Not sure if I have a problem with my Shark or if it is just me, but I find mine frustrating. When I first turned it on (I bought it used from a former dealer who kept it but never used it) it chattered like crazy. I had to adjust the sensitivity just to use it - Even on dry ground. I cannot get it to ground balance at all in the water. It is always very negative no matter how much I adjust it. What I was doing was ground balancing it in the wet sand/dry sand transition zone. That was the wettest I could get an even ground balance. Then I would go in the water with it. It seemed to be doing alright for awhile and then it started chattering again. I adjusted the sensitivty down and now the chatter is gone, but it just doesn't find much and seems to lack very good depth. This may be due to poor ground balance, I don't know.
Now, when I go shallow with my Cibola I find all kinds of stuff that the Tiger missed. It seems to go deeper and I can adjust the sensitivity for the situation which helps tremendously. I hunt on a brackish river and the bottom can change quickly. Having an adjustable sensitivity is a great asset to this type of hunting.
Anyway, after seeing how well the Cibola performed in the water this weekend it got me thinking about how nice I think a water proof Cibola would do in the water.