsturm Sent: 4/20/2003 8:22 PM
As long as the two transducers are different frequencys you wont have a problem using two different sonars at the same time

From: Jim F Sent: 5/28/2003 10:13 AM
I have a new question on this subject - Has anyone had any luck getting the transom-mounted transducer to work while under way? Right now it gives me a good picture of bait balls etc. only below 5 kts. or so; anything faster than that and all I get is a depth reading. I'm thinking about installing an adjustable transducer mount (like the temporary mounts Cabelas sells for small skiffs) so that I can push the transducer down till I get a good reading. Any experience with this?

Thanks - Jim F.

From: Redƒox Sent: 5/28/2003 5:45 PM
I have heard that flat bottomed boats trap more noise (primarily engine noise) under them, that's one reason the sounder does not function well while under way. I have significantly reduced this problem on my boat, by mounting my transducer on the trim tab. I have not tried anyone's adjustable mounts, no.
Greg

From: Redƒox Sent: 5/28/2003 5:50 PM
Here is what I did.

From: Jim F Sent: 5/29/2003 9:11 AM
Greg - I had seen what you did with your transducer. It looks pretty slick. So you still get a good picture when you're underway? I don't have trim tabs, but I thought about putting a a small tab on a vertically adjustable stainless bracket to mount the transducer on. It would basically attempt to duplicate your setup. It's a good excuse to play with my MIG welder anyway!

Jim F.

From: Redƒox Sent: 5/29/2003 10:30 AM


Yeah Jim the difference is great between the way it was before (on the transom) verses (on the tab) those are extended with that wonder plastic out to 16 inches, as you know already, I think that is one reason it gets less noise and clears up the picture on the sounder screen. I still cant go along at high speeds though, and maintain a lock, and when the depth drops off more than a 180 feet, it will loose its lock on the bottom. The way I figure is, I have my color chart plotter and the garmin G-Charting, to observe the depth anyway, while under way. I have to get back out soon and re observe and get back to you with some accurate figures.

Dusty was telling me about doing something similar way back on a much larger boat. I can't remember where that conversation took place though. It might be on these message boards? Anyway, I'm very proud of my "invention" even if old Duster beat me to it.

Greg

From: stevej Sent: 6/3/2003 8:02 PM
Red fox may have the solution, I'm running with two sounders an old Standard Horizon 2" digital readout never misses a beat until you get beyond 300' of depth but works at any speed.
My lowrance (retired) would only function when stopped for the most part but can't blame the unit as the transducer was mounted on the wrong side of the transom (in the prop wash). It did have a bad habit of getting confused by the dirty water and would need to be shut off to come back with good readings.
My Furuno has the transducer is mounted next to my standard horizon transducer (correct side of the motor but very close to the trim tabs) and is okay at speed in calm water shallow water (to 100') but gets spastic in a lumpy ocean as it loses contact with the water on occasion. Oddly enough the Furuno and the SH unit do not confuse each other when used at the same time (both using 200 Khz) the Furnuo will switch to 50 Khz in deep water.
With the limited space on the transom it's tough to get an ideal spot. I dont know what you can do about the transducer lifting out of the water in a steep swell and how sensitive the unit is to losing contact with the water. So I'm thinking a thru hull or the Red Fox approach is the answer.

stevej

From: Jim F Sent: 6/4/2003 10:34 AM
The more I read about this, the more I'm convinced that the solution is an adjustable sliding mount that let's you push the transom-mount transducer deeper into the water to keep it submerged all the time. Otherwise, it seems you could play around with this forever and pepper the transom with new mounting holes trying to get the location and depth right.

Jim F.

[Sneaks]

Airmar is coming out with a new flush mounted through hull transducer for sounders that is already "tilted" to compensate for the 12 degree deadrise C-Dorys have. Given that the C-Dory has a balsa cored hull, they require far more attention to detail when installing those transducers, even if one is willing to punch a hole in a relatively safe cockpit location.

Somewhere I read an excellent summary of the steps needed, but it went to bit heaven per usual. I would assume someone on here has installed one and I'd love to hear the procedures or even a URL laying it out.

[flagold]

JB Weld works great for a "no hole" install. If you need to change transducers, you simply disassemble the bracket and slip the new one in the old bracket. If the bracket needs changing for some reason (the almost never have to be changed), pop the seam of the JB Weld/transducer/hull with a wood chisel and it will come off.

Figure out the loation of the install, place duct tape on the transducer and put the JB Weld on the surface that mates with the hull. Leave on overnight.

[Sneaks]

Thanks Flagold, but I think you're referring to mounting a transom mount transducer without putting holes in the transom and I'm talking about a thru-hull transducer. Thru-hulls can have distinct advantages, and if it's not a huge hassle to do it I'd like to give it a try.

If it does create too many problems, your JB Weld idea sounds pretty easy and I'll remember that hint. Thanks

[Chuck S]

All my boats except the C-Dory have had thru hull speed and depth. Balsa core takes an extra day to install unless you shoot thru the bottom layer of fibreglass.

I have a transom mounted sounder on this boat.

-- Chuck

[flagold]

Indeed I was -- didn't catch the thru-hull part -- sorry for any confusion.