I haven't fished much frozen smelt in years but when I did I always put 3 or 4 in the hole frozen, not on a hook just in the hole. They should float when frozen, the water temp of just over 32 degrees will thaw them in a little while. I don't remember how long but 15-20 minutes should do it. They will build a thick layer of ice on the outside and still float as ice floats. When you need to bait a hook take one out of the water and gently bend and the ice will fall right off leaving you with a thawed smelt that will now sink so make sure its on a hook before putting back in the hole this time. I used to fish pike with tip ups in my youth but don't really have them near where I now live. frozen they tend to float thawed they don't so when thawed it hangs and looks like a live fish normally would.