Mr. Grimm and I kayaked out to place this cache together. He sat in my lap the whole time because he wasn't too sure he could swim. I reassured him that not only can he swim, his cute life jacket would keep him afloat long enough for me to save his soggy butt.
This one is above water now, but I can't guarantee that during times when the lake is up that it won't get a bit wet. It is secured very well to a tree so it should stay in place.