I have a Lowrance X87 and have replaced two transducers (the water I fish is full of stumps). I have heard that you can't shoot thru aluminum but vexilar make a shoot thru aluminum transducer. I was inquiring aboutit at the local boat store and they told me any transducer will shoot thru aluminum as long you don't have an air pocket. Has anyone tried this? Two guys that work at the boat dealer have done this and say they have no problems.