I'm in the process of setting-up an inflatable, and here's my solution. On the rear there are a couple of plastic rigging blocks which have holes running vertically through them (as well as horizontally for ropes) which are a very snug fit for a piece of 1/2" CPVC pipe, so the 2 outside smaller legs will slip down into those, and the transducer will mount on the middle (longer) leg. I will be inflating the raft today or tomorrow and will get some pics of it in-place (which will be better than the way I'm explaining it I'm sure). Do you have anything you could possibly zip-tie a temporary mount to? I looked for a pic of your kayak, but couldn't find one (would help spot something that might help), or a link to somewhere that sells them to see a pic?