Shoot Thru Vs. Transom Mount Transducer

[Nitro 882]

Hey guys,

I have a $700 depth finder/gps unit mounted at the console that has the transducer mounted in the recommended place to "shoot thru" the hull of my 19" fiberglass bass boat.

I won't mention the brand because I don't want to spend a lot of time with suggestions that I buy the"other" brand which, of course, is much better than what I have now. I only mention the price to indicate that it is a fairly good unit.

When idling around searching for cover or structure, I leave my trolling motor down and my bow mounted unit, many times, will show things that my console unit doesn't pick up.

(The front unit, by the way, is the "other" brand but only a $200 unit.)

Questions:

1. Do transducers wear out and should I replace it with another "shoot thru".

2. If so, what is a good way to remove the existing unit without putting a hole in the boat.(I'm kinda clumsy.)

3. Would I be better served with a transom mounted transducer that would eliminate the

barrier created by the hull and result in a clearer signal?

Thanks in advance for any suggestions and Happy Holidays.

Tom

[JIGFISHERMAN.]

Transom mounted can give a better signal.

I don't really think they wear out. IMO, I wouldn't remove the transducer that is shoot thru. Just leave it.

I'm curious what one shows, and the other doesn't. They won't be exact, because of the power, and resolution differences.

[Nitro 882]

Hey Jigfisherman,

Here's a good example I just remembered. My son and I were dropshotting smallmouth on Lake Champlain. The fish were chasing bait up and down a steep drop-off just offshore in 20'-25' of water.

I was on the trolling motor and as soon as the front unit would cloud up with baitfish we would get bit for about 5 minutes and the school would move by only to come back thru in 10-15 minutes. This went on for a couple hours and it was fast action when they went through.

My son was in the back of the boat and I leave the console unit on for him to view as he fishes. I would see the bait show up on my screen and say "here we go". His screen would show bait occasionally but most times not.

By the way, the console unit seems to show depth accurately but not anything suspended in the water column.

I've screwed with sensitivity settings and the like with no noticeable improvement.

I just feel the transducer is the problem but I'm only guessing.

Thanks

[JIGFISHERMAN.]

Just to make sure, is the console unit on SI/DI when this happens?

Not even sure if the unit you are talking about has SI/DI. But, if it does, regular sonar, will show fish, (baitfish, and gamefish) much better than SI/DI images.

EDIT: Nevermind, it wouldn't be SI/DI if it was shoot thru hull

[Wayne P.]

A PROPERLY installed shoot-thru 2D transducer looses very little in sensitivity in a hull that is suitable for shoot-thru use.

Yes, a transducer can wear out. It is a combination speaker/microphone that transmits and receives sound waves.

Also changes in the hull can occur due to rough water operation causing some delamination or just the installation coming loose from the hull due to hull flexing will affect performance. That most important PROPER installation, if not done correctly, will allow for the transducer to come loose from the hull.

To remove one, just chip away some of the excess epoxy from around the transducer and whack the side of it with a block of wood and hammer.

[Todd Driscoll]

A PROPERLY installed shoot-thru 2D transducer looses very little in sensitivity in a hull that is suitable for shoot-thru use.

Yes, a transducer can wear out. It is a combination speaker/microphone that transmits and receives sound waves.

Also changes in the hull can occur due to rough water operation causing some delamination or just the installation coming loose from the hull due to hull flexing will affect performance. That most important PROPER installation, if not done correctly, will allow for the transducer to come loose from the hull.

To remove one, just chip away some of the excess epoxy from around the transducer and whack the side of it with a block of wood and hammer.

Well said Wayne. I always recommend a shoot-thru installation with fiberglass boats because when done correctly, I don't see any disadvantages. It's protected from impact damage, and if mounted properly, will read just as good as one mounted on the outside because units now are powerful enough to compensate for shooting thru the hull and when in Auto mode do this on their own. Plus, you get much better returns when running on plane, especially at high speeds. My units read bottom at over 70 MPH.

I'd suggest that the average lifespan of a ducer is 3-5 years, depending on use. The ducers very rarely just quit. They gradually fade over time. Based on your description, it sounds like your ducer is weak.

[CHRGD]

I am by no means an expert on Depth finders. I can say I have the exact problem with my 2 units. Pretty much like you I have 2 different brands, front unit is mounted on the trolling motor, and the rear is on the outside of the transom. Front unit will show fish, the rear one will show nothing. I have adjusted the sensitivity, and have set them about the same, with pretty much the same results. Front unit is about 3 years old, rear unit is brand new. Both have different names, but I'm pretty sure they are made by the same company. I am starting to believe the old saying, "Saturday Morning Cartoons"

[Hi Salenity]

What did you use to mount the Transducer?

[Nitro 882]

What did you use to mount the Transducer?

It was a recommended marine epoxy.

[Nitro 882]

Hey guys'

Thanks for the help. The "ducer", as you neatly call it, is 6 or 7 years old and the unit has about 3000 hours on it based on its' internal timer. Seems like time for a replacement. Maybe Santa???????????

Happy Holidays