When I had my stealth's I had just a normal transducer and went to Clark Rubber and got some suction cups from there and poked them through the hole's the screws would normally go in on the bracket. Took a bit of forcing and a lot of swearing but I managed to get a suction cup in each hole. Worked a treat and they are still on the transducer today, wherever it is (I don't use my sounder much any more).
X is right about needing a flat surface otherwise it won't work. I had a small 7a/h battery in one of those Sistema containers you get from BigW that has the seal on it and the sounder mounted to the top of it. Totally portable and very cheap, about $5 for the container.
Mantra Kayaks Pro-StafferAdventure Outlet
Kayaks I have owned: Espri x 2, Nemo x 2, Tempo, Profish, Predator, Outback x 5, Revo x 2, Quest, Swing x 2, Adventure, Loon, Superlite x 6, Superlite X, Sprite, Noa x 2, Coosa, Tarpon 120, Acadia 370, Aspire 100, Mana x 2, Bass, Minnow2, Ultimate 12 Propel, Laker 14 x 2, Sierra 10