I've read posts where they recommend building a little dike it the area you want to mount the xducer. Then you pour mineral oil in the dyke and drop the xducer in there. You can then try your sonar out to see if you get good results. Might save you from being disappointed. If the results are good, follow the above recommendations for a permanent mount. PS I guess you could use modelers clay or something like that to make the dyke.