ok, got everything out of the box and have searched Internet for mounting the transducers and read the instructions from Lowrance on transducer mounting.

Now it seems I should probably use a "mounting plate" to reduce drilling more holes. the big question I now have is what sealant to use on the aluminum boat I have. most of the sealants I have seen are not recommended for aluminum. also, this will need sealing below the water line. thanks again. paul