Through-hull transducer?

[flyingwelshman]

At the end of last season it seemed as though my depth-sounder/fish-finder was pooched - strange lines running across the screen.

The thing is over 10 years old so I expect it needs replacing.

It is connected to an in-hull transducer.

I was hoping that I could just connect the new fish-finder / depth-sounder to the existing transducer to prevent having to screw around with holes in the hull.

Upon inspecting my hull I found a second, un-used transducer from a previous set-up.

Anyway I went to a local, well-respected, sporting goods place and asked about hooking up a new fish-finder to the old transducer.

The guy told me that it probably wasn't possible (as I kind of expected). I was looking at some transom-mounted transducers when the guy told me that Lowrance gives instructions for mounting these inside the hull. That the 200 khz models are powerful enough to act as a through-the-hull transducer.

Does anyone have any experience with this?

This would certainly make the placement better as I could mount the transducer at the bow (in front of my waste-water holding tank) instead of under the cockpit where is is now.

Any thoughts would be appreciated.

Thanks.

[Birdface]

Lots of previous posts on these.

If your deck is cored you can't put it shoot-through, you have to put it in/through-hull or on the transom mount. Find out if your deck is cored.

Older transducers really don't work with the newer stuff... the newer transducers are mostly made by one company, most of the major fish finders have proprietary plug interfaces that won't work with older cables/transducers.

[flyingwelshman]

has anyone got any experience mounting a transom-mountable transducer inside the hull so that it functions as a through-hull transducer?

Originally Posted by Birdface

Lots of previous posts on these.

If your deck is cored you can't put it shoot-through, you have to put it in/through-hull or on the transom mount. Find out if your deck is cored.

Older transducers really don't work with the newer stuff... the newer transducers are mostly made by one company, most of the major fish finders have proprietary plug interfaces that won't work with older cables/transducers.

[radly53]

On my good old boat I used a Humming Bird fish finder that I got for about $90, I glassed the transom mount to the inside of the hull on a flat spot forword of the keel. It work great and I did not have to make any new holes in the boat. That was more than ten years ago, The new owner is still using it.

Good luck

[US27inKS]

I've done this as well. Here's a thread with all the pros and cons for you.

http://www.sailnet.com/forums/gear-m...thru-hull.html

[merttan]

If you have a hanging rudder, you can install it on the rudder... That's what I did on my 22 footer and it works fine. I secured the cable with simple one layer of fiberglass cloth... It's not the best solution but beats the drilling holes for me...

For installing inside the hull, you need to find the thinnest location that's solid fiberglass not cored and will be still somewhat parallel to the bottom when you heel... Then you can install support for the transducer by glueing small pieces of wood and cover them with fiber glass, then drill screw holes on that support to install the transducer...

Inside installations do work but not as accurate as installing the tansducer in the water... Any air bubbles that passes beneath the hull can interfere, as well as, the (God forbid) any blisters that may occur at the location...

Inside hull installations are recommended for power boats, which has thin fiberglass hulls and would be affected in performance by the transducer's shape...

I wonder if you could replace the old transducer you found with a new one without making additional alterations to the boat...?

I also thought of a rather unortodox method before, I'll share it if you are interested... If you have a inner rudder setup, you can install a pipe holder to hold a small pipe (or a wooden stick) close to the transom then install the transducer at the end of that pipe. When you want to use it just put the pipe in location, when you don't need to use it store the pipe and transducer in the boat... Does it make sense to you? I could send some drawings if you want...
Best of luck...