Water proofing my hatch

When I bought my kayak I didn't realize the hatch wasn't water proof I would like to put In a through the hull transducer for a fish finder but I can't because the hatch lets water in ill post some pics of it so you can see what I'm talking about. If you guys have and ideas on how to set it up to be water proof or even installing a new one id love to hear about it. Thanks

The hatch should be waterproof in most conditions, and in rough water should only allow a bit of water in.
If it leaks badly (more than a cup or so after plowing through waves) I would take it back to the dealer & have them address it. Most likely is that the seal is damaged or not seating properly, or the hatch is warped.

 

  If the dealer can't /Won't deal with leak issues, here's what I did to solve any leaking I had on my OB hatches.  Remove the hatch base, (Top piece) and run a bead of silicon sealant around the mounting surface on the hull.  let the sealant cure required time, then reinstall the hatch.  Make sure the screws are sealed as well.  This will ensure the base of the hatch will be leak free.  If the hatch part leaks maybe try some window weather stripping foam around its perimeter.
  I removed both of my hatches (Center and rear) and did the silicon thing to them shortly after I got the hull, before it's maiden voyage, as I didn't trust the factory foam O-ring seal.  I wanted to see a nice, round bead of silicon oozed out around my hatches!

I'm not understanding how a little leakage into the hull affects your plans for a through-hull transducer?

I use Duct Seal to make a little levee around the transducer, then fill it up with water to make a "bath". In other words, I NEED a little water in the hull for my transducer to work.

Just as an FYI, I very highly recommend this setup for "mounting" the transducer. I had big problems when I used GOOP, and you can't make repairs on the water. Since the Duct Seal never hardens, you can adjust it on the water if the sonar readout doesn't look right. Usually the "adjustment" is just giving the transducer a little jiggle to dislodge a bubble from under it, and even that's rare.