You don'd have to cut a hole in the boat.
You glue the base to the boat and fill it with liquid, put the transducer in the liquid and adjust the transducer to match the dead rise of your hull. The theory is the sound waves travel better through liquid. I think this transducer workes better than the factory transducer.
https://www.youtube.com/watch?v=aGY1iMVzZT4
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