I'm looking to install Hull Shield on our boat to discourage marine growth. It only works, however, if the associated transducers are mounted directly against the hull below the waterline with no intervening insulation or sound absorbing material.

If necessary, I can mount them on the outside of the transom, but I'd prefer to mount them on the inside of the hull if possible.

The owner's manual says that balsa wood was added to the hull on the "planing surface" and to the hull sides "where necessary". I'm wondering if anyone knows what this translated to and, specifically, where I might find a couple of spots roughly three inches in diameter which meet the above criteria.

I will do my best to determine if such spots exist through inspection, but I'm hoping someone in this group might already know the answer.