There is provided a mounting system for a fish finding device to a watercraft which has a support for supporting a fish finding device on a watercraft. The support has a top, a bottom and a peripheral side wall which form a receptacle housing for a battery. Mounting means are positioned at the top of the support to receive a fish finder. Securing means are provided on the bottom of the support for mounting the support to a surface on a watercraft. Mounting means are provided for detachably securing a transducer to a watercraft.