www.iFourWinns.com

I need to replace the Lowrance depthfinder on my 91 Sundowner 255. It apparently has a thru-hull transducer and I think it went bad. Instead of replacing just the transducer, I'd like to replace it as a set so I have new technology.

I'd like to replace it and use an in-hull transducer. However, the installation instructions say that an in-hull transducer will need more preparation if its a cored hull.

Is the floor of the bilge 'cored' in a 91 Sundowner? How can I tell?

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

The prep usually involves using epoxy to seal up the layers in-between. In some cases the hole is drilled just a little larger, filled with epoxy and then re-drilled so the hole goes through epoxy only. Effectively preventing any water from getting to the layers in-between. The effort to do this is VERY worthwhile as water intrusion into the fiberglass leads to VERY big problems. It's worth doing it this way even if it's not a cored hull.

As to whether this one has a core, I don't know. You might have to ask the factory directly.

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-Bill Kearney, 2005 348 Vista

Just for the record, I have discovered that Four Winns doesnt core any part of the boat that comes into contact with water, alas, the floor of the bilge floor is solid.

An in-hull transducer, like the one I want to install, should work great! Of course, Im having trouble believing that my Lowrance went bad. Today we are going out to the bay so I can jump in and go under the boat with a scotch-brite pad to scrub the transducer on the underside of the boat.

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

I just hate the idea of drilling though the hull. If I did, I would use 2 or 3 coats of West System resin to seal the hull & 4200 to seal the transducer.

And I got kind of lucky in that sense; my current transducer is already thru-hull. Four Winns installed the depthfinder that way from the factory. The question is, how much 5200 or epoxy did they use, how much will I possibly damage the hull trying to get the old thru-hull out, and will a new thru-hull be a different size (smaller?). Too many variables for me!! lol.

Im going to scrub the transducer today, although the bottom of my boat is painted and really deters growth - its very clean although it sits in a weedy canal. Im hoping that the transducer has some growth on it, or a zebra mussel attached itself or something. That would be an easy fix!

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

They do make a transducer paint to stop that. Not sure if you know that??

Most equipment is made by 3rd party companies (like Airmar for transducers). It's usually worth looking up the model number of your current and replacement stuff to find the dimensions. That way you know ahead of time.

The epoxy isn't used to hold the transducer. It's used inside the hole before ever inserting the transducer. The epoxy gets put on the sides of the hole in order to help seal the layers within it against water intrusion. In some cases, like going with a smaller diameter unit, the hole might be plugged solid with the epoxy, allowed to completely cure and harden, and then get re-drilled to the desired size. This gives you a column through the epoxy leaving the hull layers completely isolated.

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-Bill Kearney, 2005 348 Vista

To Technologic80, what about the type that you mount/epoxy to the inside of the hull. Leave the old transducer were it is. It beats you drilling into the hull. If you do re-drill, there is a additives that you can add the resin.You can not just use pure resin on that size of a hole.

From Garmin
Inside the Hull
An in-hull transducer is installed inside the bilge of a boat hull and sends & receives its
signal through the hull. Some people prefer this mounting style, because it is not
necessary to drill through the hull. A unit cannot be damaged when a boat is trailered,
the transducer is not exposed to marine growth, and there is no drag. Additionally, a
transducer can be installed and serviced while the vessel is in the water. Most in-hull
transducers are mounted inside a liquid filled tank that is first epoxied in place. As long
as the water flow below the transducer is “clean”, it will give great high-speed
performance. However, not all hull types (cored hulls, steel hulls, etc.) are suitable for
in-hull transducer installation. In-hull transducers are recommended only for solid
fiberglass hulls.

Well, thats where the good news ends. The tranducer is a 192kz model - Lowrance exclusively used these and they were discontinued completely. I called Lowrances customer service last week, the person on the phone was about as useless as a bucket full of elbows you are paid to carry 10 feet. They said they have no information any longer on the transducer and offer no support ?? I asked if I could just get the dimensions, and the person plain and clear said "no". If you do a search, Lowrances customer service is definitely a hit or miss.

