You can mount a "permanent" fish finder on a piece of wood and use straps to attach it to your kayak. For the transducer you can also buy one of those suction cup mounts for another 20 or 30 bucks and use it with a regular fish finder. For a battery go with a lead acid sealed battery. Look at the powersonic ones. Even try cabelas, fry's, or radio shack. Make sure you get a good trickle charger though.<BR>Tight lines,<BR>Adam