The answer to how you mount a portable fish finder is of course utterly dependent upon the model and make that you have purchased and what fixings it comes with. One of the most common methods however of mounting a traditional style portable fish finder is via suction cups which are attached to the transducer. You can easily adjust the angle of the suction cups to position your fish finder before you lock it in place. If you have a castable variety, then this will ordinarily need to be tied to your boat or canoe for example with something like a length of rope or perhaps a heavy braided fishing line.\r