Steve I have the same boat and the 597 ci hd. On the advise of humminbird Greg I ended up adhering mine in the bilge for one mount at the console and one on the trolling motor for another mount on the bow. With that quick release I can switch them out pretty easily. Seems to work pretty well but I sure didn't find much working room down in the bilge. I'm sure there are better ways, but like you didn't want to drill. I suppose it would matter as to how you plan to use your new FF. I think if you do a search you will find this discussed here pretty well and especially look for humminbird Greg as a good source.
