Thru-Hull Transducer replacing old one

[scenarioL113]

I removed 2 thruhull transducers. One of them was not functional and the other one worked when it wanted to. With that said I am installing a new one for my Garmin unit.

Here are pics which show where the old ones were. I dont have too many choices but what does anyone have to say about installing the new one where one of these were.

I also will have to patch some holes which I have never done before so fell free with any tips or how to's.


https://photos.app.goo.gl/ST8g6buWBA6bSTP98
https://photos.app.goo.gl/UbxThbpd3cnxsVKB9
https://photos.app.goo.gl/LeTiFkRVmBv1EpNm9
https://photos.app.goo.gl/Bk5yJE6aZXxduHCg7
https://photos.app.goo.gl/BFg59mJNm5qkcCPHA

Thx

Frank

[Rawleigh]

Mine are in the same place. I would just say to make the fairing block as thin as possible to minimize drag. Mine stick down farther than I would like.

[Tony Meola]

Just go flush mount. You just have to have the nerve to drill a 4 inch hole in the boat.

[scenarioL113]

Tony
I looked at Capt Pats write up on it. I am not up to that task. I would like to do it that way but building the box inside the hull I think is just too much for me (especially with my skill level). I have a handful of pretty big other jobs to finish up in the next month.

[Tony Meola]

Airmar makes a mushroom style transducer. It sits flush to the hull. No need to build a box.

https://www.airmar.com/productdescription.html?id=11

All you need is a hole saw. The one I have in I used a 4 inch hole saw. A little nerve wracking, but easy. For our boats you need the one that is on a 20 degree angle.

[John F.]

Airmar makes a mushroom style transducer. It sits flush to the hull. No need to build a box.

https://www.airmar.com/productdescription.html?id=11

All you need is a hole saw. The one I have in I used a 4 inch hole saw. A little nerve wracking, but easy. For our boats you need the one that is on a 20 degree angle.

This.

[scenarioL113]

That is an excellent option but I already have the GT23 Transducer. I think the airmar would work and be better for being so "flush to the hull".

The GT23 has better frequencies to match my clear view feature unit but being I am no sonar expert and prob dont know how to use that feature anyway....

Anyway, I as always appreciate the input from all the members here.


The only thing I am not ecstatic about is the GT23 and the fairing block (together) is considerably larger than both the transducers I removed. Hopefully after I cut the fairing block to match my hull it will be more of a lower profile than it looks right now holding it in my hand.


On a side not, when installing a thruhull seacock, the mushroom has a "straight" thread that goes thru the hull and threads into the seacock. My question is what kind of sealant or dope would you put on these threads (if any)... excuse my ignorance if am ignorant

[Tony Meola]

Frank

Odds are Airmar made the transducer.

[Carl]

Seal it up with caulkseal or similar. Just has to seal, no adhesion needed unless you don't plan on installing the nut (which I Do Not Reccomend).


When I redid my bottom I removed all the old transducers and protruding thru hulls, sealed them up and installed one of those 20 degree flush mount transducers. Of course when I had to replace my sounder last year I found that transducer is not longer compatible...

[Tony Meola]

Carl

Didn't match do yo different GPS mfg? Usually they sell a crossover box to correct that.

[Carl]

I bought machine while in a semi rush when stores had very little in stock due to Covid.

Wanted to go inshore a bit to swim and I did not know waters, so instead of using new running gear to check for bottom I went out looking for a transducer for a combo unit I had bought as a chart plotter or a better unit to replace the dead depthfinder I had. Or cables to get the three old CRT units I have.

Zero stuff in stock at stores do to Covid. No cables, no transducers. Low end units came with transducers...but tired of spending money on combo units that just don't seem to hold up for me. High end units didn't seem to come with transducers and again none in stock....aside from the huge one I did not want and the grand for it was over my budget.

To your question...I really liked the Simrad Cruise unit, large screen, GPS with charts and internal antenna, depthfinder had lots of nice features and ez to use and came with a stern mount transducer. I wasn't going to mount to stern, they did not have a hockey puck in stock...but if it could connect to my flush thru hull I'd jump on it. They called Airmar and Simrad to see if they could connect...nope. Not my early model transducer and Simrad Cruise uses a proprietary connection si they didn't help.

Online there was nothing directly compatible...but could maybe fudge something together to make the flush mount work, but would loose some frequency features...

Anyway as I had limited choices, I bought hoping my transducer in a bag of water and shooting through hull would work. It did and it worked very well. So well I decided not to buy a through hull from Simrad and make a well inside boat. Simple enough, grind and smooth hull section, silicone a PVC pipe to hull, lay transducer in, route cable through slot, seal with silicone, fill with non toxic antifreeze and cap. Only hiccup may be deeper water offshore... hopefully I get to find out this year if it's a problem.

[scenarioL113]

Frank

Odds are Airmar made the transducer.

Yes Tony that is very possible that they did. The unit that I got has specific frequencies that work with the Ultra HD mode on my Garmin Unit.

The flush style unit will work but only in a single frequency range and not give me the UHD that the head unit is asking for. In reality I prob dont need that feature bc all I care about is not running aground and bottom lock for fishing structure.

If I had not already bought the transducer I may have opted for the flush mount.

@Carl

I have my GT23TM (TRANSOM MOUNT) that came with the unit set into a huge glob of silicone in the hull of my boat and it works pretty damn good. Not perfect and I lose signal sometimes but that is also bc I did a quick job with silicone and knew it was a temporary and experimental install.

I would say that if you made a permanent box and it is sealed with antifreeze and no air that will agitate inside the box, you will be good to go as a permanent transducer.

[Carl]

That's what I'm hoping. I've done the bag of water thing with hockey pucks and very pleased with the performance till I expoxied to hull and became marginal. Silicone I thought was too soft, never tried that.

I used to have Furuno with flush 20°degree angle that worked great and my bag o water transducer for Garmin combo unit which was mediocre did really well maybe a little less detail but when running it rarely lost the bottom.

Not having a ton of time to learn units they are often left in automatic when running, so maybe some is programming, some may be clearer water..

[scenarioL113]

OK, working out of my comfort zone (fiberglass work) I patched the old sitex thru-hull. I hope I dont sink...smh