Adjustable in-hull or thru-hull transducer??

[rktktpaul]

So after reading a comparison of depth finders, I bought myself not 1 but 2 Uniden QT206 depth finders. I initially bought one with the Airmar P79 adjustable in-hull transducer, which sits in an oil bath and shoots through the hull. I thought that this would be the best solution without having to drill a hole in the hull of the boat.

But the more I read about in-hull transducers, the more it seemed like there was a gray area about where to mount in the bilge for best performance, and that its not as effective as a thru-hull. So when I saw that SeaRay uses a thru-hull transducer I ordered a second Uniden with the thru-hull.

I'm now getting cold feet about installing the thru-hull. Even though I will have my SeaRay dealer install the transducer, I'm having a tough time getting past the idea of a 2 inch hole being drilled in the bottom of the hull.

What's everyone's opinion of this??

 

[Davey]

Have you considered a transom mounted transducer? I'm no expert but the instruction brochure for my depth sounder states that a transom mounted transducer experiences less errors than through the hull and the cable can either be run up on the outside of the boat or a hole for the cable to come into the boat can be drilled & sealed above the waterline thereby avoiding leakage concerns.

 

[rktktpaul]

Have you considered a transom mounted transducer? I'm no expert but the instruction brochure for my depth sounder states that a transom mounted transducer experiences less errors than through the hull and the cable can either be run up on the outside of the boat or a hole for the cable to come into the boat can be drilled & sealed above the waterline thereby avoiding leakage concerns.

I have but I'm none to keen on the idea of the transom mount. Since I've installed SmartTabs on my boat, there's not much room left between the tabs, trailer bunk location and the outdrive. I've read that the transom mounts are prone to losing reading while under plane. I don't know how true that is, but I would like to make sure that I know my depths while I'm moving.

 

[Fishnut]

I have but I'm none to keen on the idea of the transom mount. Since I've installed SmartTabs on my boat, there's not much room left between the tabs, trailer bunk location and the outdrive. I've read that the transom mounts are prone to losing reading while under plane. I don't know how true that is, but I would like to make sure that I know my depths while I'm moving.

Hey, transom mounts are okay on the fishing boat but if you stick it by your I/O the cavitation will distort the signal when you are running. Just stick it in epoxy along the centerline in front of or to the side of the thru hull and you're done(make sure its level).

 

[jhild]

I have a Humminbird unit, but I’ve had no problems using a shoot-thru transducer in my Sea Ray. I’ve found the depth readings to be accurate. They might be a little off at extreme depths, but do you really care whether you’re in 400’ or 409’ of water? I think the max depth reading for those Uniden units is only 200’. Any discrepancies you might see would be negligible.

The key to success is finding a good location for the transducer. To be honest, it’s not that hard to do. There’s no wood and shouldn’t be any air gaps down in the bilge area of your boat. Just watch out for the chines. In general, as far aft and close to the centerline as you can reach. There are plenty of methods used to test the transducer location before the final installation. If you need any helpful hints, please let me know.

 

[Sea Ray Junky]

I agree with the transom mounted comments above. This past season I mounted the exact in hull transducer you are speaking of in our 13' ridgid hull inflatable tender. It works fine when your in 4' or more of water however it never reads less than 3'-4' when you would reaaly like it to. We have the thru hull in our big boat and it reads very accurately even in the 1' -2' range when we are backing down on the anchor at the beach. I am to the point that I know 1.8' equalls 6" under my props for sterning in like this. I am considering changing out the in hull for a thru hull this season. I wouldn't worry about the thru hull installation if it is done correctly.

 

[SeaHarley]

I just finished installing a Thru-Hull transducer last night. Once you get over the delema of drilling a 2" hole, (actually a 2 3/8" hole for me) it becomes just another project.
My transducer is brass and the hole gets sealed very well so it actually is not a problem.

So, my vote is for the Thru-Hull........
Lee

 

[rktktpaul]

I will probably go with the thru-hull; I really do want to know where I am in the less than 4' depth of water range.

Thanks all for your wise guidance!!