I don't think an Ice Machine is the answer. Try mounting the Fish Finder you choose on a Yakattack Cell Block and attach a Ram mount transducer arm to it to hold the transducer over the side an in the water. It ask attaches to a Yakattack Gear Track, that makes it self contained and portable to use on more than 1 kayak. I had a Jackson Cuda 14 that had that setup with a Raymarine Dragonfly 4.7" FF. Here is a link to the Cell Block at OEX
http://www.kayakfishingsupplies.com/...m-by-yakattack