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transducer type

Posted: Mon Mar 17, 2008 5:00 pm
by jcollins
When I puchased my Lowrance unit the customer service guy said I should have no problem with a transom mounted transducer for the fish finder/sonor.
Today my mechanic tells me that I will not be happy unless I install the through-hull transducer because of prop location.
I have never been a fan of drilling more holes in the bottom of my boat then is really needed.
So, what are your thoughts? What type of transducer are others here at AOG using?

IMHO

Posted: Mon Mar 17, 2008 5:15 pm
by Legacy
In my experience, the through hull (versus shoot through) transducer mounted away from the prop(s) and as deep as possible is the best for fishing precision. Less cavitation to screw up the signal especially at speed and an accurate sense of where the all important bottom is! In the future, I'd love one of the 3D units. Good luck!!

Rick

Posted: Mon Mar 17, 2008 6:10 pm
by furball
John,
I installed a transom mount on my Chris-Craft last summer before I sold it. Thoughts; It was easy but I still had to put screw holes below the water line and about a 1/2" hole in the transom above the water line to get the transducer wire and plug end through. Clam shell and silicon to cover and seal when done. Never liked the way the wires looked across the transom. I didn't always trust it as it occasionally kicked up, so it was no longer pointing straight down. May be a real pain to push back down with a swim platform.
Other considerations, performance should be best with the thru-hull provided you mount it far enough aft to keep it in clean water at cruise and WOT. Mine drops out sometimes around 18-19 knots. I think it's because I'm getting enough air under the hull to lose tracking. If I can trim the boat down I get it back. I'd try to mount it 12" further back if you can. below are photos that show where mine is located.
Image

Image
It's about $200 more I think to go thru-hull but I think it's worth it.
John

Posted: Tue Mar 18, 2008 8:04 am
by Carl
John, here is my 2 cents. Having had both I think you would be much happier with the through hull. The problem with the transom mounts, they are closer to the suns rays and tend to get a lot of junk growing on them. I was very anal about painting them with the transducer paint (which I still use on the through hull) but after a few months they would stop working due to the turbulence caused by the growth. Last year with the through hull mount I went most of the season before it started fading in and out while cruising. After a few swipes with the scrub brush I was back in business. Mine is mounted in the same area as furballs. I use mine for fishing and am very happy.

Posted: Tue Mar 18, 2008 9:37 am
by jcollins
Furball,
I'm looking at your pictures. Is that a switch just behind your transducer? What is it?

Posted: Tue Mar 18, 2008 1:55 pm
by mhanna
I have one of each, the boat came with a thru-hull and a large color Furuno CRT. It does not work in <5ft of water.

I put in a cheaper LCD for skinny water and did not wish to have another hole in the bottom therefore I put on a transom mount.
If I were to put on another good unit I would use a thruhull, I think they are just larger therefore more sensitive and powerful transducers.

Matt

Posted: Tue Mar 18, 2008 9:05 pm
by furball
John
Here's a close-up. That's a bolt, I assume to secure and prevent twisting of the unit. The yellow insert is the size and shape of the outside transducer.
Image
It also contains a speed wheel and temp sensor.

Posted: Wed Mar 19, 2008 1:26 am
by jcollins
Thanks for all your replies. I contacted Lowrance. They will swap the transom mount for a bronze through hull. Naturally I have to pay the difference.

Posted: Thu Mar 20, 2008 4:07 pm
by Mariner
Our Albin came with a through-hull mounted transducer. At high speed, aeration of the hull causes it to stop working. It needs to be placed farther aft.

The best place for it is as far aft as it can be, but still forward of the prop. Transom mounted transducers are great for outboards or I/O's because, even on the transom, they're still forward of the prop. But on an inboard, I wouldn't recommend it. However, we had a transom mounted one on the Camano, which was an inboard, and it worked great.

Take that for what it's worth.