Goop bubbles as it cures. Any movement of the transducer just makes it worse. In spite of the bubbles, both of these gave good readings down to about 550'-650' depth; depending on conditions.
I don't think the bubbles were this bad when attached. It took a lot of force to pull these up, so it's likely that some of that was caused by the removal.
I've been pondering how I'm going to mount the transducer in my new yak. I've Gooped the last 4 that I installed. Before that I used 3M 5200. The 5200 makes an ungodly mess of things but provides a good mechanical attachment and creates a more uniform bond. Either can give acceptable results. I would rather mount it in a scupper or over the side, but I don't want the transducer cable exposed.