Will in-hull (shoot-through type) transducers work properly on a Sutphen hull and provide accurate depths?

As long as it is not a cored hull, yes. Just installed one on my fountain.

That's the issue, my understanding is the bottom is cored.

I put one on my new one. Ground it down and epoxied it to the inside. It works every once in a while. It reads depths when it wants to.

Thanks! You just saved me $250.00 and a bunch of aggravation.

I wanted to keep the transom as clean as possible with as few holes as possible which is why I decided to use that one. The transom mounted one I had before worked much better. If you need to know accurate depth often I would stick with the transom mounted one.