And I know they epoxy the hole they mount the transducer in; however, 5200 or whatever heavy duty sealant they crammed the sealing surfaces with is what scares me. There are many reports from people that I know of having to break the transducer in pieces to get it out, and usually your fiberglass/gel on the bottom of the boat gets damaged in the process.

It seems so much easier, to me, to purchase an in-hull transducer doesnt it? I mean, FW doesnt core any part of the boat that touches water, so the in-hull should work right?

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

Yeah, thats exactly what I was planning, that is, if getting under the boat today with a set of goggles and scotch-briting the transducer doesnt fix it!!

Im not going to drill anything. I drilled in the gunwall last week to put it a rod-mount for our Magma grill and I think I popped a vessel in my brain when the hole saw touched the boat...LOL. Btw, it turned out great, looks great, and I LOVE grilling off the side of the boat now with a very firm support vs. that stupid 'rail-mount' setup.

I figure if cleaning the 'ducer off today doesnt fix said issues, Im going to buy a 2" hummingbird in-dash with an in-hull 'ducer(Hummingbird seems to have the best reviews for in-hull depth finders) and install that. Ill disconnect the Lowrance 'ducer so it doesnt interfere with the new one and just leave it there.

I will definitely update this thread, once I get under that boat today. Not a great day to be swimming either; its about 79f and a little windy. My voice may be alittle higher pitch when I get back out of that water....LOL

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

Well, getting under the boat and scrubbing the thru-hull transducer accomplished nothing. Display still flashing half the time, displaying 945 feet, then 3 feet, then 89 feet (all in known 5' of water).

I threw in the towel and bought a Humminbird HRD650 with an in-hull transducer. Should be delivered at my door Monday.

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

The Humminbird 650 Depth Finder came tonight, and its now installed!

All in all, very easy to do the in-hull transducer and it (appears) to work good.

Per the directions, we put the transducer in a ziploc bag filled with water, and put the bag with the 'ducer in the bilge. Found a spot where it read correctly and quickly (right next to the old thru hull transducer, which is now disconnected). Put a large freezer sized ziploc bag of sand on top of it to hold it in place, and then went for a ride on the lake!

Did a bunch of maneuvers, came off plane, went on plane, went slow/medium/fast, went to known shallow areas, went to known deep areas... the depthfinder worked great during all tests.

Came home, finalized the install by soldering the wires behind the gauge cluster, shrink tubing the connections. Epoxied the transducer in the hull. Had to lift a large section of the floor (above the gas tank) to run the 'ducer wiring and left a pair of pliers down there (DOH!)... the floor will have to come back up tomorrow to get those pliers.

I will report back in a few days, when the slow-cure epoxy has dried for sure. Then we will really know how good it works.

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

I wanted to update my thread here... I installed a Humminbird 650 depth finder in my 1991 Sundowner 255 last year (when I created this thread) and epoxied the transducer in the bilge. I had great results.

I bought a 278 Vista this past winter and go figure - SAME depth finder, same problem. No reading under 6' and sporadic at other times.

Installed a Humminbird 650 depth finder in the 278 Vista and also epoxied the transducer in the bilge. Guess what? Great results again!!

So do not be afraid to install the depth transducer in the bilge with slow cure epoxy. Its worked for me twice now and its very easy to do. I highly recommend the Humminbird 650 - not only does it seem well built, its said to have a strong transducer wattage output (according to what Ive read on the web) and Humminbird offers great support!

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

Did you ever get your pliers back?

Glad it worked a second time for you.

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2001 Horizon 260 - 7.4 Volvo GSI DP

Hello all,
New to the sight ... new to a 20 ft 98 Horizon as well !!!

I just purchased a Humingbird combo unit / I'm thinking about putting a threw the hull transducer in the back part of the storage locker between the front seats.

Has anyone tried this ???

any thoughts good or bad would help

thanks jb

ps I am planning on using the transom mount transducer for this ..... I know i wont get water temp but is there any other downside ?