Through Hull Transducers

Wandering Sagebrush · Posted: Sun Mar 12, 2006 5:21 pm Post subject: Through Hull Transducers

Does anyone have experience with mounting a transom xducer inside the boat, and shooting through the hull? I have a Lowrance GPS/Depth finder that I can not get to give a reliable reading when at speed. Sometimes it works just fine, but frequently it is the blinking numerals of death. It is probably just turbulence around the xducer, but then I wonder if Microsoft wrote the operating system.

On the forum for my other boat fetish (Montgomery 15s), there has been quite a bit of chat about mounting the xducer internally in a pool of silicon/epoxy/silly putty (take your pick), and shooting through the glass. Does anyone know if there are any locations on the CDory that does not have a balsa sandwich? Perhaps the sump by the drain? I do not want to put a hole under the waterline....

The Montgomery crowd seems to be pretty satisfied with this arrangement.

Cliff · Posted: Sun Mar 12, 2006 5:34 pm Post subject:

I read an article that said to try it with creamey penut butter first and if it works than expoxey it in place.

Chris Bulovsky · Posted: Sun Mar 12, 2006 6:18 pm Post subject:

Try adjusting the transducer a little lower than the directions say. It may clear up your troubles. I have the Lowrance LMS-332c and have pretty good depth readings underway. Sometimes transducers wear out and need replacing.

Chris Bulovsky

JamesTXSD · Posted: Sun Mar 12, 2006 6:57 pm Post subject:

You can put the transducer in a baggie full of water and move it around the hull to see where you get the best reading. Another option is to drill out the spot in the hull to the core. Disgust

Fill with epoxy, making sure there are no bubbles (also affects the transducer performance). I have mounted a couple of them with silicone instead of epoxy, making sure to work the bubbles out. Of course, there is always on the transom. HTH

Best wishes,
Jim

SEA3PO · Posted: Sun Mar 12, 2006 7:04 pm Post subject:

I thought about that when I fitted out my boat, but thought the balsa core would destroy the signal.... what I did was mount the transducer thru hull in the very back where the bilge pump is... big mistake... there is to much turbulence in that spot... it just gets clutter once I get up on plane..... I think the transom mount is the way to go.... (next one)

Joel

Sawdust · Posted: Sun Mar 12, 2006 7:57 pm Post subject:

Hmmm -- I've tried lots of ways, all wrong. My favorite is using a thru-hull transducer, but that's a real PITA to make a fairing block that's out of the way (won't foul during loading on the trailer), etc. For serious fishing it's a great way to go and works fine under way - use this system on the Pierson Rampage (no C-Dory content, sorry). Mine also includes a thru-hull speed sensor which you can pull from the inside and clean. You can also really screw it up on the trailer when recovering. Rolling Eyes

- you can't guess how I know.

I've NEVER had one I couldn't make work when fastened externally to the transom. Takes some experimenting, and angle IS important to avoid bubbles and associated noise. Also it must be positioned where it doesn't mess up the prop.

Putting the xducer in a sealed box -- filled with water -- also works, but if you shoot through the glass the signal is going to be degraded to some extent.

I'd surely experiment with the external transom mount before giving up.

HTH (probably won't!)

Dusty

DodgeRam · Posted: Sun Mar 12, 2006 9:03 pm Post subject:

Your right about the angle of the transducer mounted outside, do not take much to change the signal. Now every time I get ready to launch the boat I try to remember to check both of my transducers for the right position. The large one is mounted between my twin engines beside the drain hole, the other one is mounted on my trim tab , they both work fine as long as I remember to check the angle with all the crap in the water they do get displaced. When I troll I do adjust the transponder on my trim tab to the reading on the fix one. Personally when cruising I pay attention to my GPS screen for depth, C-Map MAX is very detail, and on a 10'' screen very easy to look at.

Gary SEARAM

Wandering Sagebrush · Posted: Tue Mar 14, 2006 12:47 am Post subject: Thanks!

I appreciate all the feedback. Looks like there are a number of different ways to deal with this. For now, I think I will stay with the external transducer and play with depth and angle.

True Story · Posted: Tue Mar 14, 2006 8:12 am Post subject:

I'd be very interested to know if you figure out a solution to this problem WS as I have a Lowrance X-17 with the same intermittent problem. I have not tried adjusting the transducer. I finally installed a redundant digital sounder mounted in the dash for those occasions when the Lowrance starts blinking.