Can quadrabeam transducer (90deg angle) be in-hull mounted?

I read in a HowTo from another forum that tri-beam and other transducers cannot be mounted in-hull.

Now I'm freaking out as I purchased a Matrix37 with quadrabeam (90 deg angle) transducer. Along with wideside transducer.

Wideside was to be mounted outside yak on "rudder" for freshwater only...

But do you think I'll have problems with my quadrabeam inhull? More goop? I have an Ocean Kayak 13'

I have a Humminbird Matrix 35.  It has a 90-degree widebeam sonar plus the standard beam straight down.  I have it mounted in-hull and it works fine.  One thing to note, I mounted down the keel of my kayak with lots of goop so any sidebeam would contact goop, hull, and water without contact to air.

But 90-degrees isn't actually that wide.  I'm thinking you should be fine.

Do you think it possible (with enough goop) to even mount a wideside transducer in-hull?

These transducers shoot beams left/right and down (literally left and right). So the transducer is like 1" think on sides due to beam going left/right.

Just more goop on sides???

I think it'll depend on where you mount it and in what type of hull.   If you have a hull with a nice V-shape, you can mount it down in the V and have only goop and hull between you and the water.  I'd poke my head into the hull and see if there's a place you can easily mount in this manner.