Will it read though the hull of kayak

Yes, if mounted properly in a water bath. That way does seem like a lot of hassle with such easy over-side-mounts available.

It will read through the hull if you use Marine Goop. Build a dam just larger than the transducer, fill the pool with a layer of Goop, making sure not to stir any bubbles into it, and force the transducer all the way down into it. Tape or weight it down for 24 hours and yer done. I generally clean the area first with some alcohol. It'll last for years if you do it right.

That's what I did. I have mounted 100 of transducers in the slump of bass boats when in school I work for a sporting good store back in the 70. I just did not know if there was air in plalstic.

How do you get it to read water temp? I'm assuming you don't.

Thru hull transducers will read water temperature thru the hull but not very well. Just think that that the temperature of the water has to work through the hull to be measured by the transducer. By the time that happens, you have moved to a new spot that may have a different temp. Best choice is to add a small temp sensor that will be in the water.
No amount of marine goop or 3M 5200 will speed up the thermal transfer through the fiberglass or plastic to speed up that process. Aluminum boat owners get a big advantage here.

Perhaps I'm wrong and quite willing to be corrected here, but if you have a Side Imaging transducer it won't work with a through the hull install in the side imaging mode. It will work in the down imaging mode. Some believe that you loose some sensitivity with a through the hull install as well.

Most through the hull installs will perform fine on reading depth and mark some fish. If you spent the money on a high end locator, why loose some of that sensitivity that you paid for with a through the hull install?

Don't take my word as written in stone. Call your locator company and see what they say. There is a difference between "it works just fine" and "it works to it's optimum capability"

So if you bought a more expensive locator, don't install it in a through the hull installation is just one guy's opinion.

Now you do have to balance the risk / exposure of having a transducer below the boat bottom for best readings and risk of transducer damage. You must always keep this in mind and I think that is the reason for some to install through the hull. But if you paid for side imaging, through the hull and you threw your money away.

I had to repost on this thread. I just finished a conversation on the forum with Shaun Russell. He is a tournament fisherman and he runs a Bonafide SS127. That Hull design is very specific in that is resembles a pontoon style hull. It has two, very pronounced pontoons and a recessed around in the middle of the boat. His Side Imaging unit is mounted to the bottom side of the removable locator pod which is very much protected by the pontoon sides and he reports great side scanning capabilities when his locator is NOT below the bottom of the hull.

So now, I am really confused and what I thought that I knew, I still need to learn more.

Note: his transducer is in the water, not shooting through the hull from the inside of the boat, but not below the pontoons. Interesting.

the SI transducer is NOT 180 degree shot - I seem to remember seeing somewhere that the totalscan transducer is 140 or 160 degrees for SI. So as long as you have enough space to ensure that angle doesn't get blocked you can recess mount it (as long as it is still in the water). Secondary consideration is the frequency. the lower the frequency the broader the beam... I don't know how much it impacts SI - but off my own personal experience from running my new TI7 on my porta-bote it does impact it a bit. I tend to get more/deeper motor noise on left side surface - (by about 6in) when i switch to lower frequency SI.

for DI or chirp the frequency has a HUGE impact on beam size.. you see less detail but even for 20-40ft depths you see "broader" with lower frequency's.

since i couldn't find it on lowrance site - here is a simple page to explain it (not product specific) - https://www.chsmith.com.au/News/My-Beam-Angle-is-wider-than-yours.html

I have had nothing but trouble with air bubbles and add to that the "valley" in the floor of the yak..you have level that out with the goop. I am going to do a pvc arm transducer mount. Put it in the water!! lol

I ended up mounting it in a reseat scupper hole. It sits up high it the hull but still in the water. I did not like the arm over the side . Very new to this and concern about getting tangled up with it.

just put on a scotty arm mount. flimsy.. they could have done so much better...

Next Yak I choose will have to have dedicated scupper/in-water molded mount!